Stomata are the primary anatomical structures involved in water loss and gas exchange in plants. Genetic differences in stomatal frequency may have potential in breeding for increased photosynthetic or water-use efficiency. Miskin and Rasmusson (1970), for example , found that barley lines with low stomatal frequencies transpired less water than lines with high stomatal frequencies, with no observed difference in the rates of photosynthesis.
Martineau, J. R.; Williams, J. H.; and Specht, J. E.
"Research Notes: Stomatal Frequency and Heat and Drought Stress in Soybeans,"
Soybean Genetics Newsletter: Vol. 3
, Article 26.
Available at: http://lib.dr.iastate.edu/soybeangenetics/vol3/iss1/26