Department of Plant Physiology and Development, Jagiellonian University, Al. Mickiewicza 3, 31-120 Kraków, Poland.
Plant Physiol. 1988 Sep;88(1):189-93. doi: 10.1104/pp.88.1.189.
The orientation of chloroplasts from profile to face position in Mougeotia can be controlled in two ways: by a typical phytochrome-mediated system or by continuous, simultaneous irradiation with far-red and visible light. In experiments with dichromatic irradiation of Mougeotia, the light conditions applied prevented the formation of a far-red-absorbing form of phytochrome gradient in the cell. An unpolarized background of far-red light and linearly polarized monochromatic light of different wavelengths and vibrating parallel to the cell axis, if given by themselves, were completely ineffective in producing any changes in chloroplast orientation. Given together, however, changes in chloroplast orientation were induced. The action spectrum for this interaction between constant far-red and variable visible light was maximal at 620 nanometers. The chloroplast response in these dichromatic light conditions required a prolonged duration of exposure to simultaneous continuous irradiation of high fluence energy. The vibrating plane of linearly polarized 620 nanometer light had no significant influence on interaction with far-red light in chloroplast movement. The results obtained are different from the typical low energy phytochrome-mediated chloroplast orientation. This new type of chloroplast photoresponse might be mediated by an unknown sensory pigment.
在刚毛藻中，叶绿体从前到侧面位置的定向可以通过两种方式控制：通过典型的光敏素介导的系统或通过远红光和可见光的连续同时照射。在刚毛藻的双色照射实验中，所施加的光照条件防止了细胞中形成远红光吸收形式的光敏素梯度。如果本身没有非偏振的远红光背景和沿细胞轴平行振动的不同波长的线性偏振单色光，则完全无法有效地产生任何叶绿体定向变化。然而，如果将它们一起给出，则会引起叶绿体定向的变化。这种恒定远红光和可变可见光之间相互作用的作用光谱在 620 纳米处最大。在这些双色光条件下，叶绿体的反应需要长时间暴露于高能量连续照射下。620 纳米线性偏振光的振动平面对叶绿体运动中与远红光的相互作用没有明显影响。所得结果与典型的低能量光敏素介导的叶绿体定向不同。这种新型叶绿体光响应可能由未知的感光色素介导。
