Cross-virility in 2 tropical tree kinds: proof inbreeding anxiety within this communities and you can genetic divergence certainly communities †
Mcdougal thank you S. Gunatilleke and N. Gunatilleke from the Department off Botany, University away from Peradeniya to possess recommendations and you will logistic assistance; the fresh Forest Agencies regarding Sri Lanka having consent to carry out that it really works within the Sinharaja Globe Heritage Website; the brand new Botany Service, College out-of Peradeniya for usage of their establishment; S. Harischandran, H. Gamage, and you can M. Gunadasa to have advice about hand-pollinations; and you may S. Harischandran and A beneficial. Anura to possess tending greenhouse seedlings. P. Ashton, K. Bawa, N. Gunatilleke, J. Hamrick, L. Kaufman, and you will J. Mitton given useful conversations; P. Ashton, S. Dayanandan, and C. Schneider said on earlier drafts; and you may B. Wieninger assisted towards the figures. It really works was offered in part from the money from the fresh Conservation, Restaurants, & Wellness Basis, Inc.
Abstract
Knowing the spatial activities regarding get across-virility inside absolute plant communities production key understanding of biparental inbreeding depression, isolation by the distance, and you may, sooner or later, speciation. About three adults every one of a few tropical forest kinds (Syzygium rubicundum and you may Shorea cordifolia) have been per crossed having four conspecific pollen donors between self so you can woods occurring in the separate forest supplies (12 and you will 35 km range to own S. rubicundum and Sh. cordifolia, respectively). Cross-fertility is actually projected given that fruits put, seed germination, and you can seedling survivorship and top on 1 yr. A style of very get across-virility steps increased steadily that have outcrossing range, peaking during the step 1–2 kilometer for S. rubicundum and you may 1–10 km to have Sh. cordifolia, then decreasing in the anywhere between-forest crosses. But not, seed products germination and you can seedling height getting Sh. cordifolia ideal crossbreed vitality in-between-tree crosses. The new mean exercise price of nearest-neighbor mating prior to crossing with distant neighbors is 45% to have S. rubicundum and you can 0% having Sh. cordifolia. The newest mean physical fitness price of ranging from-forest crosses are 52% and you can 70% towards a couple of species. Crossing effects to the fitness decreased amongst the amount out-of fruit lay and you may step 1-yr-old seedlings. Performance indicate a robust prospect of inbreeding anxiety within this forest tree communities and partial reproductive separation certainly one of forest inside Sri Lanka’s wet area.
Quoting cross-fertility from the numerous spatial bills within this a herb species’ variety lets insight into the necessity of genetic incompatibility and inbreeding and you can outbreeding depression lower than natural conditions. Within shorter spatial balances, new restricted seed dispersal feature of a lot plant life is always to end in relatedness certainly one of near-neighbors inside the sheer populations. In which nearby plants is actually associated, mating ranging from natives (i.age., biparental inbreeding; Uyenoyama, 1986) can lead to quicker reproductive exercise due to inbreeding despair or hereditary incompatibility between mates. When you find yourself designs away from okay-level genetic relatedness was indeed revealed for a lot of herbaceous kinds (age.g., Epperson services de rencontres internationales and you can Clegg, 1986; Waser, 1987; Schoen and Latta, 1989), getting woody kinds, like angiosperms, studies to your within-population genetic design are minimal. Certain studies have found spatial clustering from adult genotypes (or alleles) inside creature-pollinated tree woods (Acer saccharum-Perry and Knowles, 1991; Swartzia simplex-Hamrick, Murawski, and you can Nason, 1993; Quercus rubra-Sork, Huang, and Wiener, 1993; Quercus laevis-Berg and you may Hamrick, 1995; Cordia alliodora-Boshier, Pursue, and you will Bawa, 1995), and others failed to support the brand new presumption from hereditary relatedness one of surrounding people (Psychotria nervosa-Dewey and you may Heywood, 1988; Alseis blackiana and you may Platypodium elegans-Hamrick, Murawski, and Nason, 1993). Regardless of models of relatedness, mating is oftentimes simply for local areas within the herbaceous types (Levin and you will Kerster, 1974; Endler, 1979; Waser and you will Price, 1983) as well as in woody kinds, especially if blooming grownups try clustered (Linhart, 1973; Stacy et al., 1996). The chance of biparental inbreeding depression inside the absolute communities might have been exhibited for a number of herbaceous and you can coniferous forest types (Coles and Fowler, 1976; Playground and you may Fowler, 1982; Levin, 1984; Schemske and you can Pautler, 1984; McCall, Mitchell-Olds, and you will Waller, 1991; Heywood, 1993; Waser and you can Rate, 1994; Trame, Coddington, and you will Paige, 1995; Byers, 1998). Very little known, not, away from biparental inbreeding despair inside natural populations out of woody angiosperms.