Figure 1From: Comparison of investigation methods of heat injury in grapevine (Vitis) and assessment to heat tolerance in different cultivars and speciesEstablishing the critical temperature (T c ) for investigating the heat injury of grape leaves using the chlorophyll a fluorescence parameters F v /F m and F o . Tc was determined from the intersection of the two regression lines extrapolated from the slow- and fast-rising portions of the temperature-dependent Fv/Fm and Fo response.Back to article page