Growth of Indian mustard (Brassica juncea L.) in response to salicylic acid under high-temperature stress

Pots holding 7 day-old seedlings of Indian mustard (Brassica juncea L.) were subjected to differential temperature stress by exposing plants to 30 or 40oC for 24 h. Seedlings were sprayed with double distilled water (DDW) or 10-5M salicylic acid (SA) at the 8-day stage and were sampled at 30 DAS. The plants exposed to temperature stress exhibited a significant (p < 0.05) decline in growth, and in levels of chlorophyll, nitrate reductase and carbonic anhydrase activities and photosynthetic parameters. A follow-up treatment with SA protected against the stress generated by temperature and significantly improved the above parameters. Antioxidative enzymes and levels of proline significantly increased in response to SA as well as to temperature stress.