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Physiological Traits (physiological + trait)
Selected AbstractsAssessing the Suitability of Various Physiological Traits to Screen Wheat Genotypes for Salt ToleranceJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2007Salah E. El-Hendawy Abstract Success of improving the salt tolerance of genotypes requires effective and reliable screening traits in breeding programs. The objective was to assess the suitability of various physiological traits to screen wheat genotypes for salt tolerance. Thirteen wheat genotypes from Egypt, Germany, Australia and India were grown in soil with two salinity levels (control and 150 mmol/L NaCl) in a greenhouse. The physiological traits (ion contents in leaves and stems, i.e. Na+, Cl,, K+, Ca2+), the ratios of K+/Na+ and Ca+/Na+ in the leaves and stems, net photosynthesis rate, stomatal conductance, transpiration rate, chlorophyll content (SPAD value), and leaf water relations, were measured at different growth stages. The physiological traits except for Na+ and Cl, in stems and the leaf transpiration rate at 150 mmol/L NaCl showed a significant genotypic variation, indicating that the traits that have a significant genotypic variation may be possibly used as screening criteria. According to the analysis of linear regression of the scores of the physiological traits against those of grain yield, however, the physiological traits of Ca2+ and Ca2+/Na+ at 45 d and final harvest with the greatest genotypic variation were ranked at the top. From a practical and economic point of view, SPAD value should be considered to be used as screening criteria and/or there is a need to develop a quick and practical approach to determine Ca2+ in plant tissues. [source] Hydrogen peroxide concentration measured in cultivation substrates during growth and fruiting of the mushrooms Agaricus bisporus and Pleurotus spp.JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2007Jean-Michel Savoie Abstract Hydrogen peroxide is suspected of being highly implicated in mushroom nutrition and in substrate bleaching during cultivation. The parameters for measuring H2O2 in compost samples were examined and the methodology was applied to samples from both compost colonized by cultivars and wild isolates of Agaricus bisporus, and wheat straw or coffee pulp colonized by Pleurotus spp. Laccase and peroxidase activities were also measured. H2O2 concentration measured after heating at 80 °C for inactivating laccases and peroxidases was probably both H2O2 pre-existing in the compost and H2O2 generated from quinones and active oxygen species. This potential H2O2 concentration increased during the vegetative growth for all the strains, in agreement with a direct relationship between H2O2 concentration and active biomass of A. bisporus or Pleurotus spp. in their cultivation substrates. Correlations were observed between H2O2 concentration and manganese peroxidase activity in cultivation substrates at the stage of primordia formation. At this stage of development, H2O2 generation via biotic or abiotic mechanisms should be an important physiological trait of mushrooms. Copyright © 2007 Society of Chemical Industry [source] Relationships of grain ,13C and ,18O with wheat phenology and yield under water-limited conditionsANNALS OF APPLIED BIOLOGY, Issue 2 2007J.P. Ferrio Abstract Stable carbon isotope composition (,13C) of dry matter has been widely investigated as a selection tool in cereal breeding programmes. However, reports on the possibilities of using stable oxygen isotope composition (,18O) as a yield predictor are very scarce and only in the absence of water stress. Indeed, it remains to be tested whether changes in phenology and stomatal conductance in response to water stress overrule the use of either ,13C or ,18O when water is limited. To answer this question, a set of 24 genotypes of bread wheat (Triticum aestivum) were assayed in two trials with different levels of deficit irrigation and a third trial under rainfed conditions in a Mediterranean climate (northwest Syria). Grain yield (GY) and phenology (duration from planting to anthesis and from anthesis to maturity) were recorded, and the ,13C and ,18O of grains were analysed to assess their suitability as GY predictors. Both ,13C and ,18O showed higher broad-sense heritabilities (H2) than GY. Genotype means of GY across trials were negatively correlated with ,13C, as previously reported, but not with ,18O. Both isotopes were correlated with grain filling duration, whereas ,18O was also strongly affected by crop duration from planting to anthesis. We concluded that ,18O of grains is not a proper physiological trait to breed for suboptimal water conditions, as its variability is almost entirely determined by crop phenology. In contrast, ,13C of grains, despite being also affected by phenology, still provides complementary information associated with GY. [source] Morphological and physiological sexual selection targets in a territorial damselflyECOLOGICAL ENTOMOLOGY, Issue 6 2009INE SWILLEN Abstract. 1Several morphological and physiological traits may shape fitness through the same performance measure. In such cases, differentiating between a scenario of many-to-one mapping, where phenotypic traits independently shape fitness leading to functional redundancy, and a scenario where traits strongly covary among each other and fitness, is needed. 2A multivariate approach was used, including morphological and physiological traits related to flight ability, a crucial performance measure in flying insects, to identify independent correlates of short-term mating success (mated versus unmated males) in the territorial damselfly Lestes viridis. 3Males with higher flight muscle mass, higher relative thorax mass, and more symmetrical hindwings, all traits presumably linked to manoeuvrability, were more likely to be mated. Unexpectedly, although relative thorax mass is often used as a proxy for flight muscle mass, both traits were selected for independently. Mated males had a higher thorax fat content than unmated males, possibly because of enhanced flight endurance. 4The finding of several independent targets of sexual selection linked to flight ability is consistent with a scenario of many-to-one mapping between phenotype and performance. Identifying such a scenario is important, because it may clarify situations where animals may show suboptimal values for some phenotypic traits shaping a performance measure, while still having high performance and fitness. We argue in the discussion that the functional approach of sexual selection provides a potent tool for examining unresolved issues in both sexual selection theory, as well as life-history theory. [source] Behavioural activity levels and expression of stress proteins under predation risk in two damselfly speciesECOLOGICAL ENTOMOLOGY, Issue 3 2009STEFANIE SLOS Abstract 1.,It has become apparent that predators may strongly decrease prey fitness without direct contact with the prey, as they induce the development of defence systems that limit the availability of energy for growth and reproduction. Recent studies suggest that stress proteins may help prey organisms deal with this stress. The pattern is not general, however, and little is known about species differences in physiological traits in coping with predator stress, and covariation of physiological with other antipredator traits. 