CN104541663B - A kind of method for treating seeds that improves direct-sowing dry paddy rice accumulated water and coerce lower germination percentage - Google Patents

Abstract

The invention discloses a seed treatment method for improving the germination rate of dry direct-seeding rice under waterlogging stress. The steps are: A. Preparation of initiators: water, calcium chloride, hydrogen peroxide, sodium selenate, and salicylic acid; B. Seed initiator soaking treatment: soak the rice seeds in the initiator, soak, and update the initiator once in the 10-14 hour; C. Rice seed back to dry: soak the rice seed in the initiator Take it out, dry it in a blast drying oven, and store the dried rice seeds in a drying oven; D. Sowing and germination: carry out in a plastic cup with a depth of 15-17 cm and a volume of 680 ml, and inject water into the cup to simulate waterlogging stress; E. Sampling measurement: Count the number of germinations every day from the first day after sowing, and take samples on the eighth day to determine the final germination rate and seedling quality. The method is easy to operate and easy to operate, solves the problem of rotten seeds and buds caused by waterlogging stress after sowing dry-directed rice, and improves the germination rate and emergence uniformity of dry-directed rice.

Description

A seed treatment method for improving germination rate of dry-seeded rice under waterlogging stress

technical field

The invention belongs to the technical field of crop cultivation, and more specifically relates to a seed treatment method for improving the germination rate of dry-directed rice under waterlogging stress. This method is suitable for pre-sowing seed treatment of dry direct-seeding rice under the conditions of artificial sowing, artificial on-demand sowing, artificial drill and mechanized direct seeding.

Background technique

Dry direct seeding of rice is a new type of high-efficiency, labor-saving, water-saving and easy-to-mechanize cultivation technology. It is also one of the preferred technologies for stabilizing the area and increasing the yield during the transition period of the current rice production technology. As a new high-efficiency water-saving cultivation technology, dry direct seeding of rice plays an irreplaceable role in stabilizing the rice planting area, and has broad development prospects in our country. However, waterlogging stress after sowing will delay the germination and emergence of direct-seeding rice, and even cause rotten seeds and buds, which is one of the important factors that limit the large-scale promotion of dry-directed direct-seeding rice.

A large number of studies have shown that seed priming treatment can significantly improve the emergence speed, emergence rate and uniformity of seeds, and can enhance the stress resistance of seeds. The principle of seed priming is to make the seeds slowly absorb water and stay in the second stage of imbibition (lag phase) under the condition of controlling the water potential. After a series of physiological and biochemical reactions occur inside the seeds, they are in a metabolic state ready to germinate. Through the priming treatment, the activity of enzymes related to the metabolism of storage substances inside the seeds increased, and the contents of soluble sugar and free proline both increased. In addition, the priming treatment can increase the respiration rate of seeds, provide enough energy for germination, and promote seed germination. The seed emergence rate and uniformity are improved, which is where the research purpose of the present invention lies.

Contents of the invention

Aiming at the waterlogging stress caused by continuous rain after sowing of dry-directed rice, the purpose of the present invention is to provide a seed treatment method for improving the germination rate of dry-directed rice under waterlogging stress. The method is simple, easy to operate, and solves the problem of drought Problems of rotten seeds, low germination rate and irregular seedling emergence caused by waterlogging stress in direct-seeding rice production. The priming treatment of rice seeds significantly improved seed vigor, thereby improving the germination rate and emergence uniformity of dry-seeded rice under waterlogging stress.

In order to achieve the above-mentioned purpose, the present invention adopts following technical scheme:

A seed treatment method for improving the germination rate of dry-directed rice under waterlogging stress, the steps of which are:

a. Initiator preparation: the types and concentrations of the initiators used are distilled water (H ₂ O, the volume of distilled water is 5 times the seed mass), calcium chloride (CaCl ₂ : 100mgL ^-1 ), hydrogen peroxide ( H ₂ O ₂ : 50μM), sodium selenate (Se: 50μM), salicylic acid (SA: 100mgL ^-1 ), according to the weight of sown rice seeds, the mass ratio of rice seeds to initiator volume was 1:5(w /v), determine the amount of initiator;

b. Rice seed initiator soaking treatment (22-26 hours): select the container according to the amount of rice seed, soak the rice seed in the initiator, the mass ratio of rice seed to initiator is 1:5 (w/v), Place the container in a dark incubator at 24-26°C for 22-26 hours, and renew the initiator every 10-14 hours;

c. Drying of rice seeds: After soaking in the initiator for 22-26 hours, take out the rice seeds and rinse them with distilled water for 50-70 seconds, dry them with absorbent paper and put them into a blast drying oven at 24-26°C to make the dried rice The moisture content of the seeds is less than 10%, and the dried rice seeds are stored at 0-4°C;

d. Sowing and germination: It is carried out in a plastic cup with a depth of 15-17cm and a volume of 680ml. For each treatment, 25 neat and consistent seeds are selected, placed on a double-layer filter paper placed at the bottom of the cup, and then poured into the plastic cup. Add 600ml (depth of 12-14cm) distilled water to simulate waterlogging stress, put the plastic cup in the artificial climate box for germination, the artificial climate box is illuminated for 11-13hd ^-1 , the light intensity is 12000lux, the relative humidity is set to 60%, and the light and dark conditions were set at 30°C and 25°C, respectively.

e. Sampling measurement: count the number of germinations every day from the first day after sowing, measure α-amylase activity and soluble sugar content on the fifth day, take samples on the eighth day to determine the final germination rate, bud length, root length, root weight, bud Fresh weight.

