施氮量对花后高温春小麦源库特征及关系的影响

Effects of Nitrogen Rates on Source-Sink Characteristics and Relationship of Spring Wheat after Anthesis under High Temperature

为确定宁夏春小麦的适宜施氮量,本研究以宁春50号为试验材料,采取裂区试验设计,主区为温度,于花后20 d设置(25±2)℃(NT)和(35±2)℃(HT)2个温度处理,副区为施氮量,设置0、75、150、225和300 kg·hm^(-2)共5个施纯氮处理,探究不同施氮量对花后高温春小麦源库特征及关系的影响。结果表明,高温使叶面积指数和净光合速率显著降低22.99%~61.31%、24.78%~50.27%,施氮量225 kg·hm^(-2)所对应的叶面积指数和净光合速率降幅最小;相同温度条件下,随施氮量的增加,叶面积指数和净光合速率先上升后下降,在施氮量为225 kg·hm^(-2)时达到峰值。高温显著降低小麦穗重、穗粒数、灌浆速率和收获指数,与常温相比,各施氮量下高温组穗粒数、灌浆速率和产量降幅分别为2.58%~30.77%、35.82%~68.83%、6.82%~20.25%,225 kg·hm^(-2)施氮量所对应的穗粒数、灌浆速率和产量降幅最小;相同温度条件下,产量在施氮量为225 kg·hm^(-2)时达到最大值,氮肥用量每增加75 kg·hm^(-2),其产量平均增加2.43 t·hm^(-2)(NT)或2.77 t·hm^(-2)(HT)。高温使各施氮量下粒数叶比和粒重叶比分别下降0.26%~30.77%、11.98%~41.59%,施氮量为225 kg·hm^(-2)时的粒叶比降幅最小。高温使春小麦源库强度减弱,影响源库关系平衡,最终导致减产,施氮可同步提高源库强度,改善源库关系,减少小麦在高温下的产量损失,以施氮量为225 kg·hm^(-2)时的抗逆增产效果最佳。本研究结果为宁夏春小麦产业发展提供了理论参考。

In order to determine the suitable nitrogen application rate of spring wheat in Ningxia,this study took Ningchun No.50 as the test material,and the split plot experimental design was adopted.The mainplot was temperature,and two temperature treatments of(25±2)℃(NT)and(35±2)℃(HT)were set at 20 days after anthesis.The split plot was the nitrogen rate,including five nitrogen rates(0,75,150,225 and 300 kg·hm^(-2)),These were used to explore the effects of different nitrogen application rates on the source-sink characteristics and relationship of spring wheat after anthesis under high temperature.The results showed that high temperature significantly reduced leaf area index and net photosynthetic rate by 22.99%-61.31%and 24.78%-50.27%,and the decrease of leaf area index and net photosynthetic rate corresponding to 225 kg·hm^(-2) was the smallest.Under the same temperature condition,leaf area index and net photosynthetic rate increased first and then decreased with the nitrogen rate increasing,and reached the peak value when nitrogen rate of 225 kg·hm^(-2).Spike weight,grain number per spike,grain filling rate and harvest index were significantly decreased at high temperature.Compared with normal temperature,grain number per spike,filling rate and yield in high temperature group under different nitrogen rates decreased by 2.58%-30.77%,35.82%-68.83%and 6.82%-20.25%,respectively.The decrease of grain number per spike,grouting rate and yield of 225 kg·hm^(-2) was the smallest.Under the same temperature,the yield reached the maximum value when nitrogen rate of 225 kg·hm^(-2).The average yield increased by 2.43 t·hm^(-2)(NT)or 2.77 t·hm^(-2)(HT)with an increase of 75 kg·hm^(-2) nitrogen.The ratio of grain number to leaf and the ratio of grain weight to leaf decreased by 0.26%to 30.77%and 11.98%to 41.59%,respectively,and the ratio of grain to leaf decreased the least at 225 kg·hm^(-2).High temperature weakened the source-sink strength of spring wheat,affected the balance of source-sink relationship,and eventually led to yield reduction.Nitrogen application could simultaneously increase the source-sink strength,improve the source-sink relationship,and reduce the yield loss of wheat under high temperature.The best effect of stress resistance and yield increase was achieved when nitrogen rate of 225 kg·hm^(-2).This study provides a reference for the development of spring wheat industry in Ningxia.