Method for raising seedlings of idesia polycarpa by grafting

Abstract

The invention provides an idesia grafting seedling raising method, relates to the technical field of grafting seedling raising, and adopts the technical scheme that the method comprises the steps of scion type determination, grafting method determination, grafting time determination and the like. According to the statistical data of the survival rate, the determination of appearance growth indexes of the grafted seedlings, and the fruit yield and quality, the optimal grafting mode is determined to be grafting in an axillary bud cut-grafting mode at the beginning of spring. The grafting combination most suitable for idesia polycarpa branch grafting is researched from different grafting periods and different grafting methods, a set of grafting method suitable for idesia polycarpa branches is established, and a set of feasible grafting method capable of achieving industrialized seedling raising is provided for asexual propagation of idesia polycarpa. And the method has important practical significance on the popularization of improved varieties of idesia polycarpa, the preservation of germplasm resources and the improvement of industrial quality and efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of grafting seedling cultivation, and more specifically relates to a method for grafting seedling cultivation of Castanopsis chinensis. Background Art

[0002] Idesia polycarpa Maxim is a deciduous tree belonging to the genus Idesia in the family Flacourtiaceae. It is also known as mountain sycamore, half-frost red, and oil grape. It is widely distributed in my country, covering 17 provinces and autonomous regions. Idesia trees produce a large amount of fruit with a high oil content, earning them the nickname "the oil depot on the tree." Idesia oil is primarily composed of unsaturated fatty acids, exceeding 82% in the fruit, including over 73% linoleic acid. It can effectively improve blood lipids and blood clots, and also has antioxidant and immune-enhancing properties. Idesia oil also contains a large number of naturally occurring active ingredients, making it a pure, natural, high-quality woody edible oil used in various industries, including industry, fertilizers, healthcare, health products, and cosmetics. Idesia grows rapidly, is highly adaptable, and is cold-resistant, barren, and drought-resistant, making it an ideal tree species for returning farmland to forests and urban greening. Therefore, the tung oil combines economic, ecological and social value, and has broad application prospects and huge development potential. As the country continues to pay attention to woody grains and oils, tung oil as a high-quality woody grain and oil has become increasingly important in edible oils.

[0003] At present, the method of seed propagation for raising Chinese tallow tree seedlings is still widely used. However, Chinese tallow tree seeds are relatively small, have a waxy layer on the surface, and have winter dormancy characteristics. Under natural conditions, the reproduction efficiency is extremely low. Its reproduction method is easily restricted by season, making it difficult to meet the growing market demand. In addition, seed propagation may cause offspring variation, making it difficult to maintain the excellent properties of the maternal parent. At present, the asexual propagation technology system of Chinese tallow tree seedlings has not yet been fully established. The asexual propagation method in raising Chinese tallow tree seedlings mainly includes three seedling raising techniques: cutting, tissue culture, and grafting. The greatest advantage of cutting seedlings is that they are simple, efficient, and inexpensive, but the exposed incision in the cutting bed easily makes the cutting seedlings infected with viruses. Tissue culture can not only breed a large number of excellent asexual seedlings in a short period of time, but also has high production efficiency. However, there are problems such as difficulty in sterilizing the primary culture, serious pollution, high operating costs, and large technical difficulties.

[0004] Grafting, as one of the asexual propagation methods of forest trees, has many advantages such as short seedling raising cycle, maintaining excellent traits and low operating costs.

[0005] Although the existing grafting technology has a high survival rate due to the fine processing, it has the problems of complicated operation and high raw material cost, such as the need to use materials such as tin foil, water loss preventer, paraffin wax, etc. during the grafting process. The technology of the present invention avoids the risk problem of field planting by determining the optimal grafting period, grafting method and scion type, does not need to apply the grafting wound, and saves management costs. In addition, the present invention studies the influence of factors such as grafting period, grafting method and scion type on the grafting survival rate and the appearance growth index of the grafted seedlings, as well as the fruit yield and quality, thereby exploring the most suitable grafting period of Castanopsis chinensis and the optimal grafting method and the most suitable scion type during this period, etc., to provide technical guidance for the breeding of improved varieties of Castanopsis chinensis and the preservation of rare germplasm resources. The present invention aims to provide a method for Castanopsis chinensis grafting seedling cultivation, to solve the existing problems in Castanopsis chinensis seedling cultivation work. Summary of the Invention

[0006] The present invention mainly addresses key production problems of existing Castanopsis chinensis grafting seedling raising technology systems, such as an imperfect system, low production efficiency, long cultivation cycle, and unstable yield and quality. A method for raising Castanopsis chinensis grafting seedlings is provided. The present invention uses one-year-old Castanopsis chinensis seedlings as rootstocks, explores the most suitable branch grafting methods for Castanopsis chinensis based on different grafting periods and different grafting methods, and develops a set of grafting technology systems for Castanopsis chinensis. The aim is to provide a grafting scheme that is both feasible and suitable for industrialized seedling raising for achieving asexual reproduction of Castanopsis chinensis. This method has important reference value and practical guiding significance for improving the quality and efficiency of the Castanopsis chinensis industry and promoting its healthy development.

[0007] The above technology of the present invention is achieved through the following technical solutions:

[0008] A method for raising seedlings of Castanopsis aviculare grafted therein comprises the following steps:

[0009] During the Beginning of Spring, select a one-year-old seedling of Castanopsis truncatum as the rootstock and a branch of Castanopsis truncatum with one axillary bud as the scion for cut grafting. The rootstock should be 10-15 cm tall and 1.0-1.6 cm in diameter, and the scion should be 2.8-3.5 cm long and approximately 0.4-1.0 cm in diameter.

