Response of chlorophyll fluorescence to dynamic light in three alpine species differing in plant architecture

摘要: A study was carried out to examine the effect of dynamic photosynthetically active photon flux density (PPFD) on photoinhibition and energy use in three herbaceous species, prostrate Saussurea superba, erect-leaved S. katochaete, half-erect-leaved Gentiana straminea, from Qinghai-Tibet Plateau. Chlorophyll fluorescence response measured under each sets high-low PPFD combinations: 1700-0, 1400-300, 1200-500 mu mol m(-2) s(-1), illuminating four frequencies: 1, 5, 15, 60 cycles per 2 h. The total light exposure time 2h integrated same all treatments. highest frequency fluctuation resulted lowest photochemical activity, level non-photochemical quenching, greatest decrease F-v/F-m (maximal efficiency PSII). 5 15 treatments higher activity than 1 cycle treatment. 1700-0 combination led more serious species. superba usually exhibited CO2 uptake rate, reduction F-v/F-m,F- smallest fraction thermal dissipation. With similar fractions dissipation, katochaete had relatively less G. straminea owing effective F-o quenching. results suggest that high fluctuating generally photoinhibition, which is periods irradiation with intensity. (c) 2005 Elsevier B.V. All rights reserved.