On stomatal behavior in the Greenland Mountain birch

Abstract

The study was conducted to determine response of birch stomata to evaporative demand and plant internal water status. The experiment was undertaken in Qinguadalenat a site with microtopographical variation. Comparisons were made between trees from a dry hill and from a moist river bank, respectively.

Under natural "stress" conditions, with high air temperature and low humidity, birches in both habitats did not exhibit any significant stomatal response to evaporative demand or low xylem-water potential. Under artificial stress two different patterns appeared. Dry habitat birches closed their stomata abruptly with decreasing xylem-water potential, while stomata! closure in moist habitat trees was gradual.