Salt-induced effects on some key morpho-physiological attributes of cotton (Gossypium hirsutum L.) at various growth stages

Salinity is a multidimensional stress affecting crop yield and productivity at various levels of plant organization. To assess salt induced adverse effects on cotton (Gossypium hirsutum L.), ten cultivars were grown in sand culture supplemented with full strength Hoagland’s nutrients solutions and different salt concentrations (0, 50, 100 and 200 mM NaCl). Salt stress markedly reduced growth attributes, relative water contents, efficiency of photosystem II, net CO2 assimilation rate (A), transpiration rate (E) and stomatal conductance in all cultivars. Reduction was maximum at the highest level of salt stress i.e. 200 mM. However, response of cotton cultivars was variable to various levels of salinity and even at various developmental stages. Cultivars RH-510, BH-118 and MNH-770 were ranked as relatively salt tolerant on the basis of their better growth performance and net CO2 assimilation rate whereas cvs. CIM-496, CIM-473 and FH-901 were relatively salt sensitive. Cultivars RH-510, BH-118 and MNH-770 exhibited high shoot fresh and dry weights, photosynthetic rate (A), and Photosystem II (Fv/Fm) efficiency at both seedling and maturity growth stages. Results suggest that selection of plants having high photosynthetic rate and biomass at seedling stage may be a good source of high yield at mature stage of growth.