CN111373902A - Method for preparing salt-tolerant zoysia japonica seed pellets - Google Patents

Abstract

The invention discloses a method for preparing salt-tolerant zoysia japonica seed pellets, which belongs to the technical field of pretreatment of seeds, and comprises the following steps of dressing healthy naked seeds with ascorbic acid, wherein the mass ratio of the naked seeds to the ascorbic acid is 1 g: (0.35-1.4) mg, ascorbic acid solution concentration is 2-8 mmol.L^‑1(ii) a And rolling the zoysia japonica seeds in a coating machine at a constant speed, alternately adding the adhesive and the powder, and uniformly stirring to uniformly coat the zoysia japonica seeds with the zoysia japonica seeds to obtain the salt-tolerant zoysia japonica pill-coated seeds. The invention adopts the ascorbic acid to mix the zoysia japonica seeds, which not only can effectively relieve the salt stress effect of the zoysia japonica seeds, but also can improve the vitality of the seeds, has a certain germination accelerating effect and achieves the purposes of promoting the germination, aligning and strengthening the seedlings of the seeds; and the volume and the weight of the zoysia japonica seeds processed by pelleting are increased, the specification is more uniform, and the mechanization and precision seeding are favorably realized.

Description

A kind of preparation method of salt-tolerant Zoysia japonica seeds

technical field

The invention belongs to the technical field of seed pretreatment, and in particular relates to a preparation method of salt-tolerant Zoysia gracilis seeds.

Background technique

Zoysia belongs to the Gramineae subfamily Chloridoideae. Zoysia japonica is a high-quality warm-season turf grass with good stress resistance such as drought resistance and salt tolerance. Alkali and trampling resistance, so it has great use value in landscaping and sports lawns, mainly distributed in Africa, Asia and the coastal areas of Australia. Liaodong Peninsula and Jiaozhou Peninsula are the most distributed areas of natural Zoysia grass grassland in my country, mainly coastal saline-alkali land. Studies have shown that saline-alkali stress will reduce the emergence number and coverage of Zoysia turfgrass turf, and prolong the turf-forming time.

As a major abiotic stress, salt stress can affect most physiological and metabolic processes such as plant seed germination, plant growth rate, and plant photosynthesis. Seeds are significantly affected by salt stress during germination and seedling growth. The imbibition and germination of seeds is determined by the substrate potential of seeds. Under salt stress conditions, the concentration of external ions in seeds is high, and the water potential decreases, which will hinder the ability of plant seeds to respond to water. The absorption of external water, when the concentration exceeds the threshold that the plant can bear, the seeds will not be able to absorb water from the environment, and the germination of seeds will be inhibited or even not germinated. In addition to affecting seed imbibition, salt stress will also cause oxidative stress to seedlings. Salt stress will increase reactive oxygen species (ROS) in plants, such as superoxide and hydrogen peroxide, which will further affect the membrane structure. The damage to the membrane system is the main cause of cell damage. The main production sites of reactive oxygen species under salt stress are on organelles such as mitochondria and chloroplasts. Studies have shown that the increase of ROS will cause damage to proteins, membrane lipids, nucleic acids, etc., thereby hindering the normal metabolic activities of plants and affecting the normal growth and development of plants. . In the studies of maize (Zea mays), rape (Brassica napus), and oats (Avena sativa), it was found that when the salt concentration reached a certain threshold, the germination potential and germination rate of seeds were reduced, and the length of seedlings was shortened, resulting in a decrease in seed vigor.

