Effect of Proline on Salt Tolerance of Orange Seedlings Citrus sinensis (L.) osbesk c.v. Mahally


A study was conducted at College of Agriculture, University of Basra duringgrowing season of 2011-2012 to study the effect of proline on salt tolerance of Mahallyorange seedlings. The study included 12 treatments which were four levels of irrigationwater salinity (0 , 4 , 8 and 12) dS/m and three concentrations of proline (0 , 75 and150) mg/L proline. Results showed that the irrigation water salinity caused decreasingin physical properties where the 12 dS/m level gave least height of seedling leavesnumber and leaf area which were 76.00 cm , 27.28 and 11.91 cm2 respectively. Prolinetreatment increased most properties a sits concentration increased. Treatment with 150mg/L proline caused highest plant height, diameter , leaves number and leaf area whichwere 82.67 cm , 0.47 cm , 42.33 and 14.83 cm , respectively. Treatment by 12 dS/mlevel chlorophyll , carbohydrates , proline , dry matter and lowest nitrogen which were1.197 mg/100 gm , 52.30 mg/100 gm , 802.96 μg/gm dry matter , 22.317% and 1.50% ,respectively. Treatment of proline at 150 mg/L increased total chlorophyll, solublecarbohydrates , free proline , dry matter and nitrogen percentage which were 1.77mg/100gm, 60.38 mg/100gm, 26.18% and 2.20% respectively. The interaction betweenirrigation water salinity level and proline significant for all physical and chemicalproperties studied.