外源钙离子对东南景天生长及锌积累的影响

采用水培试验，研究了外源添加不同浓度钙离子（Ca²⁺）对两种生态型东南景天生物量、根系形态及体内锌、钙、硫含量的影响.结果表明：随着外源Ca²⁺浓度的上升，两种生态型东南景天的干物质量均增加，且超积累生态型地上部增加显著(P<0.05)；超积累生态型根长和根表面积增加，而非超积累生态型降低；超积累生态型根、茎、叶锌含量随着外源Ca²⁺浓度的增加而上升，但各处理间差异不显著(P>0.05)，非超积累生态型地上部锌含量显著降低(P<0.05).非超积累生态型根、茎、叶钙含量与外源Ca²⁺浓度呈显著正相关(P<0.05)，超积累生态型根系硫含量与外源Ca²⁺浓度呈极显著正相关(P<0.01).外源Ca²⁺对超积累生态型东南景天锌吸收及积累有促进作用，而Ca²⁺浓度的升高抑制了非超积累生态型东南景天对锌的吸收.适当增加外源Ca²⁺可促进超积累生态型东南景天生长，改善其锌积累能力.

Effects of exogenous Ca2+ on the growth and Zn accumulation of two Sedum alfredii Hance ecotypes.

A hydroponic study was conducted to investigate the biomass, root morphology, and zinc (Zn), calcium (Ca) and sulfur (S) contents of two Sedum alfredii ecotypes under effects of different concentration calcium (Ca2+) addition. The results showed that with increasing exogenous Ca2+ concentration, the dry mass of the two S. alfredii ecotypes increased, and the shoot dry mass of hyperaccumulation ecotype increased significantly (P <0.05). The root length and root surface area of hyperaccumulation ecotype increased with increasing exogenous Ca2+ concentration, while those of non-hyperaccumulation ecotype were in adverse. The Zn accumulation in the root, stem and leaf of hyperaccumulation ecotype was increased with increasing exogenous Ca2+ concentration though the differences among Ca2+ treatments were not significant (P >0.05), while the Zn accumulation in the shoot of non-hyperaccumulation ecotype was significantly low (P <0.05). The Ca accumulation in the root, stem and leaf of non-hyperaccumulation ecotype had a significant positive correlation with the concentration of exogenous Ca2+ (P <0.05), so as the S accumulation in the root of hyperaccumulation ecotype (P <0.01). Exogenous Ca2+ promoted the Zn absorption and accumulation of hyperaccumulation ecotype, while inhibited the Zn accumulation of non-hyperaccumulation ecotype. Appropriate concentration of exogenous Ca2+ could promote the growth of hyperaccumulation ecotype S. alfredii, and improve its ability of accumulating more zinc.