Abstract
Most of literature on water deficit and water logging tolerance and resistance in faba bean, have not be widely studied. Therefore, it is important to study the different plant responses to these abiotic stresses to understand the mechanisms of tolerance. Towards this goal faba bean plants were cultivated in soil culture at different levels of field capacity, FC (Control), 2FC (flooding), 75% of FC, low water deficit (LWD) and 50% of FC, high water deficit (HWD), for 2 weeks. Fresh and dry weights of plant roots and shoots were significantly decreased under both water stresses (flooding and water deficit). Number of plant nodules was affected as exposed to high and low water deficit levels (75% & 50% FC) by about 47% and 5%, respectively. Alcohol dehydrogenase specific activity of bean roots grown under flooding stress was significantly increased as compared to absolute control while the specific activity of alcohol dehydrogenase activity (ADH) under the two levels of drought (75% & 50% FC) was less affected as compared to reference control. Also, Michael's constant (K-m) and maximum velocity (V-max) of ADH in bean roots was decreased under the two levels of drought (75% & 50% FC) and flooding stress (2FC) compared to absolute control. Transfers cross sections stained with safranin examined and photographed at 25 X of 3-weeks old roots of flooded faba been plants showing loosely parenchymal cell of cortex containing many and large intercellular spaces as compared to control and droughted plants. We concluded that flooding cause damage to Vicia faba plant more than water deficit through its effects on nodule formation and activity.