Application of trehalose in alleviating heavy metal stress on okra seedlings

Abstract

The invention discloses the application of trehalose in alleviating the stress of heavy metals on okra seedlings, and belongs to the research field of technology for alleviating heavy metal stress in plants. The invention protects the application of trehalose in alleviating the damage of okra under CdCl2 stress. The invention uses the okra variety Taiwan Wufu as the test material, studies the relationship between trehalose and the osmotic regulation, leaf damage, photosynthesis, antioxidant enzyme system, and cell membrane system of okra under CdCl2 stress, explores the mechanism of action of trehalose in plants resisting heavy metal stress, and provides a theoretical basis for its safe production in okra; the invention will have broad application space and market prospects in the agricultural field.

Description

Technical Field

[0001] The invention belongs to the research field of technology for alleviating heavy metal stress of plants, and specifically relates to an application of exogenous trehalose in alleviating CdCl2 stress of okra seedlings. Background Art

[0002] Cadmium is a non-essential nutrient element for plants. Low concentrations of cadmium promote plant growth to a certain extent, but high concentrations of cadmium are highly toxic to plants. With the development of industry, industrial wastewater and pollutants enter the soil and pollute the environment. The problem of cadmium pollution in my country's soil is serious. Studies have shown that excessive cadmium can also cause stress in plants, inhibit the synthesis of chlorophyll and photosynthesis. Under cadmium stress, plants will also show symptoms such as slow growth, short plants, chlorosis, and reduced yields. High concentrations of cadmium will destroy the metabolic balance of active oxygen in plants. The increased accumulation of active oxygen leads to membrane lipid peroxidation and reduced activity of antioxidant enzymes in plants.

[0003] Okra is rich in protein, free amino acids, carotenoids, various vitamins, mineral elements such as phosphorus, iron, potassium, calcium, and sticky substances composed of pectin and polysaccharides. It has multiple health functions and is very popular among consumers. Studies have shown that the growth of okra leaves and the activity of antioxidant enzymes are inhibited under cadmium stress, the quality of okra fruits decreases under cadmium stress, and the accumulation of cadmium in fruits will also affect human health. Therefore, it is crucial to alleviate the damage of cadmium stress to okra.

[0004] Trehalose (abbreviated as Tre) is a safe and reliable natural sugar. It is a non-reducing sugar composed of two glucose molecules with a 1,1-glycosidic bond. It is the most stable disaccharide among sugars. Its content in plants is very low. Under adverse conditions, plants can stabilize the structure and function of proteins by regulating their own trehalose content. Studies have found that trehalose is an osmotic regulating substance that can protect the antioxidant enzyme system and subcellular structure, mediate osmotic regulation and activate ROS clearance, and alleviate the damage caused by adversity to plants. Summary of the invention

[0005] The invention aims to solve the problem of high Cd content in okra seedlings grown under CdCl2 stress and provide application of trehalose in alleviating CdCl2 stress effect on okra seedlings.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions to achieve the goal:

[0007] Application of trehalose in alleviating plant CdCl2 stress damage or improving plant CdCl2 stress resistance.

[0008] Use of trehalose in at least one of the following (a1)-(a33):

[0009] (a1) Increase the trehalose content of okra under CdCl2 stress;

[0010] (a2) preparing a product for increasing the trehalose content of okra under CdCl2 stress;

[0011] (a3) Increase the proline content of okra under CdCl2 stress;

[0012] (a4) preparing a product for increasing the proline content of okra under CdCl2 stress;

[0013] (a5) Increase the chlorophyll a content of okra under CdCl2 stress;

[0014] (a6) preparing a product for increasing the chlorophyll a content of okra under CdCl2 stress;

[0015] (a7) Increase the chlorophyll b content of okra under CdCl2 stress;

[0016] (a8) preparing a product for increasing the chlorophyll b content of okra under CdCl2 stress;

[0017] (a9) Increase the total chlorophyll content of okra under CdCl2 stress;

[0018] (a10) preparing a product for increasing the total chlorophyll content of okra under CdCl2 stress;

[0019] (a11) Increase the total carotenoid content of okra under CdCl2 stress;

[0020] (a12) preparing a product for increasing the total carotenoid content of okra under CdCl2 stress;

