Pretreatment with Antioxidants Decreases the Effects of Salt Stress on Chloroplast Ultrastructure in Rice Leaf Segments (Oryza sativa L.)
Pretreatment with Antioxidants Decreases the Effects of Salt Stress on Chloroplast Ultrastructure in Rice Leaf Segments (Oryza sativa L.)
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DOI：
10.1626/pps.7.292
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发表时间：
2004-01
影响因子：
2.5
通讯作者：
K. Yamane;Shahidur Rahman;M. Kawasaki;M. Taniguchi;H. Miyake
中科院分区：
文献类型：
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作者：
K. Yamane;Shahidur Rahman;M. Kawasaki;M. Taniguchi;H. Miyake
摘要研究了盐胁迫下水稻叶绿体超微结构破坏的活性氧种类。幼苗生长3周后，从第5片叶的中间部分切下叶段（5 mm见方）。叶段在黑暗或光照条件下在200 mM NaCl中孵育24 hr。在200 mM NaCl中，叶段中的叶绿素含量在光照下在12- 24 hr之间急剧下降，但在黑暗中没有观察到减少。在电子显微镜的研究中，200 mM NaCl引起肿胀的类囊体和破坏类囊体膜在光。另一方面，在黑暗条件下未观察到超微结构变化。在一个实验中，在光中与抗氧化剂预孵育12小时后，将叶片段在200 mM NaCl中在光中孵育24小时。用抗坏血酸和苯甲酸盐预处理，分别抑制H_2O_2和H_2OH，有效地抑制了叶绿素含量的下降和叶绿体在光下NaCl的破坏。而Tiron和DABCO则分别抑制O2-和1 O2，不能抑制光下盐胁迫的影响。盐胁迫（200 mM NaCl）使Fe-SOD活性增加约8倍，但过氧化氢酶活性降低至对照的69%，抗坏血酸过氧化物酶活性不受NaCl影响。这些结果表明，盐胁迫对叶绿体的伤害依赖于光，H_2O_2和H_2OH是盐胁迫对叶绿素含量和叶绿体超微结构造成伤害的主要原因。
Abstract We investigated the kinds of active oxygen species leading to the destruction of chloroplast ultrastructure in salt-stressed rice plants. After the seedlings were grown for 3 wks, leaf segments (5 mm square) were cut from the middle portion of the 5th leaves. Leaf segments were incubated in 200 mM NaCl under dark or light conditions for 24 hr. The chlorophyll content in the leaf segments drastically decreased in light between 12- and 24 hr in 200 mM NaCl, but, no reduction was observed in the dark. In electron microscopic studies, 200 mM NaCl caused swelling of thylakoids and destruction of thylakoid membranes in light. On the other hand, no ultrastructural changes were observed under dark condition. In one experiment, leaf segments were incubated in 200 mM NaCl for 24 hr in light after preincubation with antioxidants for 12 hr in light. Pretreatment with ascorbate and benzoate, which scavenge H2O2 and ˁOH, respectively, effectively suppressed the reduction of chlorophyll content and the destruction of chloroplasts by NaCl in light. However, Tiron and DABCO, which scavenge O2- and 1O2, respectively, could not suppress the effects of salt stress in light. Fe-SOD activity was increased about eight time by salt stress (200 mM NaCl), but, catalase activity was reduced to 69% of the control and ascorbate peroxidase activity was not affected by NaCl. These results suggested that salt-induced injury in chloroplasts is dependent on light, and that H2O2 and ˁOH are responsible for the deleterious effects of salt stress on chlorophyll content and chloroplast ultrastructure.