DIFFERENCES IN FLAG LEAF PHOTOSYNTHESIS AND RESPIRATION IN BREAD WHEAT

Photosynthetic oxygen evolution in light and oxygen consumption in dar k were studied in two parental bread wheat cultivars and five selectio ns initially made for stomatal frequency. Discs cut out from flag leaf blades of field grown plants were assayed in a sensitive oxygen measu ring system over a period starting from flag leaf emergence. Chlorophy ll content, flag leaf blade area, stomatal frequency, mesophyll cell s ize and lobe number were estimated. Photosynthetic rate per unit leaf area, respiration rate per unit chlorophyll, leaf area and stomatal fr equency differences were significant. Correlations between different p arameters were drawn. Results indicate that selections made on the bas is of anatomical or morphological characters may have different photos ynthetic characteristics useful in crop improvement.