2.,To explore these issues, we quantified levels of constitutive and fish-induced stress proteins (Hsp60 and Hsp70) and anti-predator behaviours in larvae of two damselfly species that differ in lifestyle. Both stress proteins were fixed at higher levels in Erythromma najas, which has a slow lifestyle, than in Lestes sponsa, which has a fast lifestyle. Similarly, anti-predator behaviours were fixed at safer levels in E. najas than in L. sponsa. 3.,These results suggest that stress proteins may be part of anti-predator syndromes of damselfly larvae, and there may be trait co-specialisation between stress proteins and behavioural anti-predator traits. Studies formally testing these hypotheses in more species may prove rewarding in advancing our understanding of the functional integration of physiological anti-predator traits in relation to the prey's lifestyle. [source] Transmission dynamics of an iridescent virus in an experimental mosquito population: the role of host densityECOLOGICAL ENTOMOLOGY, Issue 4 2005Carlos F. Marina Abstract., 1.,The transmission of insect pathogens cannot be adequately described by direct linear functions of host and pathogen density due to heterogeneity generated from behavioural or physiological traits, or from the spatial distribution of pathogen particles. Invertebrate iridescent viruses (IIVs) can cause patent and lethal infection or a covert sub-lethal infection in insects. Aedes aegypti larvae were exposed to suspensions of IIV type 6 at two densities. High larval density increased the prevalence of aggression resulting in potentially fatal wounding. 2.,The overall prevalence of infection (patent + covert) was positively influenced by host density and increased with exposure time in both densities. The survival time of patently infected insects was extended by , 5 days compared with non-infected insects. 3.,Maximum likelihood models based on the binomial distribution were fitted to empirical results. A model incorporating heterogeneity in host susceptibility by inclusion of a pathogen-free refuge was a significantly better fit to data than an all-susceptible model, indicating that transmission is non-linear. The transmission coefficient (,) did not differ with host density whereas the faction of the population that occupied the pathogen-free refuge (,R) was significantly reduced at high host density compared with the low density treatment. 4.,The transmission of free-living infective stages of an IIV in Ae. aegypti larvae is non-linear, probably because of density-related changes in the frequency of aggressive encounters between hosts. This alters host susceptibility to infection and effectively reduces the proportion of hosts that occupy the pathogen-free refuge. [source] WATER STRESS ALTERS THE GENETIC ARCHITECTURE OF FUNCTIONAL TRAITS ASSOCIATED WITH DROUGHT ADAPTATION IN AVENA BARBATAEVOLUTION, Issue 3 2009Mark E. Sherrard Environmental stress can alter genetic variation and covariation underlying functional traits, and thus affect adaptive evolution in response to natural selection. However, the genetic basis of functional traits is rarely examined in contrasting resource environments, and consequently, there is no consensus regarding whether environmental stress constrains or facilitates adaptive evolution. We tested whether resource availability affects genetic variation for and covariation among seven physiological traits and seven morphological/performance traits by growing the annual grass Avena barbata in dry and well-watered treatments. We found that differences in the overall genetic variance,covariance (G) matrix between environments were driven by physiological traits rather than morphology and performance traits. More physiological traits were heritable in the dry treatment than the well-watered treatment and many of the genetic correlations among physiological traits were environment dependent. In contrast, genetic variation and covariation among the morphological and performance traits did not differ across treatments. Furthermore, genetic correlations between physiology and performance were stronger in the dry treatment, which contributed to differences in the overall G -matrix. Our results therefore suggest that physiological adaptation would be constrained by low heritable variation in resource-rich environments, but facilitated by higher heritable variation and stronger genetic correlations with performance traits in resource-poor environments. [source] POSTCOPULATORY FERTILIZATION BIAS AS A FORM OF CRYPTIC SEXUAL SELECTIONEVOLUTION, Issue 5 2008Ryan Calsbeek Males and females share most of their genetic material yet often experience very different selection pressures. Some traits that are adaptive when expressed in males may therefore be maladaptive when expressed in females. Recent studies demonstrating negative correlations in fitness between parents and their opposite-sex progeny suggest that natural selection may favor a reduction in trait correlations between the sexes to partially mitigate intralocus sexual conflict. We studied sex-specific forms of selection acting in Anolis lizards in the Greater Antilles, a group for which the importance of natural selection has been well documented in species-level diversification, but for which less is known about sexual selection. Using the brown anole (Anolis sagrei), we measured fitness-related variation in morphology (body size), and variation in two traits reflecting whole animal physiological condition: running endurance and immune function. Correlations between body size and physiological traits were opposite between males and females and the form of natural selection acting on physiological traits significantly differed between the sexes. Moreover, physiological traits in progeny were correlated with the body-size of their sires, but correlations were null or even negative between parents and their opposite-sex progeny. Although results based on phenotypic and genetic correlations, as well as the action of natural selection, suggest the potential for intralocus sexual conflict, females used sire body size as a cue to sort sperm for the production of either sons or daughters. Our results suggest that intralocus sexual conflict may be at least partly resolved through post-copulatory sperm choice in A. sagrei. [source] CONTRASTING PLANT PHYSIOLOGICAL ADAPTATION TO CLIMATE IN THE NATIVE AND INTRODUCED RANGE OF HYPERICUM PERFORATUMEVOLUTION, Issue 