Compared with the prior art, the present invention has the following advantages and effects:

Under waterlogging stress, water, CaCl ₂ , H ₂ O ₂ , Se, and SA priming increased the average germination rates of the two varieties by 26%, 38%, 36%, 46%, and 46%, respectively, compared with the non-priming control . Compared with the non-triggered non-waterlogged control, the shoot length, root length, bud fresh weight, root fresh weight, and seedling vigor index of waterlogged non-primed seeds decreased by 60%, 47%, 47%, 48%, and 67%, respectively . Among different priming treatments, Se and SA had the best priming effects, and the vigor index of seedlings treated with Se and SA primed was more than 3 times higher than that of non-primed seedlings under waterlogging stress. Under waterlogging stress, the α-amylase activity and soluble sugar content in seedlings treated with primed seedlings were more than 1 times higher than those of non-primed seedlings. The pre-sowing seed treatment technology involved in the present invention is applicable to all rice varieties (including indica rice, japonica rice, conventional rice and hybrid rice).

Description of drawings

Figure 1 is a schematic diagram of the germination and early seedling growth of rice seeds under normal and waterlogging stresses with different priming treatments.

Among them, Figure 1A and Figure 1B are Huang Huazhan and Yangliangyou No. 6, respectively. NP: non-initiated, HP: water-initiated, CaCl ₂ : calcium chloride-initiated, H ₂ O ₂ : hydrogen peroxide-initiated, Se: sodium selenate-initiated, SA: salicylic acid-initiated; Control: non-water-soaked control; Sub : Waterlogged. The figure shows that the priming treatment can improve the germination rate of seeds and the growth of seedlings under waterlogging stress, among which Se priming and SA priming have the best effects.

Fig. 2A is a schematic diagram of α-amylase activity of rice seeds under normal and waterlogging stresses with different priming treatments.

Fig. 2B is a schematic diagram of the soluble sugar content of rice seeds under normal and waterlogging stresses with different priming treatments.

Respectively: Figure 2A shows that relative to the non-priming control, the priming treatment can significantly increase the α-amylase activity in the seedlings under waterlogging stress; Figure 2B shows that compared with the non-priming control, the priming treatment can significantly improve the soluble sugar content.

NP: non-initiated, HP: water-initiated, CaCl ₂ : calcium chloride-initiated, H ₂ O ₂ : hydrogen peroxide-initiated, Se: sodium selenate-initiated, SA: salicylic acid-initiated; Control: non-water-soaked control; Sub : Waterlogged.

detailed description

Example 1:

A seed treatment method for improving the germination rate of dry-directed rice under waterlogging stress, the steps of which are:

1. Simulation of test materials, initiators and waterlogging conditions:

The experiment was carried out in 2014 at the Crop Physiological and Ecological Cultivation Research Center of Huazhong Agricultural University. The tested varieties were two different types of indica rice varieties: Huanghuazhan (conventional indica rice) and Yangliangyou 6 (hybrid indica rice). The types and concentrations of the initiators used are H ₂ O (the volume of distilled water is 5 times the seed mass), CaCl ₂ (calcium chloride: 100 mgL ^-1 ), H ₂ O ₂ (hydrogen peroxide: 50 μM ), Se priming (sodium selenate: 50 μM), SA priming (salicylic acid: 100 mgL ^-1 ), and non-priming seeds as a control. Waterlogging stress was simulated by adding distilled water to a depth of 13 cm into plastic cups.

2. Determination of triggering treatment, germination rate, seedling quality and other related indicators:

2.1. Soak the rice seeds in the initiator, the ratio of the mass of the rice seeds to the volume of the initiator is 1:5 (w/v), and place the container in a dark incubator at 25°C.

Renew the initiator once in 12 hours, trigger 24 hours. Take out the rice seeds and rinse them with distilled water for 1 min, dry them with absorbent paper and put them into a blast drying oven at 25°C, so that the moisture content of the dried rice seeds is less than 10%. Germination was carried out in a plastic cup with a depth of 16cm and a volume of 680ml. For each treatment, 25 uniform seeds were selected and placed on a double-layer filter paper placed at the bottom of the cup, and then 600ml (depth of 13cm) was added to the plastic cup. ) distilled water to simulate waterlogging stress, put the plastic cup into the incubator, light 12hd ^-1 , the light intensity is 12000lux, the relative humidity is set to 60%, and the temperature is set to 30°C and 25°C under light and dark conditions, respectively. The experiment adopted a completely randomized block design with 4 repetitions in total.