[0010] The planting location is southern China, further to Changsha City in Hunan Province.

[0011] Furthermore,

[0012] Described cut grafting method grafting comprises the following steps:

[0013] S1. Cut a small bevel on one side of the cut surface of the rootstock, then cut a long vertical split along the bevel where the phloem meets the cambium, leaving the cut rootstock epidermis intact.

[0014] S2. Cut a long bevel on the back of the scion bud, and then cut a small bevel on the front of the scion bud;

[0015] S3, the scion is inserted into the stock cleft, the long bevel is close to the wood of the stock, so that the long bevel of the scion is fitted with the cambium of the stock, and after fitting, the interface of the scion and the stock is wrapped and sealed with a grafting film;

[0016] S4. After the scion has germinated for a period of time, remove the grafting film on the scion and the rootstock to complete the grafting of the Castanopsis tung tree branches.

[0017] The one-year-old Castanopsis chinensis seedlings need to be healthy, free of pests and diseases, without splitting, and with complete root systems.

[0018] The step S1 is specifically as follows:

[0019] Cut a small 10-20° bevel on one side of the cut surface of the rootstock, and then cut a 1.5-2.5 cm long split vertically along the bevel where the phloem and cambium meet, and retain the cut rootstock epidermis.

[0020] The step S2 is specifically as follows:

[0021] The back of the scion bud is cut into a long bevel with a height of 1-2 cm at an angle of 60-70 degrees, and then the front of the scion bud is cut into a small bevel with a height of 0.4-0.6 cm at an angle of 40-50 degrees.

[0022] The scion should be a healthy, disease-free, and well-developed stem segment of a high-quality individual plant of Castanopsis tung oil tree. A scion with one axillary bud is preferred.

[0023] After wrapping is completed in step S3, ensure that the interface is tight and seamless, and ensure that the grafting film is not loose or damaged; place the grafted plant in a cool and ventilated environment, avoiding direct sunlight and high temperature and high humidity conditions; as the grafting interface gradually heals, the scion will begin to sprout new buds. At this time, the light and temperature can be gradually increased to promote the growth and development of the plant.

[0024] In step S4, the grafting film is dismantled 55-65 days after the scion germinates, preferably 60 days.

[0025] In step S4, the grafting film is dismantled by lightly scratching the grafting film on the outer side of the rootstock.

[0026] Remove the grafting membrane to ensure that the healed tissue is not damaged. After the grafting is completed, carry out subsequent maintenance work, such as pest and disease control, watering and fertilizing, and keeping warm.

[0027] The one-year-old seedlings of Castanopsis schefflera provided by the present invention are preferably obtained by the following steps:

[0028] (1) After the fruits mature in November, the freshly picked Chinese tallow tree fruits are sun-dried and sanded with sandpaper to separate the pulp from the seeds inside. The removed seeds are then soaked in clean water, rinsed, and placed in a ventilated place to dry in the shade. The shade-dried seeds are washed with detergent to remove surface wax before inoculation. In February of the following year after the fruits were harvested, the Chinese tallow tree seeds are stored in sand and watered regularly. When the sprouts grown from the sand storage are 2-3 cm tall, they are transplanted.

[0029] (2) In February of the third year after fruit harvesting, select healthy and pest-free one-year-old seedlings of Castanopsis chinensis as rootstocks, and select improved varieties of Castanopsis chinensis as scions;

[0030] The seeds collected in the above step (1) are from excellent individual plants of Castanopsis chinensis. The seedlings germinated from the seeds of the excellent individual plants are used as rootstock materials for subsequent grafting experiments. The seedlings should be protected from adverse stresses such as diseases and insect pests. The sand storage in step (1) refers to placing 10 cm thick river sand in a flower pot, evenly spreading the Castanopsis chinensis seeds on it, covering it with about 4 cm of river sand, and spraying carbendazim solution in time (the ratio of substrate to agent is 1200:1); the substrate ratio when transplanting the seedlings is 2:1:1 of loess, perlite, and vermiculite.

[0031] In the above step (2), the scion is a young, disease-free stem segment with buds from a high-quality single plant of Castanopsis truncatula, and the rootstock is a one-year-old healthy seedling germinated from the seeds of a high-quality single plant.

[0032] In summary, the present invention has the following beneficial effects:

[0033] The present invention conducts research from different aspects such as different grafting periods, different grafting methods, different scion types, and grafting efficiency, survival rate, yield, quality and cost, explores the most suitable time and method for grafting of Castanopsis chinensis branches, establishes a set of grafting methods suitable for Castanopsis chinensis branches, and provides a set of feasible and industrialized seedling-raising grafting methods for asexual reproduction of Castanopsis chinensis. In addition, grafting can maintain the excellent traits of the Castanopsis chinensis improved variety mother plant, which has important practical significance for the promotion of Castanopsis chinensis improved varieties and the improvement of industry quality and efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the grafting process of the fusion grafting method, the cleft grafting method and the cut grafting method in Example 1 of the present invention;

[0035] Figure 2 1 is a graph showing the growth of grafted seedlings at different grafting times, grafting methods, and scion types in Example 1 of the present invention;

[0036] Figure 3 This is a microscopic structural observation of the healing of the grafted site of the Castanopsis aviculare grafted seedlings 60 days after germination in Example 1 of the present invention;

[0037] Figure 4The wound healing conditions of the grafts obtained by adopting different grafting methods at different grafting times in Example 1 of the present invention after the grafts were debonded 2 months after budding;

