Colorleaf poplar plant shape control method

Abstract

The invention provides a color-leaf poplar plant shape control method, and belongs to the technical field of color ornamental tree planting and cultivation. According to the color-leafed poplar plant shape control method, poplar attributes and characteristics after bud mutation of a color-leafed poplar variety are comprehensively analyzed, a two-year-one-trunk color-leafed poplar seedling is cultivated through a physical and biochemical method, an internal regulation and external supplement method, a branch promotion method, a short control method and a fertilization method, more buds on a color-leafed poplar plant are promoted to branch and expand leaves, and the shape of the color-leafed poplar plant is changed from the tree shape to the leaf shape. The quality such as the branch crown layer, the fullness, the leaf number and the quality are comprehensively improved, and finally the purposes of dwarf and strong plants, shape control and quality improvement are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of cultivation of colorful ornamental trees, and particularly relates to a method for controlling the shape of colorful poplar plants. Background Art

[0002] Colorful poplar is a general term for poplars with colored leaves. The leaves, petioles and leaf veins of different varieties have different color performances. The leaf surface color changes seasonally, and the traits of each variety are stable. Colorful poplar has high ornamental value, timber value and ecological value, and is a tree species with relatively high comprehensive value.

[0003] As a bud mutation variety of Populus deltoides '2025', the colorful poplar variety has strong apical dominance. The trunk branching angle varies greatly under the influence of the environment. As it grows, the tree crown gradually shows a hugging trend, and the upper part of the whole tree crown is stronger than the lower part, which is relatively obvious. Most of the branches of poplar occur in the upper part of the branches, and the buds in the middle and lower parts are mostly in a dormant state and are not easy to sprout branches. As it grows, the whole branch is relatively loose or locally aggregated, and the overall tree crown and tree shape lack hierarchy and fullness.

[0004] In order to enable the colorful poplar variety to better display its landscape characteristics and ecological functions, there is an urgent need to form a method for controlling the shape of colorful poplar plants, enrich the morphological diversity of plants, and significantly improve the landscape application value of colorful poplar seedlings. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to some extent. For this reason, the present invention proposes a method for controlling the shape of colorful poplar plants.

[0006] The present invention proposes a method for controlling the shape of colorful poplar plants, which includes the following steps:

[0007] S1. In mid-March of the first year, select two-year-old colorful poplar stumps. 15-20 days before the buds germinate, spray a dwarfing control aqueous agent I on the top of the colorful poplar. The dwarfing control aqueous agent I includes the following components: using water as a solvent, 0.15-0.25 g of tiabendazole, 0.25-0.35 g of prohexadione-calcium, and 0.015-0.025 g of uniconazole are added to 1 L of water;

[0008] S2. In mid-to-late March of the first year, 10-15 days before the buds germinate, perform bud notching on the colorful poplar, and immediately apply a branch-promoting agent evenly on the buds after the bud notching. Based on the total mass of the branch-promoting agent being 100%, the branch-promoting agent includes the following components: gibberellin 1.6-2.0%, sodium nitrophenolate 2.4-2.6%, fulvic acid 2.8-3.2%, forchlorfenuron 1.4-1.8%, indolebutyric acid 0.8-1.2%, 28-homobrassinolide 3.8-4.2%, diethyl aminoethyl hexanoate 2.4-2.6%, ethanol 36-40%, glycerol 5-7%, and the balance is liquid lanolin;

[0009] S3. In late April of the first year, when the first- and second-level branch sprouting of the colored-leaf poplar is completed and enters the vigorous growth period of branches and leaves, spray the top shoots, leaf surfaces, and leaf petioles on the outer layer of the crown of the colored-leaf poplar with the dwarfing control aqueous agent II. The dwarfing control aqueous agent II includes the following components: using water as a solvent, adding 0.15 - 1.25 g of tiabendazole, 0.25 - 0.35 g of calcium cyclohexanecarboxylate, 0.015 - 0.025 g of uniconazole, 0.4 - 0.6 g of brassinolide, and 0.8 - 1.2 g of mepiquat chloride to 1 L of water;

[0010] S4. In late March and late April of the first year, apply the first soil fertilizer to the colored-leaf poplar respectively, and cover the soil and water it after fertilization. The first soil fertilizer has the highest nitrogen content; in late July of the first year, apply the second soil fertilizer to the colored-leaf poplar, and cover the soil and water it after fertilization. The proportion of phosphate fertilizer and potassium fertilizer in the second soil fertilizer is higher than that in the first soil fertilizer.

[0011] According to the method for controlling the shape of the colored-leaf poplar plant of the present invention, in step S1, spray the dwarfing control aqueous agent I once every 7 - 10 days, and spray 1 - 2 times in total.

[0012] According to the method for controlling the shape of the colored-leaf poplar plant of the present invention, in step S1, the last spraying of the dwarfing control aqueous agent I should be carried out 5 - 7 days before the first bud carving treatment.

[0013] According to the method for controlling the shape of the colored-leaf poplar plant of the present invention, in step S2, perform the bud carving treatment on 3 - 6 bud bodies within the range of more than 20 cm from the root and less than 10 cm from the tip of the colored-leaf poplar.

[0014] According to the method for controlling the shape of the colored-leaf poplar plant of the present invention, in step S2, 18 - 22 days after the bud carving treatment, perform the bud carving treatment on the bud bodies that have not germinated again, and then apply the branch sprouting promoter again.

[0015] According to the method for controlling the shape of the colored-leaf poplar plant of the present invention, in step S2, when the newly grown branches of the colored-leaf poplar grow to more than 30 cm, apply the branch sprouting promoter for the third time to 3 - 4 bud bodies within 10 cm from the tip of the colored-leaf poplar.

[0016] According to the method for controlling the shape of the colored-leaf poplar plant of the present invention, in step S3, spray the dwarfing control aqueous agent II once every 6 - 8 days, and spray 1 - 3 times in total.

[0017] According to the method for controlling the shape of the colored-leaf poplar plant of the present invention, in step S4,

[0018] Based on the total mass of the first soil fertilizer being 100%, the first soil fertilizer comprises the following components: potassium dihydrogen phosphate 10-14%, potassium chloride 16-20%, manganese sulfate 4-6%, ferrous sulfate 3-4%, copper sulfate 0.3-0.5%, magnesium sulfate 3-5%, zinc sulfate 0.5-0.7%, boric acid 5-7%, humic acid 4-6%, sodium nitrophenolate 4-6‰, calcium cyclanilide 2.4-2.6%, and the balance being urea;

[0019] Based on the total mass of the second soil fertilizer being 100%, the second soil fertilizer comprises the following components: potassium dihydrogen phosphate 18-22%, potassium chloride 24-26%, manganese sulfate 4-6%, ferrous sulfate 3.4-3.6%, copper sulfate 0.35-0.45%, magnesium sulfate 3.5-4.5%, zinc sulfate 0.5-4.7%, boric acid 5-7%, humic acid 4-6%, sodium nitrophenolate 4-6‰, calcium cyclanilide 2-3%, and the balance being urea.

[0020] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, it further includes step S5. In mid-March of the second year, 15-20 days before the buds germinate, spray the dwarfing control aqueous agent I on the tips of the outer branches of the colored-leaf poplar, and avoid or cover the vacant parts of the tree crown during spraying; optionally, spray the dwarfing control aqueous agent I once every 8-12 days, and spray 1-2 times in total.

