种子感光的机理及影响种子感光性的因素

种子的萌发或休眠均取决于萌发时种子内所建立起来的Pfr含量和Pfr/(Pr Pfr)比值。种子内的Pfr水平受到诸多因素的影响。光中性种子在成熟时已存在适合萌发的Pfr水平；需光种子在不同程度地接受白光或红光照射后，方可达到适宜的Pfr水平；忌光种子萌发要求的Pfr水平较低，因此萌发需要较长时间的黑暗。种子的感光性不是绝对的，母株的生长条件、种子本身的成熟度、贮藏状况、光质、光流量、光周期、萌发温度、O2供应及某些化合物的处理等都可使种子的感光性发生改变。

Mechanism of Seed Photosensitivity and Factors Influencing Seed Photosensitivity

Germination or dormancy of seeds depends on the content of Pfr and Pfr/(Pr+Pfr) ratio established in photosensitive seeds. The level of Pfr in seeds is affected by multiple factors. The non_photoblastic seeds contain appropriate Pfr level when ripen and the light_favored seed does after being irradiated with white light or red light to some degrees, but light_inhibited seeds can germinate only when they contain low Pfr after long duration in darkness. The seed photosensitivity is not absolute and influenced by the environmental conditions of mother plant, maturation degrees, storing status of seed itself, spectral composition, fluence rate, photoperiod, germination temperature, O 2 supplying state and treatments with chemicals.