Figure 2

Difference spectra for tobacco thylakoid membranes obtained by calculating D(i) = S(i+1) – S(i) from the series of measured S(i) spectra. Continuous blue curves indicate ISO difference spectra, where the temperature of the two spectra from which these difference spectra were calculated was the same. Red dash-dot curves indicate ΔT difference spectra, where there was about 3°C difference between the spectra from which these difference spectra were calculated. Arrows show the directions of the changes at the given spectrum region upon increasing temperature. Thicker lines show the different minima of the disappearing amide II band in the ISO and the ΔT spectra. The difference spectra of the studied temperature range (6–73°C) are divided into four panels according to their tendencies to change. The intensity scaling in the four panels is the same.