8 2007John L. Maron How introduced plants, which may be locally adapted to specific climatic conditions in their native range, cope with the new abiotic conditions that they encounter as exotics is not well understood. In particular, it is unclear what role plasticity versus adaptive evolution plays in enabling exotics to persist under new environmental circumstances in the introduced range. We determined the extent to which native and introduced populations of St. John's Wort (Hypericum perforatum) are genetically differentiated with respect to leaf-level morphological and physiological traits that allow plants to tolerate different climatic conditions. In common gardens in Washington and Spain, and in a greenhouse, we examined clinal variation in percent leaf nitrogen and carbon, leaf ,13C values (as an integrative measure of water use efficiency), specific leaf area (SLA), root and shoot biomass, root/shoot ratio, total leaf area, and leaf area ratio (LAR). As well, we determined whether native European H. perforatum experienced directional selection on leaf-level traits in the introduced range and we compared, across gardens, levels of plasticity in these traits. In field gardens in both Washington and Spain, native populations formed latitudinal clines in percent leaf N. In the greenhouse, native populations formed latitudinal clines in root and shoot biomass and total leaf area, and in the Washington garden only, native populations also exhibited latitudinal clines in percent leaf C and leaf ,13C. Traits that failed to show consistent latitudinal clines instead exhibited significant phenotypic plasticity. Introduced St. John's Wort populations also formed significant or marginally significant latitudinal clines in percent leaf N in Washington and Spain, percent leaf C in Washington, and in root biomass and total leaf area in the greenhouse. In the Washington common garden, there was strong directional selection among European populations for higher percent leaf N and leaf ,13C, but no selection on any other measured trait. The presence of convergent, genetically based latitudinal clines between native and introduced H. perforatum, together with previously published molecular data, suggest that native and exotic genotypes have independently adapted to a broad-scale variation in climate that varies with latitude. [source] ,-Adrenoceptor gene variation and intermediate physiological traits: prediction of distant phenotypeEXPERIMENTAL PHYSIOLOGY, Issue 7 2010John H. Eisenach Intermediate physiological phenotype is the genetic and environmental influence on functional physiological characteristics with direct prognostic relevance to distant, more complex phenotypes, such as cardiovascular and metabolic disease. Increasingly available and affordable genotyping techniques have created an explosion of information on candidate gene variation and its relationship to intermediate physiological traits. Variation in ,-adrenoceptor genes is an intense focus of investigation because ,-adrenoceptors are: (1) ubiquitous in organ system distribution; (2) integral to a multitude of physiological processes; (3) well described in cardiovascular and metabolic disease; and (4) major pharmacological treatment targets. Furthermore, knowledge of functional gene variants in these receptors predates the description of the human genome. This review highlights the influence of common gene variation in the three ,-adrenoceptor subtypes on intermediate physiological phenotype predictive of cardiovascular disease and obesity. Although further information is needed to replicate this information across populations, this review condenses and summarizes growing trends in specific pleiotropic effects of ,-adrenoceptor polymorphisms and suggests which variants may be predictive of distant phenotype. [source] Microbial community dynamics in nutrient-pulsed chemostatsFEMS MICROBIOLOGY ECOLOGY, Issue 1 2006Militza Carrero-Colón Abstract In nature, microbes are subject to nutrient fluxes. As the periodicity of nutrient flux lengthens, different physiological traits may be selected. The competitive exclusion principle stipulates that one organism will dominate these systems; however, interspecies interactions may produce a dynamic microbial community. These issues were investigated in chemostats pulsed with gelatin. Chemostats were run over 30 days with substrate addition continuously or at intervals of 0.5, 1 or 3 days. Growth rates were similar between pulse intervals. Ectoaminopeptidase activity levels remained relatively constant within a pulse interval. Bacterial community structure was monitored using denaturing gradient gel electrophoresis of PCR products of the 16S rRNA gene. There were dynamic changes at all periodicities; however, the pace of these changes decreased over time. Final communities were not identical between different treatments. The structure of persistent vs. active microbial populations was compared by denaturing gradient gel electrophoresis of the PCR and reverse transcriptase-PCR amplicons of 16S rDNA and rRNA templates, respectively. For all the chemostats, the rRNA profiles were not identical to the rDNA profiles for a sample. These experiments demonstrate that complex community dynamics can occur under environmental heterogeneities that are modest relative to those found in natural aquatic habitats. Furthermore, the physiological functionality of these dynamic communities was stable. [source] Plant functional type classifications in tropical dry forests in Costa Rica: leaf habit versus taxonomic approachesFUNCTIONAL ECOLOGY, Issue 4 2010Jennifer S. Powers Summary 1.,One way to simplify the high taxonomic diversity of plant species in vegetation models is to place species into groups based on shared, dominant traits. Many studies have suggested that morphological and physiological traits of tropical dry forest tree species vary with leaf habit (i.e. leaves from evergreen, deciduous or semi-deciduous species) and thus this characteristic may serve as a useful way to distinguish ecologically meaningful functional types. 2.,In this study we examine whether 10 plant traits vary with leaf habit in replicated leaves and individual trees of 87 species from a tropical dry forest in Costa Rica. We also looked for evidence of phylogenetic conservatism, i.e. closely related species sharing similar trait values compared to more distantly related taxa. 3.,While some of the traits varied within and among individual trees of the same species, interspecific variation accounted for 57,83% of the variance among samples. Four traits in addition to leaf habit showed evidence of phylogenetic conservatism, but these results were strongly dependent on the inclusion of the 18 species of legumes (Fabaceae) in our dataset. Contrary to our predictions, none of the traits we measured differed among leaf habits. However, five traits (wood density, leaf C, leaf N, N/P and C/N) varied significantly between legumes and other functional types. Furthermore, when all high-nitrogen non-legume taxa were compared to the high-nitrogen legumes, six traits excluding leaf N differed significantly, indicating that legumes are functionally different from other tree species beyond high N concentrations. Similarly, the 18 legume taxa (which all have compound leaves) also differed from other compound-leaved species for six traits, thus leaf type does not explain these patterns. 