[0038] Figure 5 The growth of the seedlings after the grafting and film removal using the cut grafting method in Example 1 of the present invention;

[0039] Figure 6 The effect of different grafting methods on the total root length of Castanopsis aviculare grafted seedlings in Example 2 of the present invention;

[0040] Figure 7 The effects of different grafting methods on the root surface area of ​​the grafted Castanopsis chinensis seedlings in Example 2 of the present invention are as follows;

[0041] Figure 8 The effects of different grafting methods on the root volume index of Castanopsis chinensis grafted seedlings in Example 2 of the present invention are as follows;

[0042] Figure 9 The effects of different grafting combinations on photosynthetic parameters of Castanopsis aviculare grafted seedlings in Example 3 of the present invention are as follows;

[0043] Figure 10 The flowering condition of the seedlings in the second year after grafting by the axillary bud grafting method in Example 4 of the present invention;

[0044] Figure 11 This is the state of fruiting after three years of cultivation of one-year-old Castanopsis aviculare seedlings grafted using the axillary bud grafting method in Example 4 of the present invention. DETAILED DESCRIPTION

[0045] The following examples are intended to further illustrate the present invention, but are not intended to limit the present invention.

[0046] Example 1

[0047] Effects of scion type, grafting time and grafting method on the survival rate of Castanopsis chinensis branch grafting

[0048] The present embodiment test site mainly carries out grafting research on the roof of the trees in the Central South University of Forestry and Technology in Changsha, Hunan Province. The annual average temperature of the test site is all about 16 ℃-17 ℃, and the highest temperature in the year is about 38 ℃-40 ℃, and the lowest temperature in the year is about -5 ℃-2 ℃, and the average annual precipitation is between 1200-1400mm. The experiment adopts single factor experimental design to study different scion types (terminal bud, axillary bud), different grafting times (early February Beginning of Spring, late March Equinox, early May Beginning of Summer, late June Summer Solstice, early August Beginning of Autumn, late September Autumnal Equinox, early November Beginning of Winter, late December Winter Solstice), different grafting methods (close grafting method, cleft grafting method, cut grafting method) these 3 factors on the impact of the survival and growth of the tung tree branch grafting, screening and obtaining optimal grafting combination mode and grafting time, above each combination grafting 30 strains, 3 repetitions, each treatment grafting a total of 90 strains, average value. Carry out the following operations in sequence:

[0049] 1. Select the rootstock and scion: The rootstock should be a one-year-old seedling of a high-quality individual Castanopsis truncatum plant, and the scion should be a budded stem segment from a high-quality individual Castanopsis truncatum plant. The rootstock should be 10-11 cm tall and 1.4-1.5 cm in diameter. The scion should be 3.0-3.2 cm long and 0.4-0.5 cm in diameter.

[0050] 2. Grafting: Use the fusion grafting method, cleft grafting method and cut grafting method for grafting, and use 3cm×20cm plastic grafting film as the grafting film.

[0051] Cleft grafting: Split the rootstock vertically to a depth of about 1.5-2.5cm, cut the scion into a wedge-shaped slope of about 1-2cm, insert the scion into the split of the rootstock, and bandage all the wounds. Each person can graft 400-600 plants per day using the cleft grafting method. Figure 1 As shown in B1-B4.

[0052] The grafting method is to cut the rootstock and scion at a 45° angle along the incision 1-2cm, and make the cut surface of the scion match the rootstock as much as possible. Fit the rootstock and scion together and bandage all the wounds. The grafting method can graft 300-500 plants per day. Figure 1 As shown in A1-A4.

[0053] Cutting method:

[0054] S1: Cut a 10-20° bevel on one side of the cut stock, then cut a 1.5-2.5 cm long split vertically along the bevel where the phloem meets the cambium, retaining the cut stock epidermis;

[0055] S2: Cut a long bevel of 1-2 cm in height on the back of the scion bud at an angle of 60-70 degrees, and then cut a small bevel of 0.4-0.6 cm in height on the front of the scion bud at an angle of 40-50 degrees;

[0056] S3, the scion is inserted into the stock cleft, the long bevel is close to the wood of the stock, so that the long bevel of the scion is fitted with the cambium of the stock, and after fitting, the interface of the scion and the stock is wrapped and sealed with a grafting film;

[0057] S4. After the scion has germinated for a period of time, remove the grafting film on the scion and the rootstock to complete the grafting of the tung tree branches. Figure 1 As shown in C1-C4.

[0058] The survival rate of the grafted seedlings was calculated 30 days after germination, and the survival rate formula was:

[0059] Grafting survival rate = number of scion germinated / total number of grafted rootstocks × 100%.

[0060] The data in Table 1 show that the most suitable grafting method for Castanopsis truncatula is clinch grafting at the Beginning of Spring, while the most suitable grafting method at the Vernal Equinox is cut grafting. The highest grafting survival rate at the Beginning of Spring was 83.33%. The survival rate of clinch grafting at the Beginning of Spring was 64.46% higher than that of axillary bud grafting. The highest survival rate, 83.00%, was achieved at the Vernal Equinox using cut grafting, 25.13% higher than that of axillary bud grafting. Therefore, clinch grafting is the most suitable method for terminal bud grafting at the Beginning of Spring, while cut grafting is the most suitable method for terminal bud grafting at the Vernal Equinox.

[0061] The survival rate of Castanopsis tung blossoms grafted using different grafting methods and scion types during the Beginning of Summer and Summer Solstice is extremely low. During the Beginning of Summer, the survival rate is 0.00% to 25.00%, while during the Summer Solstice, due to high rainfall and humid air, the survival rate is 0.00% to 6.00%. In terms of production, grafting in summer results in a significant waste of labor and material costs.

