Salt-induced regulation of photosynthetic capacity and ion accumulation in some genetically diverse cultivars of radish (<em>Raphanus sativus</em> L.)

Abstract

Salt-induced changes in growth, various gas exchange characteristics, and ion accumulation were examined during a greenhouse experiment on six radish (Raphanus sativus L.) cultivars i.e., Radish Red Neck, Radish Lal Pari, Radish Mino Japani, Radish 40 Days, Mannu Early and Desi. Varying levels of salt (0, 80, and 160 mM NaCl) of the growth medium markedly decreased the shoot and root dry weights, relative water contents, osmotic potential, photosynthetic and transpiration rates, stomatal conductance, substomatal CO₂ concentration, C_i /C_a ratio, water use effi ciency, leaf and root K⁺ and Ca²⁺, while increasing the leaf and root Na⁺ and Cl^- of all six radish cultivars. Of all cultivars, Mannu Early and Desi were higher in shoot and root dry weights than the other cultivars, and thus, they were ranked as relatively salt tolerant. However, none of the earlier mentioned physiological attributes was found to be an effective criterion in discriminating the six radish cultivars. Overall, the response of each cultivar to salt stress appraised using various physiological attributes was specific.