UV-B辐射增强下施硅对冬小麦光合特性和产量的影响

Effects of silicate application on photosynthesis and yield in winter wheat under elevated UV-B radiation

通过大田试验,研究UV-B增强下施硅对冬小麦光合和蒸腾生理相关参数以及产量的影响。UV-B辐射设2水平,即对照(A,自然光)和增强20%(E);施硅量设2水平,即对照(Si0,0 kg/hm2Si O2)和施硅(Si1,200kg/hm2Si O2)。结果表明,不施硅条件下(Si0),UV-B辐射处理(E)的不同生育期小麦净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)和蒸腾速率(Tr)比对照处理(A)分别降低9.21%~18.94%、7.56%~23.66%、1.24%~12.81%和13.88%~27.85%,提高气孔限制值(Ls)和水分利用率(WUE)5.07%~19.67%和2.35%~27.86%,小麦产量降低9.08%;UV-B增强下(E),施硅处理(Si1)的不同生育期小麦净光合速率(Pn)、气孔限制值(Ls)和水分利用率(WUE)比不施硅对照(Si0)分别提高5.23%~12.23%、4.61%~45.32%和18.15%~61.33%,气孔导度(Gs)、胞间CO2浓度(Ci)和蒸腾速率(Tr)分别降低6.35%~10.94%、5.41%~11.01%和6.75%~30.51%,小麦产量增加4.83%。说明UV-B增强可显著降低冬小麦叶片的净光合速率和蒸腾速率,提高水分利用率,降低冬小麦产量,而施硅可缓解UV-B辐射对冬小麦光合作用的抑制,降低蒸腾速率和提高水分利用率,使小麦不减产。

A field experiment was conducted to investigate the effects of silicate application on photosynthesis, tran-spiration and yield in winter wheat under elevated UV-B radiation. The experiment had two UV-B radiation levels,ambient UV-B （A ,ambient） and elevated UV-B radiation （E,elevated by 20%） ; and two silicate application levels,a control （Si0,0 kg/hm^2, SiO 2） and added silicate （ Si 1,200 kg/hm^2, SiO2） . The results indicated that,compared with the group of ambient UV-B radiation in the treatment of no silicate application,the net photosynthesis rate （ P it）,stomatal conductivi-ty （Gs）,intercellular CO 2 concentration （ Ci ） and transpiration rate （ Tt ）of wheat at different stages in the group of elevat-ed UV-B radiation decreased by 9.21%-18.94% , 7 .5 6%-2 3 .6 6 %, 1 .2 4% -1 2 .8 1% and 1 3 .8 8% -2 7 .8 5% , respectively,and stomatal limitation （Ls ） and water use efficiency （ WUE） increased by 5. 07% - 19. 67% and 2. 35% - 2 7 .8 6% ,wheat yield decreased by 9 .0 8% . Under elevated UV-B radiation, the treatment of silicate application signif-icantly increased P n,Ls and WUE of wheat at different sta-ges by 5 .2 3 %- 1 2 .2 3 %, 4 .6 1% - 4 5 .3 2% and 1 8 .1 5% -61.33%, respectively, decreased G^, C- and T（ by 6 .3 5 %- 1 0 .9 4 %, 5 .4 1%- 1 1 .0 1% and 6 .7 5 %- 3 0 .5 1 %, increased wheat yield by 4.83%. In conclusion, the treatment of elevated UV-B radiation significantly decreased the and Tr, in-creased WUE in winter wheat leaves, and decreased wheat yield. However, the treatment of silicate application could allevi-ate the inhibitor^^ effect of elevated UV-B radiation on P .t, decrease and WUE, and increase the yield of wheat.