Comparison of the activities of photosystem II of four table grapevine cultivars during high-temperature stress

Abstract

High-temperature stress influences the growth and development of grapevines, and plant responses to this stress vary between laboratory and natural conditions. In the present study, the responses to high-temperature stress in four grapevine cultivars (‘Summer Black’, ‘Zuijinxiang’, ‘Hupei1#’, and ‘Shenfeng’) were studied by comparing chlorophyll a fluorescence and the levels of heat-shock protein 21 (HSP21) after exposure to control (35 °C in controlled laboratory conditions or at 37 °C in a greenhouse with naturally fluctuating temperatures) and high-temperature stress treatments (45 °C in laboratory conditions or 42 °C in the field conditions). Leaf water loss in ‘Summer Black’ was less than that in the three other cultivars after treatment at 45 °C. Some parameters (ΨEo, Wk, RCQA, and Mo) of photosystem II (PSII) activity were altered in ‘Shenfeng’, ‘Zuijinxiang’, and ‘Hupei1#’, but were unaltered in ‘Summer Black’ after treatment at 45 °C. Other parameters (maximum photochemical efficiency (Fv/Fm), performance index on absorption basis (PIABS), ΦPo, ΦEo, and HSP21 levels) were altered in ‘Summer Black’, but to a lesser extent than in the three other cultivars under high-temperature stress. Unlike ‘Summer Black’, extreme injury owing to leaf water loss to ‘Shenfeng’, ‘Zuijinxiang’, and ‘Hupei1#’ could be explained by disruption of PSII activity. Furthermore, there were the observed differences in PSII activity between in laboratory and field conditions, which could be considered as the mechanisms for high-temperature acclimation and other environment factors.