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, E, P vitamins, polyunsaturated fatty acids, caro-tene, other biologically active compounds. The temperature conditions during winter-spring period is main limiting factor in sea-buckthorn introduction, and the male generative sphere is the most sensitive to unfavorable conditions. The authors investigated a microsporogenesis in Hippophaё rhamnoides L. hy-brids of various ecologo-geographic origin of Nizhny Novgorod State Agricultural Academy breeding. The stage of male gametophyte development was deter-mined on squash temporary preparation. As result of analysis the two groups of hybrids were revealed, which differ on the time of beginning and a course of the definite stages of microsporogenesis. The first group involves the hybrids with prevalence of morphophysiological determinants of Katunskii ecotype (Debyut, 5/87, 1/89 and 1/91), the second one — with prevalence of morphophysiological determinants of Baltic ecotype (Gerakl, 31/89, 1/90 and 5/93). In hybrids of the first group the beginning of microsporogenesis and the formation of microspore tetrads occur at the low sum of positive temperatures (respectively, 48.5-49.5 and 114.8-118.5 С) than in hybrids from second group (62.0-71.1 and 135.6-147.0 С). However, the maturation of pollen and blossoming (anthesis) of male plants in studying ecotypes pass practically at the same time, at the sum of positive temperatures from 171.8 to 216.6С and from 276.3 to 343.9 С, respectively. Keywords: sea buckthorn, hybrids, microsporogenesis, sum of positive temperatures.

MICROSPOROGENESIS AND DEVELOPMENT OF POLLEN GRAIN IN HYBRIDS OF SEA BUCKTHORN (Hippophaё rhamnoides L.) OF VARIOUS ECOGEOGRAPHIC ORIGIN