Cd胁迫下接种丛枝菌根真菌对秋茄幼苗生长与抗氧化酶系统的影响

Effects of Arbuscular Mycorrhizal Inoculation and Cd Stress on the Growth and Antioxidant Enzyme System of Kandelia obovata

近年来,由于工农业发展导致的河口重金属污染等的影响,红树林退化与消失的趋势相当严重,红树林的保育恢复已成为我国环境保护工作的重点.立足于丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)与红树植物的共生关系,以红树植物秋茄(Kandelia obovata(S.,L.)Yong)为试材,在施加重金属Cd(0,5,10,20,40mg/kg)的条件下,通过接种与不接种混合AMF,对比研究从红树林生境中筛选扩繁的优势AMF菌种对秋茄幼苗生长与抗氧化酶系统的影响.研究表明:接种AMF使得秋茄幼苗的生物量增加,但株高未出现明显变化.Cd胁迫引起了秋茄叶片和根系丙二醛(MDA)含量的持续上升,且超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性表现为低含量下刺激,高含量下抑制的效应.接种AMF使得MDA含量显著减少,SOD、POD、CAT活性显著增加,从而能够更好地清除活性氧,减轻Cd胁迫下秋茄的膜脂过氧化程度,保护植物.研究揭示AMF在红树林湿地生态系统中潜在的抗重金属污染生理生态功能,为红树林污染的生物修复提供了一条新思路.

In recent decades,mangroves have degenerated dramatically in China due to estuarine heavy metal pollution resulting from industrial and agricultural development.As a result,mangrove conservation and restoration have become the priority of environmental protection.Based on the symbiotic relationships of AMF and mangrove plant,the effect of AMF on the growth and antioxidant enzyme system of Kandelia obovata （S.,L.） Yong under cadmium （Cd） stress （0,5,10,20,40 mg/kg） was studied,with or without the inoculation of four dominant AMF species selected from mangrove habitat as the mixed inocula.The results showed that AMF inoculation increased the biomass of K.obovata,while no variation was observed in plant height.Cd stress caused a continuous increase of malondialdehyde （MDA） content in leaves and roots of K.obovata,and the activities of superoxide dismutase （SOD）,peroxidase （POD）,and catalase （CAT） showed a stimulation effect under low Cd treatment strength and an inhibition effect under high Cd treatment strength.AMF inoculation significantly decreased the MDA content,meanwhile,the activities of SOD,POD,and CAT were increased,thus could scavenge more reactive oxygen species （ROS）,alleviate the degree of membrane lipid peroxidation,and protect the plant cells.This research disclosed the potential function of AMF in mangrove plant against heavy metal stress for the first time,and provided a new method of mangrove pollution bioremediation.