Method for inducing regeneration seedlings of sweet potato petioles and application of method

Abstract

The invention relates to a method for inducing sweet potato petioles to regenerate seedlings and application thereof, and the method comprises the following steps: selecting sweet potato plants, cutting off the petioles, and retaining the petioles connected with leaves; the petioles connected with the leaves are inserted into a cutting medium, the humidity of the cutting medium is 30%-50%, and cultivation is conducted till the petioles regenerate seedlings. The method has universality and can be universally applied to sweet potato seeds. According to the method, the sweet potato petioles are creatively adopted, totipotency of plant cells is utilized, and the processes that the sweet potato petioles are subjected to callus regeneration, roots are regenerated from the calluses, and buds are regenerated from the roots to grow into complete plants are achieved. The new method except for stem cutting of the sweet potatoes is achieved, and the method has important significance on sweet potato seedling cultivation and open type sweet potato genetic breeding.

Description

Technical Field

[0001] The invention belongs to the technical field of breeding, and relates to a method for inducing sweet potato petioles to regenerate seedlings and application thereof. Background Art

[0002] Sweet potato (Dioscorea esculenta (Lour.) Burkill) is a perennial twining vine plant of the Dioscoreaceae family and the Dioscorea genus. The tuber has many branches at the top, the stem is left-handed, and there are thorns at the base, with T-shaped soft hairs attached; the leaves are heart-shaped, with long T-shaped soft hairs, especially on the back, and the petioles have thorns; the perianth is shallowly cup-shaped, with soft hairs attached; the fruits are less mature and triangular. The flowering period is early summer. Sweet potato is a light-loving short-day crop that likes warmth, is not cold-resistant, and is relatively drought-resistant. It is mainly distributed south of 40° north latitude. The cultivated area is the largest in Asia, followed by Africa, and the Americas are in third place. Sweet potato is a high-yield and highly adaptable food crop, which is closely related to industrial and agricultural production and people's lives. In addition to being the staple food, the tuber is also an important raw material for food processing, starch and alcohol manufacturing industries, and the roots, stems and leaves are excellent feed.

[0003] The general methods of propagation of sweet potatoes are stem cuttings and layering.

[0004] Common methods for breeding new sweet potato varieties include hybrid breeding, mutation breeding, and molecular breeding. Chromosome doubling breeding cannot be used because sweet potatoes have 90 chromosomes. In terms of hybrid breeding, sweet potatoes are self-incompatible and hexaploid, which leads to serious separation of traits in their hybrid offspring and large differences. The later seed screening, trait comparison, field planting and other factors seriously delay the new variety selection process, and excellent parents are required, which has gradually decreased. Mutagenesis breeding attempts to use radiation or highly toxic reagents, which are more harmful than beneficial, and due to the ploidy of sweet potato chromosomes, even gene mutations are difficult to have phenotypes, resulting in a very small proportion in sweet potato breeding. Molecular breeding is the mainstream breeding method in modern times, but because it requires picking axillary buds to induce callus, selecting callus to obtain embryonic callus, and then co-culturing with Pseudomonas aeruginosa, screening regeneration and other steps, and all need to be cultivated under sterile conditions, resulting in its high scientific and technological difficulty. Only a few laboratories can achieve it, which seriously limits the breeding and selection process of new sweet potato varieties.

[0005] In summary, it is of great significance to develop a method for inducing regeneration of sweet potato petioles into seedlings. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a method for inducing regenerated seedlings from sweet potato petioles and application thereof.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for inducing sweet potato petioles to regenerate into seedlings, the method comprising the following steps:

[0009] (1) Select sweet potato plants, cut them at the petiole, and keep the petiole with leaves attached;

[0010] (2) Insert the petiole with leaves attached into a cutting medium with a humidity of 30-50% and cultivate until the petiole regenerates into a seedling.

[0011] Among them, the humidity of the cutting medium is 30-50%, and you can choose 30%, 32%, 34%, 36%, 38%, 40%, 42%, 44%, 46%, 48%, 50%, etc. Other specific point values ​​within this numerical range can be selected, and I will not go into details here.

