Genotypic Differences in Photosynthesis and Partitioning of Biomass and Ions in Salinized Faba Bean
Abstract
Vicia faba (L.) is a valuable grain legume, rich in nutrients and bioactive constituents with large genotypic variability in resistance to abiotic stress. Growth and performance of two hydroponically-grown V. faba cultivars (‘Nubaria’ 1 and ‘Nubaria 2’) were investigated under the impact of 0, 20, 50, 100 and 175 mmol/L NaCl. Shoot growth of the two cultivars was moderately reduced by NaCl salinity; but root growth was robust, at the expense of either leaves in the salt-resistant ‘Nubaria 1’or stem in ‘Nubaria 2’. ‘Nubaria 1’showed better vigor and greater leafiness but lesser content of photosynthetic pigments with higher carotenoids content than ‘Nubaria 2’. Rates of transpiration and photosynthesis were higher in ‘Nubaria 2’ than ‘Nubaria 1’, with more adverse effect of salinity on transpiration than on photosynthesis. The reduced K+ and Ca2+ uptake and the enhanced Na+ uptake under salinity were associated with restriction of ion transport to the foliage, particularly the leaves. The role of stem in providing K+ and Ca2+ to and retention of Na+ away from the leaves and root under salinity stress was more evident in ‘Nubaria 1’ than ‘Nubaria 2’.