4.,Our main conclusions are that (i) a plant functional type classification based on leaf habit alone has little utility in the tropical dry forest we studied, and (ii) legumes have a different suite of traits including high leaf carbon and wood density in addition to high leaf nitrogen. Whether this result generalizes to other tropical forests is unknown, but merits future research due to the consequences of these traits for carbon storage and ecosystem processes. [source] Enhanced anti-predator defence in the presence of food stress in the water flea Daphnia magnaFUNCTIONAL ECOLOGY, Issue 2 2010Kevin Pauwels Summary 1. ,Many prey organisms show adaptive trait shifts in response to predation. These responses are often studied under benign conditions, yet energy stress may be expected to interfere with optimal shifts in trait values. 2. ,We exposed the water flea Daphnia magna to fish predation and food stress and quantified both life history responses as well as physiological responses (metabolic rate, stress proteins, energy storage and immune function) to explore the architecture of defence strategies in the face of the combined stressors and the occurrence of trade-offs associated with energy constraints. 3. ,All traits studied showed either an overall or clone-dependent response to food stress. The chronic response to predation risk was less strong for the measured physiological traits than for life history traits, and stronger under food stress than under benign conditions for age at maturity, intrinsic population growth rate and offspring performance (measured as juvenile growth). Immune function (measured as phenoloxidase activity) was lower under predation risk but only at high food, probably because minimum levels were maintained at low food. 4. ,Overall, food stress induced stronger adaptive predator-induced responses, whereas more energy was invested in reproduction under benign conditions at the cost of being less defended. Our results suggest that food stress may increase the capacity to cope with predation risk and underscore the importance of integrating responses to different stressors and traits, and show how responses towards one stressor can have consequences for the susceptibility to other stressors. [source] Xylem root and shoot hydraulics is linked to life history type in chaparral seedlingsFUNCTIONAL ECOLOGY, Issue 1 2010Robert B. Pratt Summary 1.,Shrubs in fire prone chaparral communities have evolved different life history types in response to fire. A key to understanding the evolution of life history type differences is to understand how physiological traits are linked to differences in life history type. Vascular adaptations are important for delivering an efficient and stable water supply to evergreen chaparral shrub leaves. This study tested for a link between vascular physiology and life history type in chaparral shrubs. 2.,Chaparral shrub species along the south-western coast of North America survive wildfire by three different life histories. Non-sprouters are killed by fire and re-establish exclusively through germination of fire-stimulated seeds, facultative sprouters re-establish by a combination of vegetative sprouting and fire-stimulated seeds, and obligate sprouters re-establish exclusively by vegetative sprouting because their seeds do not survive fire. Non-sprouters and facultative sprouters establish seedlings in the open canopy post fire environment, whereas obligate sprouters establish seedlings in the shady understory of the mature chaparral canopy. 3.,Seedlings of nine species (Rhamnaceae) representing three each of the different life history types were grown in deep containers in a common garden under treatments of sun and shade. Hydraulic conductance was measured using a high-pressure flow meter for all organs, and a vacuum technique was used to measure conductance of fine and woody roots. We predicted that non-sprouters would exhibit greater hydraulic efficiency than the sprouting species, and that facultative sprouters would be more efficient than the shade tolerant obligate sprouters. 4.,Non-sprouters had the greatest hydraulic conductance per unit leaf and sapwood area at the whole seedling level, whereas facultative and obligate sprouters were not different. Comparing hydraulic conductance across major organs (from fine roots to leaves) showed that the hydraulic system was well coordinated. At the whole seedling level, the root system was more of a bottleneck than the shoot system. This pattern was consistent with high resistance extraxylary pathways in roots and differences in root architecture. 5.,The greater hydraulic efficiency of the non-sprouter life history type is attributed to its post-fire pioneering habit and may partially explain the relatively high speciation in the non-sprouters. Lower hydraulic efficiency is associated with a sprouting life history and greater shade tolerance. The seedling root systems represent a hydraulic bottleneck that may place roots under especially intense selection. [source] Macrophysiology: large-scale patterns in physiological traits and their ecological implicationsFUNCTIONAL ECOLOGY, Issue 2 2004S. L. Chown First page of article [source] Maintenance of the alcohol dehydrogenase polymorphism in Tiger Salamanders, II.FUNCTIONAL ECOLOGY, Issue 1 2000Differences in biochemical function among allozymes Abstract 1.,Previous studies of Tiger Salamanders demonstrated that variation in alcohol dehydrogenase (Adh) contributed significantly to associations between multilocus heterozygosity and oxygen consumption traits, and that Adh variation was associated with levels of pond-oxygen and metamorphic ability in extreme oxygen environments. Here Adh allozymes are characterized kinetically, and relationships between Adh and oxygen-related physiological traits (ATP/Hb, 2,3-DPG/Hb) are measured. 2.,Kinetic differences were measured among Adh allozymes in the acetaldehyde-to-ethanol direction: kcat/Km ratios (the catalytic constant divided by the Michaelis,Menton constant) were significantly higher in Adh-SF than the other two genotypes, and in Adh-SS compared with Adh-FF. No significant differences were measured in the ethanol to acetaldehyde direction. 3.,Adh-SS had a significantly higher ATP/Hb than Adh-FF, with the Adh-SF intermediate. In addition, a significant interaction between Hb and body mass was measured, such that Adh-FF showed a negative relationship between Hb concentration and body mass while the other two genotypes showed a positive relationship. 