Franceschinelli Edivani Villaron, Jacobi Claudia M, Drummond Marcela Gonçalves, Resende Marcelo F Silveira
Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Goiás, 740001-970 Goiânia GO, Brazil.
Ann Bot. 2006 Apr;97(4):585-92. doi: 10.1093/aob/mcl007. Epub 2006 Jan 30.
The genetic structure and variability of two species of Vellozia (Velloziaceae) with restricted distribution in high-altitude quartzitic fields in south-eastern Brazil were studied. Vellozia epidendroides is short, grows on pebbly or sandy soil, and is pollinated by bees. Vellozia leptopetala is arborescent, grows on rock outcrops, and is pollinated by bees and hummingbirds. Both are self-incompatible and have a short, massive flowering strategy. The study aimed to associate differences in their genetic diversity and structure with their microhabitat distribution and pollination ecology.
Leaves from 106 and 139 plants of V. epidendroides and V. leptopetala, respectively, were collected from five patches of each species and prepared for electrophoretic analyses.
Five enzyme systems could be reliably scored for both species. Vellozia epidendroides showed 100 % of the loci polymorphic for almost all patches. The average number of alleles per locus ranged between 2.2 and 2.4 among patches. The Wright's fixation index (F) for this species was 0.226. A significant (p) value indicates that there is a reasonable genetic divergence among patches. Vellozia leptopetala presented 47.5 % of polymorphic loci. All levels of P, A, A(p) and of heterozygosities were lower than those of V. epidendroides. Vellozia leptopetala showed high inbreeding within patches.
The relatively high values of genetic diversity indices found for V. epidendroides may be associated with its large and widespread populations. On the other hand, the low values of genetic diversity found for V. leptopetala may be related to physical isolation on outcrops and intensive foraging by territorial hummingbirds, which may hinder gene flow among patches, aggravated by the very restricted seed dispersal characteristic of the genus, that facilitates sibling mating. It is important to stress the need to preserve the specific habitats of these species of Vellozia, in particular those of V. leptopetala that has lower genetic diversity and is restricted to rock outcrop environments.
对巴西东南部高海拔石英岩地区分布范围有限的两种绒叶草属（绒叶草科）植物的遗传结构和变异性进行了研究。附生绒叶草植株矮小，生长在卵石或沙质土壤上，由蜜蜂授粉。细瓣绒叶草为乔木状，生长在岩石露头处，由蜜蜂和蜂鸟授粉。二者均为自交不亲和，且具有短期集中开花策略。该研究旨在将它们的遗传多样性和结构差异与其微生境分布和授粉生态学联系起来。
分别从每种植物的五个斑块中采集了106株附生绒叶草和139株细瓣绒叶草的叶片，准备进行电泳分析。
两种植物的五个酶系统均可进行可靠评分。附生绒叶草几乎所有斑块的位点多态性均为100%。各斑块中每个位点的平均等位基因数在2.2至2.4之间。该物种的赖特固定指数（F）为0.226。显著（p）值表明各斑块之间存在合理的遗传分化。细瓣绒叶草的多态位点比例为47.5%。所有P、A、A（p）和杂合度水平均低于附生绒叶草。细瓣绒叶草在斑块内表现出高度自交。
附生绒叶草较高的遗传多样性指数可能与其庞大且分布广泛的种群有关。另一方面，细瓣绒叶草较低的遗传多样性可能与岩石露头处的物理隔离以及领地性蜂鸟的密集觅食有关，这可能会阻碍斑块间的基因流动，而该属非常有限的种子传播特性则加剧了这种情况，从而促进了同胞交配。必须强调保护这些绒叶草物种特定栖息地的必要性，特别是细瓣绒叶草的栖息地，其遗传多样性较低且仅限于岩石露头环境。
