Phytochrome regulation of seed germination
Phytochrome regulation of seed germination
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DOI：
10.1007/bf02506854
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发表时间：
1997-03
影响因子：
2.8
通讯作者：
T. Shinomura
中科院分区：
文献类型：
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作者：
T. Shinomura
许多植物种子的萌发都受到光照的影响。在众多的光感受器系统中，光敏色素在种子萌发过程中起着特别重要的作用。至少有五个光敏色素基因的存在导致了不同的家庭成员在种子萌发的光调节中有不同的作用的建议。拟南芥（Arabidopsis thaliana（L.）嘿首次发现光敏色素A和光敏色素B以不同的作用调节种子萌发的时间。光敏色素A光不可逆地触发种子萌发的光诱导后，在很宽的波长范围内，从UV-A，可见光，远红外线的极低通量的光照射。与此相反，光敏色素B介导的光可逆反应的特点，响应的红光和远红光的能量密度四个数量级高于PhyA响应。野生植物，如阿萨。拟南芥作为休眠种子在地下长期存活，种子萌发的时间对于优化生长和繁殖至关重要。因此，似乎合理的植物拥有至少两个不同的生理系统，用于在宽光谱范围内感知光环境，并具有不同光敏色素的灵敏度。这种冗余似乎可以提高植物在波动环境中的生存能力。
Seed germination of many plant species is influenced by light. Of the various photoreceptor systems, phytochrome plays an especially important role in seed germination. The existence of at least five phytochrome genes has led to the proposal that different members of the family have different roles in the photoregulation of seed germination. Physiological analysis of seed germination ofArabidopsis thaliana(L.) Heynh. with phytochrome-deficient mutants showed for the first time that phytochrome A and phytochrome B modulate the timing of seed germination in distinct actions. Phytochrome A photo-irreversibly triggers the photoinduction of seed germination after irradiation with extremely low fluence light in a wide range of wavelengths, from UV-A, to visible, to far-red. In contrast, phytochrome B mediates the well-characterized photoreversible reaction, responding to red and far-red light of fluences four orders of magnitude higher than those to which PhyA responds. Wild plants, such asA. thaliana, survive under ground as dormant seeds for long periods, and the timing of seed germination is crucial for optimizing growth and reproduction. It therefore seems reasonable for plants to possess at least two different physiological systems for sensing the light environment over a wide spectral range with exquisite sensitivity of different phytochromes. This redundancy seems to enhance plant survival in a fluctuating environment.