化控和密度措施对东北春玉米叶片衰老及产量的影响

Effect of Chemical Regulation and Density on Spring Maize Leaf Senescence and Yield in Northeast China

探讨不同种植密度条件下化控措施对玉米叶片衰老及产量的影响,为东北春玉米化控栽培增产提供理论和试验依据。选用东农253为玉米试验品种,设置5万,6万,7万,8万株/hm2这4个密度,在拔节期叶面喷施玉黄金(主要成分为胺鲜酯和乙烯利)。结果表明,7万株/hm2的种植密度条件下,玉黄金处理后的产量最高,达到13 290.95 kg/hm2。合理密植是获得高产的保障,化控剂的增产作用以密度增加为前提;随密度增加,清水处理株高逐渐增加,单株干质量降低,而玉黄金的使用降低了株高,增加了干质量,为获得高产创建了条件。随密度的增加,清水处理叶片SPAD值降幅增加,叶片的衰老程度增加,玉黄金处理后能增加叶片持绿性,延缓衰老。在叶片衰老过程中,清水处理随密度增加抗氧化酶(SOD、POD、CAT)活性降低,MDA含量增加,可溶性蛋白含量降低,玉黄金处理较清水处理抗氧化酶(SOD、POD、CAT)活性增强,MDA含量降低,可溶性蛋白含量增加。7万株/hm2密度处理下的相关分析和通径分析结果表明,各因子对叶片衰老的作用大小为:清水处理中MDA>可溶性蛋白>CAT>SOD>POD,玉黄金处理中MDA>可溶性蛋白>SOD>POD>CAT。在密植条件下,植物生长调节剂玉黄金的施用对增强玉米生育后期叶片抗衰老能力和提高玉米产量具有重要的应用价值。

The objective of this experiment was to investigate the effect of chemical regulation measures on leaf senescence and yield of spring maize under different plant densities,and to provide theoretical and experimental evi-dence for the effect of increase production of chemical regulation cultivation on spring maize in Northeast China. Dongnong 253 was used as material in this experiment and was planted under the densities of 50 000,60 000, 70 000,80 000 plants /ha,and sprayed the chemical regulator of Yuhuangjin with DA-6 and Ethephon as the main material at foliar during the jointing stage.The results showed that the highest maize yield could reached 1 3 290.95 kg /ha and appeared at the density of 70 000 plants /ha after the treatment of Yuhuangjin.Rational close planting was the safeguards to obtain high yield and the chemical regulator can play a role of increasing yield with the in-crease of density as the premise.With the increase of planting density,under the treatment of water,the plant height was increased,dry weight of single plant was decreased;while using Yuhuangjin could lowered the plant height,in-creased the weight of single plant and declined,which could creat the conditions for obtaining high yield.With the planting density increasing,the decline of the leaf SPAD values and the degree of the leaf aging was increased in the maize treated with water.While under the treatment of Yuhuangjin,the photosynthetic characteristics was increased and the aging was delayed.During leaf senescence,under the treatment of water and with the increase of planting nbsp;density,the activity of antioxidase （SOD,POD,CAT）were declined,the content of MDA was decreased and the content of soluble sugar was increased.Yuhuangjin increased the activity of antioxidant enzyme （SOD,POD,CAT） and the content of soluble sugar and decreased the content of MDA.The result of the correlation analysis and path a-nalysis on effect of the factors to leaf senescence at the density of 70 000 plants /ha showed that,under the treatment of water,MDA〉soluble sugar〉CAT〉SOD〉POD;under the treatment of Yuhuangjin,MDA〉soluble sugar〉SOD〉POD〉CAT.Under the condition of high density,plant growth regulator Yuhuangjin has important application value in enhancing leaf anti-aging ability during later growth stage and improving maize yield.