[0062] Autumn is the most suitable time for grafting seedlings and preserving germplasm resources using the cut grafting method, which occurs during the Autumnal Equinox. The grafting survival rate is highest during the Autumnal Equinox, while the survival rate is generally lower during the Beginning of Autumn. The survival rates of axillary and apical bud grafts using the cut grafting method during the Autumnal Equinox are both high, at 80.33% and 82.33%, respectively.

[0063] During the Beginning of Winter, the survival rates of terminal buds grafted using cleft grafting, lap grafting, and cut grafting were 47.00%, 53.33%, and 67.67%, respectively. The survival rates of axillary buds grafted using the three grafting methods were 21.67%, 40.67%, and 50.00%, respectively. The survival rates of terminal buds grafted using the cut grafting method were all higher than those of axillary buds. The survival rates of terminal buds grafted using the cut grafting method were 43.98% and 26.89% higher than those using the cleft grafting method and the lap grafting method, respectively. Therefore, the cut grafting method is the most suitable grafting combination for the Beginning of Winter.

[0064] During the winter solstice, the survival rates of terminal buds grafted using cleft grafting, lap grafting, and cut grafting were 63.67%, 82.67%, and 35.67%, respectively. The survival rates of axillary buds grafted using the three grafting methods were 46.33%, 64.33%, and 46.00%, respectively. The survival rates of terminal buds grafted using the three grafting methods were all higher than or equal to those of axillary buds. The survival rate of terminal buds grafted using the lap grafting method was 29.84% and 131.67% higher than those grafted using the cleft grafting method and the cut grafting method, respectively. Therefore, the lap grafting method is the most suitable grafting combination during the winter solstice.

[0065] Table 1 shows the grafting survival rates for different grafting periods, grafting methods, and scion types. Survival rates for terminal buds grafted at the Beginning of Spring were relatively high using all three grafting methods, with the highest survival rate reaching 83.33% for terminal buds and 67.67% for axillary buds. The highest survival rate for terminal buds grafted at the Vernal Equinox was achieved using the cut grafting method, exceeding the survival rates for all other grafting periods and grafting methods. In summer, survival rates were lower regardless of the grafting method or scion type used. Compared to axillary buds, a smaller number of plants survived with terminal buds grafted. Furthermore, autumn grafting was most effective during the Autumnal Equinox, with both axillary and terminal buds achieving survival rates exceeding 80.00%, while the highest survival rate at the Beginning of Autumn was only 21.67%. The highest survival rates for terminal buds grafted using the cleft grafting method, the lap grafting method, and the cut grafting method were achieved at the Beginning of Winter, with the lap grafting method achieving the highest survival rate at 82.67%. Therefore, the most suitable time for grafting the terminal buds of Castanopsis chinensis is the Beginning of Spring, the Vernal Equinox, the Beginning of Winter and the Winter Solstice, and the most suitable time for grafting both axillary buds and terminal buds is the Autumnal Equinox.

[0066] Table 1 Survival rate of grafted seedlings at different grafting periods, grafting methods and scion types

[0067]

[0068]

[0069] The Castanopsis chinensis seedlings treated with all the above-mentioned different grafting methods and scion types were mixed, and the growth changes of the Castanopsis chinensis grafted seedlings at six different grafting periods at 30 days, 60 days and 90 days after germination were compared (as shown in Table 2). It can be concluded that the seedlings grafted during the Beginning of Spring showed obvious growth in multiple growth indicators, and the growth of seedling height, ground diameter, new shoot length, new shoot thickness and new shoot leaf number were all the maximum values.

[0070] The average height of seedlings in the Beginning of Spring period reached 82.53cm 90 days after germination, which was 90.6%, 172.5%, 332.2%, 207.4% and 219.5% higher than those in the Vernal Equinox, Beginning of Autumn, Autumnal Equinox, Beginning of Winter and Winter Solstice respectively; the ground diameter of seedlings in the Beginning of Spring period reached 13.31mm 90 days after germination, which was 18.6%, 11.7%, 31.0%, 34.2% and 31.8% higher than those in the Vernal Equinox, Beginning of Autumn, Autumnal Equinox, Beginning of Winter and Winter Solstice respectively; the length of new shoots in the Beginning of Spring period was 70.75cm 90 days after germination, which was 13.31mm higher than those in the Vernal Equinox, Beginning of Autumn, Autumnal Equinox, Beginning of Winter and Winter Solstice respectively. They were 102.6%, 250.4%, 513.1%, 293.8% and 361.5% higher respectively; the diameter of new shoots in the Beginning of Spring period was 10.52mm at 90 days, which was higher than that in the Vernal Equinox, Beginning of Autumn, Autumnal Equinox, Beginning of Winter and Winter Solstice. Compared with these periods, the diameter of new shoots in the Beginning of Spring was 14.7%, 51.1%, 135.3%, 102.7% and 174.7% higher respectively; the number of new shoot leaves in the Beginning of Spring period was 35.11 at 90 days, which was 87.5%, 164.9%, 321.5%, 190.2% and 283.1% higher respectively than that in the Vernal Equinox, Beginning of Autumn, Autumnal Equinox, Beginning of Winter and Winter Solstice.

[0071] In summary, the growth of seedlings grafted during the Beginning of Spring in terms of seedling height, ground diameter, new shoot length, new shoot diameter, and new shoot leaf number was higher than that during other periods. Therefore, the Beginning of Spring is the most suitable period for grafting Castanopsis truncatula.

