Phenotypic Plasticity Index Research Articles

Estuarine conditions more than pH modulate the physiological flexibility of mussel Perumytilus purpuratus populations

Coasts and their marine biota are exposed to major environmental heterogeneity as a consequence of natural drivers and anthropogenic stressors. Here, individuals of the mussel Perumytilus purpuratus from two different geographical populations exposed to contrasting environmental conditions (i.e. estuarine versus open coastal conditions) were used in a reciprocal transplant and a laboratory experiment with the aim of determining the grade of of local adaptation to their native sites, as well as their sensibility to ocean acidification. After characterizing environmentally the coastal habitats, a set of life-history traits and a phenotypic plasticity index were determined for both mussel populations. From the reciprocal transplant experiment, we observed that mussels originally coming from the estuarine habitat exhibited a distinctive performance pattern usually associated with physiological stress (i.e. higher metabolic rates, lower calcification and growth rates) leading to important physiological trade-offs and higher levels of phenotypic plasticity. Alternatively, mussels originating from the open coastal site showed lower physiological phenotypic plasticity suggesting a high grade of local adaptation to their habitat. In addition, both populations responded very similarly to lower pH conditions (i.e. increased metabolic rates with no important effects on growth and calcification, and lower physiological phenotypic plasticity). The study results indicated that overall estuarine conditions more than isolated pH changes would be modulating the performance and the level of phenotypic plasticity of the two P. purpuratus geographical populations studied. Our study also emphasizes the necessity of characterizing phenotypic plasticity under multiple-driver environments to cast more accurate predictions about the susceptibility of marine biota to future climate stressors such as ocean acidification.

The effect of nitrogen and temperature changes on Solidago canadensis phenotypic plasticity and fitness

AbstractPhenotypic plasticity is commonly considered to contribute to the invasion success of invasive species. However, the importance of phenotypic plasticity, nitrogen (N) levels and warming to the invasion of invasive species is unclear. The effects of warming and N addition on the morphology, biomass allocation and biochemistry traits of Solidago canadensis and their plasticity were investigated by conducting a pot experiment. The results showed that the effect of N addition on biomass was improved for S. canadensis; whereas warming displayed no significant effect, their positive synergistic interact effect resulted in the overall significant increase in plant performance. The mean phenotypic plasticity indices (MPPI) of biochemistry and total parameters demonstrated a difference between operations, and the higher value was observed in N interaction with temperature treatments than N addition or warming alone. The observed MPPI indicated the biochemistry parameters > morphological parameters > allocation parameters. The MPPI of biochemistry parameters, morphological parameters and total parameters exhibited significant and positive correlations with N level and MPPI of morphological parameters was also significantly positively correlated with the fitness of S. canadensis. These results indicated that the global warming and N addition would make the invaded habitat more suitable for the growth of invasive S. canadensis, and even may effectively increase the invasion risk of S. canadensis through the enhanced phenotypic plasticity, which is a crucial factor to help species deal with the changing environment.

Phenotypic diversity and plasticity index of Eurycoma apiculata populations in Eastern Sumatra, Indonesia based on leaves morphology

Abstract. Zulfahmi, Purwanto E, Parjanto, Yunus A. 2020. Phenotypic diversity and plasticity index of Eurycoma apiculata populations in Eastern Sumatra, Indonesia based on leaves morphology. Biodiversitas 21: 2923-2934. Eurycoma apiculata A.W. Benn. is a protected species in Indonesia, but diversity information of this species is limited. The objective of this study was to assess the phenotypic diversity, phenotypic plasticity index, and phenotypic differentiation among populations of E. apiculata in Eastern Sumatra, Indonesia based on leaves morphology. A total of 45 traits were measured on leaves from six populations studied. The result of this found that the phenotypic variation coefficient (CV) of the characters was ranged from 7.41% to 36.97%, revealed the abundant phenotypic variation in the species. The phenotypic CV values of the population varied from 13.95% to 24.10%. The CV values of all populations from the mainland Sumatra (17.75%) were lower than that from the Riau archipelago (23.61%), which revealed that phenotypic traits in mainland Sumatra were more stable compared to populations in the Riau archipelago. The population phenotypic plasticity index value of populations ranged from 0.41 to 0.51, and it was classified as a moderate level. The phenotypic differentiation coefficient among populations in this study was relatively low (VST = 21.06%), indicating a lower phenotypic variation among populations than within populations. The scatter plot of principal component analysis and UPGMA dendrogram divided the six populations studies into two groups. The findings of this study recommend that the in-situ conservation method is an effective protection strategy for E. apiculata while ex-situ conservation method can be implemented as a supplementary method.

