title: Effect of cerium on photosynthetic characteristics of soybean seedling exposed to supplementary ultraviolet-B radiation.
abstract: Effects of cerium (Ce3+) on photosynthetic characteristics were investigated by hydroponics under laboratory conditions when soybean seedlings were exposed to two levels of supplementary UV-B radiation. UV-B radiation badly inhibited the photosynthesis in soybean seedling, leading to a reduction in net photosynthetic rate (Pn), Hill reaction activity, light saturated photosynthetic rate (Ps) and apparent quanta yield (AQY), as well as the CO2 and light saturated photosynthetic rate (Pm) and carboxulation efficiency (CE). On the contrary, Ce obviously promoted the photosynthesis of plants by increasing Hill reaction activity, accelerating electron transport and photophosphorylation, and enhancing carboxylation efficiency. For Ce+UV-B treatments, the values of photosynthetic parameters were still lower than those of the control, but obviously higher than those of UV-B treatment. The results indicated that Ce alleviated the inhibition of UV-B radiation on the photosynthesis in soybean seedling to a certain extent. In correlating of Pn with Hill activity, AQY and CE, we found that the changes of photosynthetic rate were mainly influenced by the regulating effect of Ce on Hill activity and AQY at low level (0.15 W/m(2)) of UV-B radiation, but were dominated by the regulating effect of Ce on CE at high level (0.45 W/m(2)). Thus, Ce could regulate many aspects in photosynthesis of soybean seedling under UV-B stress. The regulating mechanism was close related with the dosage of UV-B radiation.
authors.affiliation: The Key Laboratory of Industrial Biotechnology, Ministry of Education, Southern Yangtze University, Wuxi 214036, China.
authors.forename: Chan-juan
authors.initials: CJ
authors.lastname: Liang
authors.forename: Xiao-hua
authors.initials: XH
authors.lastname: Huang
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
mesh_terms: D000383:Agriculture; D002245:Carbon Dioxide / Q000378:metabolism; D002563:Cerium / Q000494:pharmacology*; D002681:China; D004579:Electron Transport / Q000187:drug effects; D005308:Fertilizers; D010785:Photophosphorylation / Q000187:drug effects; D010788:Photosynthesis / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D036226:Seedlings / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D013025:Glycine max; D014466:Ultraviolet Rays
chemical_list: D005308:Fertilizers; D002245:Carbon Dioxide; D002563:Cerium