[0012] The method for inducing the regeneration of sweet potato petioles into seedlings creatively adopts sweet potato petioles and utilizes the omnipotence of plant cells to realize the process of sweet potato petiole regeneration callus, callus regeneration root, root regeneration bud and then growing into a complete plant. The new method for realizing sweet potato stem segment cutting (bud elongation into seedling) is of great significance for sweet potato seedling cultivation and open sweet potato genetic breeding.

[0013] The method of inducing sweet potato petioles to regenerate seedlings involved in the present invention is universal and can be widely applied to sweet potato varieties, such as the starchy variety Xushu 22, the fresh-eating variety Yanshu 25, Taizhong 6, the leafy variety Fucaishu 22 and other conventional sweet potato varieties, with no significant difference in effect.

[0014] The present invention creatively discovered that when the humidity of the cutting medium is 30-50%, the petioles and leaves of sweet potatoes can absorb water and other substances through the stomata and other parts, maintain the normal life activity of the cells, and achieve the induced regeneration of sweet potato petioles. When the humidity is too high, the soil oxygen content is insufficient, and the stem segments are prone to rot. When the humidity is too low, the soil is prone to dryness, and the leaves and petioles dry up and die.

[0015] Preferably, in step (1), petioles can be induced to regenerate into seedlings with or without leaf pruning.

[0016] The present invention finds that it is better to keep all the sweet potato leaves without pruning than to prune the retained part, because the retained part is easy to mold, rot and die in a high humidity environment due to wounds on the leaves.

[0017] Preferably, the petiole retention length in step (1) is 2-10 cm (for example, 2 cm, 3 cm, 4 cm, 5 cm, 6 cm, 7 cm, 8 cm, 9 cm, 10 cm, etc.), preferably 3-7 cm. Other specific point values ​​within this numerical range can be selected and will not be described one by one here.

[0018] Preferably, the cutting medium comprises soil containing perlite, and the volume of the perlite accounts for 25-77% (e.g., 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 77%, etc.) of the total volume of the soil. This is only one of the exemplary methods for maintaining the humidity of the cutting medium at 30-50%. It can be foreseen that the humidity of the cutting medium can be maintained at 30-50% by any prior art method in the art, and the same technical effect can be obtained.

[0019] The present invention creatively finds that when the volume proportion of perlite in the soil is 25-77%, the humidity of the cutting medium can be maintained at 30-50%. When the proportion of perlite is too high, the water absorption of the cutting medium decreases, causing the soil to be easily over-dried, and the leaves and petioles to dry up and die; when the proportion of perlite is too low, the soil oxygen content is insufficient, and the stem segments are prone to rot. When the proportion of perlite is within the range defined by the present invention, the soil humidity can be maintained at 30-50%, so that the petioles and leaves of sweet potatoes can absorb water and other substances through the stomata and other parts, maintain the normal life activity of the cells, and prevent the petioles and leaves from drying up or rotting and dying.

[0020] Preferably, the cutting matrix includes perlite and vermiculite.

[0021] The present invention creatively finds that when perlite and vermiculite are used as cutting substrates, perlite can improve soil permeability, and vermiculite can improve soil moisture content and permeability, which is beneficial to inducing regeneration of sweet potato petioles.

[0022] Preferably, after the petiole is inserted into the cutting medium in step (2), the height of the leaves exposed to the soil is kept at 1-5 cm, for example 1 cm, 1.5 cm, 2 cm, 2.5 cm, 3 cm, 3.5 cm, 4 cm, 4.5 cm, 5 cm, etc., so that the leaves do not touch or touch the soil less. Other specific point values ​​within this numerical range can be selected and will not be described one by one here.

[0023] Preferably, after the petiole is inserted into the cutting medium in step (2), the method further comprises spraying hormones on the sweet potato leaves.

[0024] Preferably, the hormone comprises naphthylacetic acid (NAA) and / or indoleacetic acid (IAA).