Effect of Cadmium Dietary Intake on Midgut β-Glucosidase of Lymantria dispar Larvae

A crucial enzyme in feeding and survival of Lymantria dispar (gypsy moth) caterpillars is β-glucosidase. Considering that this herbivorous species is one of the most damaging pests, a study of the enzyme that hydrolyzes plant polysaccharides is of invaluable significance. The knowledge of glucosidase alterations helps clarify our understanding of the insect pest feeding strategy in highly polluted environments. We sought to find out whether acute and chronic exposures to cadmium (10 and 30 mg Cd/g dry food), as well as the recovery from long-term treatment, influence the specific activity of midgut β-glucosidase. Cadmium ingestion did not alter enzyme activity compared to control, regardless of the treatment duration and metal concentration. The only statistically significant increase in enzyme activity was detected during the recovery after chronic treatment at 10 mg Cd/g dry food compared to the chronic cadmium effect at the same metal concentration. During chronic treatment at a lower cadmium concentration (10 mg Cd/g dry food), the phenotypic plasticity index was higher than at the recovery from the same concentration, while the variability of plasticity among these treatments was higher after recovery. Only one enzyme isoform was detected, which indicates its ability to hydrolyze several substrates. We concluded that this enzyme is probably essential for larval nutrition and survival in the presence of high amounts of cadmium in the food.

Response strategies of Acer davidii to varying light regimes under different water conditions

Phenotypic plasticity is crucial for adaptation of plants to complex environmental gradients. It is not clear as to how phenotypic plasticity in response to a certain environmental factor is affected by another ecological factor. Water and light are important factors affecting the phenotype of plants. The interactive effects between drought and shade on plants differ markedly among studies. To address these questions, we subjected Acer davidii Franch. seedlings to five water regimes, combined with two light intensities. Drought decreased all growth and biomass parameters, and all leaf and root traits measured, and increased the root to shoot ratio and root biomass ratio. Shade decreased the shoot height, the diameter at ground height, the root surface area, and all biomass parameters, and increased leaf water content, leaf area ratio, specific leaf area, and total chlorophyll concentration. Significant interactive effects were found on all biomass parameters, half of the growth parameters, and most of the leaf and root traits; shade generally alleviated the negative effects on A. davidii seedlings to some extent. The simplified relative distance phenotypic plasticity indices (RDPIs) of A. davidii responding to light increased with the increase in soil water content whereas no significant trend was observed between the RDPIs and the light regime. The RDPIs of all growth parameters, average leaf area, and all biomass allocation parameters in response to water were greater than those of light. Phenotypic plasticity of one environmental factor might be affected by another across complex environmental conditions.

Phenotypic plasticity of stomatal and photosynthetic features of four Picea species in two contrasting common gardens.

