Spatial autocorrelation in two Iris pumila populations estimated on morphological data from natural clones and their samples grown in two different habitats

Morphological data from two Iris pumila populations (measured on native clones, on their replants into the same habitat, and on their transplants into alternative habitat) were combined with native clones spatial position and spatial autocorrelations (SA) were calculated. Naturally growing I. pumila clones revealed significant SA that were positive on small distances and negative on medium ones in both open Hillock and shaded Woodland populations. No significant SA were detected when calculated with original clone positions, but with morphometric data from replants into the experimental plot in the same habitat. Some significant SA were, however, detected when morphometric data from transplants to alternative habitat were used. Detected SA on I. pumila clones were primarilly a consequence of spatial structuring of environmental factors but also, in lesser degree, a result of genetic spatial arrangements (most probably due to patterns of gene flow).     

Seasonal dynamics of foliar antioxidative enzymes and total anthocyanins in natural populations of Iris pumila L.

Aims Plants in their natural habitats frequently cope with a multitude of abiotic stresses, such as high light intensity, extreme temperatures and water deficit, which often co-occur during periods of drought, especially in semi-arid and arid regions. Exposure of plants to stressful environmental conditions usually induce overproduction of reactive oxygen species (ROS) that, as highly toxic derivatives of O 2, can assault all cell macromolecules, leading to the disruption of cellular homeostasis and, consequently, the uncoupling of major metabolic processes, the photosynthesis and photorespiration. In order to minimize ROS-mediated cellular damage, plants have evolved highly efficient antioxidative defense systems that include both enzymatic and non-enzymatic components. Since abiotic stress can also operate as a strong evolutionary force that shapes adaptations in natural plant populations, the aim of this study was to examine the seasonal variation patterns of two distinct antioxidative systems, ROS-scavenging enzymes and anthocyanin pigments, in the leaf tissue of a steppe plant, Iris pumila, as expressed under contrasting light conditions that the species regularly experiences in the wild.Methods We selected two natural populations of I.pumila inhabiting the alternative radiation environments in the Deliblato Sands, a sun-exposed dune site and a woodland understory. The specific activity of three antioxidative enzymes, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) and the content of total anthocyanins were examined in leaves of I.pumila plants collected from each of the 31 Iris clones (17 in the exposed population and 14 in the shaded population) once during each of the three seasons, spring, summer and autumn in 2004. Specifically, a fully expanded leaf was cut from each clonal plant between 15:00 and 16:00 h, immediately frozen in liquid nitrogen and stored at ?70°C until preparation.Important findings Generally, all three antioxidative enzymes were up-regulated in summer-harvested leaves compared to their spring or autumn counterparts, as was observed for the concentration of foliar anthocyanins, indicating that strengthening of antioxidant systems was the key mechanism for long-term acclimatization of I.pumila plants to stressful environmental conditions within their natural ecological niches. When plants from contrasting radiation environments were compared, SOD and CAT activities appeared to be greater in shade-exposed than in sun-exposed leaves. Conversely, POD activity and the content of foliar anthocyanins were notably higher in foliage experiencing full sunlight relative to those developed under vegetation canopy, suggesting the synergistic function of these two molecules in protecting leaf cells against photoinhibitory and photooxidative effects of strong light.     

Ontogenetic plasticity of anatomical and ecophysiological traits and their correlations in Iris pumila plants grown in contrasting light conditions

To better understand what directs and limits the evolution of phenotype, constraints in the realization of the optimal phenotype need to be addressed. That includes estimations of variability of adaptively important traits as well as their correlation structures, but also evaluation of how they are affected by relevant environmental conditions and development phases. The aims of this study were to analyze phenotypic plasticity, genetic variability and correlation structures of important Iris pumila leaf traits in different light environments and ontogenetic phases, and estimate its evolutionary potential. Stomatal density, specific leaf area, total chlorophyll concentration and chlorophyll a/b ratio were analyzed on I. pumila full‐sib families in the seedling phase and on the same plants after 3 years of growth in contrasting light conditions typical for ontogenetic stage in question. There was a significant phenotypic plasticity in both ontogenetic stages, but significant genetic variability was detected only for chlorophyll concentrations. Correlations of the same trait between different stages were weak due to changes in environmental conditions and difference in ontogenetic reaction norms of different genotypes. Ontogenetic variability of correlation structures was detected, where correlations and integration were higher in seedlings compared with adult plants 3 years later. Correlations were affected by environmental conditions, with integration being higher in the lower light conditions, but correlations between phases being stronger in the higher light treatment. These findings demonstrated that the analyzed traits can be selected and can mostly evolve independently in different environments and ontogenetic stages, with low genetic variability as a potentially main constraint.     

