CN111436439A - Application of exogenous melatonin in improving salt tolerance of beet seedlings - Google Patents

Abstract

The invention provides an application of exogenous melatonin to improve the salt tolerance of sugar beet seedlings. Using sugar beet KWS0143 as a test material, the relationship between melatonin and leaf cell membrane damage, antioxidant enzyme system and osmotic regulating substances of sugar beet under salt stress is studied. To explore the mechanism of melatonin in plants resisting salt stress. It lays a foundation for exploring the role of melatonin in the salt resistance mechanism of sugar beet, and provides the possibility for the actual production in salt land.

Description

Application of exogenous melatonin to improve salt tolerance of sugar beet seedlings

technical field

The invention belongs to the technical field of biotechnology, and in particular relates to an application of exogenous melatonin for improving the salt tolerance of sugar beet seedlings.

Background technique

Soil salinization and secondary salinization are the main factors affecting agricultural production. Currently, about 800 million hectares of land in the world have been salinized, including 20% of arable land and nearly 50% of irrigated land (FAO). , 2009; http://www.fao.org/ag/agl/agll/spush). The area of land salinization in my country is about 99.13 million hm2, which has seriously threatened the ecological environment and the sustainable development of agriculture. Salt stress has many effects on plants: reducing chlorophyll content, causing physiological water deficit, and ion toxicity; high concentrations of salt will destroy the metabolic balance of reactive oxygen species in plants, and the increase in the accumulation of reactive oxygen species will lead to membrane lipid peroxidation, resulting in a large amount of The malondialdehyde and superoxide free radicals, etc., will eventually cause plant metabolism disorder, slow growth, and even death. How to improve the salt tolerance of crops and increase the yield of crops under salt stress has always been the focus of attention. For many years, people have cultivated salt-tolerant crop varieties through a series of methods such as transgenic, but the progress is still limited. However, due to the complexities and controversies associated with GM crops, these genes have little application in actual agricultural practice. Therefore, to find new plant growth regulators, effective ways to improve crop salt tolerance and crop yield. Melatonin (N-acetyl-5-methoxytryptamine) is a well-known animal hormone with a wide range of biological functions, such as circadian rhythm, immune regulation, tumor suppression and reduction of oxidative stress. So far, melatonin has also been found to be a ubiquitous regulator (such as an osmo-regulator, antioxidant, and growth promoter) in a variety of plant developmental processes and various stress responses.

Sugar beet (Beta vulgaris L.) is the main raw material for sugar production in the world and one of the main economic crops in my country. It occupies an extremely important position in the national economy and people's life. The aim of this study was to investigate the effects of melatonin on sugar beet growth, antioxidant enzymes and osmotic regulators under salt stress. These information provide a new way to promote the growth of sugar beet under salt stress, and also provide new ideas for the possibility of seedling raising in the production of sugar beet in saline soil.

SUMMARY OF THE INVENTION

Application of melatonin in improving salt tolerance of sugar beet.

The application of melatonin is at least one of the following (a1)-(a5):

(a1) promoting the growth of sugar beet under salt stress;

(a2) Alleviating the oxidative damage of sugar beet under salt stress;

(a3) increasing the activity of antioxidant enzymes in sugar beet under salt stress;

(a4) increasing the proline content in sugar beet under salt stress;

(a5) increasing betaine content in sugar beet under salt stress;

A product whose active ingredient is melatonin; the use of the product is at least one of the following (b1)-(b6):

(b1) promoting the growth of sugar beet under salt stress;

(b2) Alleviating oxidative damage of sugar beet under salt stress;

(b3) increasing the activity of antioxidant enzymes in sugar beet under salt stress;

(b4) increasing the proline content in sugar beet under salt stress;

(b5) increasing betaine content in sugar beet under salt stress;

The application of melatonin in production; the use of the product is at least one of the following (b1)-(b6):

(c1) promoting the growth of sugar beet under salt stress;

(c2) Alleviating oxidative damage of sugar beet under salt stress;

(c3) increasing the activity of antioxidant enzymes in sugar beet under salt stress;

(c4) increasing the proline content in sugar beet under salt stress;

(c5) increasing betaine content in sugar beet under salt stress;

A method for raising and cultivating sugar beet seedlings, comprising the following steps: using melatonin with a concentration of 0-9 mM to perform irrigation pretreatment on the sugar beet.