[0021] (a13) Increase the relative water content of okra under CdCl2 stress;

[0022] (a14) preparing a product for increasing the relative water content of okra under CdCl2 stress;

[0023] (a15) Improve the SOD activity of okra under CdCl2 stress;

[0024] (a16) preparing a product for improving the SOD activity of okra under CdCl2 stress;

[0025] (a17) Improve the GPX activity of okra under CdCl2 stress;

[0026] (a18) preparing a product for improving the GPX activity of okra under CdCl2 stress;

[0027] (a19) Improved CAT activity of okra under CdCl2 stress;

[0028] (a20) preparing a product for improving CAT activity of okra under CdCl2 stress;

[0029] (a21) Improved GR activity of okra under CdCl2 stress;

[0030] (a22) preparing a product for improving GR activity of okra under CdCl2 stress;

[0031] (a23) Improve the APX activity of okra under CdCl2 stress;

[0032] (a24) preparing a product for improving APX activity of okra under CdCl2 stress;

[0033] (a25) Improve the POD activity of okra under CdCl2 stress;

[0034] (a26) preparing a product for improving the POD activity of okra under CdCl2 stress;

[0035] (a27) Reduce the MDA content of okra under CdCl2 stress;

[0036] (a28) preparing a product for reducing the MDA content of okra under CdCl2 stress;

[0037] (a29) Reduced electrolyte permeability of okra under CdCl2 stress;

[0038] (a30) preparing a product for reducing electrolyte permeability of okra under CdCl2 stress;

[0039] (a31) Reduce the H2O2 content of okra under CdCl2 stress;

[0040] (a32) preparing a product for reducing the H2O2 content of okra under CdCl2 stress;

[0041] (a33) Improve the resistance of okra to CdCl2 stress.

[0042] In the above application, trehalose with a concentration of 1 - 100 μmol / L is sprayed on the plants' leaves.

[0043] A method for cultivating okra, comprising spraying the okra with trehalose at a concentration of 1-100 mmol / L. Preferably, the okra is sprayed with trehalose at a concentration of 1-10 mmol / L; and more preferably, the okra is sprayed with trehalose at a concentration of 10 mmol / L.

[0044] A method for alleviating CdCl2 stress damage of okra, comprising spraying the okra with trehalose at a concentration of 1-100 mmol / L. Preferably, the okra is sprayed with trehalose at a concentration of 1-10 mmol / L; further preferably, the okra is sprayed with trehalose at a concentration of 10 mmol / L.

[0045] The above-mentioned plant is any one of the following (c1) to (c3):

[0046] (c1) dicotyledons;

[0047] (c2) Malvaceae;

[0048] (c3) Okra.

[0049] The invention also protects the application of trehalose in the breeding of okra resistant to CdCl2 stress.

[0050] The present invention also protects the application of the above method in breeding okra resistant to CdCl2 stress.

[0051] In any of the above methods, the okra is specifically okra in the seedling stage.

[0052] Any of the above-mentioned okra can be Taiwan Wufu okra.

[0053] The present invention provides an application of exogenous trehalose in alleviating the stress of CdCl2 on okra seedlings: exogenous spraying of trehalose can improve the CdCl2 stress resistance of okra plants. The results of the germination rate test under 0.1 mmol / L CdCl2 stress showed that the germination rate and fresh weight of okra seeds treated with 1 and 10 mmol / L trehalose were significantly higher than those treated with 0 and 100 mmol / L trehalose, and increased by 51%, 130% and 47%, 118% respectively compared with the 0 mmol / L trehalose plants, among which the okra seedlings treated with 10 mmol / L trehalose had the best effect. The results of the pot experiment under 0.1 mmol / L CdCl2 stress showed that okra seedlings treated with exogenous trehalose grew well and had improved resistance. The fresh weight and dry weight of okra seedlings treated with 1, 10 and 100 mmol / L trehalose were significantly higher than those treated with 0 mmol / L trehalose, which were increased by 62%, 123%, 37% and 213%, 368% and 188% respectively compared with those treated with 0.0 mmol / L trehalose. The okra seedlings treated with 100 mmol / L trehalose had the best effect and expressed strong resistance to CdCl2 stress; specifically, the okra seedling materials after trehalose treatment had increased trehalose content, increased proline content, increased chlorophyll a content, increased chlorophyll b content, increased total chlorophyll content, increased total carotenoid content, increased relative water content, increased SOD activity, increased GPX activity, increased CAT activity, increased GR activity, increased APX activity, increased POD activity, decreased electrolyte permeability, decreased H2O2 content and decreased malondialdehyde content.