[0025] The present invention creatively finds that spraying naphthylacetic acid and / or indoleacetic acid on sweet potato leaves can more effectively promote the regeneration of petioles into seedlings compared with other hormones. When naphthylacetic acid and indoleacetic acid are sprayed in combination, the two play a synergistic role in promoting the regeneration of sweet potato petioles into seedlings.

[0026] Preferably, when the hormone is naphthylacetic acid, the concentration of the hormone is 0.1-3 mg / L (for example, 0.1 mg / L, 0.5 mg / L, 0.7 mg / L, 1 mg / L, 1.5 mg / L, 2 mg / L, 2.3 mg / L, 2.5 mg / L, 2.7 mg / L, 3 mg / L, etc.), preferably 2-3 mg / L. Other specific point values ​​within this numerical range can be selected, and they will not be described one by one here.

[0027] Preferably, when the hormone is indoleacetic acid, the concentration of the hormone is 0.1-3 mg / L (for example, 0.1 mg / L, 0.5 mg / L, 0.7 mg / L, 1 mg / L, 1.3 mg / L, 1.5 mg / L, 1.7 mg / L, 2 mg / L, 2.5 mg / L, 3 mg / L, etc.), preferably 1-2 mg / L. Other specific point values ​​within this numerical range can be selected, and they will not be described one by one here.

[0028] Preferably, when the hormone is a combination of naphthylacetic acid and indoleacetic acid, naphthylacetic acid and indoleacetic acid are mixed for use, and the concentrations of naphthylacetic acid and indoleacetic acid in the mixed solution are independently 0.5-2 mg / L, for example 0.5 mg / L, 0.7 mg / L, 1 mg / L, 1.3 mg / L, 1.5 mg / L, 1.7 mg / L, 2 mg / L, etc. Other specific point values ​​within this numerical range can be selected, and they will not be described one by one here.

[0029] Preferably, the spraying amount of the hormone is 0.5-1.5 mL / plant, for example, 0.5 mL / plant, 0.6 mL / plant, 0.7 mL / plant, 0.8 mL / plant, 0.9 mL / plant, 1 mL / plant, 1.1 mL / plant, 1.2 mL / plant, 1.3 mL / plant, 1.4 mL / plant, and 1.5 mL / plant. Other specific point values ​​within this numerical range can be selected, and they will not be described one by one here.

[0030] Preferably, the spraying frequency of the hormone in step (3) is once every 4-6 days, for example, 4 days, 5 days, 6 days, etc. Other specific point values ​​within this numerical range can be selected and will not be described in detail here.

[0031] Preferably, the method for inducing sweet potato petioles to regenerate seedlings comprises the following steps:

[0032] (1) Select sweet potato plants, cut them at the petiole, and keep the petiole with leaves attached;

[0033] (2) Insert the petiole with the leaves attached into the cutting medium. The humidity of the cutting medium is 30-50%, and the height of the leaves exposed above the soil is 1-5 cm.

[0034] (3) Spray the leaves with hormones every 4-6 days, 0.5-1.5 mL each time, and continue spraying until new buds grow and seedlings emerge.

[0035] In a second aspect, the present invention provides the use of the method for inducing sweet potato petioles to regenerate into seedlings according to the first aspect in sweet potato propagation, especially when seedlings are scarce.

[0036] In a third aspect, the present invention provides application of the method for inducing sweet potato petioles to regenerate into seedlings according to the first aspect in breeding new sweet potato varieties.

