ECOLOGICAL AND GEOGRAPHICAL DIFFERENTIATION AND INTEGRATIONAL PROCESSES IN THE GROUP OF CLOSELY RELATED SPECIES WITH TRANSCONTINENTAL DISTRIBUTION (ON EXAMPLE OF NORTHERN AND EASTERN ASIAN 5-NEEDLE PINES)

Goroshkevich S.N., Petrova E.A., Politov D.V., Zotikova A.P., Velisevich S.N., Khutornoi O.V., Bender O.G., Belokon M.M., Popov A.G., Kuznetsova E.A., Vasilieva G.V.

Usually investigations of diversity within a group of closely related species are carried out by morphological, karyological and molecular genetics methods. Functional and adaptive meanings of indicators in use are not known enough to analyze processes of within- and between species differentiation and integration. In our study the traditional approaches are combined with complex analysis of adaptive traits that are under natural selection influence. In climatically homogeneous area the most part of intraspecies ecological variability has a modification nature. Portion of genotypic variability depends of shape of “ecological range”. Shade-bearing species like P. sibirica comprise continues series of plant associations and consequently had a low level of variability. In light-demanding tree species, for example in P. pumila, “ecological range” is patchy and level of diversity is sufficiently higher. Using P. sibirica as an example, structure of within-species diversity along altitude transect was studied. On evidence derived from electrophoresis of allozymes it was shown that genotypic differentiation of ecotypes along highland macroslope was slight. However study of vegetative progenies growing in homogeneous environment revealed that high-altitude ecotypes essentially differed on structure of annual shoot and crown as a whole, mesophyll anatomy, contents of photosynthetic pigments and chloroplasts functional activity. Therefore, even when adaptive component of genome have not detected by modern methods of biochemical genetics, it acts to organize ecological and geographical structure of species into unique ecotypes and populations.

Genetic structure of species as a total of geographically differentiated ecotypes was observed using Siberian Stone pine clonal archive. The genotypes of 250 clones were determined by 26 loci coding for 16 enzymes. Significant relationship of allele frequency on some isozyme loci and averaged expected heterozygosity with geographic coordinates of the ecotypes was firstly revealed. In most cases allelic frequencies were correlated with latitude and longitude as well as with warm supply and continentality of the ecotypes that confirmed adaptive essence of the traits. There are three pairs of species were determined according to duration of juvenile morphogenesis and presence of matured structure at juvenile shoots: P. sibirica + P. cembra; P. koraiensis + P. armandii; P. parviflora + P. pumila. It is new argument in favor of polyphyletic origin of subsection Cembrae. Comprehensive investigation was carried out in the zone of P. sibirica and P. pumila ranges overlapping. Natural hybridization between the species took place everywhere in the zone. The species are genetically compatible and have near periods of pollination and perception. On most traits natural hybrids are intermediate in compare to parental species. In several types of plant associations the hybrids occupied a free ecological niche at the second storey of the mixed forest stands.

Investigation was supported by RFBR, grants № 07-04-00593-а и 06-04-49065а