摘要：

为给小麦耐渍稳产栽培提供参考,以扬麦25和宁麦13为材料,在拔节期设置了短期轻度渍水(SL,3 d土表下10 cm水层)、短期重度渍水(SS,3 d土表上2 cm水层)、长期轻度渍水(LL,12 d土表下10 cm水层)、长期重度渍水(LS,12 d土表上2 cm水层)处理以及对照处理(CK,保持土壤相对含水量70%~75%),研究了不同程度渍水对不同土层根系干质量和活力、地上部生长、籽粒产量及其构成的影响。结果显示,扬麦25较宁麦13具有显著高的籽粒产量、千粒质量、根系干质量、0~40 cm土层根系活力和根冠比。相比CK,SL和SS减少籽粒产量13.44%~22.45%,LL和LS减产显著增加至28.76%~37.26%,其中SL与SS间、LL与LS间籽粒产量差异均不显著。短期渍水仅轻度减少根冠生长量,且0~20 cm土层根系维持高活力,20~60 cm土层根系活力亦可恢复。长期渍水显著减少根系干质量,导致根冠生长失衡,且根系活力降低,难以恢复;上三叶易早衰,以倒三叶最明显。结果显示,渍水发生后尽快降低水位有助于土壤表层根系维持生长生理活性,降低叶片早衰风险,保障籽粒灌浆光合物质需要。

关键词: 小麦, 渍水, 胁迫程度, 根系, 籽粒产量

Abstract:

To provide references for the waterlogging-tolerance and yield-stability cultivation of wheat,the experiment was conducted to study the effects of different degrees of waterlogging on root dry weight and vigor in different soil layers,shoot growth,grain yield,and its components using Yangmai 25 and Ningmai 13 as experimental materials.The treatments included short-term mild(SL,10 cm water layer under the soil surface for 3 days),short-term severe(SS,2 cm water layer above the soil surface for 3 days),long-term mild(LL,10 cm water layer under the soil surface for 12 days),long-term severe(LS,2 cm water layer above the soil surface for 12 days)waterlogging treatments at stem-elongation stage,and control treatment(CK,maintaining the relative soil water content of 70%—75%).The results showed that Yangmai 25 showed significantly higher grain yield,1000-grain weight,root dry weight,root activity in the 0—40 cm soil layer,and ratio of root to shoot than Ningmai 13.Compared with CK,SL and SS reduced grain yield by 13.44%—22.45%,while LL and LS reduced grain yield significantly by 28.76%—37.26%.There was no significant difference in grain yield between SL and SS,LL and LS.Under the short-term waterlogging,the biomass of root and shoot were slightly reduced,the root in 0—20 cm soil layer maintained high vigor,and the vigor of root in 20—60 cm soil layer could recover.However,long-term waterlogging significantly decreased root dry weight resulting in growth imbalance of root and shoot.In addition,root activity was low and difficult to recover under long-term waterlogging,and the top-three leaves was prone to premature senescence with the top 3rd leaf showing most obvious.The results suggested that lowering water levels as soon as possible after waterlogging could help the surface roots maintain growth and physiological activity,and reduced the risk of premature leaf senescence,satisfying the photosynthetic needs for grain filling.

Key words: Wheat, Waterlogging, Degree of stress, Root system, Grain yield