The method of claim 5, wherein the sugar beet is pretreated with melatonin at a concentration of 6 mM.

A method for improving the resistance of sugar beet to salt stress, comprising the steps of: performing irrigation pretreatment on the sugar beet with melatonin at a concentration of 0-9 mM.

The method of claim 7, wherein the sugar beet is pre-irrigated with melatonin at a concentration of 6 mM.

Application of melatonin in salt-resistant exercise in sugar beet seedlings.

Application of the method described in any one of claims 5-8 in salt-resistant exercise in sugar beet seedling raising.

Any of the sugar beets described above may be sugar beet KWS0143.

The invention uses sugar beet KWS0143 as the test material to study the relationship between melatonin and the leaf cell membrane damage, antioxidant enzyme system and osmotic adjustment substances of sugar beet under salt stress, and to explore the action mechanism of melatonin in plants resisting salt stress. It lays a foundation for exploring the role of melatonin in the salt resistance mechanism of sugar beet, and provides the possibility of its production in saline soil.

Description of drawings

Fig. 1 is a graph showing the comparison of the effects of exogenous melatonin on the growth of salt-stressed sugar beet seedlings;

Figure 2 is a graph showing the comparison of the effects of exogenous melatonin on the content of malondialdehyde (MDA) in leaves of salt-stressed seedlings;

Figure 3 is a comparison chart of the effect of exogenous melatonin on the content of superoxide anion (O ₂ ^- ) in leaves of salt-stressed seedlings;

Figure 4 is a graph showing the comparison of the effects of exogenous melatonin on the activity of superoxide dismutase (SOD) in leaves of salt-stressed seedlings;

Figure 5 is a comparison chart of the effect of exogenous melatonin on peroxidase (POD) activity in leaves of salt-stressed seedlings;

Figure 6 is a comparison diagram of the effect of exogenous melatonin on the activity of catalase (CAT) in leaves of salt-stressed seedlings;

Figure 7 is a comparison chart of the effect of exogenous melatonin on the proline content of salt-stressed seedling leaves;

Figure 8 is a comparison chart of the effect of exogenous melatonin on the betaine content of leaves of salt-stressed seedlings;

Detailed ways

The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments.

The invention discloses the application of melatonin in increasing the activity of antioxidant enzymes and the content of osmotic regulating substances in plant tissues.

The plant tissue is in a salt-stressed environment. Further, the plant is a dicotyledonous plant of the family Chenopodiaceae. The concentration of the active ingredient in the melatonin is 3 to 9 mM. The Chenopodiaceae dicotyledonous plant is sugar beet KWS0143 (KWS company, Germany).

The invention also discloses a promoter for antioxidant enzyme activity and osmotic regulation substances in plant tissue, the active ingredient of which is melatonin (analytical pure, Sigma company).

Cultivation conditions: Seeds were sown in pots with vermiculite, placed in a plant growth room (23/18°C, day/night), 14 hours of light per day, light intensity of 450 μmol m ^-2 s ^-1 , relative humidity control at 60±5%. After emergence, the seedlings were irrigated and cultured with Hoagland nutrient solution, and the uniform seedlings were transferred to 1/2 Hoagland nutrient solution after 10 days. Change the culture medium every 3 days and keep the pH of the solution at 7.0.

