EFFECTS OF SALINITY ON GAS EXCHANGE ATTRIBUTES IN DIFFERENTLY ADAPTED POPULATIONS (ECOTYPES) OF CYPERUS ALOPECUROIDES ROTTB

Seven populations of Cyperus alopecuroides Rottb. from different sites of Punjab, Pakistan were evaluated for gas exchange characteristics against salinity. The experiment was conducted in totally completely randomized design with three replicates and four treatment levels 0 mM (control), 100 mM, 200 mM, 300 mM of (NaCl) salinity under full sunlight, growth conditions; average day-night temperature ranges from 38-41°C and 24-26°C, respectively and photoperiod 13 to 16h, relative humidity 46.8 to 59.3%. Salinity levels were maintained with help of ECe meter for one year. The data was subjected to statistical analysis using Microsoft Excel and Minitab statistical software's for analysis of variance (ANOVA), graph Gas exchange characteristics like CO2 assimilation rate. Transpiration rate. Sub sto-matal CO2 concentration, stomatal conductance, Water use efficiency play key role against salt stress. Decrease in CO2 assimilation rate, Transpiration rate retarded the plant growth. Which was significantly effected in site-2 populations as compared to site-1 populations. Low level of salt enhance these parameters but high levels of salinity decrease Sub stomatal CO2 concentration, stomatal conductance, and Water use efficiency. Maximum CO2 assimilation rate, minimum transpiration rate, high stomatal conductance and water use efficiency in sheikhupura sites also indicated their salt tolerant quality.