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.