New use of gamma-aminobutyric acid in increasing plant temperature-stress resistance capacity

[0019] Example 1. GABA seed soaking improves the high temperature resistance of wheat seedlings

[0020] 1. Experimental method

[0021] The material is wheat, and the variety is winter wheat Kyoto 40 (National Crop Germplasm Preservation Center).

[0022] The winter wheat Kyoto 40 was subjected to the following four treatments:

[0023] A. After soaking the wheat seeds in water for 24 hours, cultivate them with vermiculite and sand (volume ratio 7:3), and control the temperature: 25°C during the day (14 hours) and 20°C at night (10 hours). Incubation was continued at this temperature until treatments C and D were sampled simultaneously.

[0024] B. After soaking the wheat seeds with 0.5mM GABA aqueous solution for 24 hours, cultivate with vermiculite and sand (volume ratio 7:3), and control the temperature: 25°C during the day (14 hours) and 20°C at night (10 hours). Incubation was continued at this temperature until treatments C and D were sampled simultaneously.

[0025] C. After soaking the wheat seeds in water for 24 hours, cultivate with vermiculite and sand (volume ratio 7:3), and control the temperature: 25°C during the day (14 hours) and 20°C at night (10 hours). When the wheat seedlings grow to about 10 cm, high temperature stress treatment is carried out at 40°C during the day (14 hours) and 30°C at night (10 hours). Samples were taken after 48 hours of treatment.

[0026] D. After soaking the seeds of wheat with 0.5mM GABA aqueous solution for 24 hours, cultivate with vermiculite and sand (volume ratio 7:3). When the wheat seedlings grow to about 10 cm, high temperature stress treatment is carried out at 40°C during the day (14 hours) and 30°C at night (10 hours). Samples were taken after 48 hours of treatment.

[0027] After sampling, the plant height, total root length and root surface area were investigated, and the relative water content, relative electrical conductivity and malondialdehyde content of leaves were determined (see Table 1 for the results). 4 replicates were set up for each treatment.

[0028] The relative moisture content of leaves was determined by drying method. The specific method is as follows: after sampling the leaves, quickly measure the fresh weight with a balance, bake in an oven at 100°C for 30 minutes, then dry in an oven at 80°C for 48 hours, measure the dry weight with a balance, relative water content (%)=( Fresh weight-dry weight)/dry weight×100%.

[0029] Relative conductivity was determined by the conductivity meter method (Saadalla et al., 1990, Crop Sci, 30: 1243-1247). The specific measurement method is as follows: starting from 2 cm away from the tip of the leaf, cut the leaves into 1 cm long sections, take 10 sections for each treatment, rinse 3 times with 10 ml of deionized water, put them in a graduated test tube, and use deionized water. The volume was made up to 10 ml, evacuated with a vacuum pump for 2 hours, and the conductivity (C1) of the solution was measured with a conductivity meter (model EC 215, Markson Science, USA). The test tube was boiled in boiling water for 1 hour, rinsed with cold water and quickly cooled to 25°C, and then the conductivity (C2) of the solution was measured. The conductivity (Cw) of the deionized water was also measured. The relative conductivity (R, %) was calculated by the following formula: R=(C1-Cw)/(C2-Cw)×100%.

[0030] The content of malondialdehyde (MDA) was determined by the following method: 0.5 g of leaf samples were added to 5 ml of phosphate buffer (pH 7.0) with a concentration of 50 nmol/ml, ground on an ice bath, and 12000 g at 4°C Centrifuge for 15 minutes, take 2 ml of the supernatant (add 2 ml of distilled water for the control), add 2 ml of thiobarbituric acid solution with a mass percentage of 0.6%, and the mixture is reacted on a boiling water bath for 15 minutes, and after rapid cooling Centrifuge again. The supernatant was taken to measure the extinction (D) at wavelengths of 532 nm, 600 nm and 450 nm, respectively. Calculate the content of malondialdehyde (M, micromol/g fresh weight) according to the following formula: M=[6.45×(D 532 -D 600 )—0.56D 450 ]×5.

[0031] 2. Experimental results

[0032] It can be seen from the treatments A and C in Table 1 that high temperature stress inhibited the growth of wheat seedlings. It can be seen from A and B treatments that under normal growth conditions, GABA treatment can promote the growth of wheat seedlings; from C and D treatments, it can be seen that GABA treatment of wheat seeds can alleviate the inhibitory effect of high temperature stress on the growth of seedlings, increase plant height, Total root length and root surface area; high temperature stress dehydrated wheat leaves, and leaf water content decreased significantly; GABA treatment increased leaf water content under high temperature stress, decreased the electrical conductivity and malondialdehyde content of wheat leaves, and improved the resistance of wheat seedlings. Resistance to high temperature stress.

[0033] Table 1 Effects of GABA treatment on growth and tolerance of wheat seedlings under high temperature stress

[0034]

[0035] Example 2. Effects of GABA treatment on wheat yield and quality under high temperature stress

[0036] 1. Experimental method

[0037]The material was wheat, and the variety was Zhongyou 9507 (Crop Research Institute, Chinese Academy of Agricultural Sciences). The experimental site was Shangzhuang Experimental Station, Haidian District, China Agricultural University.

