Accumulation and interaction of calcium and manganese in Phytolacca americana
2009
Dou, Changming | Fu, Xiaoping | Chen, Xincai | Shi, Jiyan | Chen, Yingxu
To further understand the hyperaccumulation of Mn, the present study investigated the accumulation of Ca and Mn and their interaction in Mn hyperaccumulator pokeweed (Phytolacca americana Linn.). Exogenous Ca was observed to have a distinctive impact on the Mn phytotoxicity and accumulation in pokeweed, but exogenous Mn had little influence on the accumulation of Ca. Both Ca and Mn accumulated in pokeweed were detected to be mainly in the form of oxalate. Investigation with SEM and TEM found there were two kinds of crystals in the leaves, Ca oxalate crystals and Mn-containing crystals. Further detection showed that there was no inclusion of Mn inside the Ca oxalate crystals, and that other elements, such as C, O and P, were present in the Mn-containing crystals. These results suggest that Ca oxalate crystals in pokeweed have no direct effect on the detoxification of Mn. In addition, the finding of element P and O in the Mn-containing crystals indicates that excess Mn could be deposited by phosphate, which could contribute to Mn accumulation and detoxification in pokeweed.
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