Seed coating technology refers to a high-tech seed processing technology that uniformly coats the seed surface with a special function of seed coating agent by mechanical or manual methods to promote seed germination and enhance seed stress resistance. It can increase the added value of seeds, promote the commercialization of seeds, the precision of sowing and the standardized management of seed quality. In the early stage of the development of seed coating technology, the main purpose was to increase the volume of seeds and facilitate sowing. Since the 1980s, the research on seed treatment agents such as dry powder seed treatment agent, water slurry powder seed treatment agent, liquid solution seed treatment agent, suspended seed coating agent has been rapidly developed, and its main purpose is to be used for sterilization and insecticide. At present, seed coating technology is very mature in developed countries and is widely used in vegetables, flowers, cotton (Gossypium), wheat (Triticumaestivum), corn and other fields. my country's research on coating technology started relatively late. In the 1980s, the application of forage seed coating to aerial seeding technology achieved great results. However, the development of grass seed coating is relatively slow, mainly focusing on grass species with ecological, ornamental and forage value, such as alfalfa, Astragalusadsurgens, Trifolium repens and other leguminous plants. Grass species such as Poa, Festuca and Elymus. The study found that the coating treatment of Elymus sibiricus seeds with decomposed sheep manure improved the seed vigor and stress resistance of seedlings, and the coating treatment of Buchloedactyloides seeds with desulfurized gypsum and fly ash improved The germination rate of Bison grass seeds in saline soil. With the development and application of exogenous active substances, more and more exogenous active substances are used in seed treatment and seed coating technology to enhance seed vigor and seedling stress resistance, such as plant hormones, osmotic Regulating substances, signal molecules, etc. Studies have shown that pretreatment of cotton seeds with betaine has a positive effect on its germination, seedling growth and yield, can promote the germination of rice seeds under salt stress, and improve the germination rate of alfalfa seeds; Oryza sativa), rapeseed and celery (Apiumgraveolens) seed treatment can effectively improve seed stress resistance and seedling survival rate under stress.

At present, the coating processes of film coating, shell coating and pellet coating in domestic and foreign factories are very mature, but the coating treatment technology for promoting seed germination under different adversity conditions has always been the focus of seed processing research and practice. Salt stress is a major abiotic stress. Under high salt stress, plants will be poisoned by ions, and will also cause secondary stress, which prevents plants from normal growth and development. Seed germination is the premise for the successful establishment of lawns, and it also directly affects the time of lawn formation. Therefore, based on the influence mechanism of plant salt stress, the present invention adopts an antioxidant ascorbic acid (AsA) to carry out seed dressing treatment on the seeds, so that the seeds have an antioxidant effect when they are subjected to the oxidative stress of NaCl during the germination process of water absorption, Then the seeds are coated with pills, in order to improve the resistance of seeds to salt stress, help to improve the success rate of turfgrass planting under salt stress, and improve the utilization efficiency of saline land.

SUMMARY OF THE INVENTION

In view of the above-mentioned problems, the present invention proposes a kind of preparation method of salt-tolerant Zoysia japonica seeds, the steps are as follows:

1) Zoysia japonica seeds are dressed with ascorbic acid solution, the naked seeds and ascorbic acid mass ratio are 1g: (0.35-1.4) mg, and the ascorbic acid solution concentration is 2-8mmol·L ⁻¹ ;

2) Roll the zoysia seeds in step 1) at a uniform speed in the coating machine, alternately add the adhesive and the powder, stir evenly, and evenly wrap them on the zoysia seeds to obtain the salt-tolerant zoysia seeds .

The seed dressing time is more than 60s, and the size of the pelleted seeds is 0.7-1.2 mm.

The pellet coating composition includes: powder and adhesive.

The mass ratio of the powder to the seeds is 1:0.5-1.5; the volume-to-mass ratio (mL/g) of the adhesive and the seeds is 1:0.2-1.25.

The powder includes talc and/or bentonite; the adhesive is a hydroxymethyl cellulose solution.

The mass ratio of bentonite and talc is 1:0.8-2, and the mass fraction of the hydroxymethyl cellulose solution is 1-2%.

Before the step 1), the naked seeds of Zoysia japonica are soaked in a 10%-30% sodium hydroxide aqueous solution for 10-30min.

After the step 2), the salt-tolerant Zoysia gracilis seeds are dried at 30-35° C. for 0.5-1 h.

In the described step 2), the sticking agent and the powder are added in equal parts for multiple times, the adding times of the sticking agent is ≥ 20 times, and the adding times of the powder is ≥ 20 times.

