Muhammad Afzal Awais Ahmad Ali Abdullah Alderfasi Adel Ghoneim Mohammad Saqib Department of Plant Production, College of Food and Agricultural Sciences, King Saud University, 2460, Riyadh, Saudi Arabia Department of Soil Sciences, College of Food and Agricultural Sciences, King Saud University, 2460, Riyadh, Saudi Arabia Department of Agronomy, The Islamia University of Bahawalpur, Pakistan Proceedings of the International Academy of Ecology and Environmental Sciences ISSN 2220-8860 http://www.iaees.org/publications/journals/piaees/online-version.asp 2014 4 1 39 49 International Academy of Ecology and Environmental Sciences Hong Kong 5 November 2013 10 December 2013 1 March 2014 salinity genotypes growth physiology tolerance A greenhouse experiment was demonstrated to compare tolerance ability of four genotypes (Desi, Sanam, Kundri, Asia Bok) of Capsicum annum. L. under different levels of saline stress (i.e., control, 40, 80 and 120 mM NaCl). Growth parameters (root, shoot; fresh and dry weight) and physiological (Na+, K+, Ca++, concentration, stomatal conductance, transpiration rate, photosynthetic rate, chlorophyll a, b contents) indicators were analyzed to determine tolerability of genotypes. The results indicated that, all genotypes tolerated only under low level of salinity stress (40 mM NaCl) while a severe growth suppress in general was observed at higher levels (80 and 120 mM NaCl). Asia Bok was found more sensitive to salinity with 0.626g shoot fresh weight whereas Desi (1.103g) is comparatively salt tolerant under 120mMNaCl. Chlorophyll a and b contents and transpiration rate decreases with increases in salinity level in all genotypes with almost similar trend. Na+ accumulation increase with increase in salinity level but found maximum (14 mg g-1DW) in Asia Bok while minimum (10.8 mg g-1DW) in Desi. However K+ contents behave reversely to salt concentration and was recorded maximum in Desi (33 mg g-1DW) at maximum (120 mM NaCl concentration). Stomata conductance and transpiration rate was found maximum in Desi as compare to the all other three genotypes under all salinity levels except control. For all above physiological determinants Sanam and Asia Bok have similar behavior while Desi and Kundri have diversified under all salinity levels. Correlation between varieties and salinity resulted that continuous increase in salinity affected growth, physiological aspects and cation accumulation in chilies. DOI 10.0000/issn-2220-8860-piaees-2014-v4-0005 http://www.iaees.org/publications/journals/piaees/articles/2014-4(1)/physiological-tolerance-and-cation-accumulation.pdf