Muhammad Ashraf;. Rahmatullah;Rashid Ahmad;Ahmad Saeed Bhatti;Muhammad Afzal;A. Sarwar;Muhammad Maqsood;Shamsa Kanwa

Institute of Soil & Environmental Sciences, University of Agriculture, Faisalabad (Pakistan;Sugarcane Research Institute, Ayub Agricultural Research Institute, Faisalabad (Pakistan);Institute of Soil & Environmental Sciences, University of Agriculture, Faisalabad (Pakistan);Department of Crop Physiology, University of Agriculture, Faisalabad (Pakistan);University College of Agriculture, University of Sargodha, Sargodha (Pakistan)

sugarcane genotypes;nacl;05;si;salt;mmo

A hydroponics experiment was conducted to evaluate the role of potassium (K) and silicon (Si) in mitigating the deleterious effects of NaCl on sugarcane genotypes differing in salt tolerance. Two salt-sensitive (CPF 243 and SPF 213) and two salt-tolerant (HSF 240 and UP 77-400) sugarcane genotypes were grown for six weeks in 1/2 strength Johnson's nutrient solution. The nutrient solution was salinized by two NaCl levels (0 and 100 mmol L-1 NaCl) and supplied with two levels of K (0 and 3 mmol L-1) and Si (0 and 2 mmol L-1). Applied NaCl enhanced Na+ concentration in plant tissues and significantly (P <= 0.05) reduced shoot and root dry matter in four sugarcane genotypes. However, the magnitude of reduction was much greater in salt-sensitive genotypes than salt-tolerant genotypes. The salts interfered with the absorption of K+ and Ca2+ and significantly (P <= 0.05) decreased their uptake in sugarcane genotypes. Addition of K and Si either alone or in combination significantly (P <= 0.05) inhibited the uptake and transport of Na+ from roots to shoots and improved dry matter yields under NaCl conditions. Potassium uptake, K+/Na+ ratios, and Ca2+ and Si uptake were also significantly (P <= 0.05) increased by the addition of K and/or Si to the root medium. In this study, K and Si-enhanced salt tolerance in sugarcane genotypes was ascribed to decreased Na+ concentration and increased K+ with a resultant improvement in K+/Na+ ratio, which is a good indicator to assess plant tolerance to salt stress. However, further verification of these results is warranted under field conditions.