施氮量对甜玉米产量、品质和蔗糖代谢酶活性的影响

以甜玉米扬甜2号和超甜135为材料,设置纯氮N 0、75、225、375 kg/hm2 4个处理,研究不同施氮量对甜玉米产量、品质和蔗糖代谢酶活性的影响.结果表明,施氮显著提高甜玉米扬甜2号和超甜135鲜穗产量,两品种均以施N 225 kg/hm2产量最高,比不施氮分别增产65.15％、99.61％.甜玉米籽粒发育过程中可溶性糖和蔗糖的含量随吐丝时间呈单峰曲线变化,施氮明显提高籽粒可溶性糖和蔗糖含量,施氮量为N 225 kg/hm2时最高.氮肥对甜玉米质构特性有较大影响,施氮量增多,籽粒的硬度显著增加；脆性随着施氮量的增加表现出先升高后降低的趋势,其中以氮肥用量在N 225 kg/hm2最大.籽粒中蔗糖磷酸合成酶(SPS)和蔗糖合成酶(SS)合成方向活性的变化趋势与蔗糖含量变化一致,SS分解方向活性随籽粒灌浆进程逐渐变大.合理施氮可提高甜玉米籽粒中SPS和SS合成方向活性,增加糖分,改善品质.

Effects of nitrogen fertilization on yield,quality and enzyme activity associated with sucrose metabolism of sweet corn

To determine the effects of nitrogen fertilizer on fresh ear yield, quality and enzyme activity associated metabolism of sweet corn, a field experiment was conducted with two corn cultivars, Yangtian 2 and Chaotian 135 There were four nitrogen rates, N 0, 75, 225 and 375 kg/ha. The results show that the fresh ear yield of Yangtian 2 and Chaotian 135 are significantly increased under the nitrogen fertilization, and the yield is highest under N 225 kg/ha application. Compared with no nitrogen treatment, the yields of the treatment with N 225 kg/ha of the two cultivars are increased by 65.15% and 99.61% respectively. The contents of soluble sugar and sucrose at the grain filling stage are single peaked curves. In a proper range of nitrogen level, the contents of soluble sugar and sucrose are increased significantly with the increase of nitrogen level, and the contents are highest under N 225 kg/ha application. The rates of nitrogen fertilization have great effects on texture properties of sweet corn, the hardness of grains is significantly increased with the amount of nitrogen fertilizer increased, and the fracturability is significantly increased at first and then decreased with the increase of N fertilizer application. The value of fracturability reaches the highest level under N 225 kg/ha application. The dynamic changes of activities of sucrose phosphate synthase (SPS) and sucrose synthase (SS, synthesis) are similar to the sucrose accumulation. With the proceeding of grain filling, the activity of SS (cleavage) is gradually increased. Appropriate N fertilizer could increase the activities of SPS and SS (synthesis) and improve the content of sugar and nutrition quality of sweet corn.