When the first pair of true leaves of the seedlings were fully expanded, they were pretreated with Hoagland nutrient solution containing 4 different concentrations of melatonin (0, 3, 6 and 9 μM) for 3 days before salt treatment, and mixed with neutral salt (NaCl and 9 μM). The molar ratio of Na ₂ SO ₄ is 2:1), 1/3 of the total amount of mixed salt is added every 24h, and added in 3 times, so that the final Na concentration is 300 mM, and a control (CK, no NaCl or Na ₂ is added) is set _SO4 ).

There are 8 experimental groups, namely

(a) blank control, without adding melatonin and salt, expressed as M0;

(b) Melatonin 3 μM, denoted as M3;

(c) Melatonin 6 μM, denoted as M6;

(d) Melatonin 9 μM, denoted as M9;

(e) salt stress, expressed as M0+S;

(f) Salt stress after melatonin 3 μM pretreatment, expressed as M3+S;

(g) Salt stress after pretreatment with melatonin 6 μM, expressed as M6+S;

(h) Salt stress after pretreatment with melatonin 9 μM, denoted as M9+S.

Sampling method:

Plant leaves were sampled 1d and 7d after the end of the salt treatment. The seedlings of each treatment were randomly divided into 3 parts, the first part was used to directly determine the morphological indicators, the second part was quickly frozen in liquid nitrogen and then placed in a -80 °C ultra-low temperature refrigerator for use, and the third part was dried at 105 °C and then dried at 80 °C. dry spare;

test methods

Malondialdehyde (MDA) content was determined by thiobarbituric acid (TBA) colorimetric method; superoxide anion (O ₂ ^- ) was determined by hydroxylamine hydrochloride method; superoxide dismutase (SOD) activity was determined by nitrogen blue tetrazolium Reduction method; peroxidase (POD) activity was measured by guaiacol method; catalase (CAT) activity was measured by ultraviolet spectrophotometry; proline was measured by sulfosalicylic acid method; sugar beet The alkali content was determined by the Reid's salt method. The experiment used a randomized block design with three replicates. Different lowercase letters represent significant differences between treatments with different concentrations of melatonin under salt stress or control (P<0.05); different capital letters represent significant differences between treatments under salt stress and controls at the same concentration (P<0.05). The experimental results are as follows:

1. The effect of exogenous melatonin on the growth of salt-stressed sugar beet seedlings:

Figure 1 shows that the application of melatonin had no significant effect on the fresh and dry weight of sugar beet seedlings under non-salt stress conditions. Salt stress significantly reduced fresh weight and dry weight on day 7, by 63.02% and 58.73%, respectively. In contrast, in the plants treated with melatonin, after 7 days of salt treatment, the fresh weight of the seedlings in each treatment decreased by only 55.15%, 42.43% and 49.50%, respectively; Weight was 26.11%, 57.60% and 30.12% higher. The dry weight of seedlings in each treatment decreased by 48.98%, 35.45% and 43.68%, respectively; the dry weight of melatonin-treated seedlings was 26.82%, 57.06% and 29.90% higher than that of untreated seedlings, respectively.

2. The effect of exogenous melatonin on the content of malondialdehyde (MDA) in leaves of salt-stressed seedlings:

Figure 2 shows that under non-salt stress conditions, the application of melatonin had no significant effect on the MDA content of seedling leaves. Salt stress significantly increased the MDA content on days 1 and 7 by 174.13% and 203.61%, respectively. In contrast, in plants pretreated with melatonin, the MDA content of seedling leaves increased by only 93.34%, 68.98%, and 68.80%, respectively, after 1 day of salt treatment; meanwhile, the MDA content of melatonin-pretreated seedlings was higher than that of untreated Seedlings were 34.61%, 46.30% and 43.01% lower. In plants pretreated with melatonin, after 7 days of salt treatment, the MDA content of seedling leaves increased by only 119.55%, 76.69% and 40.82%, respectively, compared with non-salt treatment; meanwhile, the MDA content of melatonin-pretreated seedlings was 26.76%, 40.68% and 49.65% lower than untreated seedlings.

