Stomatal density and calcium concentration of six snap bean cultivars

Stomatal density of pods and leaves were determined for sis commercial snap bean cultivars (Phaseolus vulgaris L,'Evergreen', 'Hystyle', Labrador', 'T enderlake','Top Crop', and 'Venture') grown at three planting dates, in an attempt to find morphological traits that could he related to cultivar diff erences in pod Ca concentration, Snap beans were planted three times at app roximate to1-week intervals beginning 15 June 1995, and harvested 59 to 62 days after planting, Stomatal counts Here performed using a microscope link ed to a video camera, and Ca concentration determinations were made using a tomic absorption spectrophotometry. Calcium concentration and stomatal dens ity of leaf tissue was higher than that of pods, Cultivar differences for p od Ca concentration (P = 0.001) and stomatal density (P = 0.001) were obser ved although cultivars with higher pod stomatal density did not necessarily result in higher pod Ca concentration. Calcium concentration and stomatal density for leaves did not differ among cultivars, Stomatal density and Ca concentration of pods were positively correlated (R-2 = 0,37), while pod ma turity nas negatively associated to both pod Ca concentration (R-2 = 0,93), and pod stomatal density (R-2 = 0,99), The effect of planting dates was ab sent in pod Ca concentration and significant in pod stomatal density.