干旱及复水条件下接种AMF和根瘤菌对疏叶骆驼刺根系生长的影响

Effect of Double Inoculation of AMF and Rhizobia on Root Growth of Alhagi sparsifolia under Drought and Rehydration Conditions

疏叶骆驼刺为塔里木河下游优势草本植物,对下游地区防风固沙,涵养水源具有重要的生态价值。该试验以疏叶骆驼刺为研究对象,设定正常水分(土壤相对含水量70%±5%)、干旱胁迫(土壤相对含水量20%±5%)和复水处理(干旱胁迫60 d后恢复至正常水分)3个水分梯度,以及单接种丛枝菌根真菌、单接种根瘤菌、双接种丛枝菌根真菌+根瘤菌和不接种4组接种处理,分析不同水分条件下各接种处理对疏叶骆驼刺根系生长的影响。结果表明:(1)双接种丛枝菌根真菌+根瘤菌处理的疏叶骆驼刺根系AMF侵染率在干旱胁迫、复水条件下均显著降低,且低于单接种AMF处理。(2)随着正常水分→干旱胁迫→复水的水分变化,双接种处理疏叶骆驼刺根系根瘤数量先降低后增加,复水后显著高于单接种根瘤菌处理。(3)双接种处理扩大了疏叶骆驼刺的根系吸收范围,提高了根系的吸收能力,并随着正常水分→干旱胁迫→复水的水分变化,呈现先降低后增加的变化趋势。(4)双接种处理显著提高了疏叶骆驼刺根系SOD和POD活性,并随着正常水分→干旱胁迫→复水的水分变化而逐渐升高。研究发现,双接种AMF+根瘤菌处理可以显著促进疏叶骆驼刺根系的生长,增强其抗逆性,而干旱胁迫会降低AMF和根瘤菌的协同促进作用,复水后双接种AMF+根瘤菌处理的疏叶骆驼刺能及早地做出响应,对其根系生长表现出一定的补偿效应。

As a dominant herb in the lower reaches of Tarim River,Alhagi sparsifolia has important ecological value for wind prevention,sand fixation and water conservation in the lower reaches.At the same time,as a herb,it is more sensitive to ecological water transmission than Tamarix and Populus euphratica.Therefore,this paper takes A.sparsifolia as the research object,and sets three water gradients for normal water(D0,soil relative water content 70%±5%)Drought stress(D1,soil relative water content 20%±5%),rehydration treatment(D2,return to normal water after 60 days of drought stress)and four groups of inoculation treatment[single inoculation of arbuscular mycorrhizal fungi(AMF),single inoculation of rhizobia(R),double inoculation of arbuscular mycorrhizal fungi+rhizobia(AMF+R)and no inoculation]to analyze the effects of double inoculation of arbuscular mycorrhizal fungi and rhizobia on the root growth of A.sparsifolia under different water conditions.The results showed that:(1)the infection rate of AMF+R under D1 and D2 water conditions was significantly lower than that of AMF alone.(2)The number of nodules decreased first and then increased with the change of water content of D0-D1-D2.After rehydration,it was significantly higher than that of A.sparsifolia treated with rhizobium alone.(3)The root absorption range of A.sparsifolia was expanded,the root absorption capacity was improved,and they were decreased first and then increased with the change of water content of D0-D1-D2.(4)The activities of SOD and POD were significantly increased,and gradually increased with the change of water content of D0-D1-D2.It was found that double inoculation of AMF and rhizobia could significantly promote the root growth and enhance its stress resistance,while drought stress would reduce the synergistic promotion effect of AMF and rhizobia.After rehydration,double inoculation of AMF and rhizobia could respond as soon as possible and show a certain compensation effect on its root growth.