Influence of high temperature on chlorophyll fluorescence and its varietal variation in rice
2017
Aung Kyaw Phyo | Nam-Jing Chung
This study was carried out to find varietal response to heat stress by chlorophyll fluorescence. Chlorophyll fluorescence is closely correlated with photosynthetic rate. Field-grown rice were dug up at the grain filling stage, and moved to the plant growth chamber, where the temperatures were set up one after another starting from low to high temperature (25 approx 45 deg C). Fo, Fm and Fvl Fm were measured after the first dark-adaptation, and OJIP transient was measured after the second dark-adaptation. Results showed that, in all cultivars, maximum quantum efficiency of PSII phytochemistry (FvlFm) and the area above the fluorescence transient decreased as temperature increased, and both dropped abruptly at 45 deg C indicating the damage occurred in the PSII center. Among rice cultivars, damages to photosynthetic apparatus as suggested by maximum quantum efficiency of PSII phytochemistry and OJIP transient curves, which imply the presence of varietal variation in heat tolerance of rice photosynthesis.
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