Osmotic and salt stresses induced differential alteration in water-solublecarbohydrate content in wheat seedlings

Water-soluble carbohydrates contributing to genotypic differences in respon se to consecutive drought and salinity stresses in wheat seedlings were inv estigated, Total water-soluble carbohydrate, glucose, fructose, sucrose, an d fructan contents and the distribution of degree of polymerization fructan s were measured in wheat seedlings exposed to 18% poly(ethylene glycol) (PE G)-induced drought stress followed by an equiosmolar salinity. Tolerant gen otypes accumulated higher soluble carbohydrate levels than the sensitive on es. Both ionic and nonionic stresses increased the percentage distribution of reducing sugars. The concentration of the principal component of soluble carbohydrate content increased in response to drought stress and, converse ly, mostly decreased due to salt stress. PEG-induced fructan accumulation w as highest in leaves and showed a positive correlation with the drought tol erance of the varieties. Fructan content in stems increased in tolerant gen otypes but decreased in sensitive ones under NaCl treatment. Increment of p olyfructan percentage distribution was greater in tolerant varieties than i n sensitive ones.