38 research outputs found
Genetic differentiation and admixture between sibling allopolyploids in the Dactylorhiza majalis complex
Allopolyploidization often happens recurrently, but the evolutionary significance of its iterative nature is not yet fully understood. Of particular interest are the gene flow dynamics and the mechanisms that allow young sibling polyploids to remain distinct while sharing the same ploidy, heritage and overlapping distribution areas. By using eight highly variable nuclear microsatellites, newly reported here, we investigate the patterns of divergence and gene flow between 386 polyploid and 42 diploid individuals, representing the sibling allopolyploids Dactylorhiza majalis s.s. and D. traunsteineri s.l. and their parents at localities across Europe. We make use in our inference of the distinct distribution ranges of the polyploids, including areas in which they are sympatric (that is, the Alps) or allopatric (for example, Pyrenees with D. majalis only and Britain with D. traunsteineri only). Our results show a phylogeographic signal, but no clear genetic differentiation between the allopolyploids, despite the visible phenotypic divergence between them. The results indicate that gene flow between sibling Dactylorhiza allopolyploids is frequent in sympatry, with potential implications for the genetic patterns across their entire distribution range. Limited interploidal introgression is also evidenced, in particular between D. incarnata and D. traunsteineri. Altogether the allopolyploid genomes appear to be porous for introgression from related diploids and polyploids. We conclude that the observed phenotypic divergence between D. majalis and D. traunsteineri is maintained by strong divergent selection on specific genomic areas with strong penetrance, but which are short enough to remain undetected by genotyping dispersed neutral markers.UE FWF; P22260UE: Y66
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Effects of ozone and sulfur dioxide on four epiphytic bromeliads
Plants of Tillandsia balbisiana, T. paucifolia, T. recurvata and T. utriculata exposed to 0.15, 0.30 or 0.45 ppm O3 or to 0.30, 0.60 or 1.20 ppm SO2 for 6 hr or sequentially to 0.30 ppm O3 (2 hr), 0.30 ppm O3 plus 0.60 ppm SO2 (2 hr) and 0.60 ppm SO2 (2 hr) did not exhibit visible injury. Fumigations also had no effect on foliar conductance or on ΔH+ associated with Crassulacean acid metabolism. Characteristics responsible for plant tolerance to short exposures to these two gases probably included low stomatal conductance, the insulating indumentum of absorbing foliar hairs and inherently slow metabolism. Reasons for postulating that Tillandsia is a better indicator for technological metals and certain other pollutants than for brief exposures to O3 and SO2 are discussed. We also conclude that epiphytic Tillandsia spp. offer advantages over lichens for air quality assessments under appropriate conditions. As vascular plants they exhibit sensitive, easily measured responses to stress and can be transplanted with ease to areas where neither they nor lichens occur naturally. © 1992
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Active Uptake of Amino Acids by Leaves of an Epiphytic Vascular Plant, Tillandsia paucifolia (Bromeliaceae).
Specialized epidermal trichomes on the leaves of the epiphyte, Tillandsia paucifolia (Bromeliaceae) accumulate amino acids from solution. Simultaneous net uptake of 17 amino acids was determined using high performance liquid chromatography. Uptake occurs against concentration gradients at least as high as 10(4)