[0021] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, it further includes step S6. In the middle and late March of the second year, 10-15 days before the buds germinate, perform bud notching on the positions where branches are missing on the main trunk of the colored-leaf poplar, and then apply the shoot-promoting agent; optionally, 10 days after the bud notching, perform bud notching again on the buds that have not germinated on the main trunk of the colored-leaf poplar and the buds on the first-year and second-year lateral branches that have germinated, and then apply the shoot-promoting agent again; optionally, 20 days after the bud notching, apply the shoot-promoting agent for the third time on the buds on the newly grown first-year and second-year lateral branches.

[0022] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, it further includes step S7. In late April of the second year, when the branches and leaves enter the vigorous growth period, spray the dwarfing control aqueous agent II on the top tips, leaf surfaces, and petioles of the outer layer of the colored-leaf poplar tree crown; optionally, spray the dwarfing control aqueous agent II once every 6-8 days, and spray 1-3 times in total.

[0023] The advantages and technical effects brought by the method for controlling the shape of colored-leaf poplar plants of the present invention are:

[0024] 1. The present invention comprehensively analyzes the poplar attributes and the characteristics after bud mutation of the colored-leaf poplar variety, and adopts a method of combining physics and biochemistry, internal regulation and external supplementation, promoting branches, dwarfing control and fertilization to cultivate the two-year-old one-stem seedlings of the colored-leaf poplar, so as to promote more bud bodies on the colored-leaf poplar plants to sprout branches and unfold leaves, and comprehensively improve the quality in terms of tree shape, branch crown level, plumpness, leaf quantity and quality, etc., and finally achieve the purpose of making the plants short and strong, controlling the shape and increasing the quality.

[0025] 2. Before the plants germinate, by combining the dwarfing control aqueous agent I with the branch-promoting method, through physical and biochemical means, the germination and branching of the dormant buds in the middle and lower parts of the branches of the colored-leaf poplar are effectively promoted, and the number of branches at all levels of the plants is significantly increased. The dwarfing control aqueous agent I can timely control the conduction of endogenous auxin in the plants to the shoot tips during germination, inhibit apical dominance, and enable the endogenous auxin in the plants to accumulate downward and inward, accumulating a material basis for the germination of dormant buds. The bud-grooving treatment can increase the effect of blocking the sap flow and promote the germination of bud bodies. The used branch-promoting agent is a highly effective bud cell activator, which can quickly penetrate into the body after contacting the bud bodies, promote the protoplasm flow of cells, improve cell vitality, and provide a series of regulatory substances required during the germination of bud bodies to the growth of branches and leaves. Each component in the branch-promoting agent has a synergistic and cohesive promoting effect in terms of 1) activating cell activity; 2) enhancing cell vitality, promoting cell division and expansion; 3) promoting the horizontal and vertical growth of new branches; 4) enhancing the resistance of the plants and supplying nutrients to the sprouted branches.

[0026] 3. On the basis of effectively controlling the apical dominance growth and increasing the number and levels of branches and branches of the plants. Starting from late April when it enters the vigorous growth period, the dwarfing control aqueous agent II can further inhibit the apical dominance of the colored-leaf poplar, especially inhibit the vigorous growth of the strong spring shoots and summer shoots on the outer layer of the plants. Brassinolide and mepiquat chloride in the dwarfing control aqueous agent II can enable the plants to regulate the nutrients for vertical and horizontal growth during the vigorous growth period, regulate the plant height by shortening the bud node spacing, and promote the growth of the lower layer and inner layer branches, increasing the leaf-holding density, so that the colored-leaf poplar plants maintain a stable leaf quantity and total leaf area. The dwarfing control aqueous agent II can also reduce the single leaf area, increase the leaf thickness, promote the synthesis of chlorophyll and anthocyanin, and then improve the photosynthetic rate, so that the colored-leaf poplar plants are comprehensively improved in terms of tree shape, branch crown plumpness, leaf quantity and quality.

[0027] 4. The present invention timely adjusts the soil fertilizer components according to the characteristics and requirements of the colored-leaf poplar plants in different growth periods. From March to April is the early stage of controlling the shape of the colored-leaf poplar plants. A high proportion of nitrogen fertilizer can promote the germination and growth of branches. The increase of potassium and phosphorus fertilizers in July can make the roots of the colored-leaf poplar plants more developed and improve the resistance of the plants. Specific implementation mode

[0028] Embodiments of the present invention will be described in detail below. The embodiments described below are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0029] The present invention provides a method for controlling the shape of a colorful-leaf poplar plant, comprising the following steps:

[0030] S1. In mid-March of the first year, select two-year-old colorful-leaf poplar stumps. 15-20 days before the buds germinate, spray a dwarfing control aqueous agent I on the top shoots of the colorful-leaf poplar. The dwarfing control aqueous agent I comprises the following components: using water as a solvent, 0.15-0.25 g of tiabendazole, 0.25-0.35 g of prohexadione-calcium, and 0.015-0.025 g of uniconazole are added to 1 L of water;

[0031] S2. In the middle and late March of the first year, 10-15 days before the buds germinate, perform bud scarring on the colorful-leaf poplar, and immediately apply a branch-promoting agent evenly on the buds after the bud scarring. Taking the total mass of the branch-promoting agent as 100%, the branch-promoting agent comprises the following components: 1.6-2.0% of gibberellin, 2.4-2.6% of sodium nitrophenolate, 2.8-3.2% of fulvic acid, 1.4-1.8% of forchlorfenuron, 0.8-1.2% of indolebutyric acid, 3.8-4.2% of 28-homobrassinolide, 2.4-2.6% of diethyl aminoethyl hexanoate, 36-40% of ethanol, 5-7% of glycerol, and the balance is liquid lanolin;

[0032] S3. In late April of the first year, when the first-level and second-level branching of the colorful-leaf poplar is completed and enters the vigorous growth period of branches and leaves, spray a dwarfing control aqueous agent II on the top shoots, leaf surfaces, and leaf petioles on the outer layer of the colorful-leaf poplar crown. The dwarfing control aqueous agent II comprises the following components: using water as a solvent, 0.15-1.25 g of tiabendazole, 0.25-0.35 g of prohexadione-calcium, 0.015-0.025 g of uniconazole, 0.4-0.6 g of brassinolide, and 0.8-1.2 g of mepiquat chloride are added to 1 L of water;

[0033] S4. In late March and late April of the first year, apply a first soil fertilizer to the colorful-leaf poplar respectively, and cover the soil and water it after fertilization. The content of nitrogen fertilizer in the first soil fertilizer is the highest; in late July of the first year, apply a second soil fertilizer to the colorful-leaf poplar, and cover the soil and water it after fertilization. The proportion of phosphate fertilizer and potassium fertilizer in the second soil fertilizer is higher than that of the first soil fertilizer.

[0034] The present invention comprehensively analyzes the poplar attributes and the characteristics after bud mutation of the colorful-leaf poplar variety, and adopts a method of physical and biochemical, internal regulation and external supplementation, and the coordination of branch promotion, dwarfing control and fertilization to cultivate the two-year-old and one-dry seedlings of the colorful-leaf poplar, so as to promote more buds on the colorful-leaf poplar plant to branch and unfold leaves, and comprehensively improve the quality such as the tree shape, branch crown level, fullness, leaf quantity and quality, and finally achieve the purpose of plant dwarfing, shape control and quality improvement.

