Oxidative damage to thylakoid proteins in water-stressed leaves of wheat (Triticum aesti7um)

EDUARDO A. TAMBUSSI; CARLOS G. BARTOLI; J. BELTRANO; GUIAMET J.J.; JOSE´ L. ARAUS

PHYSIOLOGIA PLANTARUM

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2000 vol. 108 p. 398 - 404

0031-9317

The production of reactive oxygen species in the chloroplast decrease in photosynthetic electron transport activity and may increase under water deficit. To determine if this causes photosystem II (PSII) efficiency (Fv:Fm). Treatment of stressed oxidative damage to the photosynthetic apparatus, we analyzed leaves with L-galactono-1,4-lactone (GL) increased their ascorthe accumulation of oxidatively damaged proteins in thylakoids bic acid content and enhanced photochemical and non-photoof water-stressed wheat (Triticum aesti7um L.) leaves. Water chemical quenching of chlorophyll fluorescence. GL reduced stress was imposed on 4-week-old plants by withholding water- oxidative damage to photosynthetic proteins of droughted ing for 10 days to reach a soil water potential of about 2.0 plants, but it reverted the decrease in electron transport activity MPa. In thylakoids of water-stressed leaves there was an and PSII efficiency only partially, suggesting that other factors increase in oxidative damage, particularly in polypeptides of 68, also contributed to loss of photosystem activity in droughted 54, 41 and 24 kDa. High molecular mass oxidized (probably plants. Increasing the ascorbic acid content of leaves might be cross-linked) proteins accumulated in chloroplasts of droughted an effective strategy to protect thylakoid membranes from leaves. Oxidative damage was associated with a substantial oxidative damage in water-stressed leaves.