Silicon amelioration of manganese toxicity in Mn-sensitive and Mn-tolerant maize varieties
Silicon amelioration of manganese toxicity in Mn-sensitive and Mn-tolerant maize varieties
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DOI：
10.1016/j.envexpbot.2008.11.006
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发表时间：
2009-03-01
影响因子：
5.7
通讯作者：
Barcelo, J.
中科院分区：
文献类型：
--
作者：
Doncheva, Sn.;Poschenrieder, C.;Barcelo, J.
评价了两个玉米品种耐锰过量和硅改良的差异。干重、胼胝质积累、叶绿体超微结构和光合参数被用作胁迫指标。品种Kneja 605比品种Kneja 434更敏感。在Kneja 605过量的锰造成严重的叶绿体损伤和增强类胡萝卜素的生产，症状类似于那些引发的光合作用。在锰耐Kneja 434，相比之下，锰诱导的类胡萝卜素的浓度下降，只有轻微的变化，叶绿体中观察到。这些影响与轻度缺铁症状相似。锰诱导胼胝质积累的阈值组织浓度在Kneja 605中比在Kneja 434中低得多。因此，耐过量锰在Kneja 434不是由于更有效的排斥，但更有效的解毒和锰的区室化。组成性较厚的表皮层在Kneja 434和观察，Si诱导的改善锰毒性在Kneja 605大大增加了表皮层的厚度表明，锰存储在非光合组织可能是一个锰耐受机制在玉米。(C)2008 Elsevier B.V.保留所有权利。
Differences in tolerance to Mn excess and amelioration by Si were evaluated in two maize varieties. Dry weight, callose accumulation, chloroplast ultrastructure, and photosynthesis parameters were used as stress indicators. Variety Kneja 605 was much more Mn-sensitive than variety Kneja 434. In Kneja 605 excess Mn caused severe chloroplast damage and enhanced carotenoid production, symptoms similar to those triggered by photoinhibiton. In Mn-tolerant Kneja 434, in contrast, a Mn-induced decrease of the carotenoid concentrations, and only slight alterations in the chloroplasts were observed. These effects were similar to light Fe-deficiency symptoms. The threshold tissue concentration for Mn-induced callose accumulation was much lower in Kneja 605 than in Kneja 434. Therefore tolerance to excess Mn in Kneja 434 was not due to more efficient exclusion but to more efficient detoxification and compartmentation of Mn. The constitutively thicker epidermal layers in Kneja 434 and the observation that Si-induced amelioration of Mn toxicity in Kneja 605 substantially increased the thickness of the epidermal layers suggest that Mn storage in non-photosynthetic tissue could be a Mn tolerance mechanism in maize. (C) 2008 Elsevier B.V. All rights reserved.