[Effects of elevated CO2 on photoinhibition of strawberry leaves under different nitrogen levels].
By using PAM-2000 portable chlorophyll fluorometer and HCM-1000 photosynthesis measurement system, this paper measured the initial fluorescence (Fo), maximal photochemical efficiency of PSII (Fv/Fm), maximal fluorescence (Fm), amount of inactive PS II reaction centers (Fi-Fo), proportion of Q(B)-non-reducing PS II reaction centers [(Fi-Fo)/(Fp-Fo)], and net photosynthetic rate (Pn) of strawberry leaves under conditions of elevated CO2 (700 microl x L(-1)) and ambient CO2 (390 microl x L(-1)) at three levels of nitrogen application (12, 4 and 0.4 mmol x L(-1)). The results showed that there was a significant joint effect between CO2 and N on the photoinhibition of strawberry leaves. Under elevated CO2 condition, the Pn in treatment 12 mmol N x L(-1) increased by 62.7%, while that in treatments 4 and 0.4 mmol N x L(-1) decreased by 7.4% and 21.3%, respectively. When exposed to high light and subsequently recovered in dark for 4 hours, the strawberry leaves in treatment 12 mmol N x L(-1) showed less changes of Fm and Fv/Fm in elevated CO2 than in ambient CO2, while those in treatments 4 and 0.4 mmol N x L(-1) were in adverse, suggesting that for the strawberry leaves in elevated CO2, nitrogen deficiency could result in an acclimatized decrease of photosynthesis and an increase of photoinhibition.
Xu
Kai
K
Department of Horticulture, Zhejiang University, Hangzhou 310029, China. xukai1965@sohu.com
Guo
Yan-ping
YP
Zhang
Shang-long
SL
Wu
Hui-min
HM
D002245:Carbon Dioxide / Q000032:analysis / Q000494:pharmacology*; D002734:Chlorophyll / Q000378:metabolism; D031985:Fragaria / Q000502:physiology*; D009584:Nitrogen / Q000032:analysis*; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology
D002734:Chlorophyll; D002245:Carbon Dioxide; D009584:Nitrogen