[0054] The results show that the trehalose of the present invention has an important application in alleviating the stress effect of CdCl2 on okra seedlings. By using a trehalose crop alleviator with a determined concentration, trehalose can promote the growth of okra seedlings under CdCl2 stress, improve the tolerance of okra seedlings to CdCl2 stress, study the relationship between trehalose and the osmotic regulation, leaf damage, photosynthesis, antioxidant enzyme system, and cell membrane system of okra under CdCl2 stress, explore the mechanism of action of trehalose in plants resisting heavy metal stress, and provide a theoretical basis for its safe production in okra. The present invention will have broad application space and market prospects in the agricultural field. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 The present invention discloses the effects of different concentrations (0, 1, 10 and 100 mmol / L) of trehalose on the germination rate of okra seeds and the fresh weight of seedlings under normal conditions and 0.1 mmol / L Cl2 stress.

[0056] Figure 2The present invention identifies the resistance of okra seedlings to the mitigation effect of trehalose at different concentrations (0, 1, 10 and 100 mmol / L) under normal conditions and 0.1 mmol / L CdCl2 stress.

[0057] Figure 3 The present invention discloses the effect of 10 mmol / L trehalose on the trehalose and proline contents of okra seedlings under normal conditions and 0.1 mmol / L CdCl2 stress.

[0058] Figure 4 The present invention discloses the effects of 10 mmol / L trehalose on the contents of photosynthetic pigments (chlorophyll a, chlorophyll a, total chlorophyll and total carotenoids) in okra seedlings under normal conditions and 0.1 mmol / L CdCl2 stress.

[0059] Figure 5 The present invention discloses the effect of 10 mmol / L trehalose on malondialdehyde content, electrolyte permeability, relative water content and H2O2 content of okra seedlings under normal conditions and 0.1 mmol / L CdCl2 stress.

[0060] Figure 6 The present invention discloses the effects of 10 mmol / L trehalose on the activities of key enzymes (SOD, GPX, CAT, GR, APX, POD) in the ROS scavenging system of okra seedlings under normal conditions and 0.1 mmol / L CdCl2 stress. Implementation

[0061] The following examples are provided to facilitate a better understanding of the present invention, but are not intended to limit the present invention. The experimental methods in the following examples are conventional methods unless otherwise specified. The experimental materials used in the following examples are purchased from conventional biochemical reagents unless otherwise specified. The quantitative tests in the following examples were repeated three times, and the results were averaged.

[0062] In the embodiment, okra ( Abelmoschus esculentus ) variety Taiwan Wufu was used as the experimental material. Okra variety Taiwan Wufu, reference [Feibing Wang, Gaolei Ren, Fengsheng Li, Sitong Qi, YanXu, Bowen Wang, Yulin Yang, Yuxiu Ye, Qing Zhou, Xinhong Chen. A chalconesynthase gene AeCHS from Abelmoschus esculentus regulates flavonoidaccumulation and abiotic stress tolerance in transgenic Arabidopsis . 2018,40:97], preserved by the laboratory of Jiangsu Plant Production and Processing Practice Education Center, School of Life Sciences and Food Engineering, Huaiyin Institute of Technology.

[0063] Trehalose (Trehalose, abbreviated as Tre): purchased from Sigma.

[0064] The Cd donor was cadmium chloride (CdCl2·2H2O), which was purchased from Sigma.

