Effects du NaCl sur les Capacités Oxydases durant la Germination de Semences de Plantes Sensible ou Tolerante au Sel

Abstract

IAA oxidase, catalase and peroxidase activities of seedlings (the first day of radicle emergence) or organs of young plants (the fifth day of radicle emergence) germinated in NaCl media (0, 25, 50, 100 or 150 mM) were measured. Three species with successively lower thresholds of salinity sensitivity were measured: tomato, radish and red cabbage. NaCl sensitivity of the above enzymes was also analysed in extracts from control seedlings or plants incubated in media with different NaCl concentrations. No relation was found between enzyme activities and protein levels or Na contents of young plants; on the contrary, a good relation was observed between enzyme activity and Na contents of seedlings. Oxidase activities have similar NaCl sensitivity in the three seedlings. Comparing the enzyme activity and sensitivity with NaCl tolerance of the species, the consequences of the oxidase activities in young plants germinated in NaCl media are discussed.