Institut für Biologie II, Universität Freiburg, Schänzlestrasse 1, D-7800, Freiburg i. Br., Germany.
Planta. 1990 Feb;180(3):372-7. doi: 10.1007/BF00198788.
The intracellular localisation of phytochrome in oat (Avena sativa L. cv. Garry Oat) coleoptiles was analysed by electron microscopy. Serial ultrathin sections of resin-embedded material were indirectly immunolabeled with polyclonal antibodies against phytochrome together with a gold-coupled second antibody. The limits of detectability of sequestered areas of phytochrome (SAPs) were analysed as a function of light pretreatments and amounts of the far-red absorbing form of phytochrome (Pfr) established. In 5-d-old dark-grown Avena coleoptiles SAPs were not detectable if less than 13 units of Pfr - compared with 100 units total phytochrome of 5-d-old dark-grown seedlings - were established by a red light pulse. In other sets of experiments, seedlings were preirradiated either with a non-saturating red light pulse to allow destruction to occur or with a saturating red followed by a far-red light pulse to induce first SAP formation and then its disaggregation. These preirradiations resulted in an increase of the limit of detectability of SAP formation after a second red light pulse to 38-41 and 19-23 units Pfr, respectively. We conclude that with respect to Pfr-induced SAP formation an adaptation process exists and that our data indicate that SAP formation is not a simple self-aggregation of newly formed Pfr.
利用电子显微镜分析了燕麦(Avena sativa L. cv. Garry Oat)中胚轴细胞内光敏色素的定位。用针对光敏色素的多克隆抗体与金结合的第二抗体间接标记树脂包埋材料的连续超薄切片。分析了作为光预处理和远红吸收型光敏色素(Pfr)量的函数检测到的隔离区(SAPs)的可检测极限。在 5 天龄的黑暗生长的燕麦中胚轴中,如果通过红光脉冲建立的 Pfr 少于 13 个单位(与 5 天龄黑暗生长的幼苗中的 100 个单位总光敏色素相比),则 SAPs 不可检测。在其他实验组中,幼苗要么用非饱和红光脉冲预辐照以允许发生破坏,要么用饱和红光脉冲 followed 以远红光脉冲诱导第一个 SAP 形成,然后再使其解聚。这些预辐照导致第二次红光脉冲后 SAP 形成的可检测极限增加到 38-41 和 19-23 单位 Pfr。我们得出结论,关于 Pfr 诱导的 SAP 形成存在一个适应过程,并且我们的数据表明 SAP 形成不是新形成的 Pfr 的简单自聚集。