Van Rossum F
Plant Biology and Nature Management, Vrije Universiteit Brussel, Brussels, Belgium.
Plant Biol (Stuttg). 2009 Sep;11(5):725-37. doi: 10.1111/j.1438-8677.2008.00176.x.
In order to conserve forest plant species under the particularly high constraints that represent urban surroundings, it is necessary to identify the key factors for population persistence. This study examined within- and between-population pollen dispersal using fluorescent dye as pollen analogue, and genetic variation and structure using 15 allozyme loci in Centaurium erythraea, an insect-pollinated, early-successional forest biennial herb occurring in a peri-urban forest (Brussels urban zone, Belgium). Dye dispersal showed an exponential decay distribution, with most dye transfers occurring at short distances (<15 m), and only a few long-distance events (up to 743 m). Flowers of C. erythraea are mainly visited by Syrphids (Diptera) and small bees, which are usually considered as short-distance pollen dispersers, and occasionally by bumblebees, which are usually longer-distance pollen dispersers. Small and large dye source populations differed in dye deposition patterns. The populations showed low genetic diversity, high inbreeding coefficients (F(IS)) and high genetic differentiation (F(ST)), suggesting restricted gene flow, which can be expected for an early-successional biennial species with a predominantly selfing breeding system and fluctuating population sizes. The positive relationship between recruitment rate and allelic richness and expected heterozygosity, and the absence of significant correlations between genetic variation and population size suggest seedling recruitment from the seed bank, contributing to maintain genetic diversity. Long-distance dye dispersal events indicate pollinator movements along urban forest path and road verges. These landscape elements might therefore have a potential conservation value by contributing to connectivity of early-successional species populations located in patchy open habitats.
为了在城市环境这种具有特别高限制条件下保护森林植物物种，有必要确定种群持续存在的关键因素。本研究使用荧光染料作为花粉类似物来研究种群内和种群间的花粉传播，并利用15个等位酶位点研究了红百金花（Centaurium erythraea）的遗传变异和结构。红百金花是一种虫媒传粉、处于演替早期的森林二年生草本植物，生长在比利时布鲁塞尔市区周边的城市森林中。染料传播呈现指数衰减分布，大多数染料转移发生在短距离（<15米）内，只有少数长距离事件（可达743米）。红百金花的花朵主要由食蚜蝇（双翅目）和小蜜蜂访花，它们通常被认为是短距离花粉传播者，偶尔也有熊蜂访花，熊蜂通常是长距离花粉传播者。大小不同的染料源种群在染料沉积模式上存在差异。这些种群显示出低遗传多样性、高自交系数（F(IS)）和高遗传分化（F(ST)），表明基因流动受限，这对于一个具有主要自交繁殖系统且种群大小波动的演替早期二年生物种来说是可以预期的。补充率与等位基因丰富度和预期杂合度之间呈正相关，并且遗传变异与种群大小之间不存在显著相关性，这表明幼苗是从种子库中补充的，有助于维持遗传多样性。长距离染料传播事件表明传粉者沿着城市森林小径和路边植被移动。因此，这些景观要素可能具有潜在的保护价值，有助于位于零散开放生境中的演替早期物种种群的连通性。
