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Temperature response and photoinhibition investigated by chlorophyll fluorescence measurements for four distinct species of dipterocarp trees
Author(s) -
Kitao Mitsutoshi,
Lei Thomas T.,
Koike Takayoshi,
Tobita Hiroyuki,
Maruyama Yutaka,
Matsumoto Yoosuke,
Ang LaiHoe
Publication year - 2000
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.2000.100309.x
Subject(s) - photoinhibition , dipterocarpaceae , chlorophyll fluorescence , botany , photosynthesis , biology , horticulture , photosystem ii
The effects of strong light in combination with elevated temperatures on the photosynthetic system were examined in 4 dipterocarp tree species with ecologically different habitats. The 4 dipterocarp tree species were: Shorea platyclados originated from upper dipterocarp forests, Shorea parvifolia – lowland and hill dipterocarp forests, Shorea assamica – lowland dipterocarp forests, and Dipterocarpus oblongifolius – riparian fringes. S. platyclados and D. oblongifolius have higher growth and survival rates in open sites than S. parvifolia and S. assamica . Tolerance of high temperature among the species was assessed by determining the critical temperatures (T c ) at which the minimal fluorescence (F o ) began to rise sharply. This was measured by exposing plants to an increasing temperature of about 1°C min −1 . The intrinsic thermotolerance of the thylakoid membrane appears to be the highest for D. oblongifolius (T c =46.4°C), intermediate for S. platyclados (45.7°C), and lowest for S. parvifolia and S. assamica (45.2 and 45.3°C, respectively). The temperature‐dependent efficiency of PSII electron transport (ΔF/F′ m ), photochemical quenching (q P ), and the efficiency of light capture of open PSII (F′ v /F′ m ) were measured at the photosynthetic steady state at least 10 min after the light exposure (180 μmol m −2 s −1 PFD). Stable temperature responses of ΔF/F′ m and q P were observed in S. platyclados and D. oblongifolius , while those in S. parvifolia and S. assamica were more temperature‐dependent and severely affected at 45°C. Little difference was observed in temperature‐dependent F′ v /F′ m among species. Photoinhibitory light exposure (1600 μmol m −2 s −1 PFD) for 2 h at 40°C had little effect on the recovery kinetics from photoinhibition of S. platyclados and D. oblongifolius compared with those at 35°C. In contrast, the recovery from photoinhibition was retarded in S. parvifolia and S. assamica . These findings suggest that even at 40°C, a temperature below T c , an exposure to strong light exacerbated photoinhibition in S. parvifolia and S. assamica corresponding to the closure of PSII reaction centers, as indicated by the decrease in q P at this temperature. Thus, S. platyclados and D. oblongifolius, which occur at uplands and riparian fringes with frequent disturbances, are suggested to have higher photosynthetic tolerance to elevated temperatures contributing to a circumvention of photoinhibition.