Effect of gamma irradiation and salt stress on germination, callus, protein and proline in rice (Oryza sativa L.)

This study was carried out to determine the pretreatment effect of gamma irradiation and salt stress on improvement of germination and physiological factors, protein and proline contents in rice cultivar Taroom Hashemi. Mature and healthy seeds irradiated with 4 doses (0, 100, 200, 300 Gy) and under 3 salinity doses (0, 5, 15 and 25 mmosh/lit NaCl) were cultured. After one week, radicle length was assayed in control and treatment of MS culture. After 1 month proline and protein contents were measured. The obtained data were analyzed by SPSS using ANOVA and Duncan test. The results showed that the lowest percentage of germination and shoot length was observed in treatments under 300 Gy gamma irradiation and salinity, 15 mmosh/lit. Also minimum length of radicle was observed in treatments under 300 Gy gamma irradiation in all salinity treatments. Moreover, the lowest percentage of callus regeneration was recorded in the treatments of various doses of gamma radiation in the salt concentration 25 mmosh/lit. The callus length of 100 Gy seedlings in 5, 15 and 25 mmosh/lit salinity was highest compared to other group. With increasing irradiation and salt concentration proline content was increased. The protein content on the other hand, decreased with increasing irradiation and salinity concentration. These results show that the up-regulation of some physiological characteristics and seedling growth of rice following gamma radiation treatment may be used to control abiotic stresses such as drought and salt.