Global climate change is expected to affect mountain ecosystems significantly. Phenotypic plasticity, the ability of any genotype to produce a variety of phenotypes under different environmental conditions, is critical in determining the ability of species to acclimate to current climatic changes. Here, to simulate the impact of climate change, we compared the physiology of species of the genus Picea from different provenances and climatic conditions and quantified their phenotypic plasticity index (PPI) in two contrasting common gardens (dry vs. wet), and then considered phenotypic plastic effects on their future adaptation. The mean PPI of the photosynthetic features studied was higher than that of the stomatal features. Species grown in the arid and humid common gardens were differentiated: the stomatal length (SL) and width (SW) on the adaxial surface, the transpiration rate (Tr) and leaf mass per area (LMA) were more highly correlated with rainfall than other traits. There were no significant relationships between the observed plasticity and the species’ original habitat, except in P. crassifolia (from an arid habitat) and P. asperata (from a humid habitat). Picea crassifolia exhibited enhanced instantaneous efficiency of water use (PPI = 0.52) and the ratio of photosynthesis to respiration (PPI = 0.10) remained constant; this species was, therefore, considered to the one best able to acclimate when faced with the effects of climate change. The other three species exhibited reduced physiological activity when exposed to water limitation. These findings indicate how climate change affects the potential roles of plasticity in determining plant physiology, and provide a basis for future reforestation efforts in China.

Variation of phenotypic responses to lighting using a combination of red and blue light-emitting diodes versus darkness in seedlings of 18 vegetable genotypes

The objectives of this study were to identify traits and screen genotypes sensitive to narrow-waveband light-emitting diode light in 18 vegetable genotypes. Their phenotypic plasticity responses were examined under a combination of red (85%) and blue (15%) light-emitting diodes relative to darkness from seed germination to cotyledon unfolding. The photosynthetic photon flux density was around 316 μmol m−2s−1and the photoperiod was 17 h. Generally, light vs. dark delayed germination by reducing germination rate and increasing spread time of germination; inhibited shoot growth by reducing shoot length and fresh mass; promoted root growth by increasing root length, diameter, branching, and fresh mass; and promoted genotype-inherent colouring in leaves and stems. Shoot colour, shoot length, and (or) root branching showed higher plasticity indices than other plant traits in response to light, suggesting that some or all of these plant traits are more sensitive to lighting across the tested genotypes. Using cluster analysis based on the plasticity index, the 18 genotypes were separated into six groups that expressed response sensitivity to part or all of the above-mentioned traits. Based on the average plasticity index of all the tested plant traits, the 18 genotypes were graded into four groups using the Fisher optimal partition. Small- vs. large-seed species and the red- vs. green-leaf/root cultivars within the same species showed higher phenotypic plasticity indices in most cases, suggesting that they are more sensitive to lighting.

Simulated climate change deferentially impacts phenotypic plasticity and stoichiometric homeostasis in major food crops

Grain yield and product quality responses of major food crops to variation in resource availability continue to be important considerations in agronomic research, particularly under abiotic stresses. Indices of grain quality and phenotypic plasticity of crop cultivars with C3 or C4 metabolic pathways and producing seed with either carbohydrate, protein, oil; or a combination of carbohydrate-protein or oil-protein as their major product, were quantified for six years under two phases of single and multiple abiotic stresses. Decreasing resource availability caused by short growing season and high population density, singly or in combination, resulted in significant changes in allometric relationships among most traits under study. Temporal quantitative and qualitative differences between “heatmaps” of stress phases, partitioning and analysis of total variance due to fixed and random factors, and functional relationship at hierarchical levels of organization, indicated a shift over time of phenotypic plasticity and quality indices. Moreover, relationships of phenotypic plasticity and quality index with biomass, grain yield, macro- and micronutrients, and nutrient ratios were largely modulated by differences between crop products within metabolic pathways. However, further research is needed for in-depth understanding and insights into the interdependencies of the large number of traits that crop plants should optimize to produce economic yield combined with adequate nutritional quality under abiotic stress.

Phenotypic plasticity of life-history traits of a calanoid copepod in a tropical lake: Is the magnitude of thermal plasticity related to thermal variability?