[0072] Table 2 Effects of different grafting periods on the growth of Castanopsis chinensis grafted seedlings

[0073]

[0074]

[0075] The data in Table 3 show the growth rates of various growth indicators for Castanopsis truncatum seedlings and scions grafted during the Beginning of Spring at 30, 60, and 90 days after germination. At 90 days after germination, all growth indicators except shoot diameter were higher for Castanopsis truncatum seedlings grafted using the cut grafting method than for those grafted using the cleft and fusion grafting methods. Compared with cleft grafted axillary buds, the cut grafted axillary buds had seedling height, basal diameter, shoot length, shoot diameter, and shoot leaf number that were 8.27%, 6.16%, 9.55%, 7.87%, and 32.55% higher, respectively. Compared with fusion grafted axillary buds, the cut grafted axillary buds had seedling height, basal diameter, shoot length, shoot diameter, and shoot leaf number that were 27.14%, 16.62%, 33.61%, 13.15%, and 54.50% higher, respectively.

[0076] At 90 days after germination, the seedling height, shoot length and number of shoot leaves of the grafted seedlings with the terminal bud grafted by the cut grafting method were higher than those of the terminal bud grafted by the cleft grafting method and the fusion grafting method, but lower than those of the axillary bud grafted by the cut grafting method. The seedling height, ground diameter, shoot length, shoot diameter and number of shoot leaves of the grafted seedlings were 41.57%, 8.76%, 72.95%, 18.71% and 53.02% higher than those of the terminal bud grafted by the cleft grafting method, respectively; the seedling height, ground diameter, shoot length and number of shoot leaves of the grafted seedlings were 15.81%, 9.88%, 22.14% and 20.59% higher than those of the terminal bud grafted by the fusion grafting method, respectively.

[0077] Among the scion types using the cut grafting method, the axillary bud scion performed the best. Its seedling height, ground diameter, shoot length, shoot diameter, and number of shoot leaves were 17.40%, 9.74%, 19.15%, 17.83%, and 37.88% higher than those using the terminal bud scion, respectively. Among the scion types using the cleft grafting method, the axillary bud scion had higher seedling height and higher number of shoot leaves than the terminal bud scion, but its overall growth performance was weaker than that of the cut grafting method. Among the scion types using the fusion grafting method, the axillary bud scion had lower seedling height, ground diameter, shoot length, and number of shoot leaves than the cut grafted axillary bud. In summary, the cut grafting method for axillary buds is the most suitable method for Castanopsis truncatula grafting.

[0078] Table 3 Effects of different grafting methods and scion types on the growth of Castanopsis chinensis grafted seedlings

[0079]

[0080] As can be seen from the above, the changes in various growth indicators after grafting buds at different periods are quite different. The grafting period is the same but the grafting method is different, and there are also differences in the growth indicators after budding. The changes in seedling height and ground diameter 0-90 days after the axillary buds germinate using the cut grafting method are the largest, and the scion grows the fastest and has the best growth. The scion growth is also relatively fast after the apical buds germinate using the cut grafting method and the combined grafting method. The grafting survival rate is higher during the autumnal equinox, but the rate of change of various growth indicators of the scion after grafting buds is slower, and the growth rate of the scion after grafting at the beginning of winter and the winter solstice is also slower. The growth of the scion 30 and 60 days after germination of the scion using different grafting methods at different periods is as follows. Figure 2 As shown, Figure 2 -A. Figure 2 -B. Figure 2 -C. Figure 2 -D and Figure 2 -E represents the growth of grafts during the Beginning of Spring, Spring Equinox, Autumnal Equinox, Beginning of Winter and Winter Solstice respectively.

[0081] Observation on the microstructure of wounds of Castanopsis chinensis grafted seedlings by different grafting methods Figure 3 As shown, the axillary buds ( Figure 3 -C), grafted axillary buds ( Figure 3 -E) and grafted terminal buds ( Figure 3-F), these three grafting methods showed good healing effect 60 days after the grafted seedlings germinated. Specifically, the isolation layer of the stock and scion was tightly combined, the grafting site healed well, the cambium began to fuse, and a large number of new vascular tissues were formed. The xylem and phloem of the grafted seedlings gradually formed a whole. In particular, the isolation layer of the grafted seedlings with the combination of the cut grafting method and the apical bud basically disappeared, and the cambium of the stock and scion was basically completely fused. However, the cleft grafting method ( Figure 3 -A), cleft bud ( Figure 3 -B) and the fused terminal bud ( Figure 3 -D), the healing effect of the grafted seedlings of these three grafting methods was relatively poor after germination for 60 days. Specifically manifested as: although the isolation layer of the stock and the scion is tightly combined, and part of the cambium has completely fused, there is still an obvious isolation layer, and the cell arrangement is slightly disordered. Therefore, the influence of different grafting methods on the microstructure of the wound of the Castanopsis chinensis grafted seedlings is significant. The grafting site healing of the cut grafting terminal bud combination is best after 60 days of grafting budding.

[0082] The film is removed 2 months after the grafting buds sprout. Figure 4 The wound healing of the grafted part after different grafting methods were removed at different times (beginning of spring, spring equinox, autumnal equinox, beginning of winter and winter solstice). Figure 4 It can be seen that the healing of grafting wounds during the Beginning of Spring, Spring Equinox and Autumn Equinox is better, and when grafted during the same period, the healing of cleft grafting is poor, while the healing of cut grafting and fusion grafting is better. Figure 5 It refers to the growth of seedlings after the film is removed after grafting using the cut grafting method.