Outcrossing rates and organelle inheritance estimated from two natural populations of the Japanese endemic conifer Sciadopitys verticillata

The Japanese endemic conifer Sciadopitys verticillata is one of the most phylogenetically isolated species of all plants. Occurring in small and scattered populations, the species is currently classified as Near Threatened by the International Union for Conservation of Nature and Natural Resources (IUCN) and as Vulnerable in three prefectures of Japan. This study investigated two major factors that should impact the genetic structure of the species at both the nuclear and organelle DNA level, the mating system and the inheritance of both the chloroplast and mitochondrial genomes. The mating system is crucial to determining the degree of outcrossing of plant species and thus should have a key role in shaping the species’ population level genetic diversity and gene flow between populations but as yet has not been studied in S. verticillata. Nine mother trees and their seedling progeny from two natural populations were genotyped using genetic markers from three plant genomes (eight nuclear microsatellites and DNA sequence for the chloroplast and mitochondria). Using a maximum likelihood method implemented in the software MLTR, the study found an outcrossing rate in the seedling stage of 0.49 and 0.79 for Aburazaka and Mount Shirotori populations, respectively, and an average of 0.66 at the species level. These outcrossing rates were low for conifers and therefore may have potential deleterious implications for the conservation of the species. The test of organelle inheritance supported paternal transmission of both the chloroplast and mitochondria consistent with previous microscopic evidence.     

Physiological and morphological characterisation of Limonium species in their natural habitats: Insights into their abiotic stress responses

Background and aims

Morphological and biochemical traits of four halophytes of the genus Limonium were analysed in plants sampled from salt marshes in SE Spain. This work aimed to explore the mechanism(s) behind the adaptation of these species to stressful habitats, with particular emphasis on responses to drought.

Methods

Plants of each species together with soil samples were collected in summer, which is the most stressful season in the Mediterranean. Soil parameters and plant morphological traits were determined, and the levels of several biochemical stress markers in plants were measured using spectrophotometric assays. A multivariate analysis was performed to correlate soil and plant data.

Results

Morphological characteristics regarding the underground system topology and several biochemical traits (higher foliar Ca²⁺, sucrose and glucose, and lower proline, glycine-betaine and fructose) clearly separate L. santapolense individuals from plants of the other three species.

Conclusions

Drought tolerance of L. santapolense in the field is mostly dependent on morphological adaptations: when growing in an arid location, plants of this species develop long taproots that can extract water from the deep, moist layers of the soil.

     

Shoal choice and ultraviolet reflections in stickleback populations from different photic habitats

Grouping is a widespread phenomenon in the animal kingdom and the decision to join a group is a function of individual and environmental conditions, meaning that any advantages and disadvantages have to be pondered constantly. Shoaling decisions in fishes are communicated via a variety of factors, such as colour signals, amongst other ultraviolet (UV) signals. The sensitivity for ultraviolet signals is assumed to be costly and a function of the predominant ecological conditions. The island of North Uist, Scotland, comprises bodies of water that possess great variation in their spectral distribution, especially in the UV spectral range. We examined different populations of three‐spined stickleback (Gasterosteus aculeatus L.), which is known to use UV for visual tasks, consisting of three populations from tea‐stained lakes and four from clear‐water lakes, concerning their preferences to join a shoal viewed under UV‐present and UV‐absent conditions. Nonreproductively active sticklebacks from tea‐stained lakes significantly preferred the shoal under UV‐absent conditions, whereas sticklebacks from clear‐water lakes did not show a significant preference. Reflection measurements showed that the UV chroma (intensity) of sticklebacks from tea‐stained lakes was higher than that of sticklebacks from clear‐water, most likely contrasting maximally against the UV‐poor background or compensating for a stronger attenuation of the signal.     

