Response of callus culture and seedlings of a salt tolerant
rice variety, pokkali, was compared to that of a salt
sensitive variety, hrswa, under conditions of salinity stress
induced by incorporating different quantities of sea water
in the culture media. Seedlings of pokkali showed minimal
symptoms of salt stress under conditions of low salinity and
more severe symptoms including dry of older leaves under
high salinity Conditions. However, seedlings of hrswa
showed severe stress symptoms even under low salinity and
plant death under high salinity conditions. This superior
character of salt tolerance of pokkali over hrswa was,
however, not observed in callus cultures. In both the
cultivars, the severity of symptoms depended on the
intensity of stress. Accumulation of free proline in callus
cultures and seedlings under stress conditions was
monitored. Both pokkali and hrswa accumulated proline
in response to stress to the same level. The response was
same in callus cultures and in seedlings of both cultivars and
the rate of proline accumulation was dependent on the
intensity of stress. This, study, thus, indicates that
accumulation of proline is not indicative of salt tolerance
character in rice.