1995 Volume 41 Issue 1 Pages 31-36
Damage in leaves caused by moderate light coupled with low (10℃) or high (35℃) temperatures was estimated by comparing the changes of chlorophyll a fluorescence of leaves measured at room temperature. Detached leaves of twenty seven zoysiagrasses (4 species and hybrid types) were subjected to low or high temperature stress for 24h and 48h respectively, and the chlorophyll a fluorescence was measured after dark treatment. Fluorescence intensity was calculated as a percentage of chlorophyll a fluorescence of control measured before the temperature stress. Reduction of fluorescence intensity might suggest severe damage of PSII (photosystem II) that was observed clearly at low temperature as compared to that at high temperature in zoysiagrasses. Wide variations of fluorescence intensity was observed in zoysiagrasses both at low and high temperature stress. Zoysia tenuifolia showed the highest fluorescence intensities in average both at low and high temperature treatments, which is partially attributed to the narrow leaf blade with low light absorption. Carotenoid content in leaves showed better correlation with fluorescence intensity at 24 h than chlorophyll content in leaves in 17 strains of Z. japonca subjected to both low and high temperatures. It is suggested that carotenoid may play a protective role against photoinhibition in the leaves of Z. japonca at low temperature stress as well as at high temperature stress.