Thermoluminescence studies on the photoinhibition of pothos leaf discs at chilling, room and high temperature

Chlorophyll Fluorescence in Plant Biology

“…In natural conditions, sun light far exceeds the quantum requirements for photochemistry in photosynthesis, commonly referred as 'photoinhibition' (Misra, 1993;Misra et al 1997;2001;2007). Under these conditions, the PSII RC undergoes photoinduced damages of the D1 protein.…”

Increase in the intensity of thermoluminescence Q‐band during leaf ageing is due to a block in the electron transfer from QA to QB

“…These samples were excited by a sequence of two flashes (General Radio, Stroboslave) with a halfdecay time of 3 ms (0.5 J) white light and quickly frozen to 77K by dropping them into a Dewar containing liquid nitrogen. TL glow curves were recorded as described by Misra et al (18,19). To inhibit electron transfer between Q A and Q B in the reaction centre of photosystem II, 5 mL 10 mmol/L DCMU was added to the chloroplast thylakoid sample before illumination.…”

Thermoluminescence in Chloroplast Thylakoid

“…Photoinhibitory treatment which usually result in the decreased quantum efficiency of PSII and degradation of D1 polypeptide, do not affect the S-states but affects B-band with least effect on C-band (Misra et al, 1997;1998a). Isolated thylakoids showed a parallel decrease in Q-and B-band (Vass et al, 1988) suggesting both Q A and Q B is affected by photoinhibition.…”

“…Ohad et al (1990) reported a band shift of B-band to lower temperature, suggesting lumen acidification and redox changes in PSII. Misra et al (1997Misra et al ( , 1998a reported Q-and B-band intensity decreased with high temperature in pothos and spinach leaves. Janda et al (1999) reported membrane leakiness and grana destacking might be the reason for the changes in AG bands both at high temperature and freezing.…”