The beneficial effects of the present invention are:

1. the technology of the present invention adopts a small amount of ascorbic acid seed dressing, just can make full use of its antioxidant capacity, greatly improves the ability of Zoysia japonica seed to resist NaCl stress;

2. The present invention uses ascorbic acid to dress Zoysia seeds, which can not only effectively alleviate the salt stress effect of Zoysia seeds, but also improve the vigor of the seeds, has a certain germination effect, and achieves the promotion of seed germination, seedling growth, and strong growth. the purpose of the seedling;

3. the processing method of zoysia seed pill coat of the present invention is simple, easy to operate and program standardization; And the zoysia japonica seed volume and weight that the zoysia seed coat is processed increases, and specification is more unified, is conducive to realizing mechanization and precision sowing.

Detailed ways

Below in conjunction with specific embodiment, the present invention is described in further detail:

Example 1

1) Zoysia seed selection

Zoysia japonica seeds with clarity > 98% and germination rate > 85% were selected, soaked with 10% NaOH for 30 min to treat Zoysia japonica seeds, and dried naturally to relieve seed dormancy.

2) Ascorbic acid seed dressing

Weighing 5g of Zoysia seeds after natural drying in step 1) in No. 3 ziplock bags, with ascorbic acid (abbreviation: AsA) concentration is the ascorbic acid of 2mmol L ^-1 to carry out seed dressing treatment, control Zoysia naked seeds The mass ratio of ascorbic acid to ascorbic acid is 1g: 0.35mg, shake well for 60s, so that the active ingredients are wrapped on the surface of the seeds to form a coating layer and give full play to the role of antioxidants; pour out and dry, after the seeds are dressed, the water evaporates quickly and the coating is uniform for good.

3) Seed coating:

Nucleation stage: Pour the finished seeds into the coating machine, adjust the rotation speed to 450rpm to 550rpm, and make the seeds roll along the groove at a constant speed to ensure that the seeds have a certain falling height when they hit the baffle, and fix the atomizing disc on the In the card slot, fix the atomizing disc in the card slot, add 0.2-0.5mL of 1wt% CMC aqueous solution to the atomizing plate, spraying is completed within 1-1.5min, the surface of the seeds is moist and the seeds do not stick together (the seeds are not sticking together at this time). When hitting the baffle, the drop height decreases).

Preparing powder: 2.5g bentonite and 2.5g talc are mixed evenly, and divided into 10 parts; adhesive: 2-3ml of 1.5% CMC aqueous solution, divided into 10 parts.

Add one part of the powder, stir for 2min, the seed rolls at a constant speed at this moment (return to the original falling height when touching the baffle plate), continue to add a portion of 1.5% CMC aqueous solution in the atomizing disc to ensure that the adhesive is sprayed out in 2min. Repeat the above operation, add powder and binder alternately, until formula powder and binder are added.

Note that the adhesive and powder should be added alternately during the coating process. The binder should be added first. On the premise of ensuring that the seeds do not stick together, add an appropriate amount of powder when the surface of the seeds is wet, so that the powder is evenly wrapped on the surface of the seeds. .

Increase the spheronization period: after the first stage powder is added, adjust the rotation speed of the coating machine to 550rpm, and make the seeds rotate for 1-2min;

Preparing powder: 4g bentonite and 6g talc are mixed evenly, and divided into 10 parts; Preparing adhesive: 4-5ml of 1.5wt% CMC aqueous solution, divided into 10 parts;

Add a portion of powder and stir for 0.5-1.5min. At this time, the seeds roll at a constant speed (return to the original falling height when they hit the baffle), and continue to add a portion of 1.5wt% CMC aqueous solution for 0.5-1.5min. Repeat the above operation, add the binder and powder alternately, until the formula powder and binder are added. The powder and the adhesive are added alternately, and the adhesive and the powder should be added alternately about 20 times.

Film-forming period: After the second stage, adjust the speed of the coating machine to 600rpm, and make the seeds rotate for 2-3min;

Preparing powder: 2g talcum powder, divided into 5 parts; Preparing adhesive: 1-2ml 1.5% CMC aqueous solution, divided into 5 parts; Then add adhesive and powder alternately according to the formula, alternately carry out about 5 times, each time Stir at intervals of 10 s.

After all the formula powders are added, take out the zoysia zoysiae pelleted seeds, pass through a 24-16 mesh sieve, and screen to obtain pellets with a size of 0.7-1.2 mm. The seeds of Zoysia officinalis were dried in an oven for 0.5 h at a drying temperature of 35°C, and dried for later use.

