丛枝菌根真菌对盐碱-旱交叉胁迫下羊草幼苗生长与抗氧化酶活性的影响

何汉琼 彭晓媛 陶爽

摘要    羊草营养价值丰富、抗逆性强，是东北松嫩平原最重要的牧草之一。丛枝菌根真菌（AMF）能与绝大多数陆地植物共生，且影响其抗逆性。本文对羊草幼苗接种丛枝菌根真菌并采用NaCl、NaHCO3以及PEG来模拟不同盐（碱）-干旱胁迫条件，研究逆境交叉胁迫下共生体生长与抗氧化酶活性的变化。结果表明，在盐（碱）胁迫与干旱胁迫以及盐-旱与碱-旱交叉胁迫下，丛枝菌根真菌均一定程度提高了羊草幼苗的生物量，碱-旱互作的胁迫效应远大于盐-旱互作。盐碱和干旱胁迫下，SOD、POD和APX活性均升高，而CAT的活性则呈下降趋势，接种丛枝菌根真菌后，交叉胁迫下抗氧化酶活性同样呈上升趋势。研究结果对于深入理解羊草逆境交叉胁迫适应机理以及丛枝菌根真菌生理功能等科学问题提供了一定理论依据。

关键词    羊草;丛枝菌根真菌;盐碱;干旱;交叉胁迫;抗氧化酶

中图分类号    S154.3        文献标识码    A        文章编号   1007-5739（2019）12-0149-02

Abetract    Leymus chinensis is one of the most important forages in the Songnen Plain of Northeast China because of its rich nutritional value and strong stress resistance.Arbuscular mycorrhizal fungi（AMF）can coexist with a large number of terrestrial plants and affect their stress resistance.In this paper，AMF was inoculated into Leymus chinensis seedlings，the changes of symbiotic growth and antioxidant enzyme activities under cross stress were studied by using NaCl，NaHCO3 and PEG to simulate different types of salt（alkali）-drought stress conditions.The results showed that AMF increased the biomass of Leymus chinensis seedlings to a certain extent under salt（alkali）stress and drought stress，as well as salt-drought and alkali-drought cross-stress.The stress effect of alkali-drought interaction was much greater than that of salt-drought interaction.Under saline-alkali and drought stress，the activities of SOD，POD and APX increased，while the activities of CAT decreased.After inoculating with AMF，the activities of antioxidant enzymes also increased under cross-stress.The research results provide a theoretical basis for understanding the adaptation mechanism of the cross- stress and the physiological functions of AMF.

Key words    Leymus chinensis;AMF;saline-alkali;drought;cross-stress;antioxidant enzyme

羊草（Leymus chinensis）是禾本科多年生禾草，主要分布在我国东北地区，具有较好的耐盐碱性，对恢复退化草地有着重要意义[1]。近年来，土壤盐碱化问题日益严峻，对农牧业以及环境业发展产生了深远的影响。东北地区属干旱半干旱气候，蒸发量往往大于降水量，干旱胁迫也已经成為制约植物发展的重要非生物环境因子[2]。因此，对于松嫩丰原盐碱草地植物来说，往往面临的是盐碱胁迫与干旱胁迫形成的交叉胁迫逆境。

丛枝菌根真菌在陆地生态系统中分布广泛，能与80%以上的植物形成共生关系，与植物关系极为密切[3-4]。……