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EFFECTS OF SALINITY AND WATERLOGGING ON PHYSIOLOGICAL PROCESSES AND IONIC REGULATION IN ATRIPLEX AMNICOLA

FARKHUNDA ALA, SHOAIB ISMAIL, RAFIQ AHMAD AND RUBINA SHAHEEN

Abstract: The effects of salinity (BC: 0, 10 and 20 dS.m^-l) and waterlogging levels of 75, 100 and 125 % of soil water holding capacity on some physiological processes and ionic regulation were studied in Atriplex amnicola Paul G. Wilson in sandy loam and silty loam soils. Stomatal conductance of plants grown on sandy loam soil exhibited significant variations under the waterlogging treatments of 10 and 20 dS.m^-1 salinity levels. At low waterlogging level (75 % WHC), significant differences were recorded at different salinity levels for stomatal conductance, transpiration rate and quantum yield. In silty loam soil, non-significant variation was observed for both salinity and waterlogging treatments when analyzed one day after irrigation, but after three days, there were significant variations in stomatal conductance and transpiration rate in different salt treatments. Sodium showed maximum accumulation in leaves followed by roots and minimum in stem in both sandy and silty loam soils at different salinity and waterlogging levels. Concentration of Na ⁺ varied with time and exhibited higher amount after 8 weeks as compared to 4 weeks growth period. Chloride also showed the same pattern, however, plants grown on silty loam soil exhibited higher amount as compared to sandy loam soil. Salinity did not have any pronounced effect on the oxalate content, whereas, waterlogging did affect the oxalate concentration after 4 weeks of growth with non-significant effects after 8 weeks growth. Increase in salt concentration of the irrigation medium increased the electrical conductivity of both sandy and silty loam soils at different growth periods and with different waterlogging levels.

Biosaline Reasearch Laboratories, Department of Botany, University of Karachi, Karachi 75270, Pakistan.