Department of Biology, University of California, Los Angeles, California 90024.
Plant Physiol. 1992 Nov;100(3):1562-6. doi: 10.1104/pp.100.3.1562.
Chlorophyll a fluorescence transients from isolated Vicia faba guard cell chloroplasts were used to probe the response of these organelles to light quality. Guard cell chloroplasts were isolated from protoplasts by passing them through a 10-mum nylon net. Intact chloroplasts were purified on a Percoll gradient. Chlorophyll a fluorescence transients induced by actinic red or blue light were measured with a fluorometer equipped with a measuring beam. Actinic red light induced a monophasic quenching, and transients induced by blue light showed biphasic kinetics having a slow and a fast component. The difference between the red and blue light-induced transients could be observed over a range of fluence rates tested (200-800 mumol m(-2) s(-1)). The threshold fluence rate of blue light for the induction of the fast component of quenching was 200 mumol m(-2) s(-1), but in the presence of saturating red light, fluence rates as low as 25 mumol m(-2) s(-1) induced the fast quenching. These results indicate that guard cell chloroplasts have a specific response to blue light.
用分离的蚕豆保卫细胞叶绿体的叶绿素 a 荧光瞬变来探测这些细胞器对光质的反应。通过 10 微米的尼龙网将原生质体分离，得到完整的叶绿体。用聚蔗糖梯度分离叶绿素 a 荧光瞬变，用配备测量光束的荧光计测量。用活性红光或蓝光诱导的叶绿素 a 荧光瞬变。活性红光诱导单峰猝灭，而蓝光诱导的瞬变表现出双相动力学，具有慢和快两个成分。在测试的一系列辐照度（200-800 微摩尔·平方米-2·秒-1）范围内，可以观察到红光和蓝光诱导的瞬变之间的差异。蓝光诱导快速猝灭的快速成分的阈值辐照度为 200 微摩尔·平方米-2·秒-1，但在饱和红光存在下，低至 25 微摩尔·平方米-2·秒-1 的辐照度也能诱导快速猝灭。这些结果表明，保卫细胞叶绿体对蓝光有特定的反应。
