不同叶面营养组分对黄瓜叶片氮素营养的影响

用＾１５Ｎ示踪法研究了黄瓜中、下位叶片不同营养组合配施后＾１５Ｎ「＾１５ＮＨ４）２ＳＯ４」刊载内瓜体内的速率，运移途径及利用效率，结果表明：黄瓜叶片能有效地吸收营养元素并将其迅速转移，不同叶位施肥，植株吸收的＾１５Ｎ在体内运移主要发生在处理后７２ｈ之内，并且绝大部分转移至新生长点，老叶中＾１５Ｎ回收很少，叶面施用硫酸铵肥料的氮素在黄瓜地上部的分配率一般在５０．７－６１．８％，随吸收时间延长，黄瓜营

Effects of different foliar nutrient treatments on nitrogen nutrition of cucumber leaves

The rate and pathway of translocation of sprayed 15 N labeled ammonium sulphate into cucumber tissues and the utilizing efficiency of N were studied in pot experiments by different foliar nutrient treatments at the middle and low leaves in position respectively. The sprayed nutrients could be absorbed efficiently by the cucumber leaves and translocated immediately after spraying. The translocation of 15 N taken up by cucumber leaves predominantly occurred within 72 hours after dipping of the leaves in different position and 15 N was found largely in the growing tissues. The 15 N recovery rate of foliar ammonium sulfate fertilizer in above ground part of cucumber was in the range of 50.7% to 61.8% and could increase with prolonging of absorbing time and expansion of leaf area i.e. dipping middle leaves. Compared to foliar nitrogen application alone, the combination treatments had significant effect on the foliar N uptake and improved the N nutrition status of above ground organs of cucumber. The function was greatest when foliar application of mixed N+PK+ mixed microelements (Zn+Mn+Cu+Fe)+NPGS at middle leaf in position (the fifth leaf) of cucumber. Therefore, the balanced supplement of nutrients, suitable plant growth periods and positions of leaves sprayed should be emphasized on foliar nutrition of plants.