Effects Of Several Biostimulants On Growth And Stress Resistance Of Cherry Radish And Wheat

Although biostimulant has been discovered for many years,due to its high requirements for standardized application,strict dosage,narrow range of action concentration,and unclear action mechanism,it is difficult to achieve large-scale promotion;in addition to the application of biostimulants,there are also problems of abiotic stress in agricultural production,especially high temperature and salt stress.High temperature stress damages cell membranes,causing active oxygen bursts leading to membrane lipid peroxidation and electrolyte extravasation,affecting plant growth and development.In addition,salt stress,as one of the abiotic stresses,not only damages plants,but also leads to a lack of nutrients such as iron and phosphorus.Therefore,it is great practical significance to select the best biostimulants and appropriate concentration for the target crops and to clarify its mechanism of promoting and resisting stress.In the study,different kinds and concentrations of biostimulants,such as paecilomyces variotii,sodium humate,brassin-heteroauxin-gbberellic acid,alginic acid crude extract,peptide-chelated iron,melatonin and glycine betaine,were tested on cherry radish and wheat,we screened out the most suitable species and concentrations for the promotion of cherry radish,and explored the stress resistance mechanism of biostimulants on cherry radish through high temperature stress experiment.In addition,based on the theory of wheat laboratory culture experiment,the application of biostimulant to the study of saline-alkali soil of wheat was expected to provide theoretical and technical support for the practical application of biostimulant.The research results are as follows:（1）In the test biostimulant,compared with control treatment,the yield of radish treated with2.50×10^-3mg L^-1 paecilomyces variotii and 200mg L^-11 humic acid sodium increased by 64.2%and25.7%;2.50×10^-3mg L^-1 paecilomyces variotii treated the dry matter accumulation of radish roots and the root-shoot ratio were significantly increased by 69.1%,and 87.1%,respectively;and the total soluble protein was significantly increased by 50.1%,the peroxidase activity increased by31.3%.Under the experimental conditions,paecilomyces variotii of 2.50×10^-3mg L^-1 could significantly improve the root yield,dry matter accumulation,root shoot ratio and quality of cherry radish,and the growth promoting effect was significant.（2）Under the condition of continuous high temperature stress at 30℃,compared with HT treatment,the concentration of peptide-chelated iron at 21.0mg L^-1 significantly increased the cherry radish biomass by 26.0%;the auxin and proline content increased by 144.2%and 229.9%;in addition,the ascorbate peroxidase activity and glutathione reductase activity were significantly increased by 21.7%and 11.7%.Therefore,the application of 21.0mg L^-1 peptide-chelated iron can significantly increase the levels of endogenous hormones and the antioxidant system enzyme activity of cherry radish,thereby significantly alleviating high temperature stress damage and increasing biomass.In the high temperature（35℃）stress experiment,melatonin and glycine betaine concentrations of 29.0mg L^-1 and 17.58mg L^-1,respectively,had the best effect on promoting stress resistance,compared with HT treatment,and the biomass increased significantly by 12.9%and 44.7%,respectively.and as a significant improvement in quality indicators,soluble protein was increased by 18.7%and 14.4%respectively.At this concentration,the antioxidant enzyme activity was significantly increased,among them,the peroxidase activity was significantly increased by 45.5%and 81.0%at 27 days.In addition,the auxin content at the seedling stage was significantly increased by 28.5%and 67.4%respectively.Therefore,suitable concentrations of melatonin and glycine betaine have greater potential for increasing yield and quality under conditions of high temperature stress.（3）Under salt stress,compared with NaCl100 treatment,the above-ground fresh weight of hydroponic wheat treated with paecilomyces variotii was significantly increased by 9.8%,ascorbate peroxidase activity and ascorbic acid content were significantly increased by 20.9%and 40.9%,respectively,and the content of hydrogen peroxide and malondialdehyde were significantly reduced by 25.4%and 17.6%,respectively;the content of proline was significantly increased by 13.7%.In the field test of lightly salinized soil,compared with U treatment,the yield of wheat treated with U+ZNC was significantly increased by 27.8%.At the jointing and grain filling stages of wheat,leaf area index was increased by 13.3%and 64.8%respectively.In addition,ascorbate peroxidase activity and ascorbic acid content increased by 34.1%and 40.4%,respectively,and the hydrogen peroxide content was reduced by 19.6%and 37.7%,respectively.In this experiment,the application of paecilomyces variotii could improve the tolerance of wheat under salt stress.In conclusion,in the study,a model crop cherry radish was used to screen a low-cost biostimulant:paecilomyces variotii.The physiological and biochemical mechanism of peptide chelated iron,melatonin and glycine betaine to improve the high temperature tolerance of vegetable model crop cherry radish was explored,and paecilomyces variotii was realized in the application of salinized soil on wheat,it provides theoretical and data support for the promotion and application of biostimulants.