Effects of salinity on root morphology and nutrient acquisition by Faba Beans (Vicia faba L.)

Variations in morphology and nutrient acquisition between tap root and laterals of faba beans under different levels of NaCl salinity (0, 40 and 80 mM NaCl) were investigated. Experiments were conducted in aeroponics made possible for non-destructive sampling of root components in almost intact condition. Total shoot and root growth, leaf area and chlorophyll content were significantly reduced by salinity of 40 mM NaCl; however, effect on photosynthesis was nonsignificant. Higher root/shoot ratio was observed in the saline treatments, as shoot growth was reduced more than that of the roots. Surface area of tap root and lateral roots was reduced by 24 and 48%, respectively, indicating that lateral root was more susceptible to salinity than tap root. Considerable differences in nutrient acquisition were observed in plant parts i.e. leaves, stem, tap roots and lateral roots when subjected to salinity. The accumulation of sodium and chloride differed in different organs. Potassium and calcium contents were reduced in the 40 mM NaCl treatment in all parts except K in laterals and Ca in tap root, but these reductions were significant in the 80 mM NaCl treatment. Phosphorus content of shoot was also adversely affected by salinity at 40 mM NaCl.