[0065] Example 1 Identification and analysis of CdCl2 stress resistance in okra seedlings regulated by exogenous trehalose

[0066] 1. Analysis of germination rate of okra seeds under CdCl2 stress after treatment with different concentrations of trehalose

[0067] Referring to the method of Wang Yonghui et al. (2014) [Wang Yonghui, Chen Jianping, Zhang Peitong, Cai Liwang, Shi Qinghua, Wang Haiyang. Screening of salt-tolerant materials of okra and correlation analysis of salt tolerance during germination period. Journal of Southwest Agriculture, 2014, 27(2): 788-792], 50 plump and uniformly sized okra seeds were selected and disinfected with 5% hypochlorous acid solution for 5 min, then rinsed with distilled water for 3 times, and soaked in clean water and 0.1 mmol / L CdCl2 solution at room temperature for 24 h, respectively. Then, the seeds were placed in a transparent plastic fresh-keeping box with two layers of filter paper and an inner diameter of 12 cm, and then treated with different concentrations of trehalose (0, 1, 10 and 100 mmol / L). The treatments included: (i) adding 0, 1, 10 and 100 mmol / L trehalose to distilled water under normal conditions; (ii) adding 0.1 mmol / L trehalose to the seeds under normal conditions; Under CdCl2 conditions, 0, 1, 10 and 100 mmol / L trehalose were added. Each treatment was repeated six times. The fresh-keeping boxes were placed in an artificial climate box for germination, with a day / night temperature of 28℃ / 25℃, a day / night of 12 h each, and a humidity of 60%±1%. The radicle length of 0.2 mm was used as the seed germination mark, and the number of seeds that germinated was counted on the 5th day. Seed germination rate = (number of germinated seeds on the 5th day / total number of seeds tested) × 100%.

[0068] The results showed that the germination rate test results under 0.1 mmol / L CdCl2 stress showed that Figure 1 , germination rate of okra seeds treated with 1 and 10 mmol / L trehalose ( Figure 1 A) and fresh weight ( Figure 1 B) was significantly higher than that of 0 and 10 mmol / L trehalose treatments, and increased by 51%, 130% and 47%, 118% respectively compared with 0 mmol / L trehalose plants, among which the okra seedlings treated with 10 mmol / L trehalose had the best effect.

[0069] 2. Analysis of resistance of okra seedlings to CdCl2 stress after treatment with different concentrations of trehalose

[0070] Referring to the method of Li et al. (2022) [Hengpeng Li, Shasha Yang, Wenya Wu, Chunyan Wang, Yanyang Li, Chenzhong Wan, Yuxiu Ye, Xinhong Chen, Zunxin Wang, Laibao Hu, Feibing Wang. Physiological and biochemical mechanisms of improving salt anddrought tolerance in okra plants based on applied attapulgite clay. Advances in Biochemistry, 2022, 10:1-10], Taiwan okra seedlings were transplanted into plastic pots (19 cm in diameter) containing a mixture of turf, humus, and vermiculite (1:1:1, v / v / v) in a greenhouse. All seedlings were well watered with half-Hoagland solution for 4 weeks until the seedlings grew new leaves. Subsequently, CdCl2 stress and trehalose treatment were carried out, including: (i) Under normal conditions, each pot of okra seedlings was irrigated with clean water once every 2 days for 4 weeks, and sprayed with 0, 1, 10 and 100 mmol / L trehalose aqueous solution 3 times a day. (ii) Under CdCl2 stress treatment, each pot of okra seedlings was irrigated with 100 mL of 0.1 mmol / L CdCl2 solution once every 2 days for 4 weeks, and sprayed with 0, 1, 10 and 100 mmol / L trehalose aqueous solution 3 times a day.

[0071] The results showed that the pot test results of 0.1 mmol / L CdCl2 stress showed that Figure 2 The okra seedlings treated with exogenous trehalose grew well and had improved resistance. The fresh weight and dry weight of potted okra seedlings treated with 1, 10 and 100 mmol / L trehalose were significantly higher than those treated with 0 mmol / L trehalose, which were increased by 62%, 123%, 37% and 213%, 368%, 188% respectively compared with those treated with 0.0 mmol / L trehalose. Among them, the okra seedlings treated with 10 mmol / L trehalose had the best effect and expressed strong resistance to CdCl2 stress.

[0072] Therefore, the phenotypic identification results showed that okra plants treated with exogenous 10 mmol / L trehalose had the best CdCl2 stress resistance phenotype, which was used to analyze the physiological and biochemical mechanisms of inducing CdCl2 stress resistance.