[0035] Before the plant buds, the present invention combines the use of a dwarfing control aqueous agent I with a branch-promoting method. Through physical and biochemical means, it effectively promotes the germination and branching of dormant buds in the middle and lower parts of the branches of colored-leaf poplars, significantly increasing the number of branches at all levels of the plant. The dwarfing control aqueous agent I can timely control the conduction of endogenous auxin in the plant to the tip during the budding period, inhibit apical dominance, and enable the endogenous auxin in the plant to accumulate downward and inward, accumulating a material basis for the germination of dormant buds. The method of bud notching can increase the effect of blocking sap flow and promote the germination of bud bodies. The used branch-promoting agent is a highly effective bud cell activator. After contacting the bud bodies, it can quickly penetrate into the body, promote the protoplasmic flow of cells, improve cell vitality, and provide a series of regulatory substances required during the germination and growth process from bud bodies to branches and leaves. Each component in the branch-promoting agent has a synergistic and cohesive promoting effect in aspects such as 1) activating cell activity; 2) enhancing cell vitality, promoting cell division and expansion; 3) promoting the horizontal and vertical growth of new branches; 4) enhancing plant resistance and supplying nutrients to the germinated branches.

[0036] Based on effectively controlling apical dominance growth and increasing the number and levels of branches and shoots of the plant, starting from the late April when it enters the vigorous growth period, the dwarfing control aqueous agent II can further inhibit the apical dominance of colored-leaf poplars, especially inhibiting the vigorous growth of strong spring and summer shoots on the outer layer of the plant. Brassinolide and mepiquat chloride in the dwarfing control aqueous agent II can enable the plant to regulate nutrition for horizontal and vertical growth during the vigorous growth period, regulate the plant height by shortening the internode distance of buds, and promote the growth of branches in the lower and inner layers, increasing the leaf retention density, so that the colored-leaf poplar plant maintains a stable number of leaves and total leaf area. The dwarfing control aqueous agent II can also reduce the single leaf area, increase the leaf thickness, promote the synthesis of chlorophyll and anthocyanin, thereby improving the photosynthetic rate, comprehensively improving the colored-leaf poplar plant in terms of tree shape, branch crown fullness, leaf quantity and quality.

[0037] The present invention timely adjusts the composition of soil fertilizers according to the characteristics and requirements of colored-leaf poplar plants at different growth stages. March to April is the early stage of plant shape control. The first soil fertilizer is mainly nitrogen fertilizer. A high proportion of nitrogen fertilizer can promote the germination and growth of branches. The increase of potassium and phosphorus fertilizers in July can make the plant roots more developed and improve plant resistance.

[0038] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, in step S1, the dwarfing control aqueous agent I is sprayed once every 8 - 12 days, and a total of 1 - 2 times are sprayed.

[0039] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, in step S1, the last spraying of the dwarfing control aqueous agent I should be carried out 5-7 days before the first bud-grafting treatment. Spraying the dwarfing control aqueous agent I during the bud-grafting period can be prevented from having a negative impact on the wounds of the bud-grafting and the effect of the shoot-promoting agent.

[0040] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, in step S2, 3-6 bud bodies within the range of more than 20 cm from the root and less than 10 cm from the tip of the colored-leaf poplar are subjected to the bud-grafting treatment.

[0041] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, in step S2, 18-22 days after the bud-grafting treatment, the bud bodies that have not germinated are subjected to the bud-grafting treatment again, and then the shoot-promoting agent is applied again.

[0042] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, in step S2, when the newly generated branches of the colored-leaf poplar grow to more than 30 cm, the shoot-promoting agent is applied for the third time to 3-4 bud bodies within 10 cm from the tip of the colored-leaf poplar.

[0043] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, in step S3, the dwarfing control aqueous agent II is sprayed once every 6-8 days, and a total of 1-3 times are sprayed.

[0044] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, in step S4, based on the total mass of the first soil fertilizer being 100%, the first soil fertilizer includes the following components: potassium dihydrogen phosphate 10-14%, potassium chloride 16-20%, manganese sulfate 4-6%, ferrous sulfate 3-4%, copper sulfate 0.3-0.5%, magnesium sulfate 3-5%, zinc sulfate 0.5-0.7%, boric acid 5-7%, humic acid 4-6%, sodium nitrophenolate 4-6‰, calcium cyclamate 2.4-2.6%, and the balance is urea; in step S4, based on the total mass of the second soil fertilizer being 100%, the second soil fertilizer includes the following components: potassium dihydrogen phosphate 18-22%, potassium chloride 24-26%, manganese sulfate 4-6%, ferrous sulfate 3.4-3.6%, copper sulfate 0.35-0.45%, magnesium sulfate 3.5-4.5%, zinc sulfate 0.5-4.7%, boric acid 5-7%, humic acid 4-6%, sodium nitrophenolate 4-6‰, calcium cyclamate 2-3%, and the balance is urea.

[0045] The first soil fertilizer and the second soil fertilizer are rich in zinc, magnesium, iron, copper, boron, etc., which can well promote the carbon assimilation of leaves, assist in the synthesis and accumulation of chlorophyll, and improve the resistance of plants; elements such as potassium, manganese, and magnesium are beneficial to the activity reactions of some important pigment metabolism enzymes such as anthocyanin synthase, and can promote the synthesis and accumulation of anthocyanins in leaves. Growth regulating substances such as sodium nitrophenolate and calcium cyclanilide are added to the fertilizer, which can assist in regulating plant height, promote protoplasmic flow, enhance plant vigor, make the plants thick and strong, and improve the quality of plant shape and branches and leaves.

[0046] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, it further includes step S5. In mid-March of the second year, 15-20 days before the buds germinate, spray the short and strong control aqueous agent I on the tips of the outer branches of the colored-leaf poplar, and avoid or cover the vacant parts of the tree crown during spraying; optionally, spray the short and strong control aqueous agent I every 8-12 days, and spray 1-2 times in total.

[0047] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, it further includes step S6. In the middle and late March of the second year, 10-15 days before the buds germinate, perform budding treatment on the positions where branches are missing on the main trunk of the colored-leaf poplar, and then apply the branch-promoting agent; optionally, 10 days after the budding treatment, perform budding treatment again on the buds that have not germinated on the main trunk of the colored-leaf poplar and the buds on the first-level and second-level lateral branches germinated in the first year, and then apply the branch-promoting agent again; optionally, 20 days after the budding treatment, apply the branch-promoting agent for the third time on the buds on the newly grown first-level and second-level lateral branches.

[0048] According to the method for controlling the shape of colored-leaf poplar plants of the present invention, it further includes step S7. In late April of the second year, when the branches and leaves enter the vigorous growth period, spray the short and strong control aqueous agent II on the top tips, leaf surfaces, and leaf stalks of the outer layer of the colored-leaf poplar tree crown; optionally, spray the short and strong control aqueous agent II every 6-8 days, and spray 1-3 times in total.

[0049] The method for controlling the shape of colored-leaf poplar plants of the present invention does not have a special limitation on the variety of colored-leaf poplar, and it can be Zhonghong Poplar, Quanred Poplar, Jinhong Poplar, Xuanhong Poplar, Lianghong Poplar, etc.

[0050] 'Quanhong Poplar' and 'Jinhong Poplar' are new colored-leaf poplar varieties discovered after 'Zhonghong Poplar'. In spring, the leaves of 'Zhonghong Poplar' are purple-red and red, and gradually turn dark green as the growing season progresses. The leaves of 'Quanhong Poplar' remain purple-red and red throughout the growing season, while the leaves of 'Jinhong Poplar' present a variety of unique and beautiful colors such as purple-red, red, orange-red, orange, and golden-yellow throughout the growing season, blooming on the branches like flowers. The successful breeding of 'Quanhong Poplar' and 'Jinhong Poplar' not only shows significant changes in leaf color compared to 'Zhonghong Poplar', but also realizes a breakthrough from spring-leaf-type tree species to colored-leaf-type tree species throughout the growing season. As unique and rare poplar colored-leaf varieties with distinct leaf colors, 'Quanhong Poplar' and 'Jinhong Poplar' not only increase the diversity of colored-leaf plant species, but also increase the diversity of color changes in poplar varieties.