2.2. Count the germination situation every day from the first day after sowing until the number of germinations is constant. The standard of germination is that the length of both buds and hypocotyls exceeds 2mm. On the 8th day after sowing, 10 seedlings are randomly selected from each treatment for statistics The maximum bud length and root length, and the buds and roots are separated, and the fresh weight is weighed immediately. The samples were stored in a refrigerator at -70°C or -72 or -74 or -76 or -78 or -80°C, and the α-amylase activity and soluble sugar content were measured in time.

Analysis of test results

Effects of priming treatments on rice seed germination, seedling growth and physiological characteristics under waterlogging stress

Figure 1 shows the germination and early seedling growth of rice seeds with different priming treatments under normal and waterlogging stress. Waterlogging stress significantly reduced the germination rate of non-primed seeds. Seed priming treatment can effectively reduce the damage caused by waterlogging stress. Under waterlogging stress, water, CaCl ₂ , H ₂ O ₂ , Se and SA priming increased the average germination rates of the two varieties by 26%, 38%, 36%, 46%, 46%, respectively, compared with the non-priming control. % (see Table 1).

Waterlogging significantly inhibited the growth of rice seedlings of the two varieties, and the seedlings of the non-waterlogging and non-priming control had the largest growth (Table 1, Figure 1). Compared with the non-triggered non-waterlogged control, the shoot length, root length, bud fresh weight, root fresh weight, and seedling vigor index of waterlogged non-primed seeds decreased by 60%, 47%, 47%, 48%, and 67%, respectively . Priming alleviated the inhibition of waterlogging on the growth of rice seedlings. Among different priming treatments, Se and SA had the best priming effects. Under waterlogging stress, the vitality index of Se and SA primed seedlings was more than three times higher than that of non-primed seedlings. .

The α-amylase activity and soluble sugar content of non-primed non-waterlogged control seeds were the highest, while the α-amylase activity and soluble sugar content of waterlogged non-primed seedlings decreased by 66% and 60% respectively compared with the control. Seed priming can effectively regulate α-amylase activity and increase soluble sugar content in seedlings. Among the different priming treatments, Se and SA had the best priming effects, and the benefits of the two priming treatments were similar. The α-amylase activity and soluble sugar content of the seedlings were about two times higher than those of the waterlogged non-priming seedlings (Fig. 2A and Figure 2B).

Table 1. The germination and seedling growth of rice seeds under waterlogging stress with different priming treatments

Note: NP: non-initiated, HP: water-initiated, CaCl ₂ : calcium chloride-initiated, H ₂ O ₂ : hydrogen peroxide-initiated, Se: sodium selenate-initiated, SA: salicylic acid-initiated; Control: non-water-soaked control ; Sub: waterlogged.

Claims (1)

1. a seed treatment method improving germination rate under waterlogging stress of dry-directed rice, the steps are: a. Initiator preparation: the types and concentrations of the initiators used are: distilled water with a volume five times that of the seed mass, 100 mgL ^-1 calcium chloride, 50 μM hydrogen peroxide, 50 μM sodium selenate and 100 mgL ^-1 salicylic acid , according to the weight of sowing rice seeds, by rice seed quality and initiator volume ratio is 1:5w/v, determines the consumption of initiator; b. Rice seed initiator soaking treatment for 22-26 hours: select the container according to the amount of rice seed, soak the rice seed in the initiator, the mass ratio of rice seed to initiator volume is 1:5w/v, place the container in Initiate in a dark incubator at 24-26°C for 22-26 hours, and renew the initiator every 10-14 hours; c. Drying of rice seeds: After soaking in the initiator for 22-26 hours, take out the rice seeds and rinse them with distilled water for 50-70 seconds, dry them with absorbent paper and put them into a blast drying oven at 24-26°C to make the dried rice The moisture content of the seeds is less than 10%, and the dried rice seeds are stored at 0-4°C; d. Sowing and germination: It is carried out in a plastic cup with a depth of 15-17cm and a volume of 680ml. For each treatment, 25 neat and consistent seeds are selected, placed on a double-layer filter paper placed at the bottom of the cup, and then poured into the plastic cup. Add 600ml of distilled water at a depth of 12-14cm to simulate waterlogging stress, put the plastic cup in an artificial climate box for germination, and the artificial climate box is illuminated for 11-13hd ^-1 , the light intensity is 12000lux, and the relative humidity is set to 60%. Under dark conditions, the temperature settings were 30°C and 25°C, respectively; e. Sampling measurement: count the number of germinations every day from the first day after sowing, measure α-amylase activity and soluble sugar content on the fifth day, take samples on the eighth day to determine the final germination rate, bud length, root length, root weight, bud Fresh weight.