EFFECT OF OSMOTIC STRESS ON GERMINATION CHARACTERISTICS OF MUNGBEAN

Abstract

To investigate the effect of osmotic stress on germination characteristics and seedling growth of mungbean varieties two experiments were conducted at Crop Physiology and Ecology Laboratory, Hajee Mohammad Danesh Science and Technology University (HSTU), Dinajpur from April to May 2018. In the first experiment, seeds of ten mungbean varieties were placed for germination in plastic box on sand bed irrigated with solution of four levels of osmotic stress (Tap water, -1.5 bars, -3 bars and -4.5 bar) developed by dissolving calculating amount of PEG in tap water. In the second experiment, seeds of eight mungbean (all varieties are present in experiment 1) varieties were placed for germination in plastic box on sand bed irrigated with solution of four levels of osmotic stress (Control, 4 dSm-1, 8 dSm-1and 12 dSm-1) developed by dissolving calculating amount of NaCl in tap water. In both the experiment, speed of germination as expressed by rate of germination, co-efficient of germination and germination vigor index of all mungbean varieties were delayed with the increment of osmotic stress induced by PEG and NaCl. Shoot length, root length and seedling dry weight of seedlings were found to be affected due to the increment of osmotic stress. But the magnitude of reduction of these parameters with the increment of osmotic stress was not similar for all mungbean varieties. Stress tolerance index (STI) based on seedling dry weight indicated a wide difference in stress tolerance among the mungbean varieties in both experiments. In first experiment, the mungbean varieties - BARI Mung 5, BARI Mung 6, BARI Mung 7 and BINA Mung 6 showed higher STI value at lower, moderate and higher PEG induced osmotic stress are considered as water deficit stress tolerance mungbean varieties. In second experiment, the mungbean varieties - BARI Mung 6, BARI Mung 7, BINA Mung 6 and BINA Mung 7 showed higher STI value at lower, moderate and higher NaCl induced osmotic stress are considered as salt stress tolerance mungbean varieties.