Pollen morphology of Pinus sibirica (Pinaceae) mountain populations in the North-Eastern and South-Eastern regions of Altai

The influence of the climate humidity, mountain elevation and weather in the year of observations on the pollen morphology of the Siberian stone pine was studied. We compared the populations growing in the humid NorthEastern region of Altai (Mount Kolyushta, precipitation 867 mm/year, elevation 1350-1900 m) and the arid South-Eastern region of Altai (the Yuzhno-Chuysky ridge, precipitation 129 mm/year, elevation 1800-2100 m). It has been established that in an arid climate the body of a pollen grain is more spherical shape and larger in size, in a humid climate it is more ellipsoidal shape and smaller in size. It has been suggested that the tendency towards the formation of a spherical shape of the body of pollen grains is associated with the conditions of existence in an arid climate. Larger pollen grains were also formed in the lower mountain belts of both regions and in a year with warmer weather. Temperature has much less effect on the size of the air sacs, in contrast to the humidity of the region. In a humid climate, the sacs had an elongated shape, in an arid climate they were more rounded, but at the same time they did not differ significantly in volume. It is shown that the studied populations are more distant from each other in terms of the regional humidity factor, although the elevation and the weather also significantly influenced the pollen morphology of the Siberian stone pine.