Zhang Lingang, Wang Yading, Zhao Liqun, Shi Suyun, Zhang Lixin
Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
J Plant Physiol. 2006 Jul;163(8):818-26. doi: 10.1016/j.jplph.2005.07.011. Epub 2005 Sep 23.
When seedlings are grown in the dark, proplastids of the developing leaf differentiate into etioplasts. Greening of etiolated plastids is stimulated by light, which is sensed by various types of photoreceptors. Nitric oxide (NO) has been shown to be a bioactive molecule that could take part in this light-mediated process in plants. In this paper, we show that emission of NO in barley seedlings increased concomitantly with increasing activities of nitric oxide synthase (NOS) during the greening. Treatment with sodium nitroprusside (SNP), a NO donor, increased the accumulation of chlorophyll contents, enhanced the accumulation of thylakoid membrane proteins, such as light harvesting complex of photosystem II (LHCII) and PSIA/B, and then improved the effective quantum yield of photosystem II (PSII) (Phi(PSII)) in the light. Instead, treatment with either NO scavenger 2-phenyl-4,4,5,5-tetramentylimidazoline-1-oxyl-3-xide (PTIO) or NOS inhibitor N(omega)-nitro-l-arginine (l-NNA) retarded the greening of etiolated-seedlings. Moreover, sodium ferrocyanide, an analog of SNP, nitrite and nitrate, two NO-decomposition products did not have any effect on the greening process. These results indicated that NO, as an endogenous signaling molecule, participates in light-mediated greening of barley seedlings, and exogenous NO accelerates this process.
当幼苗在黑暗中生长时，发育叶片中的前质体分化为黄化质体。黄化质体的绿化受到光的刺激，光由各种类型的光感受器感知。一氧化氮（NO）已被证明是一种生物活性分子，可参与植物中的这种光介导过程。在本文中，我们表明，在绿化过程中，大麦幼苗中NO的释放与一氧化氮合酶（NOS）活性的增加同时发生。用NO供体硝普钠（SNP）处理增加了叶绿素含量的积累，增强了类囊体膜蛋白的积累，如光系统II（LHCII）和PSIA/B的捕光复合体，然后提高了光下光系统II（PSII）的有效量子产率（Phi(PSII)）。相反，用NO清除剂2-苯基-4,4,5,5-四甲基咪唑啉-1-氧基-3-氧化物（PTIO）或NOS抑制剂N(ω)-硝基-L-精氨酸（L-NNA）处理会延迟黄化幼苗的绿化。此外，SNP的类似物亚铁氰化钠、两种NO分解产物亚硝酸盐和硝酸盐对绿化过程没有任何影响。这些结果表明，NO作为一种内源性信号分子，参与了大麦幼苗的光介导绿化，外源NO加速了这一过程。
