Bhattacharjee Soumen
Post Graduate, Department of Botany, Hoogly Mohsin College, Chinsurah-712 101, India.
J Environ Biol. 2008 Sep;29(5):805-10.
Imposition of salinity stress during early germination imposes a secondary oxidative stress in 120-hr-old Amaranthus lividus seedlings (measured in terms of accumulation of reactive oxygen species, antioxidative defense system and oxidative membrane lipid and protein damages). Seeds of Amaranthus when treated with triadimefon along with NaCI salinity significantly enhanced the activities of catalase, peroxidase and superoxide dismutase, compared to untreated salinity stressed 5-day-old seedlings. Triadimefon treatment also reduced the accumulation of both the ROS (H2O2 and O2*-) in 5-day-old Amaranthus seedlings. When oxidative membrane damages were estimated for triadimefon treated and salinity stressed juvenile seedlings and compared with untreated salinity stressed seedlings, it shows a clear reversal in oxidative membrane damages induced by triadimefon under salinity stress. Triadimefon treatment significantly reduces the membrane lipid peroxidation and the loss of membrane protein thiol level in salinity stressed Amaranthus seedlings. That triadimefon treatment under salinity stress restores the membrane integrity and improves the post-germinative seedling growth could be supported by the data of membrane injury index (MII), relative leakage ratio (RLR), membrane permeability status (MPS), relative growth index (RGI) and mean tolerance index (MTI). SDS-PAGE of total extractible proteins revealed that some new proteins were synthesized in triadimefon treated and salinity stressed seedlings as compared to untreated and salinity stressed one. However the most remarkable feature is the up-regulation of some of the stress proteins in triadimefon treated and salinity stressed seedlings. So, it appears that significant extent of salinity tolerance exhibited by triadimefon pretreated Amaranthus seedlings could be related to the mitigation of oxidative damage to the newly assembled membrane system of juvenile tissues as well as synthesis and up-regulation of stress proteins that enhanced salinity tolerance.
在苋菜种子早期萌发过程中施加盐胁迫会对120小时龄的野生苋幼苗造成继发性氧化胁迫（通过活性氧积累、抗氧化防御系统以及氧化膜脂和蛋白质损伤来衡量）。与未处理的盐胁迫5日龄幼苗相比，用三唑酮和氯化钠盐处理苋菜种子可显著提高过氧化氢酶、过氧化物酶和超氧化物歧化酶的活性。三唑酮处理还减少了5日龄苋菜幼苗中活性氧（H2O2和O2*-）的积累。当对经三唑酮处理和盐胁迫的幼苗进行氧化膜损伤评估，并与未处理的盐胁迫幼苗进行比较时，结果显示在盐胁迫下，三唑酮诱导的氧化膜损伤明显得到逆转。三唑酮处理显著降低了盐胁迫苋菜幼苗中的膜脂过氧化和膜蛋白巯基水平的损失。膜损伤指数（MII）、相对渗漏率（RLR）、膜通透性状态（MPS）、相对生长指数（RGI）和平均耐受指数（MTI）的数据表明，盐胁迫下三唑酮处理可恢复膜完整性并改善发芽后幼苗的生长。总可提取蛋白的SDS-PAGE分析表明，与未处理和盐胁迫的幼苗相比，经三唑酮处理和盐胁迫的幼苗中合成了一些新蛋白。然而，最显著的特征是经三唑酮处理和盐胁迫的幼苗中一些胁迫蛋白的上调。因此，三唑酮预处理的苋菜幼苗表现出的显著耐盐性可能与减轻对幼嫩组织新组装膜系统的氧化损伤以及合成和上调增强耐盐性的胁迫蛋白有关。
