Involvement of reactive carbonyl species in inhibition of germination and seedling growth by salt stress in rice.

Salt stress increases levels of reactive oxygen species (ROS), leading to a variety of damages in plants. Production of reactive carbonyl species (RCS) following ROS accumulation has been reported to be closely related to damage by salt stress. We investigated effects of RCS scavengers, carnosine and pyridoxamine, on inhibition of germination and seedling growth of Nipponbare (Oryza sativa L.) by salt stress. The inhibition of germination and the seedling growth by 50 mM NaCl was alleviated by the scavengers. The scavengers suppressed the malondialdehyde accumulation and protein carbonylation but not the ROS accumulation in the salt-stressed shoots. These results indicate that suppression of RCS accumulation improves salt tolerance without affecting ROS production in rice and suggest that RCS accumulation is responsible for the inhibitory effects on seeds and seedlings in rice.