盐胁迫对不同生境白榆生理特性与耐盐性的影响

以中强度盐土、轻度盐土和非盐土3种生境白榆种子实生苗为试验材料,研究了不同程度盐胁迫(CK、2、4、6、8和10 g·kg-1)条件下3种生境白榆幼苗的耐盐阈值及生理特性.结果表明:随着土壤盐浓度的增加,中强度和轻度盐土生境白榆幼苗叶片的细胞膜透性、Na+含量和Na+/K+增幅低于非盐土生境;叶片的脯氨酸、可溶性糖和K+含量增幅高于非盐土生境;叶片淀粉含量、净光合速率、蒸腾速率、胞间CO2浓度和气孔导度降幅小于非盐土生境.不同生境白榆耐盐性的强弱顺序为:中强度盐土生境(7.76 g·kg-1)＞轻度盐土生境(7.37g·kg-1)＞非盐土生境(6.95 g·kg-1).与非盐土生境相比,中强度和轻度盐土生境白榆各项生理指标对盐土环境的适应能力更强.     

The origin and fate of morphological intermediates between wild and cultivated soybeans in their natural habitats in Japan

The spread of transgenes into the genome of wild soybean is a concern when transgenic and wild soybeans are planted sympatrically. The objectives of this study were to investigate the origin and fate of morphological intermediates between wild and cultivated soybeans in their natural habitats in Japan. Twenty nuclear microsatellite and two chloroplast dCAPS markers were used to evaluate genetic variation of 468 wild, 17 intermediate, and 12 cultivated soybean samples collected from six sites between 2003 and 2006. Allelic differentiation of microsatellite markers between wild and cultivated soybeans was sufficient to detect their hybrids. Based on levels of observed heterozygosity, intermediate soybean plants were from two generations: either F₁ or an early segregating generation. Genetic admixture analysis and parentage assignment analysis revealed that the parents of all intermediate soybean plants could be assigned to a particular wild soybean plant and late‐maturing cultivar. The chloroplast DNA haplotypes revealed that all intermediate soybean plants originated from gene flow from cultivated to wild soybeans at all sites. Based on monitoring at both the phenotypic and molecular levels, hybrids quickly disappeared from natural habitats, and secondary gene flow from these plants to wild soybean was not detected. Thus, while gene flow from transgenic soybean into wild soybean can occur, gene introgression appears to be rare in natural habitats in Japan. This is the first report on the detection of gene flow from cultivated to wild soybean at the molecular level.     

Effect of Mn toxicity on morphological and physiological changes in two <Emphasis Type="Italic">Populus cathayana</Emphasis> populations originating from different habitats

The cuttings of Populus cathayana were exposed to four different manganese (Mn) concentrations (0, 0.1, 0.5 and 1 mM) in a greenhouse to investigate the toxicity of Mn and the detoxifying responses of woody plants. Two contrasting populations of P. cathayana, which were from wet and dry climate regions in western China, respectively, were examined in our study. The results showed that high concentration of Mn caused significant decrease in shoot height, biomass accumulation, and leaf number and leaf areas. Injuries to the anatomical features of leaves were also found as the reduced thickness of palisade and spongy parenchyma, the decreased density in the conducting tissue and the collapse and split in the meristematic tissue in the central vein. Moreover, Mn treatments caused the accumulation of hydrogen peroxide (H₂O₂), and then resulted in oxidative stress indicated by the oxidation of proteins and DNA. Many physiological responses were employed to cope with the toxicity of Mn, including the increase in the contents of non-protein thiol (NP-SH), phytochelatins (PCs) and phenolics compounds and the stimulated activities of guaiacol peroxidase (GPX) and polyphenol oxidase (PPO) for the chelation of Mn and for the antioxidation of reactive oxygen species. The population from dry climate habitat showed a lower leaf concentration of Mn, higher contents of the chelators, and higher activities of GPX and PPO than did the wet climate population at the same Mn treatment, thereby possessing a superior Mn tolerance. In both populations, most of the Mn was accumulated in the shoot, which is favorable regarding phytoremediation.     

