Spearmint cultivars MSS-5, Arka, and Neera grown in nutrient culture in controlled conditions differed in plant height, number of tillers, internodal position, fresh mass, dry mass, leaf stem ratio, and chlorophyll contents. Initial transpiration rate, stomatal conductivity, and CO2 exchange rate showed better increase in MSS-5 genotype. Mn stress decreased oil content whereas the content of oil constituent carvone increased in MSS-5 and Arka. and P. Singh, A. Misra, N. K. Srivastava.