[0073] Example 2 Determination of physiological and biochemical indices of resistance of okra seedlings to CdCl2 stress

[0074] Trehalose is a safe and reliable natural sugar. It is a non-reducing sugar composed of two glucose molecules with a 1,1-glycosidic bond. It is the most stable disaccharide among sugars. Its content in plants is very low. Under adverse conditions, plants can stabilize the structure and function of proteins by regulating their own trehalose content. Studies have found that trehalose is an osmotic regulating substance that can protect antioxidant enzyme systems and subcellular structures, mediate osmotic regulation and activate ROS clearance, and alleviate the damage caused by adversity to plants.

[0075] The determination method was based on the literature [Tao Jiang, Hong Zhai, Feibing Wang, Huanan Zhou, Zengzhi Si, Shaozhen He, Qingchang Liu. Cloning and characterization of asalt tolerance-associated gene encoding trehalose-6-phosphate synthase in sweetpotato. Journal of Integrative Agriculture, 2014, 13(8):1651-1661], and the trehalose content of okra seedlings was detected. The okra plants were the leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and the leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0076] The experimental results are shown in Figure 3 A (Normal is blank control, CdCl2 stress is heavy metal stress). The results showed that after 0.1 mmol / L CdCl2 stress treatment, the trehalose content in okra plants treated with exogenous trehalose was significantly higher than that in okra plants not treated with trehalose.

[0077] Under normal conditions, the free proline content of plants is very low, but when encountering stresses such as salt and drought, the free amino acid will accumulate in large quantities, and the accumulation index is related to the stress resistance of the plant. Therefore, proline can be used as a biochemical indicator of plant stress resistance.

[0078] Determination method references [Feibing Wang, Weili Kong, Gary Wong, Lifeng Fu, RihePeng, Zhenjun Li, Quanhong Yao. AtMYB12 regulates flavonoids accumulation andabiotic stress tolerance in transgenic Arabidopsis thaliana . MolecularGenetics and Genomics, 2016, 291:1545-1559], the proline content of okra seedlings was detected. The okra plants were the leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and the leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, and sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0079] The experimental results are shown in Figure 3 In B (Normal is blank control, CdCl2 stress is heavy metal stress). The results showed that after 0.1 mmol / L CdCl2 stress treatment, the proline content in okra plants treated with exogenous trehalose was significantly higher than that in okra plants not treated with trehalose.

[0080] Chloroplasts are important organelles for plants to carry out photosynthesis and respond to stress. The photosynthetic pigments in chloroplasts include chlorophyll and carotenoids, of which chlorophyll is divided into chlorophyll a and chlorophyll b. Stress affects plant photosynthesis, increases the number of free radicals in chloroplasts, and thus destroys chlorophyll, affecting plant photosynthesis. The content of photosynthetic pigments reflects the ability of plants to carry out photosynthesis.

[0081] The determination method was based on the literature [Lichtenthaler Hartmut K, Buschmann Claus. Chlorophylls and carotenoids: measurement and characterization by UV-VISspectroscop. Current Protocols in Food Analytical Chemistry, 2001, 1], and the photosynthetic pigment content of okra seedlings was detected. The okra plants were the leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and the leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0082] The experimental results are shown in Figure 4 (Normal is blank control, CdCl2 stress is heavy metal stress). The results showed that after 0.1mmol / L CdCl2 stress treatment, the chlorophyll a ( Figure 4 A) Chlorophyll b ( Figure 4 B) Total chlorophyll ( Figure 4 C) and total carotenoid content ( Figure 4 D) was significantly higher than that of okra plants not treated with trehalose.

[0083] When plant organs age or suffer damage under adverse conditions, membrane lipid peroxidation often occurs. Malondialdehyde (MDA) is the final decomposition product of membrane lipid peroxidation, and its content can reflect the degree of damage suffered by the plant under adverse conditions. That is, the higher the MDA content, the greater the degree of damage suffered by the plant under adverse conditions.

[0084] Determination method references [Feibing Wang, Weili Kong, Gary Wong, Lifeng Fu, RihePeng, Zhenjun Li, Quanhong Yao. AtMYB12 regulates flavonoids accumulation andabiotic stress tolerance in transgenic Arabidopsis thaliana. MolecularGenetics and Genomics, 2016, 291:1545-1559], the MDA content of okra seedlings was detected. The okra plants were the leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and the leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, and sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0085] The experimental results are shown in Figure 5 A (Normal is blank control, CdCl2 stress is heavy metal stress). The results showed that after 0.1 mmol / L CdCl2 stress treatment, the MDA content in okra plants treated with exogenous trehalose was significantly lower than that in okra plants not treated with trehalose.

