光周期影响植物花时的分子机制

日长感知是植物所具有的重要的生物学功能,光周期是决定植物开花时间的关键环境因子之一。光周期的暗期长度是决定植物成花的决定因素。通过形态学和遗传学研究,揭示了光周期敏感的一些遗传特性,并确定了光敏感指数的标准。构建了光周期性状相关的分子标记连锁图谱,是进行基因定位、克隆和分子标记辅助选择的重要基础工作,也是进行光周期机理研究的有效途径。通过模式植物拟南芥的研究,建立了一个长日促进开花的遗传途径。它的机理可以综合为:光和感光信息体系结合产生信号并传导,CO表达被激活。在每日日长循环、光体系及遗传背景的变化基础上,如果CO的表达和日长状况协调,那么CO激活FT表达,随后开花。水稻、小麦、玉米等作物在光周期机理研究方面也取得了一些进展。

Molecular Mechanisms of Photoperiod Actions on Plant Flowering

Day-length sensing is an important biological function in plants and photoperiod is one of the key ambient factor determining the time of plant flowering.The darkness length in photoperiod is the crucial factor determining the formation of plant flowers.Morphological and genetic analysis revealed some photoperiod-sensitive genetic characteristics in plants and confirmed the criteria of photoperiodism index.In the meantime,the molecular marker linkage map of photoperiod-related trait was established and became important basis in gene localization,cloning and molecular marker-aided selection as well as an effective approach to studying photoperiod mechanism.And a genetic approach to helping long-day plants to flower was set up by studying modular Arabidopsis thaliana.The mechanism of the approach was summarized as follows:light and light-sensitive information were combined to form and transfer signals so that CO expression was activated.On the basis of the variation in daily day-length cycle,light system and genetic background,CO activated FT expression and then led to flowering occurrence given that CO expression and daylength were well coordinated.Some advances in photoperiod mechanism have been made in such crops as rice,wheat and corn.