TITLE:
Geographic Variation in Germination Traits in Melia azedarach and Rhaphiolepis umbellata
AUTHORS:
Tetsuto Abe, Michio Matsunaga
KEYWORDS:
Cold Stratification, Germination Strategy, Latitude, Ogasawara Islands, Widespread Tree Species
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.2 No.1,
March
4,
2011
ABSTRACT: Some plant species traits may not be uniform across populations distributed across a wide latitudinal range. This study examined intraspecies variation in the effects of cold stratification on the germination of seeds of two widespread trees, Rhaphiolepis umbellata (Rosaceae) and Melia azedarach (Meliaceae), collected from the subtropical Ogasawara Islands (southern seeds) and the temperate Japan mainland (northern seeds). Under the no-treatment control, the southern seeds germinated faster in R. umbellata and achieved a higher germination percentage in M. azedarach. The regional differences in germination performance were reduced by cold stratification. It was reasonable that these germination traits increase fitness under each climate region. Because the remote Ogasawara populations are sufficiently isolated to have developed some distinct characteristics, even common, widespread species may have important conservation value where they exist within insular biota.