放线菌Act12对Pb胁迫下黑麦草根系生长及抗性生理的影响

采用菌剂接种及盆栽实验,研究了不同水平Pb胁迫条件下放线菌Act12对黑麦草根系生长和抗性生理的影响。结果显示,土壤Pb胁迫水平不同,对黑麦草根系生长和生理特性的影响不同。接入放线菌后,黑麦草根分蘖和根鲜重较对照增加了12.3%~44.2%和19.2%~94.6%,对根系生长有显著的促进作用;接菌后根系过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和过氧化物酶(POD)活性较对照也有所增加,尤其在高浓度Pb胁迫下(500~1000 mg·kg~(-1))对3种酶的促进作用最显著;接菌显著降低了根系丙二醛(MDA)含量,显著增加了根系活力。研究表明,Pb胁迫下,放线菌Act12的接入可增强根系抗氧化酶活性,降低质膜过氧化损伤,提高根系活力和根系对Pb胁迫的耐受性,进而显著促进黑麦草根系生长。

Effects of actinomycetes Act12 on the root growth and resistant physiology of perennial ryegrass under Pb stress

An inoculation pot experiment was conducted to investigate the effects of actinomycetes Act12 on the growth and resistant physiology of perennial ryegrass under Pb stress. Results showed that different levels of Pb stress affected the growth and physiological characteristics of ryegrass roots to various degrees. However, when inoculated with actinomycetes the root tiller number and root fresh weight were increased by 12.3%~44.2% and 19.2%~94.6%, respectively compared to control, indicating that actinomycetes could significantly promote root growth.Actinomycetes-inoculation increased root enzyme activities of catalase(CAT), superoxide dismulase(SOD) and peroxidase(POD) compared to control as well particularly in high level Pb stress(500~1000 mg·kg^-1). Moreover, actinomycetes-inoculation decreased root malondiadehyde(MDA) content and increased root activity significantly.The study indicates that inoculation with Act12 could increase root antioxidant enzyme activities, reduce peroxidation damage of plasma membrane, improve root activity and Pb tolerance, and thus significantly promote root growth of ryegrass under Pb stress.