[0051] At the same time as the leaf color changes, the growth potential of 'Quanhong Poplar' and 'Jinhong Poplar' is significantly weaker than that of 'Zhonghong Poplar'. The plant height and single leaf area of two-year-old coppice seedlings of 'Quanhong Poplar' are 82.49% and 51.29% of those of 'Zhonghong Poplar' respectively; the plant height of two-year-old coppice seedlings of 'Jinhong Poplar' is 59.24% of that of 'Zhonghong Poplar' and 71.81% of that of 'Quanhong Poplar', and the single leaf area of two-year-old coppice seedlings of 'Jinhong Poplar' is 101.29% of that of 'Zhonghong Poplar'. It can be seen that both the plant height and single leaf area of the coppice seedlings of 'Quanhong Poplar' are significantly lower than those of 'Zhonghong Poplar'. The decline in the plant height of the coppice seedlings of 'Jinhong Poplar' is more obvious than that of 'Zhonghong Poplar', but the difference in the single leaf area of the coppice seedlings of 'Jinhong Poplar' and 'Zhonghong Poplar' is not significant. In horticultural shaping, slow-growing or plants with smaller leaves are easier to control into shape. Therefore, among the colored-leaf poplar varieties, 'Quanhong Poplar' and 'Jinhong Poplar' are more suitable for shaping cultivation.

[0052] The following takes 'Quanhong Poplar' and 'Jinhong Poplar' as examples to specifically illustrate the effects achieved by the method for controlling the shape of colored-leaf poplar plants of the present invention:

[0053] Compared with the plants obtained by normal cultivation (referred to as control plants), the branch promotion method (referring to spraying chlormequat control aqueous agent I and chlormequat control aqueous agent II) in the plant shape control method of the colored-leaf poplar plants of the present invention can make the first- and second-level branches of the 'All Red Poplar' and 'Golden Red Poplar' plants increase by 41.17%, 83.6% and 125.00%, 133.33% respectively compared with the control plants, and the leaf retention amount and total leaf area of the plants increase by 20.90%, 16.22% and 30.00%, 21.33% respectively. The chlormequat control method (referring to bud notching + applying branch promotion agent) in the plant shape control method of the colored-leaf poplar plants of the present invention can make the plant heights of the 'All Red Poplar' and 'Golden Red Poplar' plants decrease by 15.69% and 30.87% respectively compared with the control plants, the single leaf area decreases by 3.59% and 18.03%, and more small branches above the third level germinate. To meet the growth space and light requirements of branches at all levels, the plant heights of the 'All Red Poplar' and 'Golden Red Poplar' plants regulated by the present invention decrease by 23.53% and 36.24% respectively compared with the control plants; the branching angles of the first- and second-level branches can reach more than 90 degrees, and the growth amounts of branches at all levels are the highest; the crown diameter to plant height ratios are 0.78 and 0.76 respectively, increasing by 32.30% and 80.95% compared with the control plants. The decrease in plant height and the increase in the branching angle and crown diameter / plant height ratio can increase the light of the lower and inner leaves of the plant, thereby improving the photosynthetic efficiency of the plant. The plant shape control method of the colored-leaf poplar plants of the present invention has a better plant shape control effect on the 'All Red Poplar' and 'Golden Red Poplar' plants than other methods.

[0054] For the 'All Red Poplar' and 'Golden Red Poplar' plants obtained by the plant shape control method of the colored-leaf poplar plants of the present invention, the chlorophyll and anthocyanin contents in the leaves increase by 13.55%, 35.96% and 66.67%, 81.88% respectively compared with the control plants, and the net photosynthetic rate of the leaves increases by 64.34% and 66.43% compared with the control plants, which well promotes the carbon assimilation of the leaves and the synthesis and accumulation of pigments, greatly improves the leaf quality, and the increase in anthocyanin can increase the red levels of the leaves and make the color more intense. The red hue a* values and brightness L* values of the 'All Red Poplar' and 'Golden Red Poplar' leaves increase by 54.85%, 19.88% and 80.48%, 44.03% respectively compared with the control plants, and the hue b* values decrease by 2.21% and 4.15% respectively compared with the control plants, the yellow tone of the leaves weakens and approaches the blue tone, the leaf color is deeper, and the hue value is consistent with the expression of anthocyanin. The leaf quality of the 'All Red Poplar' and 'Golden Red Poplar' plants of the present invention is significantly improved, the leaf color is more plump, beautiful, and the photosynthetic ability is stronger, and the effect of the 'Golden Red Poplar' is more significant.

[0055] The present invention will be described in detail below with reference to the embodiments.

[0056] Example 1

[0057] The first year:

[0058] 1. Seedlings: Select two-year-old coppiced seedlings of 'All Red Poplar' and 'Golden Red Poplar' that are growing vigorously and free from pests and diseases. The height of 'All Red Poplar' is about 60 - 70 cm, and the height of 'Golden Red Poplar' is about 45 - 50 cm.

[0059] 2. Control apical dominance

[0060] Time: In mid-March, about 15 - 20 days before bud germination, when the temperature reaches above 15°C and the weather is clear for 3 - 5 days, conduct the operation at 16:00 - 18:00.

[0061] Control the apical growth dominance of 'All Red Poplar' and 'Golden Red Poplar'. Spray the dwarfing control aqueous agent I within the range of 10 cm from the top of the plant. Spray the dwarfing control aqueous agent I again after 7 days to inhibit the conduction of auxin in the plant body to the shoot tip, thereby controlling or slowing down apical dominance and promoting the germination of lower buds into lateral branches.

[0062] The dwarfing control aqueous agent I is composed of the following components: Using pure water as the solvent, add 0.2 g of tiabendazole, 0.3 g of prohexadione-calcium, and 0.02 g of uniconazole to 1 L of pure water.

[0063] Spray the dwarfing control aqueous agent I on the top of the plant using a fine mist spraying method until the top bud and the branches within 10 cm of the shoot tip are moist, and the aqueous agent does not drip or flow. If there is a dripping phenomenon after spraying, immediately rinse the part of the plant top below 10 cm with clean water to avoid the influence of the dwarfing control aqueous agent I on the germination of lower buds.

[0064] 3. Promote branching by using the method of 'bud notching + applying shoot-promoting agent'.

[0065] (1) Bud notching

[0066] Time: In the middle and late March, about 10 - 15 days before bud germination, when the temperature is stable above 15°C and the weather is clear for 5 days, conduct bud notching at 16:00 - 18:00.

[0067] Bud notching: For 'All Red Poplar', notch about 4 - 6 buds within the range more than 20 cm from the root and less than 10 cm from the shoot tip; for 'Golden Red Poplar', notch about 3 - 5 buds within the range more than 15 cm from the root and less than 10 cm from the shoot tip.

[0068] Bud notching position: Make an arc-shaped cut 0.5 cm above the bud. When cutting, use the bud as the center of the arc, tilt the tip of the knife outward at 45 degrees and cut into the xylem. Then gently peel the bark outside the wound about 1 mm along the wound with the tip of the knife to increase the effect of blocking the sap flow and promote the germination and branching of the bud.

