Effects of Light Quality on Micropropagation of Woody Species

摘要: Light is a fundamental environmental cue in the life of plants, playing crucial role, directly or indirectly, regulation plant development and growth. It represents signal to be elaborated photoperception processes by photoreceptors. Plants have evolved exquisite sensory systems for monitoring their environment initiating appropriate strategies lifetime. In order optimise acquisition light energy photosynthesis, plants developed series signal-transducing photoreceptors that regulate growth relation presence, amount, direction, duration quality incident radiation. Several families distinct photoreceptors, sensitive different regions spectrum, mediate developmental responses signals: phytochromes (red/far-red light-absorbing photoreceptor), cryptochromes (blue/UV-A phototropin, UV-B photoreceptor (Briggs Olney, 2001). Among these regulating signaltransducing best characterised, at genetic physiological levels, phytochrome family. higher family may as many five discrete members (Clack et al., 1994; Hauser 1997; Pratt 1997). Different share specific biochemical properties, are differentially expressed functional roles controlling photomorphogenesis (Whitelam Halliday, 1999; Chory Wu,