4.,These results are consistent with the hypothesis that variation at the Adh locus has adaptive and physiological significance, and that functional differences among Adh allozymes partly explain significant associations between multilocus genotype and organismal traits. [source] Nitrogen Rates and Water Stress Effects on Production, Lipid Peroxidation and Antioxidative Enzyme Activities in Two Maize (Zea mays L.) GenotypesJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 6 2007L.-X. Zhang Abstract Effects of nitrogen rates and water stress (WS) on production, lipid peroxidation and antioxidative enzyme activities in two maize (Zea mays L.) genotypes were assessed at different stages under two levels of water supply conditions. WS caused a significant decline in dry matter, grain yield and activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) whereas a marked rise in malondialdehyde (MDA) concentration was observed in leaves for the two genotypes. However, the responses of the two varieties to WS were different: significantly higher dry matter, grain yield and antioxidative enzyme activities and lower MDA content were observed for Shaandan 9 than Shaandan 911, therefore the former could be treated as a drought tolerance variety comparatively. A better correlation was obtained amongst dry matter, grain yield and physiological traits. The addition of nitrogen increased dry matter and grain yield as well as activities of SOD, POD and CAT to different levels and significantly decreased MDA content under WS. These effects were higher for Shaandan 911 than for Shaandan 9. Furthermore, a significant effect was found for Shaandan 911 between N rates for all traits unlike Shaandan 9. Hence, we suggest that nitrogen should be applied to a water-sensitive variety to bring out its potential fully under drought. [source] Lichen acclimatization on retention trees: a conservation physiology lessonJOURNAL OF APPLIED ECOLOGY, Issue 4 2009Kadi Jairus Summary 1.,Green-tree retention (GTR) has been suggested as a means to effectively support epiphytic lichen species in managed forests, given the low lichen mortality on retention trees in the short term. However, a long-term perspective requires a physiological understanding of lichen responses to logging. This study compares anatomical, morphological and physiological traits of lichens on retention trees and on intact forest trees. 2.,Thalli of nine taxa (Buellia griseovirens, Cladonia digitata, Hypogymnia physodes, Lecanora allophana, Lecanora pulicaris, Lepraria spp., Peltigera praetextata, Pertusaria amara and Phlyctis argena) were sampled from birch Betula spp. and aspen Populus tremula in GTR cuts, where they had previously been reported to survive well, and in adjacent managed forests. In the laboratory, chlorophyll fluorescence parameter Fv/Fm, thickness of the upper cortex, photobiont to mycobiont ratio and (in Lecanora species) the relative area of the apothecia were measured. 3.,All the lichen samples collected from GTR cuts appeared alive, but their Fv/Fm was significantly lower, relative areas of the apothecia were larger and the upper cortices of thalli were thicker compared with the samples from adjacent forests. No difference in photobiont to mycobiont ratio was found. These patterns were broadly consistent among species, indicating a common mechanism: while suffering from photoinhibition, the lichens had acclimatized to the open conditions and increased their investment to sexual reproduction in a few years. 4.,Synthesis and applications. The study highlights the value of a morpho-physiological framework for conservation management by pointing out that, in GTR areas, lichen survival is high-irradiation limited and heavily dependent on phenotypic plasticity. A thin upper cortex may be a common feature of the most sensitive species. To sustain epiphyte populations in managed forests, precautionary harvesting strategies (gradual felling; group-retention; extended rotations) should be preferred and large-enough populations should be preserved, even though short-term studies suggest a high survival of lichens in cut areas. [source] Greater capacity for division of labour in clones of Fragaria chiloensis from patchier habitatsJOURNAL OF ECOLOGY, Issue 3 2007SERGIO R. ROILOA Summary 1Unlike non-clonal plants, clonal plants can develop a division of labour in which connected ramets specialize to acquire different, locally abundant resources. This occurs as a plastic response to a patchy environment where two resources tend not to occur together and different ramets experience high availabilities of different resources. We hypothesized that if division of labour is an important advantage of clonal growth in such environments in nature, then clones from habitats where resource availabilities are negatively associated should show a greater capacity for division of labour than clones from habitats where resource availabilities are more uniform. 2To test this, we collected clones of Fragaria chiloensis from sand dune and grassland sites in each of three regions of the central coast of California, grew pairs of connected or severed ramets under low light and high N or under high light and low N, and measured leaf area, chlorophyll content and final dry mass. Given that previous work has indicated that high availabilities of light and N show a stronger tendency not to occur together in the dune than in the grassland sites, we expected that clones from dunes would show greater capacity for division of labour than clones from grasslands. 3Clones from dunes showed a greater capacity than clones from grasslands to specialize for acquisition of abundant N via high proportional mass of roots. Clones from the two types of habitats showed similar capacity to specialize for acquisition of abundant light via high leaf area and chlorophyll content of leaves. Specialization via leaf area and chlorophyll content took place mainly within the first half of the 60-day experiment. 4These results provide evidence that division of labour in a clonal plant has been selected for in natural habitats where high levels of different resources tend to be spatially separated. Results also show that division of labour can occur, not just via allocation of mass, but also via physiological traits, and that both morphological and physiological specialization can take place within a few weeks. 