锌胁迫对彩色豆马勃体内锌的分布和活性形态及其抗氧化系统的影响

Effects of zinc stress on the antioxidant system and the distribution and form of zinc of Pisolithus tinctorius

彩色豆马勃Pisolithustinctorius可广泛与林木建立外生菌根,其共生可促进植物生长,提高植物对重金属的耐受性。然而,关于彩色豆马勃对重金属锌(Zn)胁迫的生理响应还不完全清楚。本研究在纯培养条件下,测定了Zn胁迫对彩色豆马勃生物量、Zn的活性形态和亚细胞分布,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性,谷胱甘肽(GSH)、抗坏血酸(AsA)和黑色素含量的影响。结果表明,Zn胁迫抑制了彩色豆马勃的生长,在浓度为563μmol/L时,达到半数最大抑制浓度(IC50),在浓度为600μmol/L时,生物量降低42.6%。Zn在彩色豆马勃中以活性较低的草酸盐、难溶于水的磷酸盐、果胶酸盐以及与蛋白质呈结合态或吸着态的形式为主。Zn胁迫显著提高了彩色豆马勃菌丝中CAT、POD和SOD活性,增加了GSH和黑色素含量,但对AsA的含量没有显著影响。本研究表明,彩色豆马勃主要通过调节Zn的分布及抗氧化系统,增加黑色素含量,增强对Zn的耐受性,为外生菌根真菌修复重金属污染土壤提供了理论支持。

Pisolithus tinctorius can extensively establish ectomycorrhizas with forest trees,and the symbiosis can promote plant growth and improve plant tolerance to heavy metals.However,the physiological response of P.tinctorius to heavy metal zinc(Zn)stress is not completely clear.In this study,the effects of Zn stress on the biomass of P.tinctorius,the active form and subcellular distribution of Zn,superoxide dismutase(SOD),catalase(CAT),and peroxidase(POD)activity,glutathione(GSH),ascorbic acid(AsA)and melanin content under pure culture were analyzed.The results showed that Zn stress inhibited the growth of P.tinctorius,reaching the half maximum inhibitory concentration(IC50)at a concentration of 563μmol/L,and when the concentration was 600μmol/L,the biomass decreased by 42.6%.Zn in P.tinctorius is mainly in the form of low-activity oxalate,insoluble phosphate and pectinate,and the form of binding or sorption with protein.Zn stress significantly increased the activity of CAT,POD and SOD in P.tinctorius hyphae,increased the content of GSH and melanin,but had no significant effect on the content of AsA.This study shows that P.tinctorius mainly regulates the distribution of Zn and the antioxidant system to enhance the tolerance to Zn,and it provides theoretical support for remediation of heavy metal contaminated soil with the help of ectomycorrhizal fungi.