Comparison of arabidopsis stomatal density mutants indicates variation in water stress responses and potential epistatic effects

Recent physiological analysis of Arabidopsis stomatal density (SD) mutants indicated that SD was not the major factor controlling aboveground biomass accumulation. Despite the general theory that plants with fewer stomata have limited biomass acquisition capabilities, epf1 and several other Arabidopsis mutants varied significantly in leaf fresh weight despite having similar stomatal numbers. The indepth mechanisms controlling increased or decreased leaf area biomass remain undetermined. This work used calculations of SD, overnight water-loss, and LI6400XT measurements to reject the premise that SD is a primary factor controlling leaf biomass accumulation in Arabidopsis. With respect to our data, SD is not the primary factor influencing biomass accumulation in Arabidopsis epf1 mutants as it did not positively correlate to any of the physiological parameters examined. Further observation of morphological differences between the mutants hinted that additional pathways were interrupted when these mutants were generated. Each mutant examined showed a variation in physiological measurements despite SD. Many SD mutants also showed morphological abnormalities in addition to altered stomatal numbers. These phenotypes may indicate epistatic effects related to the mutation of SD genes in the studied mutants.