接种AMF对‘阿坝’垂穗披碱草根系耐低温生理的影响

Effects of AMF inoculation on low-temperature tolerance physiology of Elymus nutans‘Aba’roots

为明确丛枝菌根真菌(AMF)对禾本科牧草耐低温能力的影响,本研究以根内球囊霉(Glomus intraradices,GI)和‘阿坝’垂穗披碱草(Elymus nutans‘Aba’)为试验材料,通过盆栽法,探究了低温条件下[15℃/10℃,16 h/8 h(光照/黑暗)]接种根内球囊霉对‘阿坝’垂穗披碱草根系生理特性的影响。结果表明:1)低温对‘阿坝’垂穗披碱草的菌根侵染率无显著影响(P>0.05)。2)低温增加了‘阿坝’垂穗披碱草根系中过氧化氢(H_(2)O_(2))和丙二醛(MDA)含量,降低了超氧阴离子产生速率(O_(2)^(·-)),而接种GI抑制了由低温引起的H2O2和MDA含量的积累,对O_(2)^(·-)的影响不显著。3)低温增加了超氧化物歧化酶(SOD)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性,降低了过氧化氢酶(CAT)活性,其中SOD、POD和APX活性均是接种组(LT-AMF)显著低于不接种组(LT)(P<0.05)。4)低温显著增加了可溶性蛋白(SP)含量,降低了甜菜碱(Gb)含量,对游离脯氨酸(Pro)含量无显著影响,接种GI显著降低了SP含量,对Pro和Gb含量无显著影响。综上所述,接种GI能通过增加抗氧化酶活性和降低渗透胁迫强度增强‘阿坝’垂穗披碱草根系对低温的耐受能力。

In this study,we sought to determine the effects of arbuscular mycorrhizal fungi(AMF)on the low-temperature tolerance of Gramineae grasses using the fungus Glomus intraradices(GI)and grass Elymus nutans‘Aba’.Pot-based experiments were conducted to investigate the effects of inoculation with GI on the root physiological characteristics of E.nutans‘Aba’at low temperature(15℃/10℃,16 h/8 h,day/night).The results revealed that low temperature had no significant effects on the rate of mycorrhizal infection of E.nutans‘Aba’.However,low temperature was found to promote increases in the contents of hydrogen peroxide(H_(2)O_(2))and malondialdehyde(MDA)and reductions the rate of superoxide anion production(O_(2)^(·-))in the root system of E.nutans‘Aba’,whereas GI inhibited the accumulation of H2O2 and MDA caused by low temperature,although had no significant effects on O_(2)^(·-).Low temperature was also found to enhance the activities of superoxide dismutase(SOD),peroxidase(POD),and ascorbate peroxidase(APX),although caused a reduction in the activity of catalase(CAT).Moreover,the activities of SOD,POD,and APX in the inoculation group(LT-AMF)were significantly lower than those in the non-inoculation group(LT)(P<0.05).Furthermore,low temperature promoted significant increases in the content of soluble protein(SP)and reductions in the content of betaine(Gb),although had no significant effects on the content of free proline(Pro).Inoculation with GI contributed to a significant reduction in the content of SP,although had no significant effects on the contents of Pro and Gb.In conclusion,by promoting the activities of antioxidant enzymes and reducing the intensity of osmotic stress,inoculation with G.intraradices can enhance the low-temperature tolerance of E.nutans‘Aba’.