[0086] Electrolyte permeability is an indicator to measure the permeability of plant cell membranes. The lower the value, the more intact the cell membrane and the better its functionality.

[0087] Determination method references [Yujia Liu, Xiaoyu Ji, Xianguang Nie, Min Qu, LeiZheng, Zilong Tan, Huimin Zhao, Lin Huo, Shengnan Liu, Bing Zhang, YuchengWang. Arabidopsis AtbHLH112 regulates the expression of genes involved in abiotic stress tolerance by binding to their E-box and GCG-box motifs. New Phytologist, 2015, 207:692-709】, the electrolyte permeability of okra seedlings was detected. The okra plants were the leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and the leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, and sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0088] The experimental results are shown in Figure 5 Middle B (Normal is blank control, CdCl2 stress is heavy metal stress). The results showed that after 0.1 mmol / L CdCl2 stress treatment, the electrolyte permeability in okra plants treated with exogenous trehalose was significantly lower than that in okra plants not treated with trehalose.

[0089] Relative water content is an important indicator reflecting the water status of plants. The relative water content of plant tissues is positively correlated with plant stress resistance, and the relative water content of cells reflects the degree of stress on cells.

[0090] Determination method reference [Yufeng Yang, Shikai Guan, Hong Zhai, Shaozhen He, Qingchang Liu. Development and evaluation of a storage root-bearing sweet potato somatic hybrid between Ipomoea batatas (L.) Lam. and I. triloba L. Plant Cell, Tissue and Organ Culture, 2009, 99:83-89], the relative water content of okra seedlings was detected. The okra plants were the leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and the leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0091] The experimental results are shown in Figure 5 The results showed that after 0.1 mmol / L CdCl2 stress, the relative water content in okra plants treated with exogenous trehalose was significantly higher than that in okra plants not treated with trehalose.

[0092] 7. Determination of H2O2 content

[0093] When plants are in adverse conditions or aging, H2O2 accumulates due to the enhanced metabolism of active oxygen in the body. H2O2 can directly or indirectly oxidize biological macromolecules such as nucleic acids and proteins in cells and damage cell membranes, thereby accelerating cell aging and disintegration. Therefore, the higher the H2O2 content, the greater the degree of damage to plants caused by adverse conditions.

[0094] Determination method references [Feibing Wang, Weili Kong, Gary Wong, Lifeng Fu, RihePeng, Zhenjun Li, Quanhong Yao. AtMYB12regulates flavonoids accumulation andabiotic stress tolerance in transgenic Arabidopsis thaliana . MolecularGenetics and Genomics, 2016, 291:1545-1559], the H2O2 content of okra seedlings was detected. The okra plants were the leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and the leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0095] The experimental results are shown in Figure 5 D (Normal is blank control, CdCl2 stress is heavy metal stress). The results showed that after 0.1 mmol / L CdCl2 stress treatment, the H2O2 content in okra plants treated with exogenous trehalose was significantly lower than that in okra plants not treated with trehalose.

[0096] Superoxide dismutase (SOD) activity can be used as a physiological and biochemical indicator of plant stress resistance. The lower the SOD activity, the greater the degree of damage to the plant from adversity.

[0097] Determination method references [Feibing Wang, Weili Kong, Gary Wong, Lifeng Fu, RihePeng, Zhenjun Li, Quanhong Yao. AtMYB12 regulates flavonoids accumulation andabiotic stress tolerance in transgenic Arabidopsis thaliana . MolecularGenetics and Genomics, 2016, 291:1545-1559], detect the SOD activity of okra seedlings. The okra plants were the leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and the leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0098] The experimental results are shown in Figure 6A (Normal is blank control, CdCl2 stress is heavy metal stress). The results showed that after 0.1 mmol / L CdCl2 stress treatment, the SOD activity in okra plants treated with exogenous trehalose was significantly higher than that in okra plants not treated with trehalose.