[0037] Combining this method with Bacillus infection and conducting experimental operations in a conventional environment can realize molecular breeding of sweet potatoes in a conventional environment without going through callus induction, screening, and regeneration processes, and screen and cultivate new varieties, becoming a new universal sweet potato breeding method.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The method for inducing the regeneration of sweet potato petioles into seedlings involved in the present invention is universal and can be generally applied to sweet potato species. Sweet potato petioles are creatively adopted, and the omnipotence of plant cells is utilized to realize the process of sweet potato petiole regeneration callus, callus regeneration root, root regeneration bud and then growing into a complete plant. The new method for realizing sweet potato stem segment cutting (bud elongation into seedling) is of great significance for sweet potato seedling cultivation and open sweet potato genetic breeding. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a photograph of sweet potato petiole cuttings in soil in Example 1;

[0041] Figure 2 is a photograph of the regeneration of sweet potato petioles into seedlings in Example 1;

[0042] Figure 3 is a photo of the sweet potato axillary bud regeneration seedlings of comparative example 3;

[0043] Figure 4 These are photos of the regeneration of sweet potato petioles into seedlings according to Examples 39-44, wherein 1-6 are photos of the sweet potato petioles of Examples 44, 40, 41, 43, 42 and 39 at the 70th day of cultivation, respectively. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0045] In the following examples, unless otherwise specified, the reagents and consumables used were purchased from conventional reagent manufacturers in the field; unless otherwise specified, the experimental methods and technical means used were conventional methods and means in the field.

[0046] Example 1

[0047] This embodiment provides a method for inducing sweet potato petioles to regenerate seedlings, comprising the following steps:

[0048] (1) Select Yanshu 25 plants, cut the petiole 5 cm away from the leaves, and do not treat the leaves;

[0049] (2) Insert the cut leaf petiole tissue into the mixed cutting medium (perlite and vermiculite volume ratio = 1:1), and maintain the soil moisture at 35-45% through the soil's automatic water absorption capacity. Leave 1.5 cm of the petiole outside the soil and do not touch the soil. Figure 1 As shown;

[0050] (3) Spray the leaves with hormones every 5 days. The concentration of NAA in the hormone solution used is 2 mg / L, and the concentration of IAA is 1 mg / L. The spraying volume is 1 mL. Spray continuously until new buds grow and become seedlings, and three new leaves are grown. Record the time when spraying is stopped.

[0051] Example 2

[0052] This embodiment provides a method for inducing sweet potato petioles to regenerate seedlings, comprising the following steps:

[0053] (1) Select Yanshu 25 plants, cut the petiole 3 cm away from the leaves, and do not treat the leaves;

[0054] (2) Insert the cut tissue containing the leaf blade and petiole into the mixed cutting medium (perlite and vermiculite volume ratio = 1:0.5), and maintain the soil moisture at 30-40% through the automatic water absorption capacity of the soil, leaving 1 cm of the petiole outside the soil, and the leaf blade does not touch the soil;

[0055] (3) Spray the leaves with hormones every 4 days. The concentration of NAA in the hormone solution used is 2 mg / L, and the concentration of IAA is 1 mg / L. The spraying volume is 0.8 mL. Spray continuously until new buds grow and become seedlings, and three new leaves are grown. Record the time when spraying is stopped.

[0056] Example 3

[0057] This embodiment provides a method for inducing sweet potato petioles to regenerate seedlings, comprising the following steps:

[0058] (1) Select Yanshu 25 plants, cut the petiole 7 cm away from the leaves, and do not treat the leaves;

[0059] (2) Insert the cut tissue containing the leaf petiole into the mixed cutting medium (perlite and vermiculite volume ratio = 1:2), and maintain the soil moisture at 40-50% through the soil's automatic water absorption capacity. Leave the petiole 2 cm outside the soil and the leaf blade does not touch the soil;

[0060] (3) Spray the leaves with hormones every 6 days. The concentration of NAA in the hormone solution used is 2 mg / L, and the concentration of IAA is 1 mg / L. Spray continuously until new buds grow and become seedlings, and three new leaves are grown. Record the time when spraying is stopped.

[0061] Embodiment 4-13

[0062] This embodiment provides ten methods for inducing sweet potato petioles to regenerate seedlings, which differ from Example 1 only in that the hormones sprayed in step (3) are replaced by 0.1 mg / L, 0.2 mg / L, 0.4 mg / L, 0.6 mg / L, 0.8 mg / L, 1 mg / L, 1.5 mg / L, 2 mg / L, 2.5 mg / L, and 3 mg / L NAA solutions, respectively, and the spraying amount is 1 mL / plant, and other conditions remain unchanged.

