MANNITOL INDUCED SEED PRIMING ENHANCES SALT TOLERANCE CAPABILITY IN MUNGBEAN (VIGNA RADIATA) UNDER SALT STRESS

Abstract

A laboratory experiment was conducted at the Agronomy lab, Sher-e-Bangla Agricultural University, during the period from August 2013 to February 2014 to investigate the potentiality of seed priming for induction of salt tolerance capability and the pre-sowing seed treatment with mannitol on germination behavior of mungbean (BARI Mung-6 and BU-4) under salt stress conditions. The whole experiment was divided intothree experiments.In first experiment, two mungbean varieties were surface sterilized with 5% Sodium hypochlorite (NaOCl) solution, soaked in water and mannitol (2%, 4%, 6%, and 8%) for 12 hours and dry seed used as control. The highest total germination(89.99%), germination index(48.64), coefficient of velocity(21.04), energy of emergence(94.99%) and vigor index(157.00) were obtain from seeds primed in 6% mannitol for BARI Mung-6 compare to total germination (85.21%), germination index (46.61),coefficient of velocity (20.21), energy of emergence (87.88 %) and vigor index (123.30), respectively was obtained in 2% mannitol solutionfor BU-4. In second experiment, BARI Mung-6 was primed in 0, 6, 9, 12, 15, and 18 hours under both 6% mannitol solution and distilled water, respectively. Priming time 6 hours with 6% mannitol showed the best result for increasing the effectiveness in inducing salt tolerance in comparison to 6 hours distilled water priming time. In the final experiment, seeds were primed with distilled water and 6% mannitol for 6 hours; dry seed used as control and were exposed to 0, 50, 100, 150, and 200 mMNaCl induced salt stress conditions in Petri dishes. Priming with mannitol followed by water were more effective than the control seed in inducing salt tolerance of mungbean cultivars owing to enhanced germination and growth parameters under salt stress condition. From the results of the study, it was observed that seeds primed with 6% mannitol for 6 hours showed the best result in comparison to water primed seed and dry seed.