[0099] Glutathione peroxidase (GPX) is an important peroxide-degrading enzyme widely present in the body. It is a key enzyme for removing reactive oxygen species in the body and plays an important role in plant stress resistance.

[0100] Determination method references: Hong Zhai, Feibing Wang, Zengzhi Si, Jinxi Huo, LeiXing, Yanyan An, Shaozhen He, Qingchang Liu. myo -inositol-1-phosphatesynthase gene, IbMIPS1 , enhances salt and drought tolerance and stem nematoderesistance in transgenic sweetpotato. Plant Biotechnology Journal, 2016, 14:592-602】, detect GPX activity in okra seedlings. Okra plants were leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0101] The experimental results are shown in Figure 6 In B (Normal is blank control, CdCl2 stress is heavy metal stress). The results showed that after 0.1 mmol / L CdCl2 stress, the GPX activity in okra plants treated with exogenous trehalose was significantly higher than that in okra plants not treated with trehalose.

[0102] Catalase (CAT) is widely present in plant tissues and is one of the important protective enzymes. Its function is to remove H2O2 produced during metabolism to avoid the oxidative damage of H2O2 accumulation to cells. Therefore, its activity is related to the stress resistance of plants.

[0103] Determination method reference [Yufeng Yang, Shikai Guan, Hong Zhai, Shaozhen He, Qingchang Liu. Development and evaluation of a storage root-bearing sweet potato somatic hybrid between Ipomoea batatas (L.) Lam. and I. triloba L. Plant Cell, Tissue and Organ Culture, 2009, 99:83-89], to detect the CAT activity of okra seedlings. The okra plants were leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0104] The experimental results are shown in Figure 6 The results showed that after 0.1 mmol / L CdCl2 stress, the CAT activity in okra plants treated with exogenous trehalose was significantly higher than that in okra plants not treated with trehalose.

[0105] Glutathione reductase (GR) is a ubiquitous flavin enzyme that participates in the defense system of cellular stress, and its activity is related to the stress resistance of plants.

[0106] Determination method reference [Wenjin Zhang, Zhicai Xie, Lianhong Wang, Ming Li, Duoyong Lang, Xinhui Zhang. Silicon alleviates salt and drought stress of Glycyrrhiza uralensisseedling by altering antioxidant metabolism and osmoticadjustment. Journal of Plant Research, 2017, 130:611-624], detect GR activity in okra seedlings. Okra plants were leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0107] The experimental results are shown in Figure 6 D (Normal is blank control, CdCl2 stress is heavy metal stress). The results showed that after 0.1 mmol / L CdCl2 stress, the GR activity in okra plants treated with exogenous trehalose was significantly higher than that in okra plants not treated with trehalose.

[0108] Ascorbate peroxidase (APX) is one of the important antioxidant enzymes in plant active oxygen metabolism, especially the key enzyme for removing H2O2 in chloroplasts, and is also the main enzyme for vitamin C metabolism. APX activity can be used as a physiological and biochemical indicator of plant stress resistance, and its activity is related to the stress resistance of plants.

[0109] Determination method references: Hong Zhai, Feibing Wang, Zengzhi Si, Jinxi Huo, LeiXing, Yanyan An, Shaozhen He, Qingchang Liu. myo -inositol-1-phosphatesynthase gene, IbMIPS1 , enhances salt and drought tolerance and stem nematoderesistance in transgenic sweetpotato. Plant Biotechnology Journal, 2016, 14:592-602】, detect APX activity in okra seedlings. Okra plants were leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0110] The experimental results are shown in Figure 6 Middle E (Normal is blank control, CdCl2 stress is heavy metal stress). The results showed that after 0.1 mmol / L CdCl2 stress treatment, the APX activity in okra plants treated with exogenous trehalose was significantly higher than that in okra plants not treated with trehalose.

[0111] Peroxidase (POD) activity can be used as a physiological and biochemical indicator of plant stress resistance. The lower the POD activity, the greater the degree of damage to the plant caused by adversity.

