[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.