Microsporogenesis and pollen formation in Scotch pine (Pinus sylvestris L.) under modern climatic conditions of Siberia

The prolongation of the warm season during autumn, which has become typical for Siberia in the past 5–6 years, has caused changes in the terms of reproductive processes in microsporangia of Scotch pine in the Krasnoyarsk region. Meiosis has started to begin in the autumn of the year preceding pollination, and then come to an end the next spring, whereas usually this process has occurred in the spring of the year of pollination. Under such conditions the division of microsporocytes is accompanied by different abnormalities, causing various anomalies and the incomplete development of pollen grains.