Growth and physiological responses of four sugarcane varieties under salt stress condition

Abstract

Plant responses to salinity stress depend on the level of salinity, stress duration and plant genotype. Therefore the aims of this study were to determine growth and physiological responses of four sugarcane varieties under salt stress. A hydroponic experiment was conducted using split plot in completely randomized design with three levels of salinity; 0, 100, 200 mM NaCl and four sugarcane varieties; wild sugarcane (Saccharum spontaneum), forage-cane (Biotech2 (BT2)), and two cultivated cultivars (Khonkaen3 (KK3) and Suphanburi72 (SP72)). Growth and, phenotypic and physiological parameters including plant height, biomass, leaf gas exchange, chlorophyll fluorescence, total chlorophyll content, leaf water potential and electrolyte leakage were measured during stress and recovery period. Several damages and the most reduction in growth and biomass of four sugarcane varieties were found in 200 mM NaCl with high level of electrolyte leakage and high reduction in total chlorophyll content, quantum yield (Fv/Fm), net photosynthetic rate (Pn) and transpiration efficiency (TE). Saccharum spontaneum and KK3 were less reduction in total dry weight than that of BT2 and SP72 due to well stomata regulation and high performance of TE, Fv/Fm, Pn and leaf water potential, and well recovery under both salt stress conditions.