5Clonal plants dominate many habitats and include many highly invasive species. Division of labour is one of the most striking potential advantages of clonal growth, and is a remarkable instance of phenotypic plasticity in plants. This study further suggests that division of labour in clonal plants is an instance of adaptive plasticity and could therefore play a part in their widespread ecological success. [source] Linking physiological traits to impacts on community structure and function: the role of root hemiparasitic Orobanchaceae (ex-Scrophulariaceae)JOURNAL OF ECOLOGY, Issue 1 2005G. K. PHOENIX Summary 1The hemiparasitic Orobanchaceae (ex-Scrophulariaceae) are characterized by a distinctive suite of ecophysiological traits. These traits have important impacts on host plants and non-host plants, and influence interactions with other trophic levels. Ultimately, they can affect community structure and functioning. Here, we review these physiological traits and discuss their ecological consequences. 2The root hemiparasitic Orobanchaceae form a convenient subset of the parasitic angiosperms for study because: they are the most numerous and most widely distributed group of parasitic angiosperms; their physiological characteristics have been well studied; they are important in both agricultural and (semi)natural communities; and they are tractable as experimental organisms. 3Key traits include: high transpiration rates; competition with the host for nutrients and haustorial metabolism of host-derived solutes; uptake of host-derived secondary metabolites; dual autotrophic and heterotrophic carbon nutrition; distinct carbohydrate biochemistry; high nutrient concentrations in green leaf tissue and leaf litter; and small (often hairless and non-mycorrhizal) roots. 4Impacts on the host are detrimental, which can alter competitive balances between hosts and non-hosts and thus result in community change. Further impacts may result from effects on the abiotic environment, including soil water status, nutrient cycling and leaf/canopy temperatures. 5However, for non-host species and for organisms that interact with these (e.g. herbivores and pollinators) or for those that benefit from changes in the abiotic environment, the parasites may have an overall positive effect, suggesting that at the community level, hemiparasites may also be considered as mutualists. 6It is clear that through their distinctive suite of physiological traits hemiparasitic Orobanchaceae, have considerable impacts on community structure and function, can have both competitive and positive interactions with other plants, and can impact on other trophic levels. Many community level effects of parasitic plants can be considered analogous to those of other parasites, predators or herbivores. [source] Assessing the Suitability of Various Physiological Traits to Screen Wheat Genotypes for Salt ToleranceJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2007Salah E. El-Hendawy Abstract Success of improving the salt tolerance of genotypes requires effective and reliable screening traits in breeding programs. The objective was to assess the suitability of various physiological traits to screen wheat genotypes for salt tolerance. Thirteen wheat genotypes from Egypt, Germany, Australia and India were grown in soil with two salinity levels (control and 150 mmol/L NaCl) in a greenhouse. The physiological traits (ion contents in leaves and stems, i.e. Na+, Cl,, K+, Ca2+), the ratios of K+/Na+ and Ca+/Na+ in the leaves and stems, net photosynthesis rate, stomatal conductance, transpiration rate, chlorophyll content (SPAD value), and leaf water relations, were measured at different growth stages. The physiological traits except for Na+ and Cl, in stems and the leaf transpiration rate at 150 mmol/L NaCl showed a significant genotypic variation, indicating that the traits that have a significant genotypic variation may be possibly used as screening criteria. According to the analysis of linear regression of the scores of the physiological traits against those of grain yield, however, the physiological traits of Ca2+ and Ca2+/Na+ at 45 d and final harvest with the greatest genotypic variation were ranked at the top. From a practical and economic point of view, SPAD value should be considered to be used as screening criteria and/or there is a need to develop a quick and practical approach to determine Ca2+ in plant tissues. [source] Changing climate and historic-woodland structure interact to control species diversity of the ,Lobarion' epiphyte community in ScotlandJOURNAL OF VEGETATION SCIENCE, Issue 5 2007Christopher J. Ellis Abstract Question: How will changing climate and habitat structure interact to control the species diversity of lichen epiphytes? Location: Scotland. Method: Species richness (=diversity) of the epiphyte lichen community known as Lobarion (named after Lobaria pulmonaria) was quantified for 94 Populus tremula stands across Scotland, and compared in a predictive model to seven climate variables and eight measures of woodland structure. An optimum model was selected and used to project Lobarion diversity over the geographic range of the study area, based on IPCC climate change scenarios and hypothetical shifts in woodland structure. Results: Species diversity of the Lobarion community was best explained by three climate variables: (1) average annual temperature; (2) autumn and winter precipitation; in combination with (3) historic-woodland extent. Projections indicate a positive effect of predicted climate change on Lobarion diversity, consistent with the physiological traits of cyanobac-terial lichens comprising the Lobarion. However, the general response to climate is modified significantly by the effect on diversity of historic-woodland extent. Conclusions: Historic-woodland extent may exert an important control over local climate, as well as impacting upon the metapopulation dynamics of species in the Lobarion. In particular, a temporal delay in the response of Lobarion species to changed woodland structure is critical to our understanding of future climate change effects. Future Lobarion diversity (e.g. in the 2050s) may depend upon the interaction of contemporary climate (e.g. 2050s climate) and historic habitat structure (e.g. 1950s woodland extent). This is supported by previous observations for an extinction debt amongst lichen epiphytes, but suggests an extension of simple climate-response models is necessary, before their wider application to lichen epiphyte diversity. [source] Quantitative genetics parameters show partial independent evolutionary potential for body mass and metabolism in stonechats from different populationsJOURNAL OF ZOOLOGY, Issue 2 2009B. I. Tieleman Abstract Phenotypic variation in physiological traits, such as energy metabolism, is commonly subjected to adaptive interpretations, but little is known about the heritable basis or genetic correlations among physiological traits in non-domesticated species. Basal metabolic rate (BMR) and body mass are related in complex ways. We studied the quantitative genetics of BMR, residual BMR (on body mass), mass-specific BMR and body mass of stonechats originating from four different populations and bred in captivity. Heritabilities ranged from 0.2 to 0.7. The genetic variance,covariance structure implied that BMR, mass-specific BMR and body mass can in part