Number naked seeds as CK1.

The pill-coated seeds prepared by the methods of step 1) and step 3) of Example 1 without seed dressing treatment are numbered CK2.

Zoysia japonica seeds obtained by dressing the seeds with 2mM AsA solution were numbered as PZA2.

Preparation mass fraction is that the NaCl solution of 1wt% concentration is Zoysia salt stress concentration, the above-mentioned Zoysia japonica seeds are carried out on paper germination test, and infiltration filter paper is carried out seed stress treatment during the germination test, with reference to pasture seed inspection regulations ( GB/T 2930.10-2017) Zoysia seed germination standard Carry out the germination test, select 100 seeds, put them into a 11.5×11.5cm2 petri dish with ³ layers of filter paper, and set 4 repetitions. The petri dishes were placed in a lighted incubator (GXZ-380B-LED) and incubated at 20/35°C with variable temperature, light for 8 h and dark for 16 h. The first count was the 10th day, and the last count was the 28th day. Seed germination was counted every 24 hours, with the radicle breaking through the seed coat by 2 mm as the standard. After germination on the 28th day, the number of normal seedlings, the number of abnormal seedlings, the number of fresh ungerminated seeds and the number of dead seeds were counted. 10 normal seedlings were randomly taken out to measure the seedling length and root length, and weighed. The germination potential, germination rate, shoot length, root length, shoot weight, and average germination time were calculated, and the results are shown in Table 1.

Calculated according to the following formula:

Germination potential (%) = the number of normal seedlings counted for the first time/the number of tested seeds;

Germination rate (%) = the number of all normal seedlings at the end of germination / the number of tested seeds;

Average germination time=∑nt/∑n, n is the number of newly germinated seeds at time t, and t is the germination time.

1) Determination of Pelletized seed diameter

Take 100 pellet seeds at random, measure the diameter of the pellet seeds with a vernier caliper, calculate the average value, the unit is mm, and the accuracy is 0.01 mm.

2) Splitting decomposition percentage

Take 100 pill-coated seeds at random, place the seeds on moist filter paper, count the cracked grain number after 5min, calculate the percentage that cracked grain number accounts for the test pill-coated seed total grain number, and set 3 repetitions.

3) Single seed percentage

Randomly take 100 pelleted seeds, count the number of single-seed seeds (there is only one naked seed in each pelleted seed), and calculate the percentage of single-seed seeds in the tested pellets. The single-seed rate is required to be ≥98.0%.

4) Thousand seed weight

Take 100 pill-coated seeds at random, weigh their weight, repeat eight times, calculate the average weight of 100 seeds, and the weight of 1000 seeds is 10 times.

5) Multiple of pelletization

The pilling multiple refers to the thousand-grain weight of pill-coated seeds: the thousand-grain weight of naked seeds.

Under the same treatment conditions, compared with CK1 and CK2, the germination rate of the ball-coated seeds after seed dressing prepared by the present invention is increased by 12% and 14% respectively; the seedling length is increased by 0.2cm and 0.1cm respectively; the root length is increased by 2.1 cm and 0.2cm; the seedling weight increased by 0.023g and 0.014g, respectively.

The results showed that, under the stress of NaCl salt solution, Zoysia serrata seeds treated with AsA seed dressing showed a very small increase in the average germination time compared to bare seeds or undressed pelleted seeds. The germination rate was significantly improved, indicating that the use of AsA seed dressing could significantly improve the salt stress tolerance of Zoysia japonica seeds, and the parameters such as seedling length, heel length, and seedling weight were significantly better than those of bare seeds or without seed dressing. Seeds, it is further demonstrated that the use of AsA can make the seeds play an antioxidant role when they are subjected to NaCl oxidative stress during the germination process of water absorption, and at the same time promote the growth of seed roots and seedlings.

Example 2

Taking Qingdao Zoysia as material, the AsA solution with concentration of 1, 2, 4, 8mM in step 2) of Example 1 is respectively used to coat the seeds after seed dressing, and the mass ratio of Zoysia naked seed and ascorbic acid is controlled. 1g: 0.7mg. The pelleted seeds with different treatments were evaluated for their salt tolerance, and the treatment numbers of Zoysia japonica seeds were: PZA1, PZA2, PZA4, PZA8.