According to the Climatic Variability Hypothesis [CVH], thermal plasticity should be wider in organisms from temperate environments, but is unlikely to occur in tropical latitudes where temperature fluctuations are narrow. In copepods, food availability has been suggested as the main driver of phenotypic variability in adult size if the range of temperature change is less than 14°C. Leptodiaptomus garciai is a calanoid copepod inhabiting Lake Alchichica, a monomictic, tropical lake in Mexico that experiences regular, narrow temperature fluctuations but wide changes in phytoplankton availability. We investigated whether the seasonal fluctuations of temperature and food produce phenotypic variation in the life-history traits of this tropical species. We sampled L. garciai throughout a year and measured female size, egg size and number, and hatching success, along with temperature and phytoplankton biomass. The amplitude of the plastic responses was estimated with the Phenotypic Plasticity Index. This index was also computed for a published dataset of 84 copepod populations to look if there is a relationship between the amplitude of the phenotypic plasticity of adult size and seasonal change in temperature. The temperature annual range in Lake Alchichica was 3.2°C, whereas phytoplankton abundance varied 17-fold. A strong pattern of thermal plasticity in egg size and adult female size followed the inverse relationship with temperature commonly observed in temperate environments, although its adaptive value was not demonstrated. Egg number, relative reproductive effort and number of nauplii per female were clearly plastic to food availability, allowing organisms to increase their fitness. When comparing copepod species from different latitudes, we found that the magnitude of thermal plasticity of adult size is not related to the range of temperature variation; furthermore, thermal plasticity exists even in environments of limited temperature variation, where the response is more intense compared to temperate populations.

Path analysis of phenotypic traits in young cacao plants under drought conditions.

Drought is worldwide considered one of the most limiting factors of Theobroma cacao production, which can be intensified by global climate changes. In this study, we aimed to investigate the phenotypic correlation among morphological characteristics of cacao progenies submitted to irrigation and drought conditions and their partitions into direct and indirect effects. Path analysis with phenotypic plasticity index was used as criteria for estimation of basic and explanatory variables. The experiment was conducted in a greenhouse at the Cacao Research Center (CEPEC), Ilhéus, Bahia, Brazil, in a randomized block 21 x 2 factorial arrangement [21 cacao progenies obtained from complete diallel crosses and two water regimes (control and drought)] and six replications. In general, drought conditions influenced biomass production in most progenies, causing significant reductions in total leaf area, leaf number, leaf biomass, fine-roots length (diameter <1 mm), root volume and root area for considered drought intolerant. All progenies showed alterations in growth due to drought. Phenotypic plasticity was most strongly pronounced in root volume. Stem and root diameters, as well as stem dry biomass were the growth variables with the greatest direct effects on root volume under drought conditions, these characters being indicated in screening of cacao progenies drought tolerant.