[0069] (2) Apply shoot-promoting agent

[0070] After bud carving treatment, immediately apply the shoot-promoting agent evenly on the buds. Do it once for each bud, and just gently apply it evenly with a soft brush.

[0071] After 20 days, re-treat the buds that have not germinated with "bud carving + application of shoot-promoting agent". At this time, the bud carving position is 1 cm above the bud. The bud carving method and the method of applying the shoot-promoting agent are the same as the first time.

[0072] When the newly generated branches grow to more than 30 cm, spray the shoot-promoting agent on 3 - 4 buds below 10 cm of the tip to promote the generation of the next-level branches. To protect the new branches of the plant from being damaged, no bud carving treatment is carried out at this time.

[0073] Based on the total mass of the shoot-promoting agent being 100%, the shoot-promoting agent includes the following components: gibberellin (1.8%), sodium nitrophenolate (2.5%), fulvic acid (3%), forchlorfenuron (1.6%), indolebutyric acid (1%), 28-homobrassinolide (4%), amine fresh ester (2.5%), ethanol (38%), glycerol (6%), and the balance is liquid lanolin.

[0074] This shoot-promoting agent is a highly effective latent bud cell activator. After contacting the buds, it can quickly penetrate into the plant body, promote the protoplasm flow of cells, improve cell vitality, and provide a series of regulatory substances required from bud germination to branch and leaf growth. Each component in the shoot-promoting agent plays a synergistic and connecting promoting role in: activating cell activity → enhancing cell vitality, promoting cell division and expansion → promoting the horizontal and vertical growth of new branches → enhancing resistance, supplying nutrients for the growth of emerging branches and leaves → increasing the leaf pigment content, improving photosynthesis → improving leaf quality and color, etc. The selected components of the shoot-promoting agent are also plant growth regulators with low toxicity or non-toxic properties.

[0075] 4. Plant dwarfing and shape control

[0076] Time: In late April, when the first-level and second-level shoot growth of 'Full Red Poplar' and 'Golden Red Poplar' plants is basically completed and enters the vigorous growth period of branches and leaves, and the weather is clear within 3 - 5 days, carry out the operation from 17:00 to 19:00.

[0077] 10 days after the second spraying of the dwarfing control aqueous agent I, spray the dwarfing control aqueous agent II on the 'Full Red Poplar' and 'Golden Red Poplar' plants. Evenly spray the dwarfing control aqueous agent II on the top shoots, leaf surfaces, and leaf stalks on the outer layer of the tree crown until the branches and leaves are moist, and the aqueous agent does not drip or flow. Spray once every 7 days, for a total of 3 sprays.

[0078] The dwarfing control aqueous agent II is composed of the following components: using pure water as the solvent, adding 0.2 g of tiabendazole, 0.3 g of prohexadione-calcium, 0.02 g of uniconazole, 0.5 g of brassinolide, and 1 g of mepiquat chloride to 1 L of pure water.

[0079] The sprayed dwarf control agent II can further inhibit the apical dominance of the 'Quanhong Poplar' and 'Jinhong Poplar' plants, especially inhibit the growth of the strong spring and summer shoots on the outer layer of the plants. It can prevent and control the vigorous growth of branches, shorten the internode distance between buds, promote the growth of inner branches and branches, cultivate small branches, and regulate the vertical and horizontal growth of nutrients to make the plant compact and sturdy. The multi-layered crown structure can significantly increase the attachment points of the leaves of the 'Quanhong Poplar' and 'Jinhong Poplar' plants, increase the number of leaves and total leaf area of ​​the plants, and thus improve the photosynthetic capacity and resistance of the plants. The dwarf control agent II also significantly reduces the area of ​​single leaves, thickens the leaves, and makes the color more colorful and stable. The dwarf control agent II makes the 'Quanhong Poplar' and 'Jinhong Poplar' plants have comprehensive improvements and enhancements in terms of tree shape, fullness of branch crowns, number of leaves, and quality.

[0080] 5. Water and fertilizer matching management

[0081] Fertilize and water once in late March and late April, with nitrogen fertilizer as the main fertilizer.

[0082] Taking the total mass of the soil fertilizer as 100%, the soil fertilizer contains: phosphorus (potassium dihydrogen phosphate) 12%, potassium (potassium chloride) 18%, manganese (manganese sulfate) 5%, iron (ferrous sulfate) 3.5%, copper (copper sulfate) 0.4%, magnesium (magnesium sulfate) 4%, zinc (zinc sulfate) 0.6%, boron (boric acid) 6%, humic acid 5%, sodium nitrophenolate 5‰, calcium prohexadione 2.5%, and the rest is nitrogen (urea). 1-2kg is applied to each plant, and the soil is covered and watered after fertilization.

[0083] Fertilize and water once in late July, and increase the proportion of phosphorus and potassium fertilizers in the soil.

[0084] Taking the total mass of the soil fertilizer as 100%, the soil fertilizer contains: phosphorus (potassium dihydrogen phosphate) 20%, potassium (potassium chloride) 25%, manganese (manganese sulfate) 5%, iron (ferrous sulfate) 3.5%, copper (copper sulfate) 0.4%, magnesium (magnesium sulfate) 4%, zinc (zinc sulfate) 0.6%, boron (boric acid) 6%, humic acid 5%, sodium nitrophenolate 5‰, calcium prohexadione 2.5%, and the rest is nitrogen (urea). 1-2kg is applied to each plant, and the soil is covered and watered after fertilization.

[0085] March and April are the early stages of plant shape control. A high proportion of nitrogen fertilizer can promote the germination and growth of branches and trunks. The increase of potassium and phosphorus fertilizers in July can promote the development of the plant's root system and improve the plant's resistance.

[0086] In addition, the fertilizer is rich in zinc, magnesium, iron, copper, boron, etc., which can well promote the carbon assimilation of leaves, assist in synthesizing chlorophyll, and improve the photosynthetic ability of plants; elements such as potassium, manganese, and magnesium are beneficial to the activity reaction of pigment metabolism enzymes such as anthocyanin synthase, and can promote the synthesis and accumulation of anthocyanin in leaves. Growth regulators such as sodium nitrophenolate and prohexadione-calcium are added to the fertilizer, which can enhance the vitality of plants, assist in regulating plant height, promote protoplasmic flow, make the plants thick and strong, and thus improve the plant shape and the quality of branches and leaves.

[0087] In the middle and late October in autumn, apply decomposed organic fertilizer as the base fertilizer at 5 kg / plant. After fertilization, cover the soil and water. Water thoroughly before winter. Water as needed at other times.

[0088] The second year

[0089] According to the shape control situation in the first year, add branches to fill the obvious vacancies in the tree crown and cultivate new first-level branches.

[0090] 1. Control the strong dominant branches

[0091] In mid-March, about 15 - 20 days before the buds germinate, when the temperature reaches above 15°C and the weather is sunny for 3 - 5 days, carry out the operation from 16:00 to 18:00.

[0092] Spray the short-stemming control aqueous agent I on the tips of the outer branches of the plant to prevent the branches from growing rapidly. Avoid or cover the vacant parts of the tree crown during spraying.

[0093] 2. Fill vacancies and enrich branches, and adjust the lopsided crown

[0094] In late March, about 10 - 15 days before the buds germinate, focus on the positions on the main trunk where there are branch vacancies, and use the method of "bud carving + applying shoot-promoting agent" to promote the generation of first- and second-level branches and adjust the lopsided crown.

[0095] 10 days after the bud carving treatment, conduct the "bud carving + applying shoot-promoting agent" treatment again on the buds that have not germinated on the main trunk. At the same time, use the method of "bud carving + applying shoot-promoting agent" to promote the shoots of the buds on the first- and second-level lateral branches germinated in the first year.

