| Popis: |
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. |