Spatial and temporal patterns in the contribution of fish from their nursery habitats

Because anthropogenic influences threaten the degradation of many ecosystems, determining where organisms live during early life-history stages and the extent to which different areas contribute individuals to adult populations is critical for the management and conservation of a species. Working in Puget Sound, Washington State in the United States, and using a common flatfish (English sole, Parophrys vetulus), we sought to establish (using otolith chemistry) which areas contribute age-0 fish to age-1 population(s), the extent to which this pattern was consistent between two years, and whether this spatial pattern of contribution coincides with surveys of age-0 fish and/or the available area of nearshore habitat. Our study indicated completely different spatial patterns of fish nursery use between the two years of sampling. We highlight that the contribution of individuals from nursery areas is not related to density of recently settled English sole or the available area of nearshore habitat (depth <10 m) in Puget Sound, nor can we draw conclusions based on environmental data (precipitation, water salinity, light transmission, pH, dissolved oxygen, and water temperature). The results of this study highlight (1) the need for assessing the temporal patterns of nursery habitat use, and (2) that, in order to conservatively manage a species and its population(s), it may be necessary to protect several areas that are used intermittently by that species.     

Genetic variation among different populations of Aster tripolium grown on naturally and anthropogenic salt-contaminated habitats: implications for conservation strategies

The sea aster, Aster tripolium L., grows naturally in temperate regions, mainly in the salt meadows close to the coast. The species is also found in naturally and anthropogenically salt-contaminated inland habitats, such as potash mine dumps. The genetic relationships among populations from different habitats and correlations of the genotype with physiological and vegetational parameters were investigated. A. tripolium plants from five different sites close to the seashore on the North Sea island Baltrum, from five different potash mine dumps and, as an outgroup, from the seashore in Japan were probed. DNA was extracted from five plants from each of the 11 A. tripolium populations and analyzed for random amplified polymorphic DNA (RAPD). Altogether 35 polymorphic bands in 51 individuals and 45 different detectable genotypes could be identified. For evaluation of the genetic variation using RAPD bands, the neighbor-joining method, the principal coordinate analysis, and the analysis of molecular variance were applied, resulting in the classification into three genetic groups. A. tripolium plants from different ecological habitats on Baltrum were closely related while the plants growing at the deposit dumps showed a higher genetic diversity. The Japanese population was genetically very different from the German populations. Correlations between phytosociological and soil parameters and the respective genotype were not significant. The results argue for a conservation of anthropogenically salt-contaminated habitats to maintain genetic variability not only on the species level, but also within a species.     

Dominance and environmental variances: their effect on heritabilities estimated from twin data

A method for partitioning genetic variance estimated from twin data into additive and dominance variances was presented using Falconer's variance component model. The effects of dominance and environmental variances on a number of heritability estimates were also reviewed. A heritability estimate, based on the analysis of variance and the genetic variance estimates presented by HASEMAN and ELSTON and CHRISTIAN et al. which utilizes all available information from twin data, was proposed and discussed. This estimate seems to be the least affected by fluctuations in the magnitudes of dominance and environmental variances.     

Plasticity of growth rate and metabolism in Daphnia magna populations from different thermal habitats

The aim of this study was to evaluate the effect of temperature on growth and aerobic metabolism in clones of Daphnia magna from different thermal regimes. Growth rate (increment in size), somatic juvenile growth rate (increment in mass), and oxygen consumption were measured at 15 and 25 degrees C in 21 clones from one northern and two southern sites. There were no significant differences in body size and growth rate (increase in length) at both 15 and 25 degrees C among the three sites. Clones from southern site 2 had a higher mass increment than clones from the other two sites at both temperatures. Clone had a significant effect on growth (body length) and body size at both temperatures. As expected, age at maturity was lower at 25 degrees C (4.5 days) than at 15 degrees C, (11.6 days) and body sizes, after the release of the third clutch, were larger at 15 degrees C than at 25 degrees C. Northern clones had higher oxygen consumption rates and specific dynamic action (SDA) than southern clones at 15 degrees C. By contrast, southern clones from site 1 had a higher oxygen consumption and SDA than subarctic clones at 25 degrees C. Clones from southern site 2 had high oxygen consumption rates at both temperatures. Our results reveal important differences in metabolic rates among Daphnia from different thermal regimes, which were not always reflected in growth rate differences.     

