Division of Biological and Medical Research, Argonne National Laboratory, Argonne, Illinois.
Plant Physiol. 1966 May;41(5):780-6. doi: 10.1104/pp.41.5.780.
Light-induced modifications in lipoxidase metabolism and chlorophyll formation in the cotyledon of squash (Cucurbita moscata) seedlings were determined. The enzyme activity decreased as light intensity increased, but chlorophyll continued to accumulate long after lipoxidase activity had virtually disappeared. Considering the differences in the levels of irradiance required to manifest the optimal responses, and also from the results obtained with ultraviolet and red, far-red light treatments, any causal relationship between lipoxidase disappearance and chlorophyll synthesis was ruled out.The observed light-saturation phase in the chlorophyll synthesis, indicated that chlorophyll formation was initially controlled by the phytochrome system. No similar saturation stage for the enzyme responses was observed.The sensitivity of lipoxidase to prolonged light exposures suggested a strong correlation with the known photoreactions presumed to be controlled by the high energy reactive-phytochrome system. Lipoxidase metabolism is, therefore, suggested as a biochemical index for the photomorphogenic reactions similar to the ones induced by the high energy reaction.
光照诱导的西葫芦（Cucurbita moscata）幼苗子叶脂氧合酶代谢和叶绿素形成的变化被确定。随着光照强度的增加，酶活性降低，但脂氧合酶活性几乎消失后很长时间，叶绿素仍在继续积累。考虑到表现最佳反应所需的辐照度水平的差异，以及用紫外线和红光、远红光处理获得的结果，可以排除脂氧合酶消失与叶绿素合成之间的任何因果关系。观察到的叶绿素合成中的光饱和阶段表明，叶绿素的形成最初受光敏色素系统的控制。没有观察到类似的酶反应的饱和阶段。脂氧合酶对长时间光照暴露的敏感性表明，它与已知的光反应之间存在强烈的相关性，这些光反应被认为是由高能反应型光敏色素系统控制的。因此，脂氧合酶代谢被认为是光形态发生反应的生化指标，类似于由高能反应诱导的光形态发生反应。
