外源维生素B6对盐胁迫下紫花苜蓿幼苗生长及生理特性的影响OA

Soil salinization,a serious challenge to global agricultural ecosystem,has become a critical abiotic stress factor that restricts crop yield and sustainable agricultural development.Vitamin B6(VB6)is a key coenzyme involved in various enzymatic reactions and can enhance environmental adaptability by regu-lating multiple metabolic pathways.To clarify the regulatory mechanism of VB6 on the growth and physi-ological metabolism of alfalfa(Medicago sativa)seedlings under salt stress,this study used the cultivar'Zhongmu No.1'as the test material in a pot control experiment.In a preliminary experiment,we estab-lished a control(CK,normal water management),a 150 mmol/L NaCl salt stress treatment,and salt-stressed groups with foliar application of VB6 at different concentrations(10,20,50,100,200 mg/L).Based on systematic measurements of growth and physiological parameters,the optimum VB6 concentra-tion for alleviating salt stress was determined to be 50 mg/L.Based on these results,the formal experi-ment included four treatment groups:CK(normal water),V(50 mg/L VB6),S(150 mmol/L NaCl),and VS(50 mg/L VB6+150 mmol/L NaCl).The results showed that salt stress significantly inhibited seed-lings growth,reduced photosynthetic pigments content,compromised cell membrane integrity,induced reactive oxygen species accumulation,and significantly affected antioxidant enzymes activities and osmotic regulators synthesis(P<0.05).However,foliar VB6 application significantly alleviate the salt-induced growth inhibition.Specifically,growth parameters(plant height,stem diameter,leaf area)and photosyn-thetic pigments contents(chlorophyll a,chlorophyll b and carotenoid)were significantly increased.The relative conductivity,malondialdehyde,superoxide anion,and hydrogen peroxide decreased by 24.26%,34.15%,23.54%and 22.17%,respectively.Activities of superoxide dismutase,catalase,peroxidase,and ascorbate peroxidase increased by 14.84%,16.04%,27.28%,and 16.11%,respectively.Proline and soluble sugar contents increased by 16.76%and 30.64%,respectively.In conclusion,exogenous VB6 effectively alleviated salt-induced growth inhibition in alfalfa seedlings by activating antioxidant enzyme sys-tem,promoting the osmotic adjustment substances accumulation,maintaining photosynthetic pigment metabolism balance,and reducing membrane lipid peroxidation.This provides a theoretical basis for physi-ological regulation in forage cultivation on saline soil.