Department of Biology, Graduate School of Science and Engineering, University of Toyama, 3190 Gofuku, Toyama, 930-8555, Japan.
Planta. 2011 Nov;234(5):1019-30. doi: 10.1007/s00425-011-1451-7. Epub 2011 Jun 26.
To understand the regulatory mechanisms involved in tissue development by light, the kinetics of regulation of Casparian strip (CS) development in garden pea stems was studied. We found that short-term irradiation with white light delayed the development of the CS and used this delay to assess the quantitative effect of light on CS development. We examined the effect of the duration and fluence rates of white light treatment on CS development and observed a significant relationship between fluence and the delay in CS development indicating that the Bunsen-Roscoe law of reciprocity holds for this response. The effect of white light irradiation was not inhibited in the presence of a photosynthetic inhibitor, DCMU, or a carotenoid biosynthesis inhibitor, Norflurazon, indicating that the delay in CS development by light is a photomorphogenetic response rather than a subsidiary effect mediated by photosynthetic activity. An action spectrum for the response displayed a major peak in the blue-light region, suggesting a dominant role for blue-light receptors. A minor peak in the red-light region also suggested the possible involvement of phytochromes. Although phytochromes are known to contribute to blue-light responses, phytochrome-deficient mutants showed a normal delay of CS development in response to blue light, indicating that the response is not mediated by phytochrome and suggesting a role for one or more specific blue-light receptors.
为了理解光在组织发育中的调控机制，我们研究了豌豆茎中 Casparian 带（CS）发育的调控动力学。我们发现，短期的白光照射会延迟 CS 的发育，我们利用这种延迟来评估光对 CS 发育的定量影响。我们研究了白光处理的持续时间和光强对 CS 发育的影响，观察到光强与 CS 发育延迟之间存在显著的关系，表明布森罗克光强倒数定律适用于这种反应。在存在光合抑制剂 DCMU 或类胡萝卜素生物合成抑制剂 Norflurazon 的情况下，白光照射的效果没有被抑制，这表明光对 CS 发育的延迟是一种光形态发生反应，而不是由光合作用活性介导的副反应。该反应的作用光谱在蓝光区域显示出一个主要峰值，表明蓝光受体起主要作用。红光区域的一个较小峰值也表明了可能涉及光敏色素。虽然已知光敏色素参与了蓝光反应，但光敏色素缺陷突变体对蓝光的 CS 发育延迟反应正常，这表明该反应不是由光敏色素介导的，并暗示了一个或多个特定的蓝光受体的作用。
