Purpose

Agronomic practices are one of the reasons for the increasing accumulation of elements in the soil, including manganese (Mn). Our previous studies have shown that selenium (Se) ions can reduce the toxic actions of metal stress. Those, we studied the effects of Mn—treated as a stressor and Se – as a potential defense in plants.

Methods

Mn ions (10 mM) or/and Se (15 μM) were added into hydroponic nutrients of two wheat cultivares. The evaluation of the stress-generating and protective actions were analyzed by biochemical methods and microscopic observations in leaves and roots. Moreover the level of DNA methylation for these tissues was determined.

Results

Mn application caused an increase of lipid peroxidation and hydrogen peroxide content in both leaves and roots and was accompanied with a greater absorption of this element by the roots. For other elements (K, Fe, S, P), with the exception of Ca, the reduced their uptake was registered, especially in roots. For roots, Mn stimulated greater, microscopically observed, desorganization in cell structure as compared to leaves, which was accompanied by a quantitative increase in 5-methylcytosine (5-metC) in root meristem. Se application diminished the effects of Mn-stress.

Conclusions

These studies is the first in which indicated that global 5-metC level in roots enhancing from dividing meristematic cells to elongating cells of the axial cylinder and cortex. It was suggested that the rise in Ca level can lead to modification of root cells differentiations what may be one of the steps in defense mechanisms.

中文翻译：

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锰胁迫下小麦幼苗根茎反应中硒补充的意义——生化和细胞学研究

目的

农艺实践是土壤中元素积累增加的原因之一，包括锰 (Mn)。我们之前的研究表明，硒 (Se) 离子可以减少金属应力的毒性作用。那些，我们研究了锰（被视为压力源）和硒作为植物潜在防御的影响。

方法

将锰离子 (10 mM) 或/和硒 (15 μM) 添加到两种小麦品种的水培营养物中。通过生化方法和叶片和根的显微观察分析了胁迫产生和保护作用的评价。此外，还确定了这些组织的 DNA 甲基化水平。

结果

Mn application caused an increase of lipid peroxidation and hydrogen peroxide content in both leaves and roots and was accompanied with a greater absorption of this element by the roots. For other elements (K, Fe, S, P), with the exception of Ca, the reduced their uptake was registered, especially in roots. For roots, Mn stimulated greater, microscopically observed, desorganization in cell structure as compared to leaves, which was accompanied by a quantitative increase in 5-methylcytosine (5-metC) in root meristem. Se application diminished the effects of Mn-stress.

Conclusions

这些研究首次表明根中的整体 5-metC 水平从分裂的分生组织细胞提高到轴柱和皮层的伸长细胞。有人提出，Ca 水平的升高可导致根细胞分化的改变，这可能是防御机制的步骤之一。