[0063] Examples 14-23

[0064] This embodiment provides ten methods for inducing sweet potato petioles to regenerate seedlings, which differ from Example 1 only in that the hormones sprayed in step (3) are replaced by 0.1 mg / L, 0.2 mg / L, 0.4 mg / L, 0.6 mg / L, 0.8 mg / L, 1 mg / L, 1.5 mg / L, 2 mg / L, 2.5 mg / L, and 3 mg / L IAA solutions, respectively, and the spraying amount is 1 mL / plant, and other conditions remain unchanged.

[0065] Examples 24-31

[0066] This embodiment provides eight methods for inducing sweet potato petioles to regenerate into seedlings, which differ from Example 1 only in that the hormones sprayed in step (3) are replaced by mixed hormone solutions of NAA0.5mg / L+IAA0.5mg / L, NAA 0.5mg / L+IAA1mg / L, NAA0.5mg / L+IAA2mg / L, NAA1mg / L+IAA0.5mg / L, NAA 1mg / L+IAA1mg / L, NAA1mg / L+IAA2mg / L, NAA2mg / L+IAA0.5mg / L, and NAA 2mg / L+IAA 2mg / L, respectively, and the spraying amount is 1 mL / plant, and other conditions remain unchanged.

[0067] Embodiment 32

[0068] This embodiment provides a method for inducing sweet potato petioles to regenerate into seedlings, which differs from Embodiment 1 only in that in step (3), hormones are replaced with an equal volume of water, and other conditions remain unchanged.

[0069] Embodiment 33

[0070] This embodiment provides a method for inducing sweet potato petioles to regenerate into seedlings, which differs from Embodiment 1 only in that in step (2), 0.5 cm of the petioles are left outside the soil, and other conditions remain unchanged.

[0071] Embodiment 34

[0072] This embodiment provides a method for inducing sweet potato petioles to regenerate into seedlings, which differs from Embodiment 1 only in that in step (2), the petioles are left 6 cm outside the soil, and other conditions remain unchanged.

[0073] Embodiment 35

[0074] This embodiment provides a method for inducing sweet potato petioles to regenerate into seedlings, which differs from Embodiment 1 only in that step (1) the sweet potato leaves are cut perpendicular to the petiole in the middle of the leaf, leaving 1 / 2, and step (2) the petiole is left 1.5 cm outside the soil, and other conditions remain unchanged.

[0075] Embodiment 36

[0076] This embodiment provides a method for inducing sweet potato petioles to regenerate into seedlings, which differs from Embodiment 1 only in that step (1) the sweet potato leaves are cut perpendicular to the petiole in the middle of the leaf, leaving 1 / 2, and step (2) the petiole is left 2.5 cm outside the soil, and other conditions remain unchanged.

[0077] Embodiment 37

[0078] This embodiment provides a method for inducing sweet potato petioles to regenerate seedlings, which differs from Embodiment 1 only in that step (1) the sweet potato leaves are cut perpendicular to the petiole in the middle of the leaf, leaving 1 / 2, and step (2) the petiole is left 0.5 cm outside the soil, and other conditions remain unchanged.

[0079] Embodiment 38

[0080] This embodiment provides a method for inducing sweet potato petioles to regenerate seedlings, which differs from Embodiment 1 only in that step (1) the sweet potato leaves are cut perpendicular to the petiole in the middle of the leaf, leaving 1 / 2, and step (2) the petiole is left 6 cm outside the soil, and other conditions remain unchanged.

[0081] Embodiment 39

[0082] This embodiment provides a method for inducing sweet potato petioles to regenerate seedlings, comprising the following steps:

[0083] (1) Select the sweet potato plant of Taizhong No. 6, cut the petiole 5 cm away from the leaf, and do not treat the leaf;

[0084] (2) Insert the cut leaf petiole tissue into the mixed cutting medium (perlite and vermiculite volume ratio = 1:1), and maintain the soil moisture at 35-45% through the soil's automatic water absorption capacity. Leave 1.5 cm of the petiole outside the soil and the leaf does not touch the soil;

[0085] (3) Spray the leaves with hormones every 5 days. The concentration of NAA in the hormone solution used is 2 mg / L, and the concentration of IAA is 1 mg / L. The spraying volume is 1 mL. Spraying is continuous for 70 days.