[0083] The survival rate and growth of grafted Castanopsis chinensis seedlings are influenced by multiple factors, including grafting combination, grafting period, and scion type, and the relationships between these indicators are complex. To comprehensively evaluate the performance of different grafting combinations, principal component analysis (PCA) was used to analyze six indicators (survival rate, seedling height, ground diameter, shoot length, shoot diameter, and number of shoot leaves) for 36 grafting combinations. The KMO value was 0.828 after KMO and Bartlett's tests, indicating that the data were suitable for PCA. Two principal components with eigenvalues ​​greater than 1 were extracted, contributing a cumulative 88.668% to the variance. The first principal component had an eigenvalue of 4.261 and a variance contribution of 71.011%, while the second principal component had an eigenvalue of 1.059 and a variance contribution of 17.657%. The first principal component primarily represented the survival rate, while the second principal component primarily represented the number of shoot leaves. Based on the results of principal component analysis, the variance contribution rate of each principal component was used as the weight to construct the comprehensive evaluation function expression: y = 0.71011 * PC1 + 0.17657 * PC2. As shown in Table 4, the top 10 grafting combinations are: axillary bud grafting at the beginning of spring, axillary bud grafting at the beginning of spring, apical bud grafting at the beginning of spring, axillary ... vernal equinox, axillary bud grafting at the vernal equinox, axillary bud grafting at the beginning of autumn, axillary bud grafting at the beginning of autumn, and axillary bud grafting at the vernal equinox.

[0084] At the beginning of spring in early February, the six grafting combinations achieved a combined score of 13.21, the best performance. The order of grafting methods and types was: cut grafting axillary buds > cleft grafting axillary buds > fused grafting terminal buds > cut grafting terminal buds > fused grafting axillary buds > cleft grafting terminal buds, indicating that the beginning of spring is the most suitable time for both cut and cleft grafting. At the vernal equinox in late March, the six grafting combinations achieved a combined score of 1.41, second only to the beginning of spring. The order of grafting methods and grafting types is: cut grafting axillary buds > cleft grafting axillary buds > cut grafting terminal buds > combined grafting axillary buds > combined grafting terminal buds > cleft grafting terminal buds, indicating that the cut grafting and cleft grafting methods are suitable for grafting axillary buds during the Spring Equinox; in early August at the beginning of autumn, the overall score of the six grafting combinations was -0.17, which was poor, and the order of grafting methods and grafting types is: cleft grafting terminal buds > cut grafting terminal buds > cut grafting axillary buds > combined grafting terminal buds > combined grafting axillary buds > cleft grafting axillary buds, indicating that the cleft grafting method is suitable for grafting terminal buds during the Beginning of Autumn; in late September at the autumnal equinox, the overall score of the six grafting combinations was -7.96, which was the worst performance, and the order of grafting methods and grafting types is: cut grafting axillary buds > cut grafting terminal buds > combined grafting terminal buds > cleft grafting Grafting terminal buds>grafting axillary buds together>cleavage axillary buds, and the scores of cut axillary buds and cut terminal buds were relatively high, but still negative, indicating that late autumn was not suitable for grafting; in early November, at the beginning of winter, the overall score of the six grafting combinations was -2.13, among which the order of grafting methods and grafting types was: cleft grafting terminal buds>cleft grafting axillary buds>joined grafting axillary buds>cut grafting terminal buds>joined grafting terminal buds>cleft grafting axillary buds, indicating that cleft grafting was suitable for grafting axillary buds during the beginning of winter; in late December, at the winter solstice, the overall score of the six grafting combinations was -4.38, among which the order of grafting methods and grafting types was: cleft grafting axillary buds>cleft grafting terminal buds>cut grafting axillary buds>joined grafting terminal buds>cleft grafting terminal buds>joined grafting axillary buds, indicating that cleft grafting was suitable for grafting axillary buds during the winter solstice.

[0085] Table 4 Comprehensive evaluation of different grafting combinations

[0086]

[0087]

[0088] Note: 1-6 represent: early February (Beginning of Spring), late March (Vernal Equinox), early August (Beginning of Autumn), late September (Autumnal Equinox); early November (Beginning of Winter), late December (Winter Solstice); H: fusion grafting; P: cleft grafting; Q: cut grafting; D: terminal bud; Y: axillary bud.

[0089] Example 2

[0090] This example studies the effects of different scion types (terminal buds, axillary buds) and different grafting methods (joint grafting, cleft grafting, and cut grafting) on ​​the root growth of Castanopsis truncatula grafted during the Beginning of Spring by measuring the total root length, root surface area, root volume, and root diameter of Castanopsis truncatula grafted during the Beginning of Spring. Figure 6Figure 3 shows the effects of different grafting methods on the total root length of grafted Castanopsis chinensis seedlings. T1-T6 represent cleft-grafted axillary buds, cleft-grafted apical buds, fused axillary buds, fused apical buds, cut-grafted axillary buds, and cut-grafted apical buds, respectively (the same below). The results showed significant differences in the effects of different grafting methods on the total root length of grafted Castanopsis chinensis seedlings. The order of total root length, from highest to lowest, was: T5 > T4 > T6 > T1 ≈ T2 ≈ T3 > CK. The total root lengths of the T5, T4, and T6 treatments were higher than those of the other treatments. Compared with the CK, the total root lengths of the T5, T4, and T6 treatments increased by 123.43%, 76.16%, and 55.94%, respectively. The total root length of T5 reached 2.23 times that of the control group. The total root length of T3 was 50.30% lower than that of T5, indicating that this grafting method may be detrimental to root development.

