Research And Development Of Seed Coating Agent For Promoting Germination In Sorghum Under Salt Stress And Analysis Of Its Physiological Function

In this experiment,Liaoza 19 sorghum seeds were used as experimental materials.Through the selection of seed coating agents,the best formulation of seed coating agent was determined.Through the verification of pot experiment under salt stress,the regulation effect of exogenous regulator seed coating on Sorghum germination and seedlings under salt stress was revealed from the aspects of seed germination,seedlings physiology and biochemistry The main results of this experiment are as follows:1.Through the screening of exogenous regulators such as ascorbic acid,melatonin,brassinolide,salicylic acid,proline and so on,it was determined that salicylic acid and proline as the effective components of seed coating were the best for sorghum germination and seedling growth under salt stress.Through Box-Behnken response surface test analysis,the best seed coating agent was 7.8mg/L salicylic acid and 10mg/L proline.2.Under salt stress,the germination rate,plant height,root length,fresh and dry weight of aboveground part,fresh weight and dry weight of root of coated sorghum seedlings were significantly higher than those of uncoated sorghum seedlings,showing good salt tolerance.3.The relative conductivity and MDA content of coated sorghum seedlings under salt stress were lower than those of uncoated sorghum seedlings.The activities of SOD,POD,CAT and APX of coated sorghum seedlings under salt stress were significantly higher than those of uncoated sorghum seedlings,which indicated that coated sorghum seeds could significantly improve the antioxidant enzyme activity under salt stress.Therefore,coated sorghum seedlings had stronger active oxygen scavenging ability,reduced the damage of active oxygen to membrane lipids and showed better salt tolerance.4.Under salt stress,the Na⁺ content in leaves and roots of uncoated sorghum seedlings was significantly higher than that of coating treatment.The K⁺ content of coated sorghum seedlings was significantly higher than that of uncoated seedlings,and the K⁺/Na⁺ content of coated sorghum seedlings was higher than that of uncoated sorghum seedlings,and the K⁺/Na⁺ content of coated sorghum seedlings was higher than that of uncoated sorghum seedlings,and the salt tolerance was stronger.5.The content of osmoregulation substances in coated sorghum seedlings was significantly higher than that in uncoated sorghum seedlings.Under salt stress,the coated sorghum seedlings accumulated osmotic protective substances to resist osmotic stress and reduce the damage caused by salt.6.Under salt stress,the chlorophyll content of coated sorghum was significantly higher than that of uncoated sorghum.Under salt stress,the net photosynthetic rate,stomatal conductance and transpiration rate of coated sorghum were significantly higher than those without coating,and the intercellular CO₂ was significantly lower than that of uncoated sorghum.Under salt stress,the NPQ?chlorophyll fluorescence non photochemical quenching? of coated sorghum seedling leaves increased,and the thermal dissipation system started to consume excessive light energy in the form of thermal dissipation,which improved the light protection ability.Under salt stress,the QP?photochemical quenching coefficient? of the coated sorghum seedling leaves was higher than that of the uncoated treatment,and the photosynthetic activity was higher.