密度和种植方式对夏玉米酶活性和产量的影响

在豫北灌区的生产条件下,以郑单958和浚单20为试验材料,研究了不同密度和种植方式对夏玉米碳氮关键酶的影响。结果表明:生育后期夏玉米叶片硝酸还原酶(NR)、谷氨酰胺合成酶(GS)和籽粒蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)活性均呈先升高后降低的变化趋势,叶片NR和GS活性峰值出现在吐丝期,籽粒SPS和SS活性峰值出现在灌浆后15d。基因型、密度和种植方式对夏玉米生育后期叶片NR、GS和籽粒SPS、SS活性均有显著影响,而3因素间总体上没有显著的互作效应。郑单958生育后期叶片NR、GS和籽粒SPS、SS活性均显著高于浚单20,分别提高5.02%、7.40%、6.25%和4.43%。在6.75—9.00万株hm2的范围内,随着密度的增大,夏玉米生育后期叶片NR、GS和籽粒SPS、SS活性显著降低。与60cm等行距种植方式相比,80cm-40cm宽窄行种植方式下夏玉米生育后期叶片NR、GS和籽粒SPS、SS活性均显著提高,分别提高6.23%、9.25%、6.87%和2.84%。在采用宽窄行种植、密度为8.25万株hm2时,产量最高。

Effects of planting densities and modes on activities of some enzymes and yield in summer maize

Effects of different planting densities and modes on activities of key enzymes related to carbon-nitrogen metabolism in summer maize in two cultivars, Zhengdan 958 and Xundan 20, were studied under the condition of Northern Henan Province. The results showed that the activities of nitrate reductase (NR), glutamine synthetase (GS), sucrose phosphate synthetase (SPS) and sucrose synthetase (SS) in leaves increased first and decreased later during tasseling and silking stages. The activities of NR and GS in leaves reached the peak at silking stage, and the maximum of activities of SPS and SS in grains occurred at 15d after filling. Genotype, density and planting mode had significant effects on the activities of NR, GS in leaves and SPS, SS in grains during the later-growth period, but the interaction between them was indistinctive. The activities of NR, GS in leaves and SPS, SS in grains of Zhengdan 958 were higher than those of Xundan 20 (5.02%, 7.40%, 6.25% and 4.43% increases, respectively) during the later-growth period. Within the range of 67500-90000 plants per hm², the activities of these enzymes decreased significantly with the increasing of planting density. A comparison between two planting modes indicated that activities of NR, GS in leaves and SPS, SS in grains of wide-narrow row mode were higher than those of equidistant row mode (6.23%, 9.25%, 6.87% and 2.84% increases, respectively). The yield reached highest in the test plots with 82 500 plants per hm² and wide-narrow row mode.