This study was conducted to evaluate the combined effect of increasing doses of phosphate and moderate salinity on the growth and some biochemical parameters of maize seedlings. The experiments were carried out on the maize variety KB 1902 grown in hydroponic cultures under controlled conditions. Salt stress was induced by 50 mmol dm-3 NaCl at three levels of KH2PO4 (in mmol dm-3): 1.0 (standard dose in a nutrient solution), 0.25 (decreased dose), 2.0 (increased dose). After 7 days of cultivation, the plants were harvested, growth parameters were examined and assessments were made of the concentrations of photosynthetic pigments, total protein, soluble carbohydrates and free phosphate. Salt stress caused a significant reduction in the fresh and dry weight of plants, ranging from 33-45% in comparison to the plants grown without NaCl, irrespective of external phosphate concentrations. Concentrations of photosynthetic pigments and total proteins were unaffected by salinity, regardless of the external phosphorus levels. The two higher concentrations of Pi (1.0 and 2.0 mmol dm-3) in the saline nutrient medium resulted in a marked accumulation of phosphorus in the leaves of maize, whereas the lowest level of Pi (1/4 of the standard dose in the nutrient solution) had no effect on the phosphorus content. Both the increased (2 P) and decreased (1/4 P) phosphorus concentration in the external medium induced a significant increase in the content of soluble carbohydrates in the leaves of maize grown under salt stress. In brief, the response of the maize variety KB 1902 to NaCl stress at the initial stage of growth was not found to have been modified by the examined doses of phosphorus, and there was no relationship between NaCl and the increasing doses of phosphate.

21.1.2016