[0096] 20 days after the bud carving treatment, apply the shoot-promoting agent to the buds on the newly generated first- and second-level lateral branches to promote or supplement the germination of second-level and above small branches and achieve the purpose of enriching the tree crown shape.

[0097] 3. Short-stemming and shape control

[0098] In late April, when the branches and leaves enter the vigorous growth period, spray the short-stemming control aqueous agent II to carry out short-stemming and shape control of the plants.

[0099] The specific methods of bud carving, applying shoot-promoting agent, spraying short-stemming control aqueous agent, as well as water and fertilizer management are the same as those in the first year.

[0100] Comparative Example 1

[0101] Normal cultivation, without bud notching, without spraying dwarfing control agent I, dwarfing control agent II, or shoot promotion agent, and with conventional field soil water and fertilizer management.

[0102] Comparative Example 2

[0103] The method of Comparative Example 2 is the same as that of Example 1, except that dwarfing control treatment is not carried out, that is, dwarfing control agent I and dwarfing control agent II are not sprayed.

[0104] Comparative Example 3

[0105] The method of Comparative Example 3 is the same as that of Example 1, except that shoot promotion treatment is not carried out, bud notching is not carried out, and shoot promotion agent is not sprayed.

[0106] Comparative Example 4

[0107] The method of Comparative Example 4 is the same as that of Example 1, except that after the "bud notching + application of shoot promotion agent" method is used to promote branch occurrence for two consecutive years, only three sprays of dwarfing control agent II are carried out starting from late April of the second year, that is, dwarfing control agent I and dwarfing control agent II are not sprayed in the first year, and dwarfing control agent I is not sprayed in the second year.

[0108] Comparative Example 5

[0109] The method of Comparative Example 5 is the same as that of Example 1, except that after the "bud notching + application of shoot promotion agent" method is used to promote branch occurrence for two consecutive years, three sprays of dwarfing control agent II are carried out starting from late April of each year, that is, dwarfing control agent I is not sprayed in both the first year and the second year.

[0110] Effect analysis:

[0111] (1) Influence of the plant shape control method of colored leaf poplar on the leaf quality of the plant

[0112] Under the condition that the cultivation conditions and management measures (such as planting density, tillage, irrigation and drainage, etc.) are the same. In mid-August of the first year, the photosynthetic characteristics, pigment content, leaf color parameters, leaves, plant height, and crown width / plant height of the plants in Example 1 and Comparative Example 1 were measured. The results are shown in Table 1.

[0113] Table 1. Influence of the methods of Example 1 and Comparative Example 1 on the photosynthetic characteristics, pigment content, leaf color parameters, leaves, plant height, and crown width / plant height of the plants

[0114]

[0115] Table 1 results show that: The method of Example 1 significantly increased the net photosynthetic rate Pn, total chlorophyll TCH, and anthocyanin TA content in the leaves of 'Quanhong Poplar' and 'Jinhong Poplar' plants. The Pn, TCH, and TA of 'Quanhong Poplar' and 'Jinhong Poplar' plants increased by 64.34%, 13.55%, 35.96% and 66.43%, 66.67%, 81.88% respectively compared with those of the plants in Comparative Example 1. The increase in TCH of 'Quanhong Poplar' was relatively small, mainly because the leaves already contained a relatively high amount of chlorophyll. The significant increase in TCH of 'Jinhong Poplar' is of great significance for improving plant function and resistance. The increase in TA content of 'Jinhong Poplar' was very significant and much higher than that of 'Quanhong Poplar'. The changes and ratios of anthocyanin and chlorophyll content in the leaves can directly affect the expression of leaf color. Among them, the increase in anthocyanin can improve the red color level of the leaves and make the color more intense. The method of Example 1 greatly increased the synthesis and accumulation of photosynthetic and non-photosynthetic pigments in the leaves of 'Quanhong Poplar' and 'Jinhong Poplar' plants, promoted leaf carbon assimilation, improved photosynthetic capacity, and greatly improved the quality of plant leaves. The effect on 'Jinhong Poplar' was more significant.

[0116] The a* value (red-green hue) and L* value (brightness) of the leaves of 'Quanhong Poplar' and 'Jinhong Poplar' plants in Example 1 increased significantly, while the b* value (yellow hue) of the leaves decreased slightly. The a* and L* values of the leaves of 'Quanhong Poplar' and 'Jinhong Poplar' plants increased by 54.85%, 19.88% and 80.48%, 44.03% respectively compared with those of the plants in Comparative Example 1, indicating that the red color of the leaves became heavier and the brightness became higher. The change in the a* value of the leaf color parameter was consistent with the change in anthocyanin content, and the synthesis and accumulation of anthocyanin in the leaves were presented in terms of color. The b* values of the leaves decreased by 2.21% and 4.15% respectively compared with those of the plants in Comparative Example 1, indicating that the yellow tone of the leaves weakened and approached the blue tone, and the leaf color became more intense and profound. The effect on 'Jinhong Poplar' was more significant.

[0117] The method of Example 1 significantly increased the leaf retention number of 'Quanhong Poplar' and 'Jinhong Poplar' plants, reduced the single leaf area and plant height. Finally, the total leaf area and crown width / plant height of 'Quanhong Poplar' plants increased by 15.74% and 32.20% respectively compared with those of the plants in Comparative Example 1, and the total leaf area and crown width / plant height of 'Jinhong Poplar' plants increased by 2.32% and 80.95% respectively compared with those of the plants in Comparative Example 1. The regulatory effect on 'Jinhong Poplar' was more significant.

[0118] The method of Example 1 adjusts the dwarfing control aqueous agent and soil fertilizer components in a timely manner according to the characteristics and requirements of the plants of 'Quanhong Poplar' and 'Jinhong Poplar' at different growth stages. Brassinolide and mepiquat chloride in the dwarfing control aqueous agent II can effectively shorten the internode distance of the plants during the vigorous growth period in spring and summer, control the height growth, increase the leaf retention and leaf thickness, make the leaves smaller, and increase the synthesis of chlorophyll and anthocyanin in the leaves, improve the photosynthetic rate, make the plant type strong and compact, and the leaves are thick and brightly colored. The fertilizer is rich in zinc, magnesium, iron, copper, boron, etc., which can well promote the carbon assimilation of the leaves, assist in the synthesis and accumulation of chlorophyll, and improve the resistance of the plants; elements such as potassium, manganese, and magnesium are beneficial to the active reaction of some important pigment metabolism enzymes such as anthocyanin synthase, and can promote the synthesis and accumulation of anthocyanin in the leaves. Growth regulators such as sodium nitrophenolate and prohexadione-calcium are added to the fertilizer, which can assist in regulating the plant height, promote the protoplasmic flow, enhance the plant vigor, make the plants thick and strong, and thus improve the plant shape and the quality of branches and leaves.

[0119] (2) Effects of the shoot promotion treatment and the dwarfing control treatment on the plant shape control effect of the plants

[0120] Under the condition that the cultivation conditions and management measures (such as planting density, tillage, irrigation and drainage, etc.) are the same. In mid-August of the second year, the branching, leaves, plant height, crown width / plant height, etc. of the plants in Comparative Examples 1-3 were investigated. The results are shown in Table 2.