川西林线交错带岷江冷杉幼苗异龄叶形态对长期模拟增温的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 川西林线交错带岷江冷杉幼苗异龄叶形态对长期模拟增温的响应 DOI: 10.5846/stxb201708031393 作者: 作者单位: 四川农业大学,旺苍县林业和园林局,河南大学生命科学学院,甘肃农业大学林学院,四川农业大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31670477） Long-term warming effects on leaf traits of different-aged needles of Abies faxoniana seedlings in a treeline ecotone in western Sichuan Author: Affiliation: Sichuan Agricultural University,,,,Sichuan Agricultural University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:全球气候变暖对高纬度、高海拔地区的植物形态产生强烈影响。川西林线交错带是青藏高原东部高寒生态系统的重要组成部分，对全球变化极度敏感。以川西林线交错带岷江冷杉（Abies faxoniana）幼苗异龄叶为对象，采用原位开顶式生长室（Open-top chamber，OTCs）模拟增温，研究了长期模拟增温下岷江冷杉幼苗异龄叶片叶长、叶厚等叶形态的响应，采用表型可塑性指数和变异系数对叶形态的可塑性进行分析。结果表明：增温限制岷江冷杉幼苗叶片的增长、增宽和叶面积、体积的扩大，使叶长、叶宽、叶面积、叶体积分别较对照减小12.77%、11.86%、17.76%、11.49%；增温促进叶片厚度的增加，较对照增加7.27%；除叶长宽比外，增温对其余叶形态均产生显著影响（P < 0.05）。叶形态对模拟增温的响应具有显著的年龄差异（P < 0.05）。温度、叶龄的交互效应对叶长和叶面积影响显著（P < 0.05），对叶宽和叶厚影响不显著（P > 0.05）。两种表型可塑性分析结果表明，除1 a叶叶长外，增温不同程度增大各叶形态可塑性。长期增温使冷杉幼苗叶片有旱生倾向且形态值更发散。研究提供了岷江冷杉幼苗叶片对长期增温的差异性响应证据，为评估青藏高原东缘优势植物对响应气候变暖提供了基础数据和理论参考。 Abstract:Global warming has a strong effect on plant traits at high latitudes and high altitudes. To explore plant adaptability to global warming, more ecologists focus on the responses of leaf traits to warming, because the leaf is the key photosynthetic organs and sensitive to climat change. Previous studies have proved that warming directly influenced the plant leaf area, leaf life, phenology, and lateral growth. More evidence has shown that the responses of leaf traits to warming is highly species-specific. However, none of these studies included specific leaf traits or focused on the effects of long-term warming. In generally, different leaf traits respond differently to simulated warming, and these provide insights into how key plant speceis adapt to climate change. Abies faxoniana is one of the important woody species in subalpine coniferous forests. Could A. faxoniana expand to a higher altitude region (e.g. treeline ecotone) in the future climate warming scenario? Therefore, we used in situ open-top chambers to simulate warming and study the long-term effects of warming on leaf traits (leaf length, leaf width,and leaf thickness) and leaf plasticity at different ages (annual, biennial, and triennial) of A. faxoniana seedlings. The goals of this study were to determine how A. faxoniana changed their leaf traits and corresponding plasticity under simulated warming conditions.The results showed that simulated warming had a negative effect on the length, width, volume, and area of needles (reduced 12.77%, 11.86%, 11.49%, and 17.76%, respectively), whereas simulated warming had a positive effect on leaf thickness (increased 7.27%, P < 0.05). The responses of leaf traits to simulated warming had a significant differences in the age (P < 0.05). Combined the effects of simulated warming and leaf age, leaf length, and leaf area had been changed significantly (P < 0.05), whereas the reponses of leaf width and leaf thickness to simulated waming were the opposite. Phenotypic plasticity index (PPI) and coefficient of variation (CV) showed that simulated warming promoted the plasticity of leaf traits, leaf length of the annual leaves excepted. However, there were significant inter-annual differences in the effects of warming on leaves of different ages. In summary, the present study suggests that A. faxoniana seedlings leaves could adapt to global warming via regulating leaf traits to enhance its plasticity. 参考文献 相似文献 引证文献

Morphoanatomical plasticity of Tibouchina clavata (Melastomataceae) in ombrophilous forest and restinga forest

Structural adjustments in plants may occur in response to environmental constraints, which may influence plant growth and development, as well as patterns of species coexistence. The present study aimed to evaluate the plastic responses of Tibouchina clavata (Melastomataceae) occurring in two forest formations governed by different environmental conditions. Ten leaves of ten individuals were collected in each formation, for a total of n = 100 per area. as were stem samples, for measuring architectural, morphological and foliar traits. Environmental variables considered included edaphic nutrition, water availability and light radiation. The phenotypic plasticity index was calculated for each trait. Morphoanatomical traits varied among populations with greater emphasis on plant height and stem diameter, in contrast to the lower variation observed for leaf traits. Foliar morphoanatomy met the expected pattern for plants that grow under conditions of greater luminosity. Greater development of the aerial system (height and diameter of the stem) was observed in the plants of the ombrophilous forest, indicating that this growth is related to the soil fertility and water availability. The phenotypic plasticity index indicates low plasticity for T. clavata in the geographic distribution studied.