Shoot density of Miscanthus sinensis populations in different habitats and their maintenance mechanisms in relation to shoot growth

Journal of Plant Research - How perennial grass populations are maintained in different climates is poorly understood at the level of individual shoots (ramets). During the years 1982–1987...     

Phenotypic and genotypic variation of Phragmites australis: A comparative study of clones originating from two populations of different age

Populations of common reed (Phragmites australis [Cav.] Trin. Ex Steud.) were studied in the littoral zones of two human-made lakes in the Třeboň Basin (South Bohemia, Czech Republic): (1) Opatovický fishpond, a 500-year-old fishpond, and (2) Halámky sand pit, a new lake formed by sand extraction in the 1970–1990s. Clones were identified using the RAPD method within morphologically different stands. The clones were propagated vegetatively and cultivated under comparable conditions in a common garden experiment for one vegetation season. Morphological and growth characteristics of the cultivated plants were recorded and compared with those found in the original reed stands. The younger (30-year old) population was genotypically more diverse than the older (500-year old) population. In addition, the younger population demonstrated correspondence of genotypic and phenotypic variation, while the older did not. The results indicate that the genetically determined morphological features (especially shoot length) are manifested more fully in the phenotype of the plants of the younger (Halámky) population, whereas environmental factors affect the phenotype to a greater extent in the older (Opatovický) population.     

Distribution of fungi on two mite species and their habitats in Egypt

Fungi associated with two mite species,Acotyledon krameri andTyrophagus putrescentiœ, and their habitats were studied using 1% glucose-Czapek's and potato-dextrose agar media at 28±2°C. A total of 54 species and one variety belonging to 25 genera were recovered from different habitats of mite species; 36 species and one variety belonging to 18 genera were associated with mite bodies. Nearly most fungal species isolated from mite bodies were also encountered in their habitats. The most common species wereAspergillus flavus, A. fumigatus, A. niger, Mucor racemosus, Nectria hœmatococca. A. terreus, Scopulariopsis brevicaulis andTrichurus spiralis were isolated only from mite bodies whereasFusarium oxysporum, Penicillium chrysogenum, P. corylophilum, P. funiculosum andRhizopus stolonifer were recovered from the mite habitats.A. krameri individuals survived well onCunninghamella elegans, F. oxysporum andM. racemosus cultured on both type of media, whereasCylindrocarpon destructans was best forT. putrescentiœ survival.     

Variation in performance on two grape cultivars within and among populations of grape Phylloxera from wild and cultivated habitats

When an indigenous insect becomes a pest, comparisons of performance of pest and non-pest populations on crop plants and of genetic variation in that performance may provide insight into the evolution of pest populations. To measure such genetic variation, 8–15 clones of the grape phylloxera (Daktulosphaira vitifoliae Fitch) were collected from wild grapevines in each of 3 geographically isolated sites (populations) and from commercial vineyards in northern California. A complete life table was made for clonal replicates from populations collected from wild grapevines on each of two commercial grape cultivars, the susceptibleVitis vinifera (L.) cultivar Cabernet Sauvignon, and the phylloxera-resistant rootstock ‘AxR # 1’. Variation in mean performance on these two hosts was partitioned among clones within collection sites and among sites. Performance measures included an individual analog to the intrinsic rate of increase (r), age at first oviposition, fecundity in the first ten days of reproduction, total fecundity, and longevity. The overall performance of phylloxera from the wild grapevines on the resistant cultivar AxR # 1 was greater than or equal to that on the susceptible cultivar Cabernet Sauvignon. There was significant variation among clones within populations from wild grapes in the rate of increase on ‘AxR # 1’ and marginally significant clonal variation in some of the component paramters. There was no significant variation among clones within populations on ‘Cabernet Sauvignon’ and no significant differences between populations on either crop in any trait. In a second experiment we compared the relative performance of 15–17 clones from wild grapevines and from commercial vineyards when reared on ‘Cabernet Sauvignon’ and ‘AxR # 1’. Phylloxera from commercial vineyards had much higher overall performance on ‘Cabernet Sauvignon’ than did phylloxera from the wild grapevines. Phylloxera from the commercial vineyard also had higher performance on ‘Cabernet Sauvignon’ than on ‘AxR′ 1’ but the performance of the phylloxera from wild and commercial grapes did not differ on ‘AxR # 1’. Our results show that there is genetic variation in traits related to performance on a resistant rootstock within these indigenous non-pest populations of phylloxera, but not among them. The pattern of performance of pest and non-pest populations on two commercial cultivars suggests that current levels of phylloxera performance on crop cultivars are the result of adaptation to those cultivars which has occurred while phylloxera has been associated with viticulture. Implications of these results for understanding the recent adaptation of phylloxera to ‘AxR # 1’ in California are also discussed.     

