亏水预处理对冬小麦生理生长特性与产量的影响

Effects of Water Deficit Priming on Physiological Growth Characteristics and Yield of Winter Wheat

摘要:

为揭示间歇和持续性亏水预处理对冬小麦生理生长特性及产量的影响，探明不同预处理模式对冬小麦耐旱性的调控效应，于2020---2022年开展了2季冬小麦试验，设置不同水分亏缺预处理（间歇性亏缺（I）、持续性亏缺（P））、不同亏缺程度（（65%~75%）FC（田间持水量）（D1）、（55%~65%）FC（D2））与对照组（（75%~85%）FC，WW）。结果表明，与WW相比，花后干旱胁迫导致光合速率（Pn）、气孔导度（gs）和蒸腾速率显著降低，而间歇中度亏水预处理（ID2）Pn和gs显著高于未预处理（DS）。花后干旱胁迫显著降低地上部和根系生长，导致地上部干质量、总根长及根干质量分别较WW处理平均降低23.1%、13.7%和12.6%。ID2和持续性轻度亏水预处理（PD1）能显著提高中、下土层根系生长和分布，有利于促进地上部和籽粒氮吸收。与WW相比，DS处理花前干物质对籽粒贡献率、籽粒氮积累量及蛋白质产量分别降低24.3%、22.6%和10.4%，但ID2和PD1处理显著高于DS处理。ID2处理产量和收获指数分别较DS处理提高29.4%和19.2%，产量水分利用效率和氮素利用效率分别较DS处理提高42.7%和12.5%。尽管持续性中度亏水预处理未能显著改善冬小麦产量，但2年平均产量和生物量水分利用效率分别较DS处理增加31.3%和26.6%。总之，间歇性中度亏水预处理能够缓解花后干旱胁迫对冬小麦生长和生产的不利影响。研究结果可为干旱地区冬小麦抗逆栽培及水氮利用效率提升提供理论依据。

Abstract:

Aiming to investigate the effects of intermittent (I) and persistent (P) water deficit priming on the growth, physiological traits, and yield of winter wheat, and elucidate the regulatory effects of different priming modes on the drought tolerance of winter wheat, a two-year winter wheat experiment was conducted from 2020 to 2022, involving different water deficit priming modes (intermittent water deficit, I;persistent water deficit, P), water deficit levels ((65%~75%)FC, D1;(55%~65%)FC, D2), and control group ((75%~85%)FC, WW). Compared with WW, post-anthesis drought stress resulted in significant reductions in photosynthetic rate (Pn), stomatal conductance (gs), and transpiration rate. However, intermittent moderate water deficit priming (ID2) showed significantly higher Pn and gs than no priming (DS). Post-anthesis drought stress significantly reduced aboveground and root growth, resulting in 23.1%, 13.7%, and 12.6% decreases in aboveground dry mass, total root length, and root dry mass, respectively, compared with WW. ID2 and persistent mild water deficit priming (PD1) improved root growth and distribution in the middle and lower soil layers, leading to increased N accumulation in aboveground parts and grains. Compared with WW, DS treatment reduced the contribution of dry matter to grains, grain N accumulation, and protein yield by 24.3%, 22.6%, and 10.4%, respectively, while ID2 and PD1 treatments showed significantly higher values for these indicators than the DS treatment. Moreover, grain yield and harvest index of ID2 treatment were increased by 29.4% and 19.2% respectively compared with that of DS treatment, while WUEg and NUEg were increased by 42.7% and 12.5% respectively. Although persistent moderate deficit priming did not increase wheat yield, it improved WUEg and WUEb by 31.3% and 26.6%, respectively, compared with DS. Collectively, intermittent moderate water deficit priming mitigated the adverse effects of post-anthesis drought stress on winter wheat growth and production. The research findings can provide theoretical support for enhancing stress-resistant cultivation and improving water-N use efficiency of winter wheat in arid regions.