不同供铁水平下垂穗披碱草铁吸收特性及对其他矿质元素吸收的影响

用石英砂培养法研究了在不同供铁水平下，垂穗披碱草铁的吸收特性，对锰、镁、钙、硫、氮、磷、钾吸收的影响以及其铁缺乏和过剩的临界值。结果表明，在供铁０．５～１０μｇ·ｇ－１范围内，垂穗披碱草地上部和根的铁吸收方程分别为ｙ＝１２９．４６＋７２．９４ｌｏｇｘ和ｙ＝２８４．１＋１２３．４ｌｏｇｘ。随着供铁浓度的增加，垂穗披碱草根中锰和钙的吸收减少，但没有影响其向地上部的转移，地上部仅在缺铁时锰和钙的积累增大；高浓度供铁，减少了植物中氮的积累；不同供铁水平对镁、硫、磷、钾的吸收影响不大。铁的适宜供应，促进了垂穗披碱草的正常生长，其铁缺乏和中毒的临界水平分别为１３０和２００μｇ·ｇ－１。

Absorption of Element Fe by Elymus nutans at Different Levelsof Supply and its Effect on Absorption of Other Minerals

The characteristics of Fe absorption at different supply levels and its effect on the absorption of other elements, including Mn, Mg, Ca, S, N, P and K, by Elymus nutans were studied through plants grown on quartz sand in a greenhouse. The critical values of Fe deficiency and surplus by the plant were also determined. The results indicated that, within 0.510.0 g/g of Fe supply, the absorption of Fe could be described by an equation as y=129.46+72.94 log x for the aboveground parts, while y=284.1+123.4 log x for the roots of the plant. With an increase in Fe concentration supplied, the absorption of Mn and Ca by roots decreased, but their upward transfer was not affected. The accumulation of Mn and Ca in the aboveground part of the plant would increase when that part of the plant showed Fe deficiency. A supply of Fe in high concentration decreased N accumulation in the plant. Different concentrations of Fe supplied did not significantly affect the absorption of Mg, S, P and K. An appropriate nutans supply of Fe promoted normal growth of Elymus nutans, and the critical levels of Fe deficiency and poisoning were determined as 130 g/g and 200 g/g, respectively.