[0086] Examples 40-43

[0087] This embodiment provides four methods for inducing sweet potato petioles to regenerate into seedlings. The difference between this method and Example 39 is that the hormone sprayed in step (3) is replaced with the hormone in the table, the spraying amount is 1 mL, and other conditions remain unchanged.

[0088] Group hormone Embodiment 40 NAA 2mg / L Embodiment 41 NAA 1mg / L Embodiment 42 IAA 1.5mg / L Comparative Example 43 water

[0089] Embodiment 44

[0090] The present embodiment provides a method for inducing sweet potato petioles to regenerate into seedlings, which differs from Example 39 only in that step (1) the leaf blade is cut in the middle of the leaf blade perpendicular to the petiole direction, leaving 1 / 2, and step (3) hormones are not sprayed, but an equal volume of water is sprayed, and other conditions remain unchanged.

[0091] Comparative Example 1

[0092] This comparative example provides a method for inducing sweet potato petioles to regenerate seedlings, which differs from Example 1 only in that in step (2), the cutting medium is replaced with perlite and vermiculite in a volume ratio of 1:0.1, the soil maintains soil moisture at 5-15% through its automatic water absorption capacity, and other conditions remain unchanged.

[0093] Comparative Example 2

[0094] This comparative example provides a method for inducing sweet potato petioles to regenerate seedlings, which differs from Example 1 only in that in step (2), the cutting medium is replaced with perlite and vermiculite in a volume ratio of 1:5, the soil maintains soil moisture at 70-80% through its automatic water absorption capacity, and other conditions remain unchanged.

[0095] Comparative Example 3

[0096] The present comparative example provides a method for regenerating sweet potato axillary buds into seedlings (a method for regenerating sweet potato stem segments by cuttings), which differs from Example 1 in that, in step (1), a Yanshu 25 plant is selected, and the petiole is cut near the connection between the petiole and the stem segment so that the cut tissue is connected to the stem segment with the axillary buds, and the leaves are not processed, and other conditions remain unchanged.

[0097] Test Example 1

[0098] This test example observed the growth status of the sweet potato petioles induced to regenerate seedlings in Examples 1-38 and Comparative Examples 1-3.

[0099] The growth conditions of Examples 1-3 were observed. The calli of Examples 1-3 appeared on the 2nd day, the 2nd day, and the 3rd day, respectively. The roots appeared on the 5th day, the 6th day, and the 6th day, respectively. New shoots grew on the 45th day, the 47th day, and the 46th day, respectively. The induced regeneration of potato petioles was successfully achieved.

[0100] The growth conditions of Examples 4-13 were observed. When NAA was sprayed on the leaves alone, green or white calli appeared at the base of the petiole on the 3rd to 5th day, and white roots grew on the calli on the 8th to 15th day. As the concentration increased, the time required first decreased and then leveled off. When the concentration was 2.5 mg / L and 3 mg / L, calli appeared on the 3rd day and roots appeared on the 8th day.

[0101] The growth conditions of Examples 14-23 were observed. When IAA was sprayed on the leaves alone, green or white calli appeared at the base of the petiole on the 2nd to 4th day, and white roots grew on the calli on the 5th to 10th day. As the concentration increased, the time required first decreased and then increased. When the concentration was 1.5 mg / L, calli appeared on the 2nd day and roots appeared on the 5th day.

[0102] The growth conditions of Example 1 and Examples 24-31 were observed. When the mixed solution of NAA and IAA was sprayed on the leaves, green or white callus appeared at the base of the petiole on the 2nd to 8th day, and white roots grew on the callus on the 5th to 10th day. When the concentration of NAA in the mixed solution was 2 mg / L and the concentration of IAA was 1 mg / L, callus appeared on the 2nd day and roots appeared on the 5th day.

