锌在再力花体内的富集性及亚细胞分布和化学形态研究

为研究Zn在再力花(Thalia dealbata Fraser)体内的富集性及亚细胞分布和化学形态,依次设定0(CK)、0.075 mmol.L 1、0.250 mmol.L 1、0.500 mmol.L 1、1.000 mmol.L 1、2.000 mmol.L 16个Zn处理浓度,对再力花进行水培培养的胁迫试验。结果表明:再力花不能有效地将Zn运输到地上部,Zn主要积累在根部。在系列Zn浓度处理下,转运系数均<1,得出再力花并非超富集植物。在此基础上,采用差速离心技术和化学试剂逐步提取法,研究Zn在该植物根系中的亚细胞分布和化学形态。结果表明:低浓度0(CK),0.075mmol.L 1,0.250 mmol.L 1]Zn处理下,Zn主要分布于再力花根部的细胞壁、细胞核及叶绿体中;Zn在再力花根部的存在形态主要是乙醇提取态,占50%以上,其次是氯化钠提取态。随着Zn处理浓度的提高(0.500 mmol.L 1,1.000 mmol.L 1,2.000 mmol.L 1),细胞溶质成为Zn的最主要分布位点,分别占31.15%、45.12%和56.44%,其次为细胞壁;乙醇提取态的比例有所下降,氯化钠提取态、水提取态的比例则随着处理浓度的提高而提高至30%以上,成为Zn在再力花根部的三大存在形态。

Determinating zinc accumulation, sub-cellular distribution and chemical forms of Thalia dealbata Fraser

In this study, 6 zinc concentrations were used in Thalia dealbata Fraser aquaculture to determine the enrichment, and root sub-cellular fraction distribution and chemical forms of zinc of T. dealbata. The zinc concentrations were 0 (CK), 0.075 mmol·L^-1, 0.250 mmol·L^-1, 0.500 mmol·L^-1, 1.000 mmol·L^-1 and 2.000 mmol·L^-1. The results showed the zinc was not effectively transportable to the above-ground part of T. dealbata and was mainly accumulated in roots.T. dealbata was not a hyper-accumulator as all the transfer coefficients were less than 1 under different zinc concentrations. On that basis, differential centrifugation technique and sequential chemical extraction method were used to study sub-cellular distribution and chemical forms of zinc in roots of T. dealbata. The results showed that under low znic concentrations (CK, 0.075 mmol·L^-1 and 0.250 mmol·L^-1), zinc was mainly bounded to cell walls, cell nucli and chloroplasts. Ethanol extractable zinc was in a dominant extractable state and accounted for over 50%, followed by NaCl extractable zinc in T. dealbata roots. With increasing zinc concentrations (0.500 mmol·L^-1, 1.000 mmol·L^-1 and 2.000 mmol·L^-1), cytosol became the main zinc distribution site in T. dealbata roots, followed by cell walls. Zinc in cytosol respectively accounted for 31.15%, 45.12% and 56.44%. The proportion of ethanol extractable zinc dropped while NaCl and water extractable zinc increased with increasing zinc concentration, accounting for over 30% of extracted zinc. Ethanol, NaCl and water extractable zinc were the three main zinc chemical forms.