花前渍水预处理对花后渍水逆境下扬麦9号籽粒产量和品质的影响

以扬麦9号为材料，研究花前渍水预处理对花后渍水逆境下小麦籽粒产量和品质的影响。结果表明，与未进行渍水预处理相比，花前渍水预处理提高了小麦植株对花后渍害的抗性，生物产量、收获指数和千粒重显著提高，进而显著提高了籽粒产量；花前渍水预处理显著提高花后氮素积累量及其对籽粒氮素的贡献率，降低了花前贮藏氮素运转量及其对籽粒氮素的贡献率，进而引起籽粒球蛋白含量提高，但显著降低了清蛋白、醇溶蛋白、谷蛋白和全蛋白质含量、以及干湿面筋含量和沉降值；花前渍水预处理还提高了籽粒直链淀粉和总淀粉含量和降落值，降低了支/直链淀粉比，显著提高了面粉峰值粘度、低谷粘度、崩解值、最终粘度、回冷值和峰值时间，但对糊化温度无显著影响。

Effects of hardening by pre-anthesis waterlogging on grain yield and quality of post-anthesis waterlogged wheat (Triticum aestivum L. cv Yangmai 9)

Waterlogging is becoming one of the major constraints for wheat production and has resulted in severe reductions in both grain yield and quality over the world. Waterlogging events after anthesis usually cause much greater yield loss than those before anthesis. To explore approaches to alleviate the adverse effects of post-anthesis waterlogging on grain yield and quality, a pot experiment with winter wheat (Triticum aestivum L. cv Yangmai 9) was conducted. Before anthesis wheat plants were subjected to two water treatments: (1) the Control, where the soil relative water content was maintained at 70 80%, and, (2) a waterlogging pretreatment (maintaining a 1-2 cm water layer above the soil for 2 days). This pretreatment was repeated three times, i.e. at the seven-leaf, the nine-leaf stage and the heading stage. At 7 days after anthesis, plants from both treatments were further divided into two sub-groups and separately subjected to two water treatments lasting for 7 days each. Thus, four treatments were established from 7 DAA onwards: (1) pre-anthesis waterlogging hardening and post-anthesis waterlogging (WW); (2) pre-anthesis waterlogging only (WC); (3) control: non-waterlogging stress during both pre-anthesis and post-anthesis (CC); (4) post-anthesis waterlogging only (CW). The effects of the pre-anthesis waterlogging pretreatment (PWP) on grain yield and quality were then studied. The aim of this study was to test the hypothesis that short-term waterlogging pre-conditioning before anthesis can improve tolerance to post-anthesis waterlogging. It was foundthat waterlogging at both pre- and post-anthesis reduced grain yield and affected grain quality. However, PWP significantly increased biomass, harvest index, 1000-kernel weight, and consequently improved grain yield of wheat under post-anthesis waterlogging, compared with the non-pretreated plants. PWP also enhanced post-anthesis nitrogen accumulation and its contribution to grain nitrogen, while decreased the redistribution of nitrogen accumulated before anthesis as well as the contribution to grain nitrogen. Finally, PWP caused significant increases in contents of globulin, flour dry gluten,wet gluten and sedimentation volume, and resulted in reductions in the contents of albumin, gliadin, glutelin and total protein in the grain. In addition, PWP increased contents of amylase and total starch, and falling number and enhanced peak viscosity, holding trough viscosity, breakdown, final viscosity, setback and peak time. However, PWP did not significantly affect the pasting temperature. We concluded that waterlogging pre-treatment before anthesis could essentially improve the tolerance of wheat plants to severe waterlogging after anthesis, as exemplified by increases in grain yield and the modifications on grain quality traits.