[0103] The subsequent continuous spraying of Examples 1, 9-12, 20, and 32 was observed. When Example 1 was sprayed with a combination of NAA 2mg / L+IAA 1mg / L, new sprouts grew on the 45th day, and the spraying was stopped after the 50th day; when Example 20 was sprayed with IAA 1.5mg / L alone, new sprouts grew on the 57th day, and the spraying was stopped after the 60th day; when Examples 9-12 were sprayed with NAA 1mg / L alone, new sprouts grew on the 78th day, when NAA 1.5mg / L was sprayed alone, new sprouts grew on the 87th day, when NAA 2mg / L was sprayed alone, new sprouts grew on the 76th day, and when NAA 2.5mg / L was sprayed alone, new sprouts grew on the 91st day; when Example 32 was not sprayed with hormones, new sprouts grew on the 123rd day. This fully verifies that spraying the hormones NAA and IAA alone or in combination with NAA and IAA on leaves is beneficial to the induction of regeneration of sweet potato petioles, and NAA and IAA play a synergistic role in the induction of regeneration of sweet potato petioles. When NAA and IAA are sprayed in combination, the regeneration of roots and regeneration of seedlings is the fastest, which is better than spraying IAA alone, and significantly better than spraying NAA alone.

[0104] The growth conditions of Examples 33-34 were observed. In Example 33, the petiole of the complete leaf was exposed to the soil less than 1 cm, the leaf was easily in contact with the soil, the contact part was moldy and rotten, and in some cases the whole plant was rotten; in Example 34, when the petiole was exposed to the soil more than 5 cm, the leaf surface was dry, the water absorption was slow, and the leaf was easy to lose water, turn green and die. It can be seen that the better height of the leaf exposed to the soil is 1-5 cm, and the optimal range is 1-2 cm.

[0105] Observe the growth conditions of Examples 35-38. When the sweet potato leaves were cut at 1 / 2, the wounds generally rotted and molded within 3-5 days after cutting, and a few wounds were charred. When the leaf samples were cut, the closer the wounds were to the soil, the easier it was to mold. The farther away, the easier it was for the wounds to lose water and wilt until the entire leaf withered. The height of the leaves above the soil was 1-5 cm, and the optimal range was 1.5-2.5 cm.

[0106] The growth conditions of Comparative Examples 1-2 were observed. In Comparative Example 1, due to the high proportion of perlite and the low proportion of vermiculite, the water absorption of the cutting medium decreased, resulting in the soil being easily over-dried, and the leaves and petioles drying up and dying; in Comparative Example 2, due to the high proportion of vermiculite and the low proportion of perlite, the soil oxygen content was insufficient, and the stem segment rotted.

[0107] The growth conditions of Example 1 and Comparative Example 3 are as follows: Figure 2 and Figure 3 As shown, it can be seen that Example 1 ( Figure 2 ) in the sweet potato petiole regeneration seedlings, the base of the petiole first callus, callus regeneration root, root swelling after the root on the root seedling, seedling and petiole there is a clear distance, while the comparative example 3 ( Figure 3 ) There are regenerated seedlings from axillary buds of sweet potato, and the new seedlings grow from the bud point at the base of the petiole without going through the callus process, which is actually a method of regenerating sweet potato stem segments by cutting. This fully illustrates that the method of inducing regeneration of sweet potato petioles is achieved by retaining 2-10 cm of the petiole of the sweet potato and keeping the cut petiole at an appropriate distance from the stem segment to avoid regeneration of axillary buds into seedlings.

[0108] Test Example 2

[0109] In this test example, the sweet potato petioles involved in Examples 39-44 were photographed on the 70th day of cultivation, and the results obtained were as follows: Figure 4 As shown, 1 is Example 44 (the leaves are halved without spraying hormones), 2 is Example 40 (NAA 2 mg / L, leaves are broken during transportation at the later stage), 3 is Example 41 (NAA 1 mg / L), 4 is Example 43 (the leaves are intact without spraying hormones), 5 is Example 42 (IAA 1.5 mg / L), and 6 is Example 39 (NAA 2 mg / L+IAA 1 mg / L).

