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Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) are ubiquitous contaminants and can be considerably accumulated by natural plants. In order to elucidate the biochemical and physiological responses of plant to PCDD/Fs, tobacco Bright Yellow-2 (BY-2) cells were selected as model plant and treated with time- and concentration-dependent PCDD/Fs. The toxic effect and oxidative stress caused by PCDD/Fs were evident, which could be indicted by the reduction in fresh mass, the increase in malondialdehyde (MDA) content, and the damage of tobacco cell ultrastructure. PCDD/Fs tolerance was correlated with changes in antioxidant system and hormones of tobacco cells. Superoxide dismutase (SOD) and peroxidase (POD) exhibited peak enzyme activities at the PCDD/Fs concentration of 1000 ng WHO98-TEQ g−1 fresh weight. Glutathione reductase (GR) enzyme activity increased monotonically at high level PCDD/Fs, but the activity of catalase (CAT) was only slightly affected at all treatment. Meanwhile, the exposure to PCDD/Fs resulted in the changes of hormones content. With the increase of exposure concentration of PCDD/Fs, the levels of indole-3-acetic acid (IAA) and abscisic acid (ABA) increased, whereas the concentration of jasmonates (JAs) decreased. The above results suggest that tobacco cells had the ability to cope with the oxidative stress induced by low concentration of PCDD/Fs through increasing the activities of antioxidant enzymes and alternating plant hormones levels. However, oxidative stress and toxicity would burst out when plant cells were exposed to the high levels of PCDD/Fs. 相似文献
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砷(As)污染对作物生长有毒害作用,导致作物品质和产量降低,因此亟需采取安全有效的策略以减轻其毒害.采用水培法,通过荧光探针定位技术、差速离心技术和傅里叶红外光谱技术(FTIR)研究外源茉莉酸(JA)对水稻幼苗As积累及抗逆应答的影响.结果表明,外源添加JA使水稻地下部和地上部的As含量分别降低31.4%和51.4%,显著降低细胞壁和细胞液中的As含量.JA改变亚细胞组分中As的分布比例,使细胞壁中As的分布比例提高16.4%,细胞液中As的分布比例降低17.3%,增强细胞壁对As的固定,减少细胞液中的As含量.此外,JA提高根细胞中SOD、CAT、GSH和PEPC的水平,降低H2 O2和MDA含量,减轻脂质过氧化损伤,调节碳氮代谢,缓解As毒害.研究为水稻As污染防治提供了新思路. 相似文献
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