Kataria Sunita, Jajoo Anjana, Guruprasad Kadur N
School of Life Science, Devi Ahilya University, Khandwa Road, Indore 452001, India.
School of Life Science, Devi Ahilya University, Khandwa Road, Indore 452001, India.
J Photochem Photobiol B. 2014 Aug;137:55-66. doi: 10.1016/j.jphotobiol.2014.02.004. Epub 2014 Feb 15.
Increased UV-B radiation on the earth's surface due to depletion of stratospheric ozone layer is one of the changes of current climate-change pattern. The deleterious effects of UV-B radiation on photosynthesis and photosynthetic productivity of plants are reviewed. Perusal of relevant literature reveals that UV-B radiation inflicts damage to the photosynthetic apparatus of green plants at multiple sites. The sites of damage include oxygen evolving complex, D1/D2 reaction center proteins and other components on the donor and acceptor sides of PS II. The radiation inactivates light harvesting complex II and alters gene expression for synthesis of PS II reaction center proteins. Mn cluster of water oxidation complex is the most important primary target of UV-B stress whereas D1 and D2 proteins, quinone molecules and cytochrome b are the subsequent targets of UV-B. In addition, photosynthetic carbon reduction is also sensitive to UV-B radiation which has a direct effect on the activity and content of Rubisco. Some indirect effects of UV-B radiation include changes in photosynthetic pigments, stomatal conductance and leaf and canopy morphology. The failure of protective mechanisms makes PS II further vulnerable to the UV-B radiation. Reactive oxygen species are involved in UV-B induced responses in plants, both as signaling and damaging agents. Exclusion of ambient UV components under field conditions results in the enhancement of the rate of photosynthesis, PS II efficiency and subsequently increases the biomass accumulation and crop yield. It is concluded that predicted future increase in UV-B irradiation will have significant impact on the photosynthetic efficiency and the productivity of higher plants.
由于平流层臭氧层损耗导致地球表面紫外线B辐射增加，是当前气候变化模式的变化之一。本文综述了紫外线B辐射对植物光合作用和光合生产力的有害影响。查阅相关文献发现，紫外线B辐射会在多个部位对绿色植物的光合机构造成损害。损害部位包括放氧复合体、D1/D2反应中心蛋白以及光合系统II供体侧和受体侧的其他成分。这种辐射会使光捕获复合体II失活，并改变光合系统II反应中心蛋白合成的基因表达。水氧化复合体的锰簇是紫外线B胁迫的最重要初级靶点，而D1和D2蛋白、醌分子和细胞色素b是紫外线B的后续靶点。此外，光合碳还原对紫外线B辐射也很敏感，紫外线B辐射会直接影响核酮糖-1,5-二磷酸羧化酶/加氧酶（Rubisco）的活性和含量。紫外线B辐射的一些间接影响包括光合色素、气孔导度以及叶片和冠层形态的变化。保护机制失效使光合系统II更容易受到紫外线B辐射的影响。活性氧作为信号分子和破坏剂参与了植物中紫外线B诱导的反应。在田间条件下排除环境中的紫外线成分会提高光合作用速率、光合系统II效率，进而增加生物量积累和作物产量。得出的结论是，预计未来紫外线B辐射增加将对高等植物的光合效率和生产力产生重大影响。