3. The effect of exogenous melatonin on the content of superoxide anion (O ₂ ^- ) in leaves of salt-stressed seedlings:

Figure 3 shows that under non-salt stress conditions, the application of melatonin had no significant effect on the O ₂ -content ^of seedling leaves. Salt stress significantly increased by 55.54% and 72.90% on days 1 and 7, respectively. In contrast, in plants pretreated with melatonin, the O ₂ -content ^of seedling leaves increased by only 40.67%, 16.52%, and 20.01%, respectively, after 1 day of salt treatment; at the same time, the O ₂ -content of melatonin ^- pretreated seedlings 18.87%, 31.24% and 24.25% lower than untreated seedlings, respectively. In plants pretreated with melatonin, after 7 days of salt treatment, the O ₂ ^- content of seedling leaves increased by only 30.65%, 17.02% and 19.75%, respectively, compared with non-salt treatment; ₂ ^- content was 17.08%, 23.19% and 17.89% lower than that of untreated seedlings, respectively.

4. The effect of exogenous melatonin on the activity of superoxide dismutase (SOD) in leaves of salt-stressed seedlings:

Figure 4 shows that under non-salt stress conditions, application of melatonin had no significant effect on SOD activity in seedling leaves. Salt stress was reduced by 38.74% and 18.23% on days 1 and 7, respectively. In contrast, in plants pretreated with melatonin, after 1 day of salt treatment, the SOD activity of seedling leaves decreased by only 20.78%, increased by 2.01% and decreased by 16.56%, respectively; meanwhile, the SOD activity of melatonin-pretreated seedlings was higher than Untreated seedlings increased by 33.53%, 68.46% and 26.31%. In plants pretreated with melatonin, after 7 days of salt treatment, the SOD activity of seedling leaves decreased by only 6.24%, increased by 1.04%, and decreased by 14.09%, respectively, compared with non-salt treatment; meanwhile, SOD of melatonin-pretreated seedlings The activities were 21.09%, 29.76% and 14.21% higher than that of untreated seedlings, respectively.

5. Effects of exogenous melatonin on peroxidase (POD) activity in leaves of salt-stressed seedlings:

Figure 5 shows that under non-salt stress conditions, application of melatonin had no significant effect on POD activity in seedling leaves. Salt stress increased by 94.17% and 101.67% on days 1 and 7, respectively. In contrast, in plants pretreated with melatonin, the POD activity of seedling leaves increased by only 360.32%, 390.88%, and 146.47%, respectively, after 1 day of salt treatment; Seedlings increased by 106.12%, 174.55% and 21.61%. In plants pretreated with melatonin, after 7 days of salt treatment, the POD activity of seedling leaves increased by only 195.61%, 389.50% and 119.11%, respectively, compared with non-salt treatment; meanwhile, the POD activities of melatonin-pretreated seedlings were Compared with untreated seedlings, it increased by 39.83%, 122.41% and 2.28%.

6. The effect of exogenous melatonin on the activity of catalase (CAT) in leaves of salt-stressed seedlings:

Figure 6 shows that under non-salt stress conditions, application of melatonin had no significant effect on CAT activity in seedling leaves. Salt stress decreased by 13.98% and increased by 33.29% on days 1 and 7, respectively. In contrast, in plants pretreated with melatonin, CAT activity in seedling leaves increased by only 14.07%, 51.75%, and 33.75%, respectively, after 1 day of salt treatment; Seedlings increased by 31.60%, 75.07% and 55.87%. In plants pretreated with melatonin, after 7 days of salt treatment, the CAT activity of seedling leaves was only increased by 69.32%, 99.43% and 66.84%, respectively, compared with non-salt treatment; meanwhile, the CAT activity of melatonin-pretreated seedlings, respectively Compared with untreated seedlings, it increased by 28.02%, 49.90% and 25.41%.

