Cd Distribution and Subcellular Localization in Leaf and Its Effects on Growth of Soybean(Glycine max) Seedlings

镉在大豆幼苗叶中的亚细胞分配、定位及其对幼苗生长的影响(英文)

In order to investigate Cd accumulation, subcellular distribution, and local-ization in soybean seedlings leaves, soybean seedlings were cultivated in solution containing different concentrations of Cd. The results showed that most Cd associ-ated with the cellwal s and soluble fractions, and a minor part of Cd presented in mitochondria fractions, nuclear and chloroplast fractions, especial y exposure to high Cd concentrations. Under 20.00 mg/L Cd stress, Cd subcellular distribution fol owed a sequence as： soluble fractions （55.00%）＆gt;cellwal s （30.0%）＆gt;mitochondria fractions （8.21%）＆gt;nuclear and chloroplast fractions （6.79%）. Deposited Cd black particles were observed in cellwal s, chloroplasts, nuclei, and vacuoles through electrical microscope slice. This fact indicated that the cellwal s of soybean leaves were the first protecting organel es from Cd toxicity, and the cellwal s and soluble fractions were the main place for Cd storage. Due to Cd accumulated in the organel es, the intercellular space was enlarged and the subcellular structure was damaged, especial y for the chloroplasts.

该研究采用水培试验方法,用不同浓度的Cd溶液培养大豆幼苗14天,研究了Cd在大豆幼苗叶片中的累积、亚细胞分配与定位及幼苗的生长状况。结果表明:低浓度的Cd对大豆幼苗的生长具有刺激效应,但高浓度的Cd胁迫能抑制其生长;叶中Cd随着溶液中Cd浓度的增加而显著增加;在高浓度Cd胁迫下,绝大部分Cd束缚在细胞壁和可溶性成分中,少部分储存在细胞核、叶绿体、线粒体等细胞器中;在细胞壁、叶绿体、细胞核和液泡中可以观察到黑色Cd颗粒沉淀;细胞间隙扩大,亚细胞结构受损尤其是叶绿体;细胞壁是叶细胞保护内部细胞器的第一屏障,细胞壁和细胞可溶性成分是储存Cd的主要部位。