[0038] The following four treatments were performed on Zhongyou 9507:

[0039] A. During the flowering period, spray the leaves evenly with clean water.

[0040] B. The leaves were sprayed uniformly with an aqueous solution with a concentration of 0.01 mM GABA during flowering.

[0041] C. During the flowering period, the foliage is uniformly sprayed with water; the wheat grain filling period (10 days after flowering - 23 days after flowering) is subjected to high temperature stress treatment for 2 weeks, and the temperature is 48 ° C during the day (12 hours)/night (12 hours) 29°C.

[0042] D. In the flowering stage, the foliage is uniformly sprayed with a concentration of 0.01 mM GABA; the wheat grain filling stage (10 days after flowering - 23 days after flowering) is subjected to high temperature stress treatment for 2 weeks, and the temperature is 48 ° C during the day (12 hours) / night (12 hours) 29°C.

[0043] The 1000-grain weight and the number of grains per ear of the treated wheat were investigated at harvest, the yield was calculated, and the quality analysis of crude protein content, sedimentation value, and dry and wet gluten content was carried out (see Table 2 for the results). The crude protein content is determined according to the Chinese national standard "Grain and Oilseed Inspection-Determination of Crude Protein (GB/T 5511-1985)", and the sedimentation value is determined according to the Chinese national standard "Wheat flour sedimentation value determination method (GB/T 15685-1995)" , The dry gluten content is determined according to the Chinese national standard "Wheat Flour Dry Gluten Determination Method (GB/T 14607-1993)", and the wet gluten content is determined according to the Chinese National Standard "Wheat Flour Wet Gluten Determination Method (GB/T 14608-1993)".

[0044] 2. Experimental results

[0045] It can be seen from the treatments A and C in Table 2 that high temperature stress greatly reduced the yield and quality of wheat. It can be seen from the A and B treatments that under normal growth conditions, GABA treatment can increase the 1000-grain weight, grain number per ear and yield of wheat and improve the quality of wheat. It can be seen from the treatments C and D in Table 2 that GABA treatment significantly increased the 1000-grain weight, grain number per ear and yield of wheat under high temperature stress, indicating that GABA treatment can alleviate the wheat yield reduction caused by high temperature stress and improve wheat quality.

[0046] Table 2 Effects of GABA treatment on wheat yield and quality under high temperature stress

[0047]

[0048]

[0049] Example 3. GABA improves the low temperature stress tolerance of cotton seedlings

[0050] 1. Experimental method

[0051] The material was cotton, and the variety was Zhongmian 45 (Cotton Research Institute, Chinese Academy of Agricultural Sciences). The seeds were soaked in water for 24 hours, and cultivated in plastic pots with flower soil and vermiculite (volume ratio of 7:3), with 4 plants per pot. The test was carried out in a light incubator, the light time was 14 hours, the day (12 hours) was 28°C, the night (12 hours) was 24°C, and the light intensity was 400 μmol.m -2.s -1 , 66% relative humidity.

[0052] 10 days after emergence, the following three kinds of treatments were respectively carried out to the Chinese cotton 45, and the illumination time, intensity and relative humidity of each treatment were the same as above:

[0053] A. Spray clean water on cotton leaves, treat at 20°C after 3 days, and take samples after 3 days of treatment.

[0054] B. Spray clean water on the cotton leaves, carry out low temperature treatment at 5°C after 3 days, and take samples after 3 days of treatment.

[0055] C. Spray 5mM GABA aqueous solution on the cotton leaves, perform low temperature treatment at 5°C after 3 days, and take samples after 3 days of treatment.

[0056] The true leaves after the above three treatments were taken to measure SOD (superoxide dismutase), POD (peroxidase), CAT (catalase), activity and soluble protein, soluble sugar and proline content (results were respectively See Tables 3 and 4) with 3 replicates per treatment.

[0057] SOD, POD, CAT activity, soluble protein, soluble sugar content (anthrone colorimetric method), proline content (acidic ninhydrin colorimetric method) determination methods and specific operations, see the Plant Physiology Experiment Guide edited by Zou Qi et al. ( China Agricultural Press, 2000).

[0058] 2. Experimental results

[0059] It can be seen from Table 3 that low temperature stress increased the activities of SOD, POD and CAT in cotton leaves, and the increase range was further increased after GABA treatment, reaching a significant level of difference (the experimental data were processed with SAS data software, and Duncan's new repolarization was used. The difference between different treatments was significantly different (P<0.05)), GABA improved the adaptability of cotton seedlings to low temperature stress by regulating the activity of protective enzymes. At the same time, GABA treatment increased the contents of soluble protein, soluble sugar and proline in cotton leaves, and enhanced the resistance of seedlings to low temperature stress.

[0060] Table 3 Effects of GABA treatment on low temperature stress cotton seedlings

[0061]

[0062] Table 4 Effects of GABA treatment on low temperature stress cotton seedlings

[0063]