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作 者 ：黄建国;杨邦俊;袁玲

期 刊 ：植物营养与肥料学报 1995年 1卷 1期 页码：38-43

关键词：小麦；钾离子吸收；动力学；

Keywords:Wheat, Absorption of K ion. Kinetic,

摘 要 ：小麦不同品种吸收钾离子(K⁺)的动力学参数不同。米氏常数(Km)以绵阳11最大,红矮1最小;最大吸收速率(1max)繁6最高,红芒22最低。供试小麦各品种吸收K⁺的补偿点(Cmin)≤3.44μ.mol/L,远低于一般土壤溶液中的K⁺浓度,说明土壤溶液中K⁺浓度与小麦吸收K⁺的需要相适应。此外,硝酸根(NO₃)、吲哚乙酸(IAA)和稀土显著促进小麦吸收K⁺;但铵离子(NH₄⁺)显著抑制K⁺吸收;尿素对小麦吸收K⁺无显著影响。动力学参数的测定表明,NH₄⁺抑制K⁺吸收的原因是提高了小麦吸收K⁺的Km;而NO₃和稀土产生促进作用的原因分别是吸收K⁺的Imax增加和Km减少。IAA能促进H⁺分泌,导致小麦吸收K⁺的速率提高。

Abstract:A solution culture experiment indicated that wheat varieties varied in kinetic parameters of K⁺ absorption. The smallest values of Michealis constant for K⁺ absorption (Km) was found with var. Hongai 1. and maximum rate of K uptake (Imax) was found with Hongmang 22. The greatest value of km for K⁺ absorption was obtained with Manyang 11 and the greatest value of Imax was observed with Fan 6. The compensa-, tion concentrations for K⁺ uptake (Cmin≤3.44μmol/L) by the tested wheat varieties were lower than K⁺ concentrations in soil solutions of commonly cultivated soils. This result showed that K⁺ contents in many soil solutions are adaptable to the requirement for K⁺ uptake by wheat. Moreover, NH₄⁺ inhibited K⁺ uptake in contrast to NO₃^- , rare earth and indole acetic acid (IAA) which promoted K absorption. No obvious effect of urea on K⁺ uptake was observed. The reason for the inhibitation by NH₄⁺ was that Km for K⁺ uptake was increased. The promotion by NO₃^- was accounted for by Imax increment. The enhancement of K⁺ uptake by rare earth can be explained by Km decrement. IAA Promoted H⁺ efflux which caused increasing in the rate of K⁺ uptake.

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