Estimating heat tolerance among plant species by two chlorophyll fluorescence parameters
Weng, J.H.(National Chung-Hsing Univ., Taichung (Taiwan). Dept. of Life Science)E-mail:[email protected] | Lai, M.F.
The heat tolerance of 8 temperate- and 1 subtropical-origin C3 species as well as 17 tropical-origin ones, including C3, C4, and CAM species, was estimated using both Fo-T curve and the ratio of chlorophyll fluorescence parameters, prior to and after high temperature treatment. The critical temperature (Tc) of all temperate-origin species ranged between 40-46 deg C in winter and between 32-48 deg C in summer. Those for 1 subtropical-, 12 tropical-origin C3, 1 CAM and 4 C4 species ranged between 25-44 deg C, 35-48 deg C, 41-47 deg C and 45-46 deg C, respectively. When leaves were exposed to 45 deg C for 20 min, a significant correlation between RFv/m (the ratio of Fv/Fm before and after 45 deg C treatment) and Tc was observed for all the tested plants, except for the tropical-origin C3 species. Thus, Tc might not be a suitable index of heat tolerance for plants with wide range of environmental adaptation.
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