[0110] Depend on Figure 4 It can be seen that Example 39 has the best effect, not only growing new plants, but also producing a small potato; Example 42 is second, growing new plants, and the roots are slightly swollen locally; Example 40 is third, no new plants are seen, but the roots are slightly swollen locally; Example 41 is third, no new plants are seen, and no swelling is seen, but there is a tendency to swelling; Examples 43 and 44 have the worst growth, but they still survive, and the main roots are also red and can develop and swell later. This fully verifies that spraying the hormones NAA, IAA alone and NAA and IAA in combination on the leaves are beneficial to the induced regeneration of sweet potato petioles, and NAA and IAA have a synergistic effect on the induced regeneration of sweet potato petioles. The effect of spraying NAA and IAA in combination is better than spraying IAA alone, and is significantly better than spraying NAA alone.

[0111] The applicant declares that the present invention illustrates the technical solution of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0112] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0113] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A method for inducing sweet potato petioles to regenerate seedlings, characterized in that: The method comprises the following steps: (1) Select sweet potato plants, cut them at the petiole, and keep the petiole with leaves attached; (2) Insert the petiole with leaves attached into a cutting medium with a humidity of 30-50% and cultivate until the petiole regenerates into a seedling.

2. The method for inducing sweet potato petioles to regenerate seedlings according to claim 1, characterized in that: The petiole retention length in step (1) is 2-10 cm, preferably 3-7 cm.

3. The method for inducing sweet potato petioles to regenerate seedlings according to claim 1 or 2, characterized in that: The cutting medium in step (2) comprises soil containing perlite, and the volume of the perlite accounts for 25-77% of the total volume of the soil.

4. The method for inducing sweet potato petioles to regenerate seedlings according to any one of claims 1 to 3, characterized in that: In step (2), after the petiole is inserted into the cutting medium, the height of the leaf blade exposed from the soil is kept at 1-5 cm.

5. The method for inducing sweet potato petioles to regenerate seedlings according to any one of claims 1 to 4, characterized in that: After the petiole is inserted into the cutting medium in step (2), the method further comprises spraying hormones on the sweet potato leaves; Preferably, the hormone comprises naphthylacetic acid and / or indoleacetic acid.

6. The method for inducing sweet potato petioles to regenerate seedlings according to claim 5, characterized in that: When the hormone is naphthylacetic acid, the concentration of the hormone is 0.1-3 mg / L, preferably 2-3 mg / L; Preferably, when the hormone is indoleacetic acid, the concentration of the hormone is 0.1-3 mg / L, preferably 1-2 mg / L; Preferably, when the hormone is a combination of naphthylacetic acid and indoleacetic acid, the naphthylacetic acid and indoleacetic acid are mixed before use, and the concentrations of naphthylacetic acid and indoleacetic acid in the mixed solution are independently 0.5-2 mg / L.

7. The method for inducing sweet potato petioles to regenerate seedlings according to claim 5 or 6, characterized in that: The spraying amount of the hormone is 0.5-1.5 mL / plant; Preferably, the hormone is sprayed once every 4-6 days.

8. The method for inducing sweet potato petioles to regenerate seedlings according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: (1) Select sweet potato plants, cut them at the petiole, and keep the petiole with leaves attached; (2) Insert the petiole with the leaves attached into the cutting medium. The humidity of the cutting medium is 30-50%, and the height of the leaves exposed above the soil is 1-5 cm. (3) Spray the leaves with hormones every 4-6 days, 0.5-1.5 mL each time, and continue spraying until new buds grow and seedlings emerge.

9. Use of the method for inducing sweet potato petioles to regenerate seedlings according to any one of claims 1 to 8 in sweet potato propagation.

10. Use of the method for inducing sweet potato petioles to regenerate seedlings according to any one of claims 1 to 8 in breeding new sweet potato varieties.

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