Geographic Differences in the Seed Germination of Paper Birch (Betula Papyrifera)

Abstract

The effects of light and temperature on germination of paper birch (Betula papyrifera Marsh.) were examined in seeds from different geographic locations. Under continuous light at 14–18 C northern seed sources germinated more rapidly and achieved higher germination percentages than southern ones. Seed source influenced the range of temperatures over which germination occurred. Northern seeds had a wider temperature range than southern ones due to depression of the low temperature limit in northern seeds. At 15 C, seeds exhibited a photoperiodic‐like response with progressive increases in germination as daily photoperiod was increased. This was not a true photoperiodic effect because seeds responded to the total amount of light rather than to the relative length of light and dark periods. It is suggested that at temperatures near 15 C, this response may be important in preventing fall germination. Prechilling at 3 C promoted subsequent dark germination in most seed sources tested, and northern seeds were much more sensitive to the treatments than southern seeds. In some seeds the prechilling stimulus was lost with protracted storage at 3 C; this was observed in both northern and southern seeds. Prechilling enhanced the seeds’ sensitivity to subsequent light. Although acquisition of the prechilling stimulus does not serve to measure the length of winter in these seeds, the high light sensitivity induced by prechilling probably accelerates spring germination. Northern seeds typically had thinner, more translucent pericarps than their southern counterparts.

Differentiation of seed germination traits in relation to the natural habitats of threeUlmusspecies in Japan

“…Furthermore, the variable germination traits of the three Ulmus species selected under the specific disturbance regimes may be different even among populations grown under different disturbance regimes or/and geographical environments (Bevington 1986;Skordilis and Thanos 1995). Because the disturbance regimes (e.g.…”

Reservoir de graines des sols de sapinieres boreales au nord du Lac Saint-Jean

“…Les graines de cette espèce germent lorsqu'elles sont exposées à la lumière (Bevington et Hoyle, 1981;Bevington, 1986) et il est typique de constater son apparition dans les coupes (Marks, 1974;Grime, 1979). La germination de Betula papyrifera s'observe sur le terrain par des pourcentages de recouvrement élevés des strates arbustives et herbacées dans les parcelles perturbées, alors qu'ils sont faibles ou nuls dans les parcelles non perturbées (tableau 1).…”

Beneficial effects of cold-moist stratification on seed germination behaviors of Abies pindrow and Picea smithiana

“…Seed germination of most temperate coniferous species is inhibited by evolved trait seed dormancy (Leadem 1986;West et al 1970;Singh 1989). Cold-moist stratification is a commonly used practice to break dormancy in seeds and to attain vigorous, speedy, maximum, and uniform germination for laboratory testing, green house and nursery sowing (Fowler et al 1964), which has been reported in many studies on conifers (Mergen 1963;Fowler et al 1964;Roberts et al 1982;Wang et al 2000;) and several hardwood seeds (Schopmeyer 1974;Villiers 1971;Nikolaeva 1977;Bevington 1986;Barnett et al 1978;Farmer et al 1972;Farmer 1974;Farmer et al 1981).…”