Stahlberg R, Van Volkenburgh E, Cleland R E
Department of Botany, University of Washington, Seattle 98195, USA.
Planta. 2000 Dec;212(1):1-8. doi: 10.1007/s004250000365.
There has been persisting controversy over the role of photosynthesis in the stimulation of the plasma membrane H+-ATPase and growth of dicotyledonous leaves by light. To investigate this, we compared the effects of light on growth, H+ net efflux and membrane potential (Vm) of strips which contained either only chlorophyll-free (white) mesophyll cells or chlorophyll-containing (green) cells cut from variegated Coleus leaves. White mesophyll cells responded to white, blue and red light with a hyperpolarization of Vm, an acidification of the apoplast and a promotion of growth, all of which began after a lag of 2-7 min. In contrast, green mesophyll cells showed a biphasic light response in which the hyperpolarization and the acidification were preceded by a rapid depolarization of Vm and an alkalinization of the apoplast. Nevertheless, green and white tissues showed comparable growth promotions in response to light. The light response of the leaf mesophyll is a composite of two separate photosystems. The initial depolarization and alkalinization are mediated by photosynthesis and blocked by 3-(3,4-dichlorophenyl)-1,1-dimethylurea. The slower hyperpolarization, acidification and growth response, on the other hand, are clearly in response to light absorption by pigments other than chlorophyll.
关于光合作用在光刺激双子叶植物叶片质膜H⁺ - ATP酶及生长过程中所起的作用，一直存在争议。为了对此进行研究，我们比较了光对从斑叶彩叶草叶片切下的仅含无叶绿素（白色）叶肉细胞的条带或含叶绿素（绿色）细胞的条带的生长、H⁺净外流和膜电位（Vm）的影响。白色叶肉细胞对白光、蓝光和红光的反应是Vm超极化、质外体酸化和生长促进，所有这些反应在延迟2 - 7分钟后开始。相比之下，绿色叶肉细胞表现出双相光反应，其中Vm快速去极化和质外体碱化先于超极化和酸化。然而，绿色和白色组织对光的生长促进作用相当。叶片叶肉的光反应是两个独立光系统的综合表现。最初的去极化和碱化由光合作用介导，并被3 -（3,4 - 二氯苯基）- 1,1 - 二甲基脲阻断。另一方面，较慢的超极化、酸化和生长反应显然是对叶绿素以外的色素吸收光的反应。
