锰在商陆叶片的细胞分布及化学形态分析

Subcellular Distribution and Chemical Fractions of Manganese in Leaves of Hyperaccumulator Phytolacca acinosa Roxb.

商陆(Phytolacca acinosa Roxb.)是在中国境内首次发现的锰超积累植物,叶片是商陆累积锰的主要器官。本文主要采用化学分析、差速离心及色谱技术对商陆叶片锰的细胞分布和化学形态进行了研究并探讨了商陆超累积和解毒锰的机制。细胞分配的结果表明,锰主要分布在商陆叶片的细胞质可溶性部分(含液泡),含量高达74%-82%,细胞壁结合的锰占总锰的15%-20%,细胞器锰含量最少,仅为3%-6%。不同提取剂的实验结果表明,商陆叶片中的Mn均以水提取态为主,为总Mn含量的83%-91%;不同锰浓度处理下,商陆叶片草酸含量高于500μmol·g-1(干重),达到干重的9%-11%,但不同锰浓度处理下草酸的含量并无明显变化趋势,表明高含量的草酸的累积是商陆本身具有的特性,而非外界锰的诱导产生。

Phytolacca acinosa Roxb. （P. acinosa） is a Mn hyperaccumulating plant firstly found in China. To understand the accumulation mechanism of Mn in leaves of P. acinosa, the distribution and species of Mn in P. acinosa leaves were investigated in this study. Results showed that Mn preferred to accumulate in the supernatant part, accounting for 74%～82% of the total Mn in the leaves. About 15%～20% of the total Mn combined with cell wall, while only 3%～6% of total Mn in organelles. 83%～91% Mn in the leaves was water extractable with different extracting agents. The oxalic acid concentration in the leaves was more than 500 μmol·g^-1 （DW）, contributing to 9%～11% of total dry weight of leaves. However, the oxalic acid concentration in leaves did not increase with the application of Mn, indicating that oxalic acid was not induced by exogenous Mn contents.