[0121] Table 2. Effects of the methods in Comparative Examples 1-3 on the branching, leaves, plant height and crown width / plant height of the plants

[0122]

[0123] From the comparison between Comparative Examples 2-3 and Comparative Example 1, the plant shape control effects of the shoot promotion treatment and the dwarfing control treatment can be seen. The results in Table 2 show that: both the shoot promotion treatment and the dwarfing control treatment can effectively promote the generation of the first-level and second-level branches of the plants of 'Quanhong Poplar' and 'Jinhong Poplar', and increase the occurrence of small branches above the third level. The shoot promotion treatment and the dwarfing control treatment respectively increased the first-level and second-level branches of the 'Quanhong Poplar' plants by 41.17%, 83.6% and 16.67%, 39.34% compared with Comparative Example 1; the shoot promotion treatment and the dwarfing control treatment respectively increased the first-level and second-level branches of the 'Jinhong Poplar' plants by 125.00%, 133.33% and 75.00%, 41.67% compared with Comparative Example 1. It can be seen that the shoot promotion treatment has a better effect on promoting the generation of the first-level and second-level branches of the buds than the dwarfing control treatment, while the dwarfing control treatment is more helpful for the plants to produce small branches above the third level.

[0124] The branch-promoting treatment and the dwarfing control treatment increased the leaf number and total leaf area of the ‘All-Red Poplar’ plants by 20.90% and 20.24%, and 16.22% and 12.05% respectively compared with Comparative Example 1, while the single leaf area decreased by 0.55% and 3.59% respectively compared with Comparative Example 1. The branch-promoting treatment and the dwarfing control treatment increased the leaf number and total leaf area of the ‘Golden-Red Poplar’ plants by 30.00% and 13.62%, and 21.33% and -0.55% respectively compared with Comparative Example 1, while the single leaf area decreased by 12.60% and 18.03% respectively compared with Comparative Example 1. Both the branch-promoting treatment and the dwarfing control treatment can effectively increase the leaf-holding quantity of the ‘All-Red Poplar’ and ‘Golden-Red Poplar’ plants, reduce the single leaf area, and keep the total leaf area of the plants from decreasing or even increasing. Comparatively, the branch-promoting treatment can more effectively promote the generation of plant branches and increase the leaf-holding quantity of the plants, while the dwarfing control treatment is more effective in reducing the single leaf area of the leaves, making the leaves significantly smaller.

[0125] Both the branch-promoting treatment and the dwarfing control treatment can inhibit the height growth of the ‘All-Red Poplar’ and ‘Golden-Red Poplar’ plants to varying degrees and increase the ratio of plant crown width to plant height. The branch-promoting treatment and the dwarfing control treatment methods decreased the plant height of the ‘All-Red Poplar’ and ‘Golden-Red Poplar’ by 5.88%, 15.69% and 5.37%, 30.87% respectively compared with Comparative Example 1. The crown width / plant height ratio of the ‘All-Red Poplar’ and ‘Golden-Red Poplar’ plants treated with the dwarfing control treatment is significantly higher than that of the branch-promoting treatment, making the plant shape shorter, sturdier and more plump.

[0126] Generally speaking, the branch-promoting treatment has a more significant effect on promoting the generation of more branches at different levels of the ‘All-Red Poplar’ and ‘Golden-Red Poplar’ plants, increasing the branching level and leaf-holding quantity; while the dwarfing control treatment has a more obvious effect on regulating the height growth of the ‘All-Red Poplar’ and ‘Golden-Red Poplar’ plants, increasing the crown width / plant height ratio and making the leaves smaller. The shape control and shaping effects of the ‘Golden-Red Poplar’ plants are higher than those of the ‘All-Red Poplar’.

[0127] (3) Effects of different application methods of “branch promotion” and “dwarfing control” on the shape control effect of plants

[0128] Under the condition that the cultivation conditions and management measures (such as planting density, tillage, irrigation and drainage, etc.) are the same. In the first year, the lengths of the branches at all levels of the plants in Example 1 and Comparative Examples 4-5 were investigated before spraying the dwarfing control aqueous agent II. In the second year, in mid-August, the lengths of the branches at all levels, plant height, crown width, etc. of the plants in Example 1 and Comparative Examples 4-5 were investigated, and the branch growth amount was calculated. The results are shown in Table 3.

[0129] Table 3. Effects of the methods of Example 1 and Comparative Examples 4-5 on the branch growth amount, leaves, plant height, crown width and crown width / plant height of plants

[0130]

[0131]

[0132] From the comparison between Example 1 and Comparative Examples 4 - 5, it can be seen the influence of different application methods of "branch - promoting treatment" and "dwarfing control treatment" on the plant shape - controlling effect.

[0133] The results in Table 3 show that: Compared with Comparative Example 5, the method of Example 1 more significantly inhibited the growth of the plant height and primary branches of 'Full - red Poplar' and 'Golden - red Poplar' plants. The growth amounts of the plant height and primary branches of 'Full - red Poplar' and 'Golden - red Poplar' plants decreased by 8.45% and 19.63%, and 10.38% and 21.15% respectively compared with those of the plants in Comparative Example 5. The influence on secondary branches was not significant. The method of Example 1 also more significantly promoted the growth of branches smaller than the third - level branches. The growth amounts of branches smaller than the third - level branches of 'Full - red Poplar' and 'Golden - red Poplar' plants increased by 38.10% and 21.43% respectively compared with those of the plants in Comparative Example 5. The leaf number, single - leaf area and total leaf area of the 'Full - red Poplar' plants in Example 1 decreased by 3.44%, 0.93% and 4.33% respectively compared with those of the plants in Comparative Example 5, and the leaf number, single - leaf area and total leaf area of the 'Golden - red Poplar' plants in Example 1 decreased by 0.95%, 1.76% and 2.70% respectively compared with those of the plants in Comparative Example 5.

[0134] Compared with Comparative Example 4, the method of Example 1 more significantly inhibited the growth of the plant height, primary and secondary branches of 'Full - red Poplar' and 'Golden - red Poplar' plants. The plant height decreased by 22.00% and 30.66% respectively compared with those of the plants in Comparative Example 4, and the growth amounts of primary and secondary branches decreased by 29.51% and 17.24%, and 32.79% and 26.67% respectively. At the same time, the method of Example 1 had a more prominent promoting effect on the growth of branches smaller than the third - level branches. The growth amounts of branches smaller than the third - level branches of 'Full - red Poplar' and 'Golden - red Poplar' plants increased by 61.11% and 54.55% respectively compared with those of the plants in Comparative Example 4. The leaf number, single - leaf area and total leaf area of the 'Full - red Poplar' plants in Example 1 decreased by 0.95%, 1.60% and 2.54% respectively compared with those of the plants in Comparative Example 4, and the leaf number, single - leaf area and total leaf area of the 'Golden - red Poplar' plants in Example 1 decreased by - 1.46%, 8.17% and 6.83% respectively compared with those of the plants in Comparative Example 4.

[0135] This is because spraying the top of the plants of 'All Red Poplar' and 'Golden Red Poplar' with the dwarfing control aqueous agent I before the bud break for two consecutive years can timely control the conduction of auxin in the plants to the top during the bud break, and inhibit the apical dominance growth. Spraying the dwarfing control aqueous agent II can further inhibit the apical dominance of the plants, especially prevent the emergence of stronger branches in the first-level and second-level branches and the excessive growth of summer shoots, and control the height and crown shape of the plants. At the same time, the downward and inward accumulation of endogenous auxin in the branches can increase the branching angle of the first-level and second-level branches of the 'All Red Poplar' and 'Golden Red Poplar' plants to more than 90 degrees, thereby increasing the germination and growth space of the second-level and third-level branches, cultivating small branches of the plants, promoting the growth of inner branches and branches, and regulating the nutrition for vertical and horizontal growth, making the plant type compact and dwarf.

