Cooperation of xanthophyll cycle with water-water cycle in the protection of photosystems 1 and 2 against inactivation during chilling stress under low irradiance

Abstract

The xanthophyll cycle and the water-water cycle had different functional significance in chilling-sensitive sweet pepper upon exposure to chilling temperature (4 °C) under low irradiance (100 µmol m -2 s -1 ) for 6 h. During chilling stress, effects of non-photochemical quenching (NPQ) on photosystem 2 (PS2) in dithiothreitol (DTT) fed leaves remained distinguishable from that of the water-water cycle in diethyldithiocarbamate (DDTC) fed leaves. In DTT-fed leaves, NPQ decreased greatly accompanied by visible inhibition of the de-epoxidized ratio of the xanthophyll cycle, and maximum photochemical efficiency of PS2 (F v /F m ) decreased markedly. Thus the xanthophyll cycle-dependent NPQ could protect PS2 through energy dissipation under chilling stress. However, NPQ had a slighter effect on photosystem 1 (PS1) in DTT-fed leaves than in DDTC-fed leaves, whereas effects of the water-water cycle on PS1 remained distinguishable from that of NPQ. Inhibiting superoxide dismutase (SOD) activity increased the accumulation of O 2 , the oxidation level of P700 (P700 + ) decreased markedly relative to the control and DTT-fed leaves. Both F v /F m and NPQ changed little in DDTC-fed leaves accompanied by little change of (A+Z)/(V+A+Z). This is the active oxygen species inducing PS1 photoinhibition in sweet pepper. The water-water cycle can be interrupted easily at chilling temperature. We propose that during chilling stress under low irradiance, the xanthophyll cycle-dependent NPQ has the main function to protect PS2, whereas the water-water cycle is not only the pathway to dissipate energy but also the dominant factor causing PS1 chilling-sensitivity in sweet pepper.

Accumulation of antioxidants and antioxidant activity in tomato, Solanum lycopersicum, are enhanced by the transcription factor SlICE1

“…Our study demonstrates that SlICE1 plays an important role in the regulation of antioxidant activity and antioxidant accumulation. Cold stress also a ects the integrity of plant membranes and their lipid composition through the accumulation of ROS, which causes peroxidation of membrane lipids (Kratsch and Wise 2000;Li et al 2005). Peroxidation of unsaturated lipids may be the cause of increased membrane rigidity in tropical and subtropical plants exposed to low temperature stresses (Lee et al 2003); therefore, reduction of ROS is important for survival.…”

Seasonal changes in anthocyanin contents and in activities of xanthophyll and ascorbate–glutathione cycles in Sabina species derived from different environments

“…The ascorbate-glutathione pathway in chloroplasts has a role in dissipating excess energy in chloroplasts (Asada 1999). A similar increase in the electron flux through the W-W cycle was observed when the CO 2 assimilation had been suppressed by low temperatures (Hirotsu et al 2004;Li et al 2005).…”

Overexpression of Arabidopsis CBF1 gene in transgenic tobacco alleviates photoinhibition of PSII and PSI during chilling stress under low irradiance

“…Since the photosynthetic apparatus is susceptible to chilling stress (Sonoike and Terashima, 1994;Sonoike et al, 1995;Li et al, 2003Li et al, , 2005 and CBF1 could improve plants' cold tolerance (Hsieh et al, 2002a;Zhang et al, 2004), we examined the role of CBF1 in the protection of the photosynthetic apparatus under chilling stress. In the present work, the related protective mechanisms were examined by comparing the Arabidopsis CBF1 transgenic lines with the wild type plants.…”

“…2). The reasons that PSI of chilling-sensitive plants was subjected to photoinhibition at chilling temperature and low irradiance have been attributed to an accumulation of reducing power on the acceptor side of PSI caused by chilling stress under low irradiance (Sonoike and Terashima, 1994;Sonoike et al, 1995;Li et al, 2003Li et al, , 2005. Under the chilling stress, the loss of available electron acceptors caused the decrease of P700 + in the wild type leaves (Fig.…”