POTENTIAL OF PRIMING IN IMPROVING GERMINATION, SEEDLING GROWTH AND NUTRIENT STATUS OF CALOTROPIS PROCERA UNDER SALINITY

In the present study, various priming methods were applied to assess the germination response, growth and nutritional value of C. procera under different salinity levels. In screening phase, seeds were primed with distilled water, ascorbic acid (50 mg L-1), NaCl (0.3%) and thiourea (0.3%), grown under salinity levels: 40, 80, 120, 160, 300, 340, 380 and 420 mM NaCl. No germination was observed above 160 mM of NaCl and salinity up to this level was selected for further experiment. In the second phase, primed seeds were germinated in pots under controlled conditions to study the growth and nutritional value of C. procera. The results indicated that ascorbic acid (50 mgL(-1)) at 120 mM salinity level was the most effective treatment for growth attributes: shoot and root length (15.10 cm, 16.30cm), shoot fresh and dry weight (8.05 g, 1.61 g), root fresh and dry weight (6.06 g, 1.73 g), respectively. Chlorophyll content was higher at 120 mM salinity level with 0.3% of thiourea. Nutrients like potassium (K+), cadmium (Cd2+) and zinc (Zn2+) were greater at 120 mM salinity level with ascorbic acid while Na+ concentration was highest at 160 mM salinity level in both shoot and root (9118 ppm, 2657 ppm) with 0.3% of NaCl priming as compared to other nutrients. It was concluded that under high salt stress, priming with ascorbic acid could enhance seed germination, growth behavior, and nutritional value compared to other treatments by triggering antioxidant defense mechanisms in the seed of C. procera.