[0136] The plant heights of the 'All Red Poplar' and 'Golden Red Poplar' plants in Example 1 were significantly lower than those of the plants in Comparative Example 4 and Comparative Example 5, while the reduction ranges of the plant crown widths, the number of leaves held, and the total leaf area were much smaller than the reduction range of the plant height. This shows that the dwarfing control aqueous agent regulates the plant height by increasing the crown layers and shortening the internode distance between buds. The rich branching layers and relatively dense bud nodes allow the plants to have more leaf attachment points, enabling the 'All Red Poplar' and 'Golden Red Poplar' plants to maintain a stable number of leaves and total leaf area. At the same time, the dwarfing control aqueous agent can significantly reduce the single leaf area of the leaves of 'All Red Poplar' and 'Golden Red Poplar'. The effect of the dwarfing control aqueous agent II is better than that of the dwarfing control aqueous agent I, and the influence on the leaf size of 'Golden Red Poplar' is greater than that of 'All Red Poplar'.

[0137] In the present invention, the terms "an embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0138] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for controlling the shape of a colored-leaf poplar plant, characterized in that, It includes the following steps: S1. In mid-March of the first year, select two-year-old coppiced seedlings of colorful poplar. 15 - 20 days before the buds germinate, spray the dwarfing control aqueous agent I on the top shoots of the colorful poplar. The dwarfing control aqueous agent I includes the following components: using water as a solvent, adding 0.15 - 0.25 g of tiabendazole, 0.25 - 0.35 g of prohexadione-calcium, and 0.015 - 0.025 g of uniconazole per 1 L of water; S2. In late March of the first year, 10 - 15 days before the buds germinate, perform bud notching on the colorful poplar. Immediately after the bud notching, evenly apply the shoot promotion agent on the buds. Calculated based on the total mass of the shoot promotion agent being 100%, the shoot promotion agent includes the following components: gibberellin 1.6 - 2.0%, sodium nitrophenolate 2.4 - 2.6%, fulvic acid 2.8 - 3.2%, forchlorfenuron 1.4 - 1.8%, indolebutyric acid 0.8 - 1.2%, 28-homobrassinolide 3.8 - 4.2%, diethyl aminoethyl hexanoate 2.4 - 2.6%, ethanol 36 - 40%, glycerol 5 - 7%, and the balance is liquid lanolin; S3. In late April of the first year, when the primary and secondary shoots of the colorful poplar are completed and enter the vigorous growth period of branches and leaves, spray the dwarfing control aqueous agent II on the top shoots, leaf surfaces, and petioles of the outer layer of the colorful poplar crown. The dwarfing control aqueous agent II includes the following components: using water as a solvent, adding 0.15 - 1.25 g of tiabendazole, 0.25 - 0.35 g of prohexadione-calcium, 0.015 - 0.025 g of uniconazole, 0.4 - 0.6 g of brassinolide, and 0.8 - 1.2 g of mepiquat chloride per 1 L of water; S4. In late March and late April of the first year, apply the first soil fertilizer to the colorful poplar respectively, and cover the soil and water it after fertilization. The content of nitrogen fertilizer in the first soil fertilizer is the highest; in late July of the first year, apply the second soil fertilizer to the colorful poplar, and cover the soil and water it after fertilization. The ratio of phosphate fertilizer and potassium fertilizer in the second soil fertilizer is higher than that in the first soil fertilizer.

2. The method for controlling the shape of colored-leaf poplar plants according to claim 1, wherein In step S1, spray the dwarfing control aqueous agent I once every 7 - 10 days, and spray 1 - 2 times in total; optionally, the last spraying of the dwarfing control aqueous agent I should be carried out 5 - 7 days before the first bud notching treatment.

3. The method for controlling the shape of the colored-leaf poplar plant according to claim 1, wherein In step S2, perform the bud notching treatment on 3 - 6 buds within the range of more than 20 cm from the root and less than 10 cm from the shoot tip of the colorful poplar.

4. The method for controlling the shape of colored-leaf poplar plants according to claim 1 or 3, characterized in that, In step S2, 18 - 22 days after the bud notching treatment, perform the bud notching treatment on the buds that have not germinated again, and then apply the shoot promotion agent again.

5. The method for controlling the shape of the colored-leaf poplar plant according to claim 1, wherein, In step S2, when the newly grown branches of the colorful poplar grow to more than 30 cm, apply the shoot promotion agent for the third time on 3 - 4 buds within 10 cm from the shoot tip of the colorful poplar.

6. The method for controlling the shape of the colored-leaf poplar plant according to claim 1, wherein In step S3, spray the dwarfing control aqueous agent II once every 6 - 8 days, and spray 1 - 3 times in total.

7. The method for controlling the shape of the colored-leaf poplar plant according to claim 1, characterized in that, In step S4, Based on the total mass of the first soil fertilizer being 100%, the first soil fertilizer comprises the following components: potassium dihydrogen phosphate 10 - 14%, potassium chloride 16 - 20%, manganese sulfate 4 - 6%, ferrous sulfate 3 - 4%, copper sulfate 0.3 - 0.5%, magnesium sulfate 3 - 5%, zinc sulfate 0.5 - 0.7%, boric acid 5 - 7%, humic acid 4 - 6%, compound nitrophenolate sodium 4 - 6‰, calcium cyclaconate 2.4 - 2.6%, and the balance being urea; Based on the total mass of the second soil fertilizer being 100%, the second soil fertilizer comprises the following components: potassium dihydrogen phosphate 18 - 22%, potassium chloride 24 - 26%, manganese sulfate 4 - 6%, ferrous sulfate 3.4 - 3.6%, copper sulfate 0.35 - 0.45%, magnesium sulfate 3.5 - 4.5%, zinc sulfate 0.5 - 4.7%, boric acid 5 - 7%, humic acid 4 - 6%, compound nitrophenolate sodium 4 - 6‰, calcium cyclaconate 2 - 3%, and the balance being urea.

8. The method for controlling the shape of colorful-leaf poplar plants according to claim 1, characterized in that, It further includes step S5. In mid-March of the second year, 15 - 20 days before the buds germinate, spray the dwarfing control aqueous agent I on the tips of the outer branches of the colored poplar, and avoid or cover the vacant parts of the tree crown during spraying; optionally, spray the dwarfing control aqueous agent I every 8 - 12 days, and spray 1 - 2 times in total.

9. The method for controlling the shape of a colored-leaf poplar plant according to claim 1, characterized in that, It further includes step S6. In the middle and late March of the second year, 10 - 15 days before the buds germinate, perform bud notching on the positions where branches are missing on the main trunk of the colored poplar, and then apply the branch-promoting agent; optionally, 10 days after the bud notching, perform bud notching again on the buds that have not germinated on the main trunk of the colored poplar and the buds on the first-year-generated primary and secondary lateral branches, and then apply the branch-promoting agent again; optionally, 20 days after the bud notching, apply the branch-promoting agent for the third time on the buds on the newly generated primary and secondary lateral branches.

10. The method for controlling the shape of the colored-leaf poplar plant according to claim 1, wherein, It further includes step S7. In late April of the second year, when the branches and leaves enter the vigorous growth period, spray the dwarfing control aqueous agent II on the top tips, leaf surfaces, and leaf stalks of the outer layer of the colored poplar tree crown; optionally, spray the dwarfing control aqueous agent II every 6 - 8 days, and spray 1 - 3 times in total.

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