不同灌浆阶段弱光对小麦产量与籽粒灌浆速率的影响

Effects of Shading Stress at Different Grain Filling Stages on Yield and Grain Filling of Winter Wheat

选用两小麦品种,在小麦开花后不同时期,于大田条件下模拟弱光照天气,研究弱光胁迫对小麦产量及籽粒灌浆的影响。结果表明,灌浆期弱光胁迫显著降低小麦产量与籽粒重。不同灌浆期弱光胁迫对籽粒重的影响不同,灌浆前期弱光胁迫由于减少了穗粒数,其中主要是降低了上位粒数,而使对籽粒重的降幅相对较小。弱光对小麦下位籽粒重的降幅大于上位籽粒重。用Logistic方程可拟合各处理籽粒增重进程,并由小麦下、上位籽粒重与其灌浆特征参数的相关性分析可知,花后弱光胁迫使小麦品种籽粒重的降低,主要是由弱光处理籽粒平均灌浆速率和渐增期灌浆速率显著低于对照造成的,而灌浆持续期长短和最大灌浆速率出现时间对其影响较小。

Two wheat cultivars were used for investigating the effects of shading stress at different grain filling stages on yield and grain filling of winter wheat.The field was shading by the black nets with 90% shading over the plants in early（6~9d after anthesis,S1）,middle（16~19d after anthesis,S2） and late（26~29d after anthesis,S3） grain filling.The results showed that shading stress at grain filling stage had a great effect on grain yield.Compared with control（CK）,three shading stages all caused a significant decrease in the yield.Shading stress after anthesis significantly decreased the grain weight.The grain weight had great difference in treatments.The low light stress of S1 treatment reduced the kernel number per spike.In fact,it reduced the upper kernel number per spike,and the decrease extent of grain weight of S1 treatment was lower than S2 and S3 treatment.The deceases in grain weight in shading took place mainly in basal kernels.Simulating the process of grain filling of basal and upper kernels in different treatments with Logistic Equation,and correlation analysis showed that it was mean grain filling rate and gradual increase period grain filling rate,but not grain filling duration that declined the grain weight under shading stress.