玉米受精和早期子粒发育过程及逆境胁迫对其影响

玉米受精及子粒发育早期是决定穗粒数及粒重的重要时期,也是对环境变化相对较敏感的阶段。受精极核需要经历游离核、细胞化和细胞分化3个阶段形成胚乳,受精卵同样需要一系列的分裂分化形成最终的胚。玉米受精前极易遭受不良环境的影响,导致性器官发育不正常,影响花粉或花丝活力间接影响玉米受精过程。受精过程中的环境胁迫会通过阻碍花粉与花丝的识别、减缓花粉管在花丝中的延伸速率影响受精过程。子粒发育早期主要是受精极核分裂分化形成胚乳、受精卵分裂分化形成胚的过程,该阶段遭受环境胁迫下,胚乳细胞分裂受阻影响子粒库容。研究表明,逆境胁迫条件下,玉米的受精及子粒早期发育过程与碳水化合物的代谢以及激素的合成密切相关。

Maize Fertilization and Early Stage of Seed Development and Impacts on Them Exposed to Stresses

The stages of fertilization and early grain development are essential for determining maize grain number and grain weight, and also a relatively sensitive stage for environmental changes. The fertilized polar nucleus needs to undergo free nuclear phase, cellularized and cell differentiation to form the endosperm, and the fertilized eggs also need a series of division and differentiation to form embryo. The previous period of fertilization is sensitive to the adverse environment, the maize form the abnormal sexual organs under stresses, meanwhile, affecting the pollen and silk vigor fertilization process. The stresses happened in the fertilization process mainly hinder the identification of pollen and flower silk and slow down pollen tube extension rate in the filament. At the early stage of grain development, the fertilization polar nuclei and fertilization eggs are divided and differentiated to form the endosperm and embryo, respectively, suffer the adverse environment will decrease grain storage capacity by hindering the endosperm cell division. Many researches have shown that stresses affect maize fertilization and early grain development through influencing the carbohydrate metabolism and hormone synthesis.