Two bean cultivars with different ozone-sensitivity, i.e. the O3-sensitive Cannellino and the O3-tolerant Top Crop, were exposed to acute O3-stress with the aim of evaluating physiological and biochemical traits responsible for O3-tolerance. The cultivars differed in their constitutive ability to prevent and counter O3-induced oxidative damage. The ability to dissipate excess-energy, via regulated and unregulated nonphotochemical quenching mechanisms (NPQ, NO) was constitutively greater in Top Crop than in Cannellino, and allowed the O3-tolerant cultivar to compensate light-induced declines in PSII and preserve photosystem II from excitation-energy to a superior degree than the O3-sensitive one. The inevitable generation of reactive oxygen species was countered to a significantly smaller extent in the O3-sensitive cultivar, because of constitutively lower activities of superoxide dismutase and catalase than the O3-tolerant cultivar. Indeed, Cannellino underwent an early accumulation of H2O2 and an almost complete disruption of cell structure and irreversible damages in the photosynthetic apparatus.
Ozone tolerance in Phaseolus vulgaris depends on more than one mechanism
GUIDI, LUCIA;
2010
Abstract
Two bean cultivars with different ozone-sensitivity, i.e. the O3-sensitive Cannellino and the O3-tolerant Top Crop, were exposed to acute O3-stress with the aim of evaluating physiological and biochemical traits responsible for O3-tolerance. The cultivars differed in their constitutive ability to prevent and counter O3-induced oxidative damage. The ability to dissipate excess-energy, via regulated and unregulated nonphotochemical quenching mechanisms (NPQ, NO) was constitutively greater in Top Crop than in Cannellino, and allowed the O3-tolerant cultivar to compensate light-induced declines in PSII and preserve photosystem II from excitation-energy to a superior degree than the O3-sensitive one. The inevitable generation of reactive oxygen species was countered to a significantly smaller extent in the O3-sensitive cultivar, because of constitutively lower activities of superoxide dismutase and catalase than the O3-tolerant cultivar. Indeed, Cannellino underwent an early accumulation of H2O2 and an almost complete disruption of cell structure and irreversible damages in the photosynthetic apparatus.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