[0112] Determination method references [Feibing Wang, Weili Kong, Gary Wong, Lifeng Fu, RihePeng, Zhenjun Li, Quanhong Yao. AtMYB12 regulates flavonoids accumulation andabiotic stress tolerance in transgenic Arabidopsis thaliana . MolecularGenetics and Genomics, 2016, 291:1545-1559], the POD activity of okra seedlings was detected. The okra plants were the leaves of okra seedlings without stress in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks, and the leaves of okra seedlings treated with 0.1 mmol / L CdCl2 in the above potted identification, sprayed with 10 mmol / L trehalose aqueous solution for 2 weeks. The experiment was repeated three times, and the results were averaged.

[0113] The experimental results are shown in Figure 6 F (Normal is blank control, CdCl2 stress is heavy metal stress). The results showed that after 0.1 mmol / L CdCl2 stress, the POD activity in okra plants treated with exogenous trehalose was significantly higher than that in okra plants not treated with trehalose.

[0114] The results of physiological and biochemical indexes showed that exogenous trehalose treatment significantly improved the CdCl2 stress resistance of okra plants. The relationship between trehalose and osmotic regulation, leaf damage, photosynthesis, antioxidant enzyme system, and cell membrane system of okra under CdCl2 stress was studied, and the mechanism of trehalose in plant resistance to heavy metal stress was explored, providing a theoretical basis for its safe production in okra.

Claims

1. Use of trehalose in at least one of the following (a1)-(a33): (a1) Increase the trehalose content of okra under CdCl2 stress; (a2) preparing a product for increasing the trehalose content of okra under CdCl2 stress; (a3) Increase the proline content of okra under CdCl2 stress; (a4) preparing a product for increasing the proline content of okra under CdCl2 stress; (a5) Increase the chlorophyll a content of okra under CdCl2 stress; (a6) preparing a product for increasing the chlorophyll a content of okra under CdCl2 stress; (a7) Increase the chlorophyll b content of okra under CdCl2 stress; (a8) preparing a product for increasing the chlorophyll b content of okra under CdCl2 stress; (a9) Increase the total chlorophyll content of okra under CdCl2 stress; (a10) preparing a product for increasing the total chlorophyll content of okra under CdCl2 stress; (a11) Increase the total carotenoid content of okra under CdCl2 stress; (a12) preparing a product for increasing the total carotenoid content of okra under CdCl2 stress; (a13) Increase the relative water content of okra under CdCl2 stress; (a14) preparing a product for increasing the relative water content of okra under CdCl2 stress; (a15) Improve the SOD activity of okra under CdCl2 stress; (a16) preparing a product for improving the SOD activity of okra under CdCl2 stress; (a17) Improve the GPX activity of okra under CdCl2 stress; (a18) preparing a product for improving the GPX activity of okra under CdCl2 stress; (a19) Improved CAT activity of okra under CdCl2 stress; (a20) preparing a product for improving CAT activity of okra under CdCl2 stress; (a21) Improved GR activity of okra under CdCl2 stress; (a22) preparing a product for improving GR activity of okra under CdCl2 stress; (a23) Improve the APX activity of okra under CdCl2 stress; (a24) preparing a product for improving APX activity of okra under CdCl2 stress; (a25) Improve the POD activity of okra under CdCl2 stress; (a26) preparing a product for improving the POD activity of okra under CdCl2 stress; (a27) Reduce the MDA content of okra under CdCl2 stress; (a28) preparing a product for reducing the MDA content of okra under CdCl2 stress; (a29) Reduced electrolyte permeability of okra under CdCl2 stress; (a30) preparing a product for reducing electrolyte permeability of okra under CdCl2 stress; (a31) Reduce the H2O2 content of okra under CdCl2 stress; (a32) preparing a product for reducing the H2O2 content of okra under CdCl2 stress; (a33) Improve the resistance of okra to CdCl2 stress.

2. The use according to claim 1, characterized in that: Trehalose was sprayed on the plants with a concentration of 1-100 μmol / L.

3. A method for alleviating CdCl2 stress damage in okra, characterized in that: Trehalose with a concentration of 1-100 mmol / L is sprayed on the okra leaves.

4. The method according to claim 3, characterized in that: Trehalose with a concentration of 1-10 mmol / L is used to spray the okra on its leaves.

5. The method according to claim 4, characterized in that: The okra was foliarly sprayed with trehalose at a concentration of 10 mmol / L.

6. Application of trehalose in breeding of okra resistant to CdCl2 stress.

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