Short-term physiological plasticity: Trade-off between drought and recovery responses in three Mediterranean Cistus species.

Short‐term physiological plasticity allows plants to thrive in highly variable environments such as the Mediterranean ecosystems. In such context, plants that maximize physiological performance under favorable conditions, such as Cistus spp., are generally reported to have a great cost in terms of plasticity (i.e., a high short‐term physiological plasticity) due to the severe reduction of physiological performance when stress factors occur. However, Cistus spp. also show a noticeable resilience ability in response to stress factors. We hypothesized that in Cistus species the short‐term physiological response to stress and that to subsequent recovery can show a positive trade‐off to offset the costs of the photosynthetic decline under drought. Gas exchange, chlorophyll fluorescence, and water relations were measured in C. salvifolius, C. monspeliensis, and C. creticus subsp. eriocephalus during an imposed experimental drought and subsequent recovery. Plants were grown outdoor in common garden conditions from seeds of different provenances. The short‐term physiological response to stress and that to recovery were quantified via phenotypic plasticity index (PIstress and PIrecovery, respectively). A linear regression analysis was used to identify the hypothesized trade‐off PIstress–PIrecovery. Accordingly, we found a positive trade‐off between PIstress and PIrecovery, which was consistent across species and provenances. This result contributes in explaining the profit, more than the cost, of a higher physiological plasticity in response to short‐term stress imposition for Cistus spp because the costs of a higher PIstress are payed back by an as much higher PIrecovery. The absence of leaf shedding during short‐term drought supports this view. The trade‐off well described the relative variations of gas exchange and water relation parameters. Moreover, the results were in accordance with the ecology of this species and provide the first evidence of a consistent trade‐off between the short‐term physiological responses to drought and recovery phases in Mediterranean species.

Plasticidade da folha e lenho de cinco espécies lenhosas em duas áreas de restinga no Sul do Brasil

This study examined comparatively the plasticity of five “lenhosas” species occurring in two areas of salt marsh in Santa Catarina State, as follow: Clusia criuva Cambess., Myrsine venosa A. DC., Ocotea pulchella (Nees e Mart.) Mez, Pera glabrata (Schott) Poepp. Ex Baill and T ernstroemia brasiliensis Cambess . Functional attributes of leaf and stem were measured, and in the fi eld trees’ height and diameter were taken at breast height. The environmental heterogeneity was characterized by chemical analysis of the soil, thickness of litter and gravimetric moisture. For each morphological and anatomical attribute the phenotypic plasticity index was calculated. Leaf traits showed variation among the areas in all studied species, especially regarding specifi c leaf area. Wood attributes changed little, showing a higher inheritability of characters or similar responses to the water condition from the point of view of water resources’ use of. The results corroborate to other studies indicating that leaf is more plastic to habitats variations

Seedling response to environmental variability: The relationship between phenotypic plasticity and evolutionary history in closely related Eucalyptus species.

Phenotypic plasticity is an important means through which organisms cope with environmental variability. We investigated seedling plasticity in the green ash eucalypts within a phylogenetic framework to examine the relationship between plasticity and evolutionary history. The green ashes are a diverse group, which include the tallest flowering plant in the world (Eucalyptus regnans) and a rare mallee less than 1 m tall (E. cunninghamii). Seedlings of 12 species were exposed to high and low nutrient and water availability in a factorial experiment. Leaf trait and total plant plasticity were evaluated using the phenotypic plasticity index. A phylogeny of the species was estimated using genome-wide scans. We found significant differences in functional traits across species, growth forms, and substrates in response to changes in resource availability. Many traits (e.g., leaf width) were highly plastic for most species. Interspecific differences in leaf-level plasticity was significant, however plasticity was not correlated with phylogeny. Species with broader environmental niches had higher leaf-level plasticity than species with narrower environmental ranges. Plastic responses to environmental variability can differ widely among closely related species, and plasticity is therefore likely to be associated with many factors, including habitat and range size, as well as evolutionary history. Our results provided insights for species delimitation in Eucalyptus, which have management implications. Because of the high number of rare species and that other species are commercially important, a more comprehensive understanding of plasticity is essential for predicting their response to changing climates.

