Ce(Ⅲ)对UV-B辐射下大豆幼苗水分代谢的影响

Influence of Cerium on Water Metabolism of Soybean Seedlings under Supplementary UV-B Radiation Stress

采用水培法研究Ce(Ш)对紫外辐射(UV-B,280-320nm)胁迫下大豆(Glycine max)幼苗根系活力、光合速率(Pn)、蒸腾速率(Tr)的影响。静态实验结果表明:20mg.L-1CeC l3处理抑制了UV-B辐射引起的根系活力降低;动态曲线显示,较之CK,20mg.L-1CeC l3提高了大豆幼苗的Pn和Tr,UV-B辐射处理使Pn、Tr下降,Ce(Ш)+UV-B处理下Pn、Tr的下降趋势得到缓解,且最终达到较好的恢复效果。低UV-B(0.15W.m-2)辐射胁迫使得大豆幼苗水分利用效率(WUE)高于CK(第1天-第4天),但恢复期(第6天-第9天)WUE急剧下降;高UV-B(0.45W.m-2)辐射下WUE低于CK,降幅明显。Ce(Ш)+UV-B组大豆幼苗WUE下降幅度小于UV-B组,且恢复后期(第7天-第9天)WUE迅速提升。实验结果表明Ce(Ш)有效缓解了UV-B辐射对大豆幼苗水分代谢的胁迫。

The soybean （Glycine max） seedlings were treated by Cerium and exposed to ultraviolet-B radiation （UV-B, 280 -320nm） with hydroponics under laboratory conditions to study the influence of the Cerium （ Ⅲ） on root activity, photosynthetic rate （ Pn）, transpiration rate （Tr） of the soybean seedlings. The results of the static experiments showed that the root activity of the soybean seedlings declined under the 20mg · L^-1 CeC13 treatment induced by UV-B radiation. The Dynamic experimental results showed that the Pn and Tr of the soybean seedlings by 20mg· L^-1 CeCl3 treatment increased comparing to the control. The UV-B radiation caused the decline of the Pn and Tr of the soybean seedlings, while the Ce（ Ⅲ ） plus UV-B treatments eased the decline trend of the Pn and Tr and accelerated their recovery paces. The water use efficiency （WUE） of soybean seedlings increased under UV-B radiation （0.15W · m^-2） stress during first four days, and then decreased sharply during the recovery periods from the sixth day to ninth day. The WUE declined obviously under high dose UV-B radiation stress. The range of the WUE by Ce （ Ⅲ ） plus UV-B treatments was smaller than that by UV-B treatment, while its WUE increased at a faster pace during recovery periods from the seventh day to ninth day. The results of the experiments showed that the Ce （ Ⅲ ） played an effective role to ease the UV-B radiation stress on the water metabolism of soybean seedlings.