Farshian Shadi, Khara Jalil, Parviz Malekzadeh
Department of Biology, Faculty of Science, Urmia University, Urmia, Iran.
Pak J Biol Sci. 2007 Jun 1;10(11):1865-9. doi: 10.3923/pjbs.2007.1865.1869.
Zinc is one of the eight trace elements which are essential for the normal healthy growth and reproduction of crop plants. Plants possess cellular mechanisms that may be involved in the detoxification of heavy metals and thus confer plants a better tolerance against them. Arbuscular mycorrhizal fungi colonization is one of these mechanisms. Here, the effect of mycorrhizal fungus G. etunicatum on Zn toxicity tolerance through enhanced activity of some of antioxidant enzymes has been studied. Treatments were applied in triplicates of two factorial analyses: (a) mycorrhizal and non-mycorrhizal; (b) 5 levels of Zinc (0, 1.5, 3.5, 5.5, 7.5 mM). Zinc was added to modified Hoagland's nutrient solution (with half P concentration). Plants were grown in growth chamber for 10 weeks. Toxicity symptoms such as necrosis and chlorosis appeared on the leaves. Activity of detoxifying enzymes Guaiacol peroxidase (GUPX) and Ascorbate peroxidase (APX) were measured. GPX activity in roots and shoots of mycorrhizal and non-mycorrhizal plants was increased. Also, APX activity increased in roots and shoots ofmycorrhizal and non-mycorrhizal plants. Root length colonization (RLC) was measured by gridline intersect method. Mycorrhizal colonization decreased due to Zinc exposure. The results indicate the probable role of arbuscular mycorrhizal colonization in stress tolerance.
锌是作物正常健康生长和繁殖所必需的八种微量元素之一。植物具有可能参与重金属解毒的细胞机制，从而使植物对重金属具有更好的耐受性。丛枝菌根真菌定殖就是其中一种机制。在此，研究了菌根真菌埃氏巨孢囊霉通过增强某些抗氧化酶的活性对锌毒性耐受性的影响。处理进行了两个因素分析的三次重复：（a）菌根和非菌根；（b）5个锌水平（0、1.5、3.5、5.5、7.5 mM）。将锌添加到改良的霍格兰营养液（磷浓度减半）中。植物在生长室中生长10周。叶片上出现了坏死和黄化等毒性症状。测定了解毒酶愈创木酚过氧化物酶（GUPX）和抗坏血酸过氧化物酶（APX）的活性。菌根和非菌根植物根和地上部分的GPX活性均增加。此外，菌根和非菌根植物根和地上部分的APX活性也增加。通过网格交叉法测量根长度定殖率（RLC）。由于锌暴露，菌根定殖减少。结果表明丛枝菌根定殖在胁迫耐受性中可能发挥的作用。