evolve independently of each other, because we found genetic correlations deviating significantly from one and minus one. BMR, mass-specific BMR and body mass further differed among populations at the phenotypic level; differences in the genetic correlation among populations are discussed. [source] Comparative community physiology: nonconvergence in water relations among three semi-arid shrub communitiesNEW PHYTOLOGIST, Issue 1 2008Anna L. Jacobsen Summary ,,Plant adaptations to the environment are limited, and therefore plants in similar environments may display similar functional and physiological traits, a pattern termed functional convergence. Evidence was examined for functional convergence among 28 evergreen woody shrubs from three plant communities of the semi-arid winter rainfall region of southern California. ,,Both leaf and water relations traits were examined, including seasonal stomatal conductance (gs), specific leaf area (SLA), leaf specific conductivity (Kl), seasonal water potential (,w), stem cavitation resistance (,50), and xylem density. ,,Species display community-specific suites of xylem and leaf traits consistent with different patterns of water use among communities, with coastal sage scrub species utilizing shallow pulses of water, Mojave Desert scrub species relying on deeper water reserves, and chaparral species utilizing both shallow and deep moisture reserves. Communities displayed similar degrees of water stress, with a community-level minimum ,w (,wmin) of c. ,4.6 Mpa, similar to other arid communities. Pooled across sites, there was a strong correlation between ,wmin and xylem density, suggesting that these traits are broadly related and predictive of one another. ,This comparative community physiology approach may be useful in testing hypotheses of functional convergence across structurally similar semi-arid communities. [source] Energetic consequences of being a Homo erectus femaleAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2002Leslie C. Aiello Body size is one of the most important characteristics of any animal because it affects a range of behavioral, ecological, and physiological traits including energy requirements, choice of food, reproductive strategies, predation risk, range size, and locomotor style. This article focuses on the implications of being large bodied for Homo erectus females, estimated to have been over 50% heavier than average australopithecine females. The energy requirements of these hominins are modeled using data on activity patterns, body mass, and life history from living primates. Particular attention is given to the inferred energetic costs of reproduction for Homo erectus females based on chimpanzee and human reproductive scheduling. Daily energy requirements during gestation and lactation would have been significantly higher for Homo erectus females, as would total energetic cost per offspring if the australopithecines and Homo erectus had similar reproductive schedules (gestation and lactation lengths and interbirth intervals). Shortening the interbirth interval could considerably reduce the costs per offspring to Homo erectus and have the added advantage of increasing reproductive output. The mother would, however, incur additional daily costs of caring for the dependent offspring. If Homo erectus females adopted this reproductive strategy, it would necessarily imply a revolution in the way in which females obtained and utilized energy to support their increased energetic requirements. This transformation is likely to have occurred on several levels involving cooperative economic division of labor, locomotor energetics, menopause, organ size, and other physiological mechanisms for reducing the energetic load on females. Am. J. Hum. Biol. 14:551,565, 2002. © 2002 Wiley-Liss, Inc. [source] Stomatal crypts may facilitate diffusion of CO2 to adaxial mesophyll cells in thick sclerophyllsPLANT CELL & ENVIRONMENT, Issue 11 2009FOTEINI HASSIOTOU ABSTRACT In some plants, stomata are exclusively located in epidermal depressions called crypts. It has been argued that crypts function to reduce transpiration; however, the occurrence of crypts in species from both arid and wet environments suggests that crypts may play another role. The genus Banksia was chosen to examine quantitative relationships between crypt morphology and leaf structural and physiological traits to gain insight into the functional significance of crypts. Crypt resistance to water vapour and CO2 diffusion was calculated by treating crypts as an additional boundary layer partially covering one leaf surface. Gas exchange measurements of polypropylene meshes confirmed the validity of this approach. Stomatal resistance was calculated as leaf resistance minus calculated crypt resistance. Stomata contributed significantly more than crypts to leaf resistance. Crypt depth increased and accounted for an increasing proportion of leaf resistance in species with greater leaf thickness and leaf dry mass per area. All Banksia species examined with leaves thicker than 0.6 mm had their stomata in deep crypts. We propose that crypts function to facilitate CO2 diffusion from the abaxial surface to adaxial palisade cells in thick leaves. This and other possible functions of stomatal crypts, including a role in water use, are discussed. [source] Fallback foods, eclectic omnivores, and the packaging problemAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2009Stuart A. Altmann Abstract For omnivorous primates, as for other selective omnivores, the array of potential foods in their home ranges present a twofold problem: not all nutrients are present in any food in the requisite amounts or proportions and not all toxins and other costs are absent. Costs and benefits are inextricably linked. This so-called packaging problem is particularly acute during periods, often seasonal, when the benefit-to-cost ratios of available foods are especially low and animals must subsist on fallback foods. Thus, fallback foods represent the packaging problem in extreme form. The use of fallback foods by omnivorous primates is part of a suite of interconnected adaptations to the packaging problem, the commingling of costs and benefits in accessing food and other vital resources. These adaptations occur at every level of biological organization. This article surveys 16 types of potential adaptations of omnivorous primates to fallback foods and the packaging problem. Behavioral adaptations, in addition to finding and feeding on fallback foods, include minimizing costs and requirements, exploiting food outbreaks, living in social groups and learning from others, and shifting the home range. Adaptive anatomical and physiological traits include unspecialized guts and dentition, binocular color vision, agile bodies and limbs, Meissner's corpuscles in finger tips, enlargement of the neocortex, internal storage of foods and nutrients, and ability internally to synthesize compounds not readily available in the habitat. Finally, during periods requiring prolonged use of fallback foods, life history components may undergo changes, including reduction of parental investment, extended interbirth intervals, seasonal breeding or, in the extreme, aborted fetuses. Am J Phys Anthropol 140:615,629, 2009. © 2009 Wiley-Liss, Inc. [source] Molecular characterization of swine leucocyte antigen class II genes in outbred pig populationsANIMAL GENETICS, Issue 4 2010C.