The NaCl salinity stress (0–150 mM) drastically reduced seed germination in two high yielding cultivars of Indian mustard (Brassica juncia L.) i.e. Pusa Jai Kisan (reduced from15.28% at 50 mM to 77% at 150 mM) and Pusa Bold (reduced from 35.13% at 50 mM to 82.44% at 150 mM)). The inhibition was more pronounced during the first 24 hours and as a function of time, more seedlings could manage to germinate. The Seedling Vigour Index (SVI) was severally affected in both cultivars; however Pusa Bold was more sensitive to the salinity in terms of SVI than that of Pusa Jai Kisan. The salinity reduced elongation of radicle and plumule as a function of NaCl concentration available in the rhizosphere of plants as well as, as a function of day after NaCl application. The seedling elongation up to seven days was drastically reduced in both the cultivars. The biomass production in terms of fresh and dry weight and the moisture content of seedlings was also inhibited due to increase in the salinity levels. Amongst some biochemical parameters the photosynthetic pigments i.e. chlorophyll and carotenoids were decreased drastically. The carbohydrate content of leaves was however least affected. The salt tolerance index (STI) was higher in Pusa Jai Kisan as compared with Pusa Bold especially at higher levels of the salts. Results indicate that B. juncia cv. Pusa Jai Kisan posses a higher level of tolerance to NaCl salinity as compared to that in the cultivar Pusa Bold during early growth phase of the seedlings.
Brassica, Carbohydrate, Pigment, Salinity and salt tolerance index
