Effects of irradiance on the photosynthetic traits, antioxidative enzymes, and growth of Cryptotaenia japonica
2015
Liu, K. | Zhou, S. B. | Wu, X. Y. | Liu, F. | Li, G. X.
Growth, photosynthetic characteristics, chlorophyll (Chl) fluorescence parameters, and peroxidation of membrane lipids of Cryptotaenia japonica were studied under differing irradiances (15, 35, 60, and 100 % of full irradiance). At full irradiance, C. japonica exhibited a typical decline in net photosynthetic rate (PN) at midday, which was not observed in the other irradiance treatments. This indicates a possible photoinhibition for C. japonica at the high irradiance. Diurnal patterns of stomatal conductance (gₛ) were remarkably similar to those of PN in each irradiance treatment, and the intercellular CO₂ concentration (cᵢ) had the opposite trend. C. japonica growing under 60 % of the full irradiance exhibited the highest plant height, stem diameter, leaf area, and biomass. The initial fluorescence (F₀) value was lowest at 60 % of the full irradiance. Maximal fluorescence (Fₘ), potential activity of photosystem II (PS II) (Fᵥ/F₀), and maximal photochemical efficiency of PS II (Fᵥ/Fₘ) values were highest at 60 % of full irradiance and lowest at 15 % of the full irradiance. The malondialdehyde (MDA) content in 15 % and 100 % of the full irradiance were higher than under the other irradiances. During the treatment, catalase, peroxidase, and superoxide dismutase activities firstly increased and then declined under 15 % and 100 % of the full irradiance and were steadily low under 60 % of the full irradiance, indicating a low production of reactive oxygen species. Therefore, C. japonica thrived best under 60 % of the full irradiance.
显示更多 [+] 显示较少 [-]