Growth and Physiological Responses of Tomato Landrace “Rohaba”(Lycopersicon Esculentum Mill.) to in Vitro Induced Water Deficit

Influence of in vitro induced water deficit upon vegetative growth and physiology of tomato landrace “Rohaba” (Lycopersicon esculentum Mill.), was investigated using 0.1, 0.2, 0.3 and 0.4 M sucrose, or 0, 0.1, 0.2 and 0.3 M sorbitol or mannitol as osmotic agents. Shoot height and shoot fresh weight were significantly reduced as sucrose was increased to 0.4 M. While a significant increase in shoot dry weight was obtained when sucrose levels were increased, rooting percentage and root number decreased. Root length was significantly increased at 0.3 M and reduced at 0.4 M sucrose. In the case of sorbitol, shoot height was significantly reduced at 0.3 M, shoot fresh and dry weight were significantly reduced as sorbitol levels were increased in the media. Rooting percentage, root number and root length were not affected at all by the sorbitol levels. When using mannitol, shoot height was significantly increased at 0.1 M and then significantly reduced at 0.2 M and 0.3 M. Shoot dry weight and fresh weight were reduced as mannitol levels were increased. Rooting percentage and root number were enhanced at 0.1 M. Root length was increased in response to different mannitol levels. The osmotic potential of tomato microshoots was significantly reduced (became more negative) as sucrose, sorbitol, or mannitol levels were increased. Tomato microshoots contents of N, K, Mg, Na and ash percentage were reduced significantly in response to increased levels of sucrose, sorbitol, or mannitol. Ca and P contents were not affected by elevated concentrations of osmoticums. Fiber content of tomato microshoots was not significantly affected at all by the sucrose levels, but a significant reduction in fiber content was obtained as sorbitol and mannitol levels were increased. Reducing sugar percentage, carbohydrate percentage and proline accumulation were increased and the protein (crude and soluble) and fat contents were reduced as the levels of sucrose, sorbitol and mannitol were increased