种植密度对转基因棉氮、磷、钾吸收和利用的影响

在江苏地区棉花高产条件下,研究了种植密度(12000、21000、30000、39000、48000和57000 plant/hm2)对转基因棉湘杂棉8号养分吸收和利用的影响.结果表明,随种植密度的增加,棉株氮、磷、钾养分累积吸收量均呈线性升高,而生殖器官氮、磷、钾养分累积吸收量和养分经济系数则呈抛物线函数变化,均以30000 plant/hm2密度为最高,与皮棉产量的变化趋势完全相同.种植密度对开花至盛花阶段棉株养分吸收比率的影响大于其他阶段,密度增大显著降低植株在开花～盛花阶段氮、磷、钾的吸收比例.随种植密度的增加,每生产100 kg皮棉的养分摄取量逐渐上升,但对钾的吸收比例明显下降.高密度显著降低了上、中、下不同部位果枝的氮、磷、钾养分浓度和提高了不同部位果枝的群体养分吸收量,并使果枝营养早衰,下部果枝表现尤其明显,这与铃重的果枝空间分布相吻合.

Effects of planting density on uptake and utilization of N,P and K of transgenic cotton

Planting density is an important practice for cotton production. In order to study the effects of different planting densities on nutrition uptake and yield of transgenic cotton cultivar, Xiangzamian 8, a field experiment was conducted by using six planting densities, 12000, 21000, 30000, 39000, 48000 and 57000 plant/ha, under high yield cultivated conditions in Jiangsu. The results show that the accumulative amounts of N, P and K in cotton plants are increased when the planting density is increased, while the N, P and K accumulative amounts and nutrient economic coefficients in the reproductive organs are in parabola functions, and the N, P and K accumulative amounts and nutrient economic coefficients in the reproductive organ are the highest under the 30000 plant/ha. In addition, the highest lint yield is 1610.3 kg/ha under the 30000 plant/ha. The percentages of N, P and K uptakes of cotton are the highest from the initial flowering stage to the peak flowering stage during the whole development stages, and the percentages of N, P and K uptakes from the initial flowering stage to the peak flowering stage are reduced when the planting density is increased. With the increase of plant density, the nutrient uptakes per 100 kg lint are increased, but the percentage of K uptake is reduced. Increasing the planting density reduces N, P, and K contents and enhances N, P, and K accumulations per plant in different fruit branches, but accelerates branch senescence, especially the lower branches. These results are consistent with the weights of bolls in different fruit branches.