Comparison of Chlorophyll Fluorescence of Cool and Warm Season Grasses at Chilling and High Temperatures

Abstract

Photoinhibitory damage under chilling (10℃) or heat (35℃) condition with moderate light intensity was estimated by comparing chlorophyll fluorescence of detached leaves. Five cool season grasses showed higher chlorophyll fluorescence at 10℃ as compared to 6 warm. season grasses. Reversed result was obtained at 35℃. Cool season grasses showed severe leaching of chlorophyll at 35℃ with complete depression of chlorophyll fluorescence. As one of the protection mechanism, carotenoid content was measured after heat or chilling treatment. There was no clear relationship between chlorophyll fluorescence and carotenoids except when cool season grasses were subjected to 10℃, suggesting a possible involvement of carotenoids for photoprotection in these grasses at low temperature.