蒙古沙拐枣种群形态和同工酶变异的比较研究

调查和测定了中国西北荒漠地区的蒙古沙拐枣(Calligomum mongolicum Turcz)5个种群的形态学指标,应用方差分析(MANOVA)、主成分分析(PCA)和聚类分析,对种群间及种群内的形态性状进行研究。结果表明,种群间的形态变异差异显著。植株高度、种子刺毛长度和种子重量指标具有较强的形态差异性分析意义。形态差异(欧氏距离)与种群间基因流动(地理距离)间没有发现相关关系。聚类分析结果表明,种群M1与M2亲缘关系最近,种群M5与其他种群的亲缘关系相对较远;采用垂直板聚丙烯酰胺电泳技术对5个种群的3个酶系统进行了遗传多样性分析,结果表明,种群M5与其他种群的遗传一致度稍低(0．8197～0．8902)以外,其余各种群遗传一致度较高(0．8480～0．9505),体现其亲缘关系较近。依据Nei的遗传距离进行聚类,结果与形态聚类结果有一定的相似性。     

不同生境下青海湖裸鲤(Gymnocypris przewalskii)两亚种鳃形态差异及其功能适应

该研究比较观察青海湖裸鲤(Gymnocypris przewalskii)两亚种(青海湖裸鲤指名亚种(Gymnocypris przewalskii przewalskii)和青海湖裸鲤甘子河亚种(Gymnocypris przewalskii ganzihonensis))鳃的形态及显微结构。结果显示,指名亚种的第一鳃弓鳃耙数多、密集且较长,而甘子河亚种则耙数少、稀疏且短;两者的鳃丝间距及鳃小片间距无明显差异,指名亚种的鳃丝较长;指名亚种扁平上皮细胞形态以不规则椭圆形为主,鳃丝表面有黏液细胞,其上分布的氯细胞数量多于甘子河亚种,而甘子河亚种扁平上皮细胞的形态以六边形为主,鳃丝表皮未观察到黏液细胞。由此推测,青海湖裸鲤两亚种鳃形态的差异与其食性和栖息环境相适应。     

达赉湖自然保护区冬春季鸟类生物多样性与生境的关系

2004年4月-5月,利用样带法对达赉湖自然保护区5种主要生境类型中冬春季鸟类生物多样性进行了调查,利用Shannon-Wiener指数和Smith相关性系数分析了这5种生境类型中冬春季鸟类的生物多样性、区系、鸟类的群落组成、群落间的相似性和均匀度。结果表明,古北界鸟类是组成达赉湖鸟类群落的主体(约占冬春季鸟类的86%);芦苇湿地的鸟类多样性接近于芦苇甸的2倍:芦苇湿地鸟类群落的物种多样性最高(Shannon-Wiener指数为1.3001),而芦苇甸中鸟类群落的物种多样性最低(Shannon-Wiener指数为0.6629);芦苇湿地和芦苇甸两鸟类群落组成的相关性指数仅为0.038;从具有共同物种的多少考虑,典型草原和芨芨草原鸟类群落之间的关联较大。