Kendrick R E, Spruit C J
Laboratory of Plant Physiological Research, Agricultural University, Wageningen, The Netherlands.
Plant Physiol. 1973 Oct;52(4):327-31. doi: 10.1104/pp.52.4.327.
In vitro data support a scheme of phytochrome phototransformation involving intermediates in a sequential pathway. The fraction of total phytochrome maintained as intermediate under conditions of pigment cycling as well as the rate of the dark reversion of the far red-absorbing (Pfr) to the red-absorbing form of phytochrome (Pr) has been shown to depend on the molecular environment of the phytochrome molecules. Inverse dark reversion of Pr to Pfr has been observed in vitro. These results contribute toward an understanding of the observed paradoxes between physiological experiments and measurements of the amount and state of phytochrome in vivo. The in vivo spectrophotometric assay measures an average of the properties of phytochrome in different cellular environments, whereas a particular physiological response may be controlled by phytochrome molecules in one particular environment. It is therefore possible that all phytochrome is potentially active and triggers specific responses by virtue of its localization.
体外实验数据支持一种光敏色素光转化机制，该机制涉及一系列途径中的中间体。在色素循环条件下，作为中间体维持的总光敏色素比例，以及远红光吸收型（Pfr）向红光吸收型光敏色素（Pr）的暗逆转速率，已被证明取决于光敏色素分子的分子环境。在体外已观察到Pr向Pfr的反向暗逆转。这些结果有助于理解生理实验与体内光敏色素含量和状态测量之间所观察到的矛盾。体内分光光度测定法测量的是不同细胞环境中光敏色素性质的平均值，而特定的生理反应可能由一种特定环境中的光敏色素分子控制。因此，所有光敏色素都可能具有潜在活性，并因其定位而触发特定反应。