The NaCl solutions with mass fractions of 1wt% and 1.25wt% were prepared as the concentration of Zoysia salt stress. The above Zoysia seeds were subjected to a paper germination test, and the filter paper was soaked in the germination test to perform seed stress treatment. Refer to forage grass Seed Inspection Regulations (GB/T 2930.10-2017) The germination test of Zoysia seed germination is carried out. The germination of the seeds is counted every 24 hours, and the radicle breaks through the seed coat by 2mm as the standard. After the germination is completed on the 28th day, the number of normal seedlings is counted , the number of abnormal seedlings, the number of fresh ungerminated seeds and the number of dead seeds, and randomly take out 10 normal seedlings from the petri dish to measure the seedling length and root length, and weigh them. The germination potential, germination rate, shoot length, root length, shoot weight, and average germination time were calculated, and the results are shown in Table 1.

The results showed that, under the same conditions, under the stress of salt solution with NaCl concentration of 1.00wt% and 1.25wt%, after AsA seed dressing treatment, Zoysia serrata seeds were better than bare seeds or without seed dressing. , although the average germination time increased slightly, the seed germination rate was significantly improved, indicating that the use of AsA seed dressing can significantly improve the salt stress tolerance of Zoysia japonica seeds, and parameters such as seedling length, heel length, and seedling weight can be improved. Both were significantly better than naked seeds or non-dressed ball-coated seeds. It was further demonstrated that the use of AsA to make seeds play an antioxidant role when they were subjected to NaCl oxidative stress during the germination process of seeds, while promoting the growth of seed roots and seedlings.

As can be seen from the contents of Table 1, using the AsA seed dressing with a concentration of 2-8mM, the mass ratio of control Zoysia bare seed and ascorbic acid is 1g: 1.4mg, and the obtained pill-coated seeds have salt stress tolerance (expressed by NaCl mass fraction). ) is: 0<salt stress tolerance≤1.25wt%.

Table 1 Effects of salt solution stress with different contents of AsA on germination of Zoysia japonica seeds

Note: Under the same NaCl concentration stress, different lowercase letters represent significant differences among different AsA treatments (P<0.05).

Claims (9)

1. A method for preparing salt-tolerant zoysia japonica seed pellets is characterized by comprising the following steps:

1) seed dressing is carried out on zoysia japonica seeds by using an ascorbic acid solution, wherein the mass ratio of the naked seeds to the ascorbic acid is 1 g: (0.35-1.4) mg, ascorbic acid solution concentration is 2-8 mmol.L^-1；

2) Rolling the zoysia japonica seeds obtained in the step 1) in a coating machine at a constant speed, alternately adding the adhesive and the powder, and uniformly stirring to uniformly coat the zoysia japonica seeds with the zoysia japonica seeds to obtain the salt-tolerant zoysia japonica pill-coated seeds.

2. The method of claim 1, wherein the seed dressing time is over 60s and the size of the pelleted seed is 0.7-1.2 mm.

3. The method of claim 1, wherein the pill coating composition comprises: powders and adhesives.

4. The method as claimed in claim 3, wherein the mass ratio of the powder to the seeds is 1: 0.5-1.5; the volume-to-mass ratio (mL/g) of the adhesive to the seeds is 1: 0.2 to 1.25.

5. The method of claim 3, wherein the powder comprises talc and/or bentonite; the adhesive is hydroxymethyl cellulose solution.

6. The method according to claim 5, wherein the mass ratio of the bentonite to the talcum powder is 1: 0.8 to 2 percent, and the mass fraction of the hydroxymethyl cellulose solution is 1 to 2 percent.

7. The method as claimed in claim 1, wherein before the step 1), the seeds of the grass of Japanese lawngrass are soaked in 10% -30% sodium hydroxide aqueous solution for 10-30 min.

8. The method as claimed in claim 1, wherein after the step 2), the salt-tolerant zoysia japonica pellet seed is dried at 30-35 ℃ for 0.5-1 h.

9. The method as claimed in claim 1, wherein the adhesive and the powder in step 2) are added in a plurality of times, wherein the adhesive is added more than or equal to 20 times, and the powder is added more than or equal to 20 times.