[0091] Figure 7 The study investigated the effects of different grafting methods on the root surface area of ​​grafted Castanopsis chinensis seedlings. The results showed significant differences in the effects of different grafting methods on the root surface area of ​​the Castanopsis chinensis seedlings. The order of root surface area, from highest to lowest, was: T4 > T5 > T6 > CK ≈ T3 > T1 > T2. The root surface areas of the T4, T5, and T6 treatments were 93.0%, 84.6%, and 41.4% higher than those of the control group, respectively.

[0092] Figure 8 The effects of different grafting methods on root volume in grafted Castanopsis chinensis seedlings were analyzed. Significant differences were observed among the grafting methods, with the root volume ranking from highest to lowest being: T4 > T5 > T6 > T3 > CK > T1 > T2. T4 had the highest root volume, increasing by 104.2% compared to the control. T5 and T6 also significantly increased their root volumes by 47.5% and 24.6%, respectively. The root volumes of the T1 and T2 treatments were significantly lower than those of the control, decreasing by 18.2% and 30.8%, respectively. There was no significant difference in root volume between the T3 treatment and the control.

[0093] Example 3

[0094] This example explores the photosynthetic parameters of grafted seedlings under different grafting combinations by measuring the net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr). Figure 9 To investigate the effects of different grafting periods, grafting methods and scion types on the photosynthetic parameters of Castanopsis aviculare grafted seedlings 90 days after germination.

[0095] From the perspective of different grafting periods, the photosynthetic performance of seedlings grafted at the beginning of spring was better, especially the axillary buds (12.6±0.83μmol·m -2 ·s -1 ) and axillary buds (11.91±0.64μmol·m - 2 s -1) had a significantly higher net photosynthetic rate than the other treatments. Stomatal conductance and transpiration rate were also at a high level, indicating that the temperature and light conditions at this time were favorable for photosynthesis. The net photosynthetic rate of the axillary buds grafted during the Beginning of Autumn was higher (11.18±0.34μmol·m - 2 s - 1), but the net photosynthetic rates of the other treatments were generally lower, which may be related to the temperature drop and weakening of light at this time. The photosynthetic performance of the seedlings grafted during the Beginning of Winter and the Winter Solstice was significantly poor, with the net photosynthetic rate generally lower than 10 μmol·m - 2 s - 1. Stomatal conductance and transpiration rate also decreased significantly, indicating that the low temperature environment significantly inhibited photosynthesis.

[0096] The different grafting methods showed higher net photosynthetic rates in multiple stages, especially in the grafted axillary buds at the beginning of spring (12.6±0.83μmol·m - 2 s - 1) and the apical buds at the winter solstice (12.84±0.39μmol·m - 2 s - 1). Stomatal conductance and transpiration rate were also at a high level, indicating that the grafting method was beneficial to gas exchange and water transport; the cut grafting method performed better during the beginning of spring, especially the cut grafted axillary buds (11.91±0.64μmol·m - 2 s - 1), but the net photosynthetic rate of the grafted buds was significantly lower during the beginning of winter (7.08±0.05μmol·m - 2 s - 1); photosynthetic parameters of cleft grafting showed great differences. The stomatal conductance of cleft grafted buds was higher during the beginning of autumn (0.27±0.03mol·m - 2 s - 1), but the stomatal conductance of cleft-jointed axillary buds was significantly lower during the winter solstice (0.07±0.01 mol·m -2 ·s -1 ).

[0097] Axillary bud grafts exhibited higher net photosynthetic rates in some combinations, such as cleft grafts, fused grafts, and cut grafts at the beginning of spring. However, terminal bud grafts also performed better at certain times, such as cleft grafts at the autumnal equinox. Stomatal conductance and transpiration rates were also generally higher, indicating that axillary bud grafts possessed stronger photosynthetic capacity and water use efficiency.

[0098] In summary, net photosynthetic rates were higher in some treatments during the Beginning of Spring and Beginning of Autumn. The splicing method performed better on some photosynthetic parameters, but no clear pattern of advantages between different scion types was observed for any of these parameters. Therefore, the photosynthetic efficiency of grafted seedlings is related to factors such as light intensity and temperature during the grafting period, and is unrelated to scion type.

[0099] Example 4

[0100] If grafted during the beginning of spring, the Chinese tallow tree seedlings will begin to bloom in April of the second year after grafting, and the flowering period is from April to May ( Figure 10 ), and fruiting begins in October and November. This example measured the flowering, fruit yield and quality of Castanopsis truncatula grafted using different grafting methods and different scion types.

[0101] Table 6 shows the flowering rates of different grafting combinations for Castanopsis truncatula. Flowering rate = number of flowering plants / total number of plants × 100%. Table 6 shows that the flowering rate was higher for cut grafting at the Beginning of Spring, reaching 82.67%, while the flowering rate for cleft grafting was relatively lower at all times. Furthermore, the axillary buds grafted at the Beginning of Spring had the longest flower spikes, measuring 6.80 cm, and the highest number of flowers per spike, reaching 41.67. In terms of flower size, both the axillary buds and terminal buds grafted at the Beginning of Spring had larger flowers in both transverse and longitudinal diameters. Although the survival rate of axillary buds grafted at the Beginning of Spring was lower than that of grafting at the Beginning of Spring, the Vernal Equinox, the Autumnal Equinox, and the Winter Solstice, the grafting method performed better in terms of seedling height, ground diameter, and shoot length than grafting methods at other times. This suggests that grafting at the Beginning of Spring facilitates the vegetative growth of grafted seedlings and provides a foundation for subsequent reproductive growth. The flowering rates of axillary buds grafted by cutting at the Beginning of Spring were 9.74%, 13.00%, 11.30% and 12.89% higher than those grafted by terminal buds at the Beginning of Spring, the Vernal Equinox, the Autumnal Equinox and the Winter Solstice respectively. The best grafting method is to graft axillary buds by cutting at the Beginning of Spring.

