Effects of salinity and nitrogen rates on accumulation off mineral nutrients and physiological response in wheat

摘要

The influence of Nitrogen (N) rates on grain yield, nutrient uptake, carbohydrate and praline concentrations of wheat(Triticum aestivum L. Var Chamran) grown under saline conditions was studied in a field experiment. The treatments comprised five levels of salinity 1.5, 5, 10, 15 and 20 ds/m in main plot and three nitrogen levels 50, 100 and 150 kg N ha~(-1) in sub plots. Salinity treatments were imposed on a clay-loam soil by irrigation with waters salinized with NaCl and CaCl_2 (5:1 by weight). Data showed by increasing salinity levels grain yield decreased, but N application increased plant growth and grain yield across all levels of salinity. The harvest index (%) and persentage of assimilate from stem to seeds was increased with salinity. N treatmets had not significat on them. it was mainly achieved by the accumulation of carbohydrate and proline in green laef tissue. Proline concentrations ranged from 9.34 to 16.69 μmol g~(-1) fresh wt in 1.5 and 20 ds/m at Flowering stage. By increasing N, proline concentration increased. Salinity had similar effect on carbohydrate accumilations in leaves and by increasing salinity levels, carbohydrate concetrations from 8.59 to 22.25 μg Glucose per g fresh wt in 1.5 and 20 ds/m increased. By increasing N, carbohydrate concentrations increased. The nutrient uptake were influenced by both salinity and N treatments. Concentrations of potassium (K) decreased with salinity in shoot and seed and was higher with N supply in shoot. N had not significat on K in seed. Whereas concentrations of sodium (Na) and calcium (Ca) were higher with salinity and N application in both shoot and seed. Magnesium (Mg) in shoot and seed was high with salinity and N, but N had not sigificant on Mg in seed. Examination of ion ratios indicated that K:Na ratio decreased with increasing salinity in shoot and seed. K:Na were higher with N application in shoot and low in seed. The effects of salinity and N fertilizer on Zinc(Zn) content in seed was not significantly different and in shoot increased by N and salinity treatments. Concentration of iron (Fe) in both shoot and seed was increased with salinity and N levels. Copper (Cu) content in shoot increased with salinity and N tratments. Cu in seed decreased with salinity and increased with N. it was concluded that the plant growth, yield, biochemical components and nutrient concentration of shoot and seed could depend upon N and level of salinity.