茉莉酸调控下东南景天根际氮循环与镉富集效应研究OA

Cadmium(Cd)contamination seriously threatens farmland ecological security,and improving the remediation efficiency of hyperaccumulator plants is critical for the management of Cd-contaminated soils.Sedum alfredii Hance was used as the test plant,and a soil culture system was employed to evaluate the regulatory effects of exogenous jasmonic acid(JA)on plant growth,Cd accumulation,nitrogen metabolism,and the rhizosphere microecology.The results showed that JA significantly promoted plant growth and increased Cd accumulation in the shoots.JA treatment significantly increased NH4+-N and NO3--N contents in plants and enhanced the activities of key nitrogen metabolism enzymes,including nitrate reductase and glutamine synthetase.Meanwhile,JA treatment significantly increased dissolved organic carbon(DOC)and dissolved organic nitrogen(DON)contents,as well as the activities of urease,sucrase,and acid phosphatase in the rhizosphere soil,indicating that rhizosphere nitrogen cycling and nutrient transformation processes were strengthened by JA.Microbial community analysis showed that JA treatment increased bacterial and fungal diversity and selectively enriched plant growth-promoting bacteria,nitrogen-cycling functional microorganisms,and Cd-tolerant microorganisms,thereby significantly improving the rhizosphere microecological structure.Comprehensive analysis indicated that JA enhanced Cd accumulation efficiency in Sedum alfredii by synergistically promoting plant nitrogen metabolism,rhizosphere nitrogen cycling,and the structure of microbial functional groups.This study reveals a new pathway for Cd remediation mediated by plant hormones through the coordinated regulation of the"plant-rhizosphere-microorganism"system and provides a theoretical basis for improving the remediation potential of hyperaccumulator plants.