Plasticidade morfoanatômica foliar de Tibouchina clavata (Melastomataceae) ocorrente em duas formações de restinga

Resumo Respostas plásticas em plantas podem ser induzidas pela heterogeneidade espacial, sendo a restinga um ecossistema favorável á compreensão dessas respostas em função das condições ambientais limitantes que apresenta. O presente estudo avaliou de forma comparada as respostas plásticas foliares em duas populações de Tibouchina clavata (Melastomataceae) habitando as formações herbácea e florestal da restinga do Parque Estadual Acaraí, localizada em São Francisco do Sul-SC. Nos dez indivíduos amostrais de cada formação foram mensurados atributos morfoanatômicos foliares e do caule. Variáveis ambientais como nutrição edáfica, umidade gravimétrica e radiação luminosa foram mensuradas. As médias obtidas para cada variável foram comparadas pelo teste t de Student. Para cada atributo, foi calculado o índice de plasticidade fenotípica. Atributos morfológicos e anatômicos diferenciaram as duas populações entre si, sendo a população da formação herbácea tipicamente xeromórfica em função das condições ambientais mais restritivas. Condições mais favoráveis dadas pela maior oferta de nutrientes e água no ambiente florestal proporcionaram maior investimento dos indivíduos em crescimento. Atributos anatômicos mostraram-se pouco plásticos quando comparados aos morfológicos. T. clavata demonstrou ser uma espécie morfologicamente plástica que permite a compreensão dos efeitos dos fatores limitantes da restinga sobre o desenvolvimento vegetal, com destaque ás condições nutricional, hídrica e lumínica que induzem ao xeromorfismo.

Plant responses to simulated warming and drought: a comparative study of functional plasticity between congeneric mid and high elevation species

Aims: Effects of climate change, especially changes in temperatures and precipitation patterns, are particularly pronounced in alpine regions. In response, plants may exhibit phenotypic plasticity in key functional traits allowing short-term adjustment to novel conditions. However, little is known about the degree of phenotypic plasticity of high elevation species relative to mid elevation congeners. Methods: We transplanted 14 herbaceous perennial species from high elevation into two common gardens (1050 and 2000 m.a.s.l.) in the Swiss Alps, and we examined plastic responses in key functional traits to changes in temperature and soil water availability. This design was replicated with 14 congeneric species from mid elevation to assess if the degree of phenotypic plasticity differs between mid and high elevation species. Survival was assessed across two growing seasons, while aboveground biomass and specific leaf area (SLA) were measured after the first growing season, and biomass allocation to belowground and reproductive structures after the second. Moreover, a phenotypic plasticity index was calculated for the functional traits to compare the degree of plasticity between mid and high elevation species. Important Findings: Aboveground biomass was higher in mid elevation species relative to high elevation congeners in all treatments, yet decreased for both with elevation and drought. Similarly, SLA decreased with elevation and drought. Root mass fraction (RMF) was generally higher in high elevation species, and decreased with drought at the lower site. Drought increased the allocation to reproductive structures, especially when plants were grown at their elevation of origin. Interestingly, no difference was found in the degree of phenotypic plasticity averaged across mid and high elevation species for any of the studied functional traits. These results indicate that phenotypic plasticity in the focal traits did not depend on the elevation of origin of the species. Plasticity was not related to environmental heterogeneity, nor constrained by selective pressures at high elevation. However, both species groups showed a remarkable capacity for short-term acclimation to a prospective climate through rapid adjustments in key functional traits.

Contrasting phenotypic plasticity in the photoprotective strategies of the invasive species Carpobrotus edulis and the coexisting native species Crithmum maritimum.