-S. Ho Summary The highly polymorphic swine leucocyte antigen (SLA) genes are among the most important determinants of swine immune responses to disease and vaccines. Accurate and effective SLA genotyping methods are required to understand how SLA gene polymorphisms affect immunity, especially in outbred pigs with diverse genetic backgrounds. In this study, we present a simple and rapid molecular-based typing system for characterizing SLA class II alleles of the DRB1, DQB1 and DQA loci. This system utilizes a set of 47 sequence-specific PCR primers developed to differentiate alleles by groups that share similar sequence motifs. We applied this typing method to investigate the SLA class II diversity in four populations of outbred pigs (n = 206) and characterized a total of 19 SLA class II haplotypes, six of which were shared by at least three of the sampled pig populations. We found that Lr-0.1 (DRB1*01XX,DQB1*01XX,DQA*01XX) was the most prevalent haplotype with a combined frequency of 16.0%, followed by Lr-0.2 (DRB1*02XX,DQB1*02XX,DQA*02XX) with 14.6% and Lr-0.15b (DRB1*04XX,DQB1*0202,DQA*02XX) with 14.1%. Over 70% of the pigs (n = 147) had at least one copy of one of these three haplotypes. The PCR-based typing system described in this study demonstrates a reliable and unambiguous detection method for SLA class II alleles. It will be a valuable tool for studying the influence of SLA diversity on various immunological, pathological and physiological traits in outbred pigs. [source] Phenotyping approaches for physiological breeding and gene discovery in wheatANNALS OF APPLIED BIOLOGY, Issue 3 2009M. Reynolds Abstract Conceptual models of drought-adaptive traits have been used in breeding to accumulate complementary physiological traits (PT) in selected progeny, resulting in distribution of advanced lines to rain-fed environments worldwide by the International Maize and Wheat Improvement Center (CIMMYT). Key steps in PT breeding at CIMMYT include characterisation of crossing block lines for stress adaptive mechanisms, strategic crossing among parents that encompass as many target traits as possible and early generation selection (EGS) of bulks for canopy temperature (CT). The approach has been successful using both elite × elite crosses as well as three way crosses involving stress adapted landraces. Other EGS techniques that are amenable to high throughput include measurement of spectral reflectance indices and stomatal aperture-related traits. Their genetic- and cost-effectiveness are supported by realisation of genetic yield gains in response to trait selection, and by economic analysis, respectively. Continual reselection within restricted gene pools is likely to lead to diminishing returns, however, exotic parents can be used to introduce new allelic diversity. Examples include landraces from the primary gene pool, and products of inter-specific hybridisation with the secondary gene pool consisting of closely related wheat genomes. Both approaches have been successful in introducing stress-adaptive traits. The main problem with knowing which genetic resource to use in wide-crossing is the uncertainty with which phenotypic expression can be extrapolated from one genome/genepool to another because of their unimproved or undomesticated genetic backgrounds. Nonetheless, their PT expression can be measured and used as a basis for investing in crossing or wide crossing. Discovering the genetic basis of PT is highly complex because putative QTLs may interact with environment and genetic background, including genes of major effect. Detection of QTLs was improved in mapping populations where flowering time was controlled, while new mapping populations have been designed by screening potential parents that do not contrast in the Rht, Ppd and Vrn alleles. Association genetics mapping is another approach that can be employed for gene discovery using exclusively agronomically improved material, thereby minimising the probability of identifying yield QTLs whose alleles have been already improved by conventional breeding. [source] Variation in ecophysiology and carbon economy of invasive and native woody vines of riparian zones in south-eastern QueenslandAUSTRAL ECOLOGY, Issue 6 2010OLUSEGUN O. OSUNKOYA Abstract Exotic and invasive woody vines are major environmental weeds of riparian areas, rainforest communities and remnant natural vegetation in coastal eastern Australia, where they smother standing vegetation, including large trees, and cause canopy collapse. We investigated, through glasshouse resource manipulative experiments, the ecophysiological traits that might facilitate faster growth, better resource acquisition and/or utilization and thus dominance of four exotic and invasive vines of South East Queensland, Australia, compared with their native counterparts. Relative growth rate was not significantly different between the two groups but water use efficiency (WUE) was higher in the native species while the converse was observed for light use efficiency (quantum efficiency, AQE) and maximum photosynthesis on a mass basis (). The invasive species, as a group, also exhibited higher respiration load, higher light compensation point and higher specific leaf area. There were stronger correlations of leaf traits and greater structural (but not physiological) plasticity in invasive species than in their native counterparts. The scaling coefficients of resource use efficiencies (WUE, AQE and respiration efficiency) as well as those of fitness (biomass accumulated) versus many of the performance traits examined did not differ between the two species-origin groups, but there were indications of significant shifts in elevation (intercept values) and shifts along common slopes in many of these relationships , signalling differences in carbon economy (revenue returned per unit energy invested) and/or resource usage. Using ordination and based on 14 ecophysiological attributes, a fair level of separation between the two groups was achieved (51.5% explanatory power), with AQE, light compensation point, respiration load, WUE, specific leaf area and leaf area ratio, in decreasing order, being the main drivers. This study suggests similarity in trait plasticity, especially for physiological traits, but there appear to be fundamental differences in carbon economy and resource conservation between native and invasive vine species. [source] | |||||||||||||||||||||||||