7. Effects of exogenous melatonin on proline content in leaves of salt-stressed seedlings:

Figure 7 shows that under non-salt stress conditions, the application of melatonin had no significant effect on the proline content of seedling leaves. Salt stress increased by 82.37% and 23.39% on the 1st and 7th days, respectively. In contrast, in plants pretreated with melatonin, the proline content of seedling leaves increased by only 237.00%, 479.70%, and 132.87%, respectively, after 1 day of salt treatment; meanwhile, the proline content of melatonin-pretreated seedlings Compared with untreated seedlings, it increased by 91.22%, 216.95% and 28.21%, respectively. In plants pretreated with melatonin, after 7 days of salt treatment, the proline content of seedling leaves increased by only 44.93%, 99.22% and 83.67%, respectively, compared with non-salt treatment; at the same time, the proline content of melatonin-pretreated seedlings The amino acid content was increased by 13.39%, 67.91% and 52.30% compared with the untreated seedlings, respectively.

8. The effect of exogenous melatonin on the content of betaine in leaves of salt-stressed seedlings:

Figure 5 shows that under non-salt stress conditions, the application of melatonin had no significant effect on the betaine content of seedling leaves. Salt stress increased by 3.54% and 76.16% on days 1 and 7, respectively. In contrast, in plants pretreated with melatonin, the betaine content of seedling leaves increased by only 6.33%, 13.82%, and 4.37%, respectively, after 1 day of salt treatment; meanwhile, the betaine content of melatonin-pretreated seedlings was higher than Untreated seedlings increased by 3.17%, 12.67% and 4.43%. In plants pretreated with melatonin, after 7 days of salt treatment, the betaine content of seedling leaves increased by only 106.79%, 167.50% and 157.12%, respectively, compared with non-salt treatment; meanwhile, the betaine content of melatonin-pretreated seedlings The contents were increased by 4.86%, 34.78% and 29.89% compared with untreated seedlings, respectively.

Claims (10)

1. An application of exogenous melatonin for improving the salt tolerance of sugar beet seedlings. 2. the application of melatonin according to claim 1 is at least one of following (a1)-(a5): (a1) promoting the growth of sugar beet under salt stress; (a2) Alleviating the oxidative damage of sugar beet under salt stress; (a3) increasing the activity of antioxidant enzymes in sugar beet under salt stress; (a4) increasing the proline content in sugar beet under salt stress; (a5) Increase betaine content in sugar beet under salt stress. 3. A product whose active ingredient is melatonin; the use of the product is at least one of the following (b1)-(b6): (b1) promoting the growth of sugar beet under salt stress; (b2) Alleviating oxidative damage of sugar beet under salt stress; (b3) increasing the activity of antioxidant enzymes in sugar beet under salt stress; (b4) increasing the proline content in sugar beet under salt stress; (b5) Increase betaine content in sugar beet under salt stress. 4. The application of melatonin in production; the use of the product is at least one of the following (b1)-(b6): (c1) promoting the growth of sugar beet under salt stress; (c2) Alleviating oxidative damage of sugar beet under salt stress; (c3) increasing the activity of antioxidant enzymes in sugar beet under salt stress; (c4) increasing the proline content in sugar beet under salt stress; (c5) Increase betaine content in sugar beet under salt stress. 5. A method for raising and cultivating sugar beet seedlings, comprising the steps of: irrigating the sugar beet with a concentration of 0-9 mM melatonin. 6. The method of claim 5, wherein the sugar beet is pretreated with melatonin at a concentration of 6 mM. 7. A method for improving the resistance of sugar beet to salt stress, comprising the steps of: irrigating the sugar beet with melatonin at a concentration of 0-9 mM. 8. The method of claim 7, wherein the sugar beet is subjected to irrigation pretreatment with melatonin at a concentration of 6 mM. 9. The application of melatonin in salt-resistant exercise of sugar beet seedlings. 10. Application of the method described in any one of claims 5-8 in salt-resistant exercise in sugar beet seedling raising.

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