小麦生育中后期干旱高温对籽粒产量形成过程的影响机制及缓解措施

Impacts Mechanism of Drought and Heat Stress in the Middle and Late Growing Period on Wheat Grain Yield Formation Process and Mitigation Measures

在复杂的气候条件下,小麦更加频繁地遭受干旱高温逆境的影响,使产量降低。小麦单位面积穗数一定时,穗粒数和粒重是决定产量的主要因素。干旱高温逆境下,幼穗分化能力降低,小穗小花原基数量较少,花药和花活力降低,抑制胚和胚乳发育,致使小穗分化数量减少,可育小花数目降低,小花受精失败、籽粒败育,穗粒数降低。小麦穗粒数建成后,干旱高温降低胚乳细胞分化和生长速率,胚乳细胞数目降低,库容降低,同时改变籽粒灌浆特性,粒重降低。可见,干旱高温对小麦产量形成的影响涉及小穗分化、小花发育、小花受精、籽粒建成、籽粒灌浆等一系列复杂过程。本文从穗粒数形成的每一个阶段及粒重积累的过程全面系统地介绍了干旱高温逆境下小麦产量降低的生理机制,并总结小麦生产中应对干旱高温逆境采取的缓解措施。明确影响穗粒数形成的关键阶段及粒重积累的关键代谢途径,为小麦抗逆品种选育以及抗逆栽培技术提供理论依据。

The wheat development impacted by drought and heat more frequently in the complex climatic conditions,thus yield was decreased.Wheat yield is determined by the kernel number per spike and kernel weight for a given spike number.The differentiation of ability of female spike,the number of spikelet floret primordium,the anther and pollen activity decrease,and the development of embryo and endosperm were inhibited in drought and heat stress,resulted in decreases of the number of spikelet differentiation,the fertile florets,fertilization florets,and grain abortion,and the grain number per spike was reduced.After the grain number per spike was established,the drought and heat stress reduce the rate of endosperm cells differentiation and growth.The number of endosperm cells and storage capacity decrease.Meanwhile,the grain filling characteristics are changed,and the grain weight decrease.Thus,the effects of drought and high temperature on wheat yield formation involves a series of complex processes such as spikelet differentiation,floret development,floret fertilization,grain building and grain filling.This paper introduce the physiological mechanism of wheat yield reduction from the stage of grain number formation and the process of grain weight accumulation in wheat production.The mitigation measures taken in wheat production to deal with drought and high temperature are summarized.Clarifying the key stage affecting the formation of ear grain number and the key metabolic pathway of grain weight accumulation can provide a theoretical basis for the breeding and cultivation techniques of the stress-resistant wheat varieties.