渍害胁迫时期和持续时间对冬小麦产量及其构成因素的影响

为研究渍害胁迫时期和持续时间对小麦产量及其构成因素的定量化影响，以扬麦13号为供试品种，在拔节期、孕穗期和灌浆期，开展不同渍害胁迫持续时间（0、5、10和15 d）的盆栽试验，观测不同渍害胁迫处理下小麦产量及其构成因素的变化。结果表明，不同生育时期发生渍害胁迫均可导致小麦减产，且随渍害胁迫时间的延长，小麦产量下降均达到显著水平（P<0.05）。渍害胁迫造成的减产呈现为孕穗期>拔节期>灌浆期，渍害胁迫每增加1天，孕穗期、拔节期和灌浆期小麦单株产量分别下降0.79、0.59和0.48 g，表明孕穗期是小麦渍害胁迫的敏感期。此外，不同生育时期渍害胁迫对小麦产量构成的影响存在明显差异。拔节期渍害胁迫同时降低小麦株穗数、穗粒数和千粒重，但主要通过降低小麦穗粒数造成产量下降；灌浆期渍害胁迫对小麦株穗数和穗粒数的影响较小，主要通过降低千粒重造成小麦产量下降；孕穗期处于小麦从营养生长转为生殖生长阶段，此时发生渍害胁迫，对小麦株穗数和穗粒数的影响大于灌浆期，对千粒重的影响大于拔节期，因此，孕穗期渍害胁迫造成小麦减产最严重。为预防渍害胁迫造成小麦严重减产，应在孕穗期前后密切关注天气状况，在田间及时开沟排水。

Effect of Waterlogging Stress Duration at Different Growth Stages on Yield and Its Components of Winter Wheat

Waterlogging stress at different growth stages might have different effects on winter wheat yield,but the quantitative effects of waterlogging stress duration on wheat yield and its components are still unclear. To comprehensively evaluate the effects of waterlogging stress on winter wheat yield,Yangmai 13 was selected as the experimental cultivar,and pot experiment with different waterlogging stress duration (0,5,10 and 15 d) was conducted at jointing,booting and grain-filling stages,respectively,in the present study. Variations of winter wheat yield and its components under different treatments were investigated. Results of the two-year pot experiment showed that,waterlogging stress at different growth stages all caused yield losses of winter wheat,and the yield at different growth stages all showed a significant loss (P<0.05) as the increase of waterlogging stress duration. The waterlogging induced yield losses showed a tendency that booting stage> jointing stage> grain-filling stage. The yield per plant was decreased by 0.79,0.59 and 0.48 g,respectively,for an extra day under stress,indicating that booting stage is the most sensitive growth stage of winter wheat to waterlogging stress,compared with jointing and grain-filling stages. Furthermore,waterlogging stress at different stages showed distinctly different effects on yield components. Waterlogging stress at jointing stage led to a reduction in spike number per plant,kernel number per spike and thousand-kernel weight simultaneously. And the yield loss at jointing stage was mainly resulted from the reduction of kernel number per spike. Waterlogging stress at grain-filling stage had a limited effect on spike number per plant and kernel number per spike,due to that the two yield components had been determined at early growth stage. The yield loss at grain-filling stage was mainly resulted from the reduction of thousand-kernel weight. Booting stage is the stage when vegetative growth converts to reproductive growth. Thus,waterlogging stress at this stage always induced more yield losses. By comparing the yield component,the reduction of spike number per plant and kernel number per spike were more severe under waterlogging stress at booting stage than that at grain-filling stage,while reduction of thousand-kernel weight was more severe under waterlogging stress at booting stage than that at jointing stage. The results could explain why waterlogging stress at booting stage,compared with the other two growth stages,was most sensitive to the winter wheat yield,and induced a more severe yield loss. To prevent the yield loss caused by waterlogging stress,meteorological conditions around booting stage should be paid close attention to,and ditching for drainage should be conducted simultaneously in the field for winter wheat production. Results of the present study showed that yield losses caused by waterlogging stress were closely related to the growth stage of winter wheat.