University of the Algarve

About: University of the Algarve is a education organization based out in Faro, Portugal. It is known for research contribution in the topics: Population & Tourism. The organization has 3649 authors who have published 10303 publications receiving 233536 citations.

Recent evolution in Baltic Fucus vesiculosus: reduced tolerance to emersion stresses compared to intertidal (North Sea) populations

Abstract: The Baltic is a young, brackish and non-tidal sea, supporting an impoverished marine flora compared with adjacent open coastal areas. Populations of the normally intertidal brown alga Fucus vesiculosus L. are permanently submerged in the Baltic. We tested the hypothesis that these populations have evolved a reduced ability to withstand water-stresses caused by aerial exposure (desiccation and freezing), relative to adjacent intertidal populations in the North Sea. Desiccation and freezing tolerance were compared using chlorophyll fluorescence to monitor photosynthetic sta- tus during stress and recovery. To control for the influence of growth salinity on stress tolerance, the experimental material consisted of either adult algae cross-acclimated at Baltic and North Sea salin- ities (6.5 and 20 to 24 practical salinity units (psu), respectively), or juveniles from both populations grown in the Baltic from embryos (submersed, 6.5 psu). Baltic algae were less able to recover maxi- mum photochemical yield (Fv/Fm) after freezing at -15°C than North Sea algae, and neither acclima- tion (adults) or growth salinity (juveniles) accounted for between-population differences. During des- iccation at 5°C, differences in the response of variable fluorescence (Fv), as well as in initial fluorescence (F0) and Fv during recovery, indicated that impaired photoprotective processes may con- tribute to the inability of Baltic algae to fully recover Fv/Fm after stress, in contrast to North Sea algae which displayed dynamic and rapidly recoverable reductions of Fv/Fm. Subsequent desiccation experiments during the summer (at 25°C) showed that, relative to North Sea algae, the effective pho- tochemical yield (ΔF/Fm') of Baltic algae started to decline at lower tissue-water content (TWC) and recovered less completely after a return to seawater. A critical TWC of ca 10% for Baltic populations was identified, below which ΔF/Fm' did not fully recover. In addition, Baltic algae were less able to regain initial TWC during recovery. These results indicate that, in ca 7500 yr since the recruitment of the present marine flora to the Baltic, F. vesiculosus has evolved reduced tolerance to emersion stresses compared to adjacent intertidal populations.

Endemic Plant Species Conservation: Biotechnological Approaches.

Abstract: Endemic plant species are usually more vulnerable to anthropogenic threats and natural changes and, therefore, hold a higher extinction risk. The preservation of these species is a major concern on a worldwide context and in situ protection alone will not guarantee their conservation. Ex situ conservation measures must be undertaken to support the conservation of these species, and seed banking is the more efficient and cost-effective method. However, when seed banking is not an option, alternative approaches should be considered. Biotechnological tools provide new and complementary options for plant conservation including short-, medium-, and long-term strategies, and their application for plant species conservation has increased considerably in the last years. This review provides information about the status of the use biotechnology-based techniques for the conservation of endemic plant species. Particular attention is given to cryopreservation, since is the only long-term ex situ conservation strategy that can complement and support the other conservation measures. The cryopreservation of plant genetic resources is, however, more focused on crop or economically important species and few studies are available for endemic plant species. The plant material used, the cryopreservation methods employed, and the assessment of cryogenic effects are reviewed. The reasons to explain the difficulties in cryopreserving these species are discussed and new strategies are proposed to facilitate and increase the interest on this matter. We expect that further studies on the conservation of endemic plant species will increase in a near future, thus contributing to maintain these valuable genetic resources.

Nuclear protein phylogenies support the monophyly of the three bryophyte groups (Bryophyta Schimp.).

Abstract: Unraveling the phylogenetic relationships between the four major lineages of terrestrial plants (mosses, liverworts, hornworts, and vascular plants) is essential for an understanding of the evolution of traits specific to land plants, such as their complex life cycles, and the evolutionary development of stomata and vascular tissue. Well supported phylogenetic hypotheses resulting from different data and methods are often incongruent due to processes of nucleotide evolution that are difficult to model, for example substitutional saturation and composition heterogeneity. We reanalysed a large published dataset of nuclear data and modelled these processes using degenerate-codon recoding and tree-heterogeneous composition substitution models. Our analyses resolved bryophytes as a monophyletic group and showed that the nonnonmonophyly of the clade that is supported by the analysis of nuclear nucleotide data is due solely to fast-evolving synonymous substitutions. The current congruence among phylogenies of both nuclear and chloroplast analyses lent considerable support to the conclusion that the bryophytes are a monophyletic group. An initial split between bryophytes and vascular plants implies that the bryophyte life cycle (with a dominant gametophyte nurturing an unbranched sporophyte) may not be ancestral to all land plants and that stomata are likely to be a symplesiomorphy among embryophytes.