XVI International Botanical Congess

Pollen germination and growth in vitro was investigated under variable pH conditions in two species of Aquilegia (Ranunculaceae). A. caerulea James. was obtained from the Snowy Mountains of Wyoming, while A. canadensis L. was obtained from West Virginia and Virginia. These two locations experience differences in average ambient rain acidity, rainfall pH at the western site is > 5.0, while rainfall pH from the eastern site is < 4.3. Fresh pollen was placed in Brewbaker Kwack media adjusted with nitric and sulfuric acid to provide treatments ranging from pH 3.5 to pH 7.5. Samples were incubated for 2 hours in a shaking bath at 25 degrees Centigrade. In the western species, maximum germination occurred at pH 5.5 with a significant decline at pH 4.5 and pH 3.5. In the eastern species, maximum germination occurred at pH 4.5.