Photoprotective strategies vary greatly within the plant kingdom and reflect a plant's physiological status and capacity to cope with environment variations. The plasticity and intensity of these responses may determine plant success. Invasive species are reported to show increased vigor to displace native species. Describing the mechanisms that confer such vigor is essential to understanding the success of invasive species. We performed an experiment whereby two species were monitored: Carpobrotus edulis, an aggressive invasive species in the Mediterranean basin, and Crithmum maritimum, a coexisting native species in the Cap de Creus Natural Park (NE Spain). We analyzed their photoprotective responses to seasonal environmental dynamics by comparing the capacity of the invader to respond to the local environmental stresses throughout the year. Our study analyses ecophysiological markers and photoprotective strategies to gain an insight into the success of invaders. We found that both species showed completely different but effective photoprotective strategies: in summer, C. edulis took special advantage of the xanthophyll cycle, whereas the success of C. maritimum in summer stemmed from morphological changes and alterations on β-carotene content. Winter also presented differences between the species, as the native showed reduced Fv /Fm ratios. Our experimental design allowed us to introduce a new approach to compare phenotypic plasticity: the integrated phenotypic plasticity index (PPint ), defined as the maximum Euclidian distance between phenotypes, using a combination of different variables to describe them. This index revealed significantly greater phenotypic plasticity in the invasive species compared to the native species.

A morphophysiological analysis of the effects of drought and shade on Catalpa bungei plantlets

The interactive effects of shade and drought on the morphological and physiological traits of Catalpa bungei plantlets were assessed. Seedling growth, biomass, biomass allocation, leaf morphology, chlorophyll (Chl) content and gas-exchange parameters were measured in plants raised for 3 months under three light levels [80% (HI), 50% (MI), 30% (LI)] and two water levels [moisture (M) and drought (D)]. The results showed that shade greatly decreased growth, biomass, leaf area (LA) and Chl a/b; increased specific leaf area (SLA) and Chl content; and reduced photosynthetic rate (P n). Drought reduced the growth, biomass, LA, SLA, Chl a/b, P n, stomatal conductance (G s), transpiration rate (T r) and intercellular carbon dioxide concentration (C i) and increased the Chl content. Stomatal closure was an early physiological response to water stress. Light, water and their interaction significantly affected plant traits and their bivariate relationships. The phenotypic plasticity index of light (0.47) was much higher than that of water (0.21), indicating that light was the main driver of the variations observed. Under drought stress, growth, biomass, leaf and stem biomass allocation significantly decreased in the HI and MI environments, whereas no significant difference was observed in growth or biomass parameters under the LI condition. Furthermore, no significant difference was observed in P n, G s, or T r under the LI condition under water stress. Our results showed that shade did not alter the negative effects caused by drought stress in MI but did alleviate the negative effects of the LI condition. In summary, the effect of drought on C. bungei plantlets depends on the irradiance conditions.

Morphological plasticity of Ilex theezans Mart. ex Reissek (Aquifoliaceae) in two restinga vegetation of Santa Catarina coastal plain

The restinga, an environment of the rain Forest, is an ecosystem by the seacoast composed of diverse plant communities commonly found in sandy and undeveloped soils. This study aims to investigate possible intraspecific differences in Ilex theezans species, whose distribution in restinga includes two heterogeneous formations, shrub-tree restinga and transition forest. The study focused on a restinga remnant area located in Acaraí State Park, in the city of São Francisco do Sul (SC, Brazil). In each environment, five adult individuals were selected and had wood samples collected from their stems at breast height and 25 leaves of the third and fourth nodes of the outer canopy branches sampled. Chemical and physical soil variables were analyzed for each formation. The results show that there are significant differences between the leaf and the stem functional attributes and soil data analyzed, but as the PPI (Phenotypic Plasticity Index), the species Ilex theezans in the studied formations present low plastic potential.