[0102] Table 6 Effects of different grafting combinations on flowering of Castanopsis chinensis

[0103]

[0104]

[0105] As shown in Table 7, the fruit clusters of the “cut grafting method + axillary bud” combination were the longest in the six periods of Beginning of Spring, Spring Equinox, Beginning of Autumn, Autumnal Equinox, Beginning of Winter and Winter Solstice, while the fruit clusters of the cleft grafting method were relatively short. In addition, the number of fruits per cluster under the Beginning of Spring cut grafting method + axillary bud combination treatment was the largest, the weight of ten fresh fruits was the heaviest, and the number of single fruits was relatively large, indicating that this method is conducive to increasing fruit yield. The horizontal and vertical diameters of the fruits of Castanopsis tung oil trees grafted by the cut grafting method were relatively large, and the horizontal and vertical diameters of the fruits did not differ much when the scion types were different, and the fruits were relatively full. Figure 11The fruiting condition of the grafted tung tree seedlings was treated by cutting the axillary buds at the beginning of spring. The grafted seedlings began to bear fruit in May and June. Figure 11 -A), the fruit enters the ripening period in October-November ( Figure 11 -B). If 60 Castanopsis truncatula seedlings are grafted per acre, the expected fruit yield is highest in the third year after grafting using the axillary bud grafting method at the Beginning of Spring. This method is 43.15%, 31.42%, 31.55%, and 62.37% higher than grafting the terminal buds at the Beginning of Spring, the Spring Equinox, the Autumnal Equinox, and the Winter Solstice, respectively. Comprehensively evaluating various indicators, the "cut grafting + axillary bud grafting" method performs optimally across multiple criteria, making it an ideal grafting combination for increasing Castanopsis truncatula fruit yield and quality.

[0106] Table 7 Effects of different grafting combinations on the yield and quality of Castanopsis sylvestris fruit

[0107]

[0108]

[0109] The cost of grafting Castanopsis truncatum varies significantly under different grafting combinations, as shown in Table 8. According to production experience, the lower the grafting survival rate, the greater the number of scions required for subsequent grafting, which in turn increases the material and labor costs. Furthermore, the cut grafting method allows for easier alignment of the rootstock and scion wounds. Each person can graft 800-1000 Castanopsis truncatum seedlings per day, resulting in a manual grafting cost of at least 0.20 yuan per plant. One mu of land can support 10,000 Castanopsis truncatum seedlings, with a manual grafting cost of at least 2000 yuan per mu. As shown in Table 8, the cost of grafting using the "joint bud grafting" method is the highest, costing 6100 yuan per mu to graft 10,000 Castanopsis truncatum seedlings. The cost of grafting using the "cut bud grafting" method is the lowest, at 3500 yuan. Therefore, the cut grafting method is the best choice for Castanopsis truncatum seedling cultivation.

[0110] Table 8 The cost of grafting and breeding 10,000 Castanopsis chinensis seedlings per mu in the current year

[0111]

Claims

1. A method for raising seedlings of Castanopsis chinensis by grafting, characterized in that: The following steps are involved: During the beginning of spring, one-year-old seedlings of Castanopsis chinensis are selected as rootstocks, and branches of Castanopsis chinensis with an axillary bud are selected as scions for cut grafting.

2. The method according to claim 1, characterized in that The height of the rootstock is 10-15 cm, the diameter is 1.0-1.6 cm, the length of the scion is 2.8-3.5 cm, and the diameter is 0.4-1.0 cm.

3. The method according to claim 1, characterized in that Cultivation locations include southern China.

4. The method according to claim 3, characterized in that The planting location is Changsha City, Hunan Province.

5. The method according to claim 1, wherein Described cut grafting method grafting comprises the following steps: S1. Cut a small bevel on one side of the cut surface of the rootstock, then cut a long vertical split along the bevel where the phloem meets the cambium, leaving the cut rootstock epidermis intact. S2. Cut a long bevel on the back of the scion bud, and then cut a small bevel on the front of the scion bud; S3, the scion is inserted into the stock cleft, the long bevel is close to the wood of the stock, so that the long bevel of the scion is fitted with the cambium of the stock, and after fitting, the interface of the scion and the stock is wrapped and sealed with a grafting film; S4. After the scion has germinated for a period of time, remove the grafting film on the scion and the rootstock to complete the grafting of the Castanopsis tung tree branches.

6. The method according to claim 1, characterized in that The one-year-old Castanopsis tung oil seedlings need to be healthy, free of pests and diseases, without splitting, and with complete root systems; the scion should be branches with a low degree of lignification.

7. The method according to claim 5, characterized in that The step S1 is specifically as follows: Cut a small 10-20° bevel on one side of the cut surface of the rootstock, and then cut a 1.5-2.5 cm long split vertically along the bevel where the phloem and cambium meet, and retain the cut rootstock epidermis.

8. The method according to claim 5, characterized in that The step S2 is specifically as follows: The back of the scion bud is cut into a long bevel with a height of 1-2 cm at an angle of 60-70 degrees, and then the front of the scion bud is cut into a small bevel with a height of 0.4-0.6 cm at an angle of 40-50 degrees.

9. The method according to claim 5, characterized in that In step S4, the grafting film is dismantled 55-65 days after the scion germinates.

10. The method according to claim 5, characterized in that In step S4, the grafting film is dismantled by lightly scratching the grafting film on the outer side of the rootstock.

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