Cross-fertility in 2 exotic tree variety: proof of inbreeding anxiety inside populations and you may genetic divergence certainly one of communities †
Cross-virility in 2 warm tree species: evidence of inbreeding despair in this communities and you may hereditary divergence among populations †
The author thanks a lot S. Gunatilleke and you may Letter. Gunatilleke in the Company regarding Botany, School regarding Peradeniya to have information and logistic service; the latest Forest Department out of Sri Lanka getting consent to carry out that it works in the Sinharaja Globe Society Web site; the new Botany Agencies, College or university regarding Peradeniya to be used of their facilities; S. Harischandran, H. Gamage, and you can Meters. Gunadasa for help with hands-pollinations; and S. Harischandran and you will An excellent. Anura having tending greenhouse seedlings. P. Ashton, K. Bawa, Letter. Gunatilleke, J. Hamrick, L. Kaufman, and you will J. Mitton given beneficial talks; P. Ashton, S. Dayanandan, and C. Schneider mentioned towards the prior to drafts; and B. Wieninger assisted towards figures. Which functions is actually supported to some extent by funds from the fresh Preservation, Dining, & Wellness Base, Inc.
Abstract
Understanding the spatial designs regarding get across-fertility from inside the pure bush populations yields key understanding of biparental inbreeding despair, isolation because of the length, and you can, fundamentally, speciation. About three grownups every one of a few exotic forest types (Syzygium rubicundum and Shorea cordifolia) was basically for every single crossed with five conspecific pollen donors ranging from self to trees occurring inside the independent forest reserves (12 and you may 35 kilometres length for S. rubicundum and you may Sh. cordifolia, respectively). Cross-virility try estimated because the fresh fruit lay, vegetables germination, and you will seedling survivorship and you can top within step 1 yr. Technique of extremely mix-fertility tips improved steadily that have outcrossing range, peaking on step 1–2 km having S. rubicundum and you can step one–10 kilometres to own Sh. cordifolia, then declining at the anywhere between-forest crosses. Yet not, seed products germination and you may seedling level to have Sh. cordifolia recommended crossbreed energy in between-tree crosses. The newest imply exercise cost of nearest-neighbor mating in accordance with crossing with an increase of faraway natives are forty five% to have S. rubicundum and you will 0% to possess Sh. cordifolia. The mean exercise cost of ranging from-forest crosses is 52% and you can 70% on the one or two kinds. Crossing effects on the exercise diminished involving the level out-of good fresh fruit place and you will 1-yr-old seedlings. Overall performance imply a powerful possibility inbreeding despair contained in this tree tree communities and you can limited reproductive isolation one of forest inside Sri Lanka’s wet region.
Quoting get across-fertility in the numerous spatial bills inside a plant species’ assortment allows understanding of the importance of genetic incompatibility and inbreeding and you can outbreeding depression lower than absolute standards. Within faster spatial bills, the fresh limited seed dispersal characteristic of numerous flowers should end in relatedness certainly close-neighbors inside the natural communities. Where nearby flowers is associated, mating between residents (we.e., biparental inbreeding; Uyenoyama, 1986) could lead to reduced reproductive fitness due to inbreeding depression otherwise genetic incompatibility ranging from mates. If you find yourself models out of good-level hereditary relatedness were shown for a number of herbaceous species (e.g., Epperson and you will Clegg, 1986; Waser, 1987; Schoen and you can Latta, 1989), to own woody species, such as for instance angiosperms, analysis toward within-populace genetic build try limited. Certain research has shown spatial clustering out of adult genotypes (otherwise alleles) from inside the animal-pollinated forest trees (Acer saccharum-Perry and you can Knowles, 1991; Swartzia simplex-Hamrick, Murawski, and Nason, 1993; Quercus rubra-Sork, Huang, and you can Wiener, 1993; Quercus laevis-Berg and Hamrick, 1995; Cordia alliodora-Boshier, Pursue, and Bawa, 1995), while some failed to help with new expectation out-of genetic relatedness certainly nearby grownups (Psychotria nervosa-Dewey and you will Heywood, 1988; Alseis blackiana and you can Platypodium elegans-Hamrick, Murawski, and you will Nason, 1993). Irrespective of models of relatedness, mating is sometimes limited to local communities inside the herbaceous variety (Levin and you can Kerster, 1974; Endler, 1979; Waser and you will Rate, 1983) and also in woody types, particularly when flowering adults are clustered (Linhart, revues des applications de rencontres politiques 1973; Stacy ainsi que al., 1996). The chance of biparental inbreeding anxiety inside the natural communities has been shown for a lot of herbaceous and you can coniferous tree kinds (Coles and you can Fowler, 1976; Park and you may Fowler, 1982; Levin, 1984; Schemske and you will Pautler, 1984; McCall, Mitchell-Olds, and you can Waller, 1991; Heywood, 1993; Waser and Price, 1994; Trame, Coddington, and you will Paige, 1995; Byers, 1998). Little or no is known, yet not, off biparental inbreeding depression into the sheer communities out of woody angiosperms.