Israel Oceanographic and Limnological Research, P.O.B. 8030, Haifa 31080, Israel.
Plant Physiol. 1990 Apr;92(4):891-8. doi: 10.1104/pp.92.4.891.
The time course of adaptation from a high to a low photon flux density was studied in the marine chlorophyte Dunaliella tertiolecta. A one-step transition from 700 to 70 micromole quanta per square meter per second resulted in a reduction of doubling rate from 1.1 to 0.4 per day within 24 hours, followed by a slower accumulation of photosynthetic pigments, light harvesting antenna complexes, Photosystem II reaction centers and structural lipids that constitute the thylakoid membranes. Photoregulated changes in the biochemical composition of the thylakoid proteins and lipids were functionally accompanied by decreases in the minimal photosynthetic quantum requirement and photosynthetic capacity, and an increase in the minimal turnover time for in vivo electron transport from water to CO(2). Analysis of de novo synthesis of thylakoid membranes and proteins indicates that a high light to low light transition leads to a transient in carbon metabolism away from lipid biosynthesis toward the synthesis of the light harvesting antenna protein complexes, accompanied by a slower restoration rate of reaction centers and thylakoid membranes. This pattern of sequential synthesis of light harvesting complexes followed by reaction centers and membranes, appears to optimize light harvesting capabilities as cells adapt to low photon flux densities.
我们研究了海洋绿藻杜氏盐藻从高光强到低光强适应的时程。从 700 到 70 μmol 量子/平方米/秒的一步转变，在 24 小时内将倍增率从每天 1.1 降低到 0.4，随后是光合作用色素、光捕获天线复合物、光系统 II 反应中心和构成类囊体膜的结构脂质的缓慢积累。类囊体蛋白和脂质的光调节生化组成变化伴随着最小光合作用量子需求和光合作用能力的降低，以及体内水到 CO2 的电子传递最小周转率的增加。对类囊体膜和蛋白质从头合成的分析表明，高光强到低光强的转变导致碳代谢暂时偏离脂类生物合成，转向光捕获天线蛋白复合物的合成，同时反应中心和类囊体膜的恢复速度较慢。这种光捕获复合物先于反应中心和膜合成的顺序合成模式，似乎使细胞在适应低光强时能够优化光捕获能力。
