长柔毛委陵菜对锌的吸收动力学特性

Kinetic characteristics of Zn uptake by Potentilla griffithii Hook.f.var.velutina Card.

采用水培方法研究了不同Zn处理水平和处理时间下长柔毛委陵菜对锌的吸收动力学特性．结果表明，在10mg·L^-1 Zn处理下，植株地上部和根系的Zn含量均在第8天达到最高值，分别为2．49×10^3mg·kg^-1和2．21×10^3mg·kg^-1；在100mg·L^-1 Zn处理下，植株地上部的Zn含量在第16天达最高值1．23×10^3mg·kg^-1，而根系Zn含量不存在饱和现象．在0—160mg·L^-1 Zn处理下，植株叶片和叶柄Zn含量随Zn处理水平的提高显著增加，Zn浓度大于160mg·L^-1后，植株叶片和叶柄Zn含量不再随介质中Zn浓度的提高而增加（甚至减少），根系含Zn含量与介质中的Zn浓度和培养时间呈正相关，且根系Zn吸收动力学曲线具有二型性，即开始为快速的线性吸收，随后是较缓慢的饱和吸收，两者分界点约在1～2h。这可能分别与根细胞壁吸附Zn和Zn跨根细胞膜运输有关．

The kinetic characteristics of Zn uptake by Potentilla griffithii Hook. f. var. velutina Card. were studied with hydroponic culture under different Zn supply and its exposure time. When the Zn supply was 10 mg · L^-1, the Zn concentration in shoot and root reached the peak on the 8th day, being 2. 49×10^3mg·kg^-1 and 2. 21 × 10^3 mg · kg^-1 , respectively; while when the supply was 100 mg · L^-1, the Zn concentration in shoot reached the maximum （ 1.23 ×10^3mg·kg^-1 ） on the 16^th day, but that in root did not exhibit saturation. The Zn concentration in leaf and leafstalk increased with increasing Zn supply from 0 to 160 mg · L^-1, but had no increase or even decreased when the Zn supply was higher than 160 mg · L^-1. The Zn concentration in root exhibited a positive correlation with Zn supply and its exposure time, and the kinetic curve of Zn uptake fitted linear-quadratic （LQ） model, i. e. , fast linear uptake first and slow saturation uptake later, with the dividing point at about 1-2 hours＇ exposure, which could be related with the Zn adsorption on root cell wall and the Zn transportation across the cell membrane.