NTA对玉米体内Cu、Zn的积累及亚细胞分布的影响

通过向多金属复合污染土壤中加入螯合剂氨三乙酸(NTA)并运用差速离心法研究了NTA对玉米根、茎和叶中Cu、Zn亚细胞分布的影响.结果表明:Cu和Zn在玉米细胞内的分布特征与其吸收和富集重金属能力密切相关,NTA能显著促进Cu和Zn在玉米体内的吸收和积累并且影响重金属在细胞壁和液泡内的分布.在玉米细胞内,细胞壁是Cu的主要结合位点,其次为含液泡的细胞质部分,只有少量的Cu分布在叶绿体、线粒体、细胞核等细胞器组分中;Zn更趋向于分布在以液泡为主的细胞质中,并且在细胞器中也有较高的分布.在NTA诱导下,Cu和Zn在液泡内的分布呈强化趋势,有从细胞壁向细胞质转移的趋势,叶片中细胞器的重金属也部分向细胞质转移.

Influence of NTA on Accumulation and Subcellular Distribution of Copper and Zinc in Corn(Zea mays)

The differential centrifugation method was used to study the subcellular distribution of Cu and Zn in the roots,stems and leaves of corn(zea mays) growing on multi-metal contaminated soil with the addition of chelator Nitrilotriacetic Acid(NTA).The results show that the subcellular distributions of Cu and Zn have significant relationship with the ability of metal uptake and accumulation in corn.NTA could evidently promote the uptake and accumulation of Cu and Zn in corn and affect on their distribution in cell wall and vacuole.Most of Cu was bound to the cell wall fraction and secondly cytoplasm fraction and only a small quantity of Cu bound to organelle fractions.For Zn,however,most of Zn was bound to cytoplasm fraction and there was more Zn bound to organelles than Cu.Under the inducement of NTA,there were increasing Cu and Zn bound to cytoplasm fraction,which mostly came from cell wall fraction and partly came from organelle fractions.