Subcellular distribution of chromium in accumulating plant Leersia hexandra Swartz
Subcellular distribution of chromium in accumulating plant Leersia hexandra Swartz
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积累植物Leersia hexandra Swartz体内铬的亚细胞分布
DOI：
10.1007/s11104-009-9907-2
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发表时间：
2009-09-01
期刊：
影响因子：
4.9
通讯作者：
Hu, Cheng
中科院分区：
文献类型：
--
作者：
Liu, Jie;Duan, Chang-Qun;Hu, Cheng
采用差速离心、透射电镜和X射线能谱分析等方法，研究了铬在中国特有的富铬植物李氏禾（Leersia hexandra Swartz）中的亚细胞分布。含铬组织的亚细胞分级表明，大部分积累的铬被隔离到细胞壁在根和叶片中的液泡。当植物生长在含有60 mg L−1 Cr的营养液中时，83.2%的根Cr位于细胞壁部分，而57.5%的叶Cr位于液泡和细胞质部分。透射电子显微镜分析表明，这些细胞室含有特别是电子致密区。能量色散X射线谱显示电子致密区含有高Cr。然而，没有铬处理的植物细胞中从未观察到暗电子沉淀。在所有处理组（5、30和60 mg L-1）中，含有最低水平Cr的组分是根和叶中的细胞器组分。这些结果表明，铬在L. hexandra优先储存在根的细胞壁和叶的液泡中。这一现象使铬离子从代谢活性区室（叶绿体、线粒体）中转移，从而降低了铬对植物细胞的毒性。
The subcellular distribution of chromium in Leersia hexandra Swartz, a Cr-accumulating plant found in China, was studied by differential centrifugation, transmission electron microscope and energy dispersive analysis of X-ray. Subcellular fractionation of Cr-containing tissues showed that most of the accumulated Cr was isolated to the cell walls in roots and the vacuoles in leaves. When the plant was grown in a nutrient solution containing 60 mg L−1 Cr, 83.2% of the root Cr was localized in the cell wall fraction, while 57.5% of leaf Cr was localized in the vacuole and cytoplasm fraction. Transmission electron microscopic analysis revealed that those cell compartments contained especially electron dense areas. Energy dispersive X-ray spectra showed the electron dense areas contained high Cr. However, the dark electron precipitates were never observed in the plant cells without Cr treatment. In all treatment groups (5, 30 and 60 mg L−1), the fraction containing the lowest level of Cr was the organelle fraction in roots as well as leaves. These results indicated that Cr accumulated in the L. hexandra was preferentially stored in the cell walls of roots and the vacuoles of leaves. This phenomenon diverted Cr ions from metabolically active compartment (chloroplast, mitochondria), resulting in a reduction of Cr toxicity in the plant cell.