Farshian Shadi, Khara Jalil, Malekzadeh Parviz
Faculty of Science, Urmia University, Urmia, Iran.
Pak J Biol Sci. 2007 Jul 15;10(14):2363-7. doi: 10.3923/pjbs.2007.2363.2367.
The effects of zinc toxicity on growth, chlorophyll, total sugar and protein content and mineral content of lettuce plants infected or not by Arbuscular Mycorrhizal (Am) fungus Glomus etunicatum and treated with nutrient solution containing 0, 1.5, 3.5, 5.5, 7.5 mM ZnSO, were studied. The introduction of Zn caused a decrease in the inhibiting effect of zinc on dry weight of roots and shoots of lettuce plant infected by Am in contrary with non-Am plants. This increase observed in dry weight may be due to improvement of Phosphorous uptake by mycorrhizal fungi. The decrease in dry weight of non-Am plants may be because of inhibitory effects of zinc on growth. Chlorophyll and total sugar content decreased in both Am and non-Am plants, which indicate the toxic effect of Zn on photosynthesis and carbohydrate metabolism. Mycorrhizal plants due to changing the translocation of Zn and sequestering in the hypha could elevate the effects of Zn to some extent. Total protein content increased in Am plants, probably due to induction of antioxidant enzymes and some stress proteins but reduced in non-Am plants which maybe caused by toxic effects of Zn on protein synthesis. Alleviating the severe effects of Am fungus observed in this study aroused an interest in considering the role of Am fungi in protection and elevation the sever effects of heavy metals in plants.
研究了锌毒性对接种或未接种丛枝菌根（AM）真菌幼套球囊霉（Glomus etunicatum）且用含0、1.5、3.5、5.5、7.5 mM硫酸锌（ZnSO₄）的营养液处理的生菜植株生长、叶绿素、总糖和蛋白质含量以及矿物质含量的影响。与未接种AM的植株相反，锌的引入导致锌对接种AM的生菜植株根系和地上部干重的抑制作用减弱。观察到的干重增加可能是由于菌根真菌对磷吸收的改善。未接种AM的植株干重下降可能是由于锌对生长的抑制作用。接种和未接种AM的植株中叶绿素和总糖含量均下降，这表明锌对光合作用和碳水化合物代谢具有毒性作用。菌根植物由于改变了锌的转运并将其螯合在菌丝中，在一定程度上可能会增强锌的影响。接种AM的植株中总蛋白质含量增加，可能是由于抗氧化酶和一些胁迫蛋白的诱导，但未接种AM的植株中总蛋白质含量降低，这可能是由于锌对蛋白质合成的毒性作用所致。本研究中观察到的减轻AM真菌严重影响的现象引发了人们对考虑AM真菌在保护植物以及提高植物对重金属严重影响的耐受性方面作用的兴趣。
