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作 者 ：魏红旭, 徐程扬, 马履一, 江俐妮, 李雪莲, 杨卓

期 刊 ：植物营养与肥料学报 2010年 16卷 2期 页码：407-412

关键词：落叶松；吸收动力学；氮；根系；

Keywords:Larix olgensis, absorption kinetics, nitrogen, root,

摘 要 ：采用养分吸收动力学原理并利用溶液培养法研究了不同生长期的长白落叶松苗木对NH⁺₄和NO^-₃的吸收特点。结果表明，单一氮源条件下，苗木根系吸收NH⁺₄、NO^-₃的速率均随着苗木的生长呈下降趋势，并且苗木对于NH⁺₄的吸收速率整体上高于NO^-₃。与无NO^-₃时相比，在速生期加入NO^-₃会影响载体与NH⁺₄的亲和力，从而大幅度降低苗木对于NH⁺₄的吸收速率，但不会明显影响苗木在生长初期和木质化期对于NH⁺₄的吸收速率。与单一NO^-₃为N源时相比，NH⁺₄的加入会降低苗木在速生期对于NO^-₃的载体亲和力，从而影响其吸收速率，但是会明显提高根系在生长初期吸收NO^-₃的载体数量和速率。在长白落叶松苗木的养分培育过程中，为了提高苗木对于氮的利用效率，建议以铵态氮肥为主，但是在其生长初期可以适当增施硝态氮肥。

Abstract:Hydroponic experiments were carried out to study the kinetics of NH⁺₄ and NO^-₃ uptake by root of Larix olgensis seedling. The results indicate that the uptake rates of NH⁺₄ and NO^-₃ uptake are both decreased as the seedling growth, and NH⁺₄ uptake is totally more efficient than NO^-₃. When both NH⁺₄ and NO^-₃ are supplied, compatibility of seedling root with NH⁺₄ and NO^-₃ in fast growing period would be influenced negatively, which leads to the decrease of uptake rates of both ions. However, when both NH⁺₄ and NO^-₃ are supplied in early growth period, the uptake rates of the ions would be influenced negatively, or even NO^-₃ uptake would be promoted because of carriers of NO^-₃ stimulated by NH⁺₄ input compared to single NO^-₃ as N source. It is concluded that NH⁺₄ fertilization is recommended in Larix olgensis seedling cultivation throughout the whole growth period, which could improve the efficiency of N uptake, and both NH⁺₄ and NO^-₃ as N source of fertilizers should be applied at the early growth period.

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