REPRODUCTIVE-BIOLOGY AND POPULATION GENETIC-STRUCTURE OF KANDELIA-CANDEL (RHIZOPHORACEAE), A VIVIPAROUS MANGROVE SPECIES

The pollination biology, mating system, and population genetic structu re-of Kandelia candel were investigated. Field observations on its pol lination and reproductive biology suggested that this species is polli nator dependent for fruit set, and bee activities can lead to substant ial geitonogamous selfing. Quantitative analysis of the mating system parameters was performed using progeny arrays assayed for allozyme mar kers. Multilocus outcrossing rates (t(m)) were estimated to be 0.697 /- 0.091 and 0.797 +/- 0.062 in two populations. In comparison to othe r plant species with mixed-mating system, the level of allozyme variat ion was very low in the 13 populations sampled along the coastlines of Hong Kong. At the species level, the proportion of polymorphic loci w as 20%, number of alleles per locus was 1.2, and heterozygosity was 0. 0362. The total gene diversity was primarily distributed within popula tions (H-S = 0.0339), and the coefficient of genetic differentiation a mong populations was low (G(ST) = 0.064). This pattern of population g enetic structure suggests that gene how, primarily in the form of wate r-dispersed seedlings in viviparous mangrove species, is not as limite d as previously thought. However, microgeographic pattern in allele fr equency at the marker loci could still be detected between the western and eastern coastal populations.