Leaf Stomatal Traits Research Articles

The role of tree size, wood anatomical and leaf stomatal traits in shaping tree hydraulic efficiency and safety in a South Asian tropical moist forest

The role of tree size, wood anatomical and leaf stomatal traits in shaping tree hydraulic efficiency and safety in a South Asian tropical moist forest

Leaf stomatal traits rather than anatomical traits regulate gross primary productivity of moso bamboo (Phyllostachys edulis) stands.

Leaf stomatal and anatomical traits strongly influence plant productivity. Understanding the environmental adaptation mechanisms of leaf stomatal and anatomical traits and their relationship with ecosystem productivity is essential to better understand and predict the long-term adaptation strategies to climate change of moso bamboo forests. Here, we selected 6 sites within the moso bamboo distribution area, measured 3 leaf stomatal traits and 10 leaf anatomical traits of unmanaged moso bamboo stands. We explored the spatial variation characteristics of these traits and their response to environmental changes, assessed the relationships among these traits at regional scales through network analysis, and tested the direct and indirect effects of environmental, leaf stomatal and anatomical traits on gross primary productivity (GPP) of bamboo stands using structural equation modeling (SEM). The results showed that both climate and soil factors significantly affected leaf stomatal and anatomical traits of moso bamboo. Solar radiation (SR) and mean annual precipitation (MAP) out of the climatic factors were the key drivers of variation in leaf stomatal and anatomical traits, respectively. Soil moisture and nutrients out of the soil properties significantly affected both leaf stomatal and anatomical traits of moso bamboo. Network analysis further indicated that there was a significant correlation between leaf stomata and anatomical traits. Stomatal size (SS) showed the highest centrality value at the regional scale, indicating that it plays a key role in adjusting the adaptation of plants to external environmental conditions. SEM analysis showed that environment did not directly but indirectly affect GPP via stomatal performance. The environment explained 53.3% and 39.2% of the variation in leaf stomatal and anatomical traits, respectively, and leaf stomatal traits explained 20.8% of the regional variation in GPP. Our results demonstrate a direct effect of leaf stomatal traits rather than leaf anatomical traits on bamboo ecosystem productivity, which provides new insights into model predictions of bamboo forests under global climate change.

Transcriptome and anatomical studies reveal alterations in leaf thickness under long-term drought stress in tobacco

Drought is one of the foremost environmental factors that limit the growth of plants. Leaf thickness (LT) is an important quantitative trait in plant physiology. The experiment was carried out in a growth room and the plants were divided into two groups such as well-watered and drought-stressed. This work investigated leaf growth in terms of leaf surface growth and expansion rate, leaf stomata traits, LT, anticlinal growth, and leaf cell layers. The results showed that the leaf area and leaf surface expansion rate were decreased by drought stress (DS). Similarly, LT, anticlinal expansion rate, palisade and spongy tissue thickness, and their related expansion rates were also decreased at different days’ time points (DTP) of DS. However, a steady increase was observed in the aforementioned parameters after 12 DTP of DS. The stomatal density increased while stomata size decreased at 3 DTP and 12 DTP (low leaf water potential and relative leaf water content at these time points) and vice versa at 24 DTP compared with the well-watered plants indicating adaptations in these traits in response to DS, and thus the leaf water status played a role in the regulation of leaf stomata traits. The cell length decreased in the upper epidermis, palisade and spongy tissues by DS up to 12 DTP led to lower LT while an increase was observed after 12 DTP that resulted in higher LT. The increase in the LT was supported by the upregulation of starch and sucrose metabolism, glycerolipid metabolism, protein processing in endoplasmic reticulum pathways at 18 DTP along with the differentially expressed genes induced that were related to cell wall remodeling (cellulose, expansin, xyloglucans) and cell expansion (auxin response factors and aquaporin). The results explain the response of leaf thickness to drought stress and show alterations in LT and leaf stomatal traits. This study might serve as a valuable source of gene information for functional studies and provide a theoretical basis to understand leaf growth in terms of leaf anatomy and leaf stomatal traits under drought stress.

Predicting ecosystem productivity based on plant community traits.

With the rapid accumulation of plant trait data, major opportunities have arisen for the integration of these data into predicting ecosystem primary productivity across a range of spatial extents. Traditionally, traits have been used to explain physiological productivity at cell, organ, or plant scales, but scaling up to the ecosystem scale has remained challenging. Here, we show the need to combine measures of community-level traits and environmental factors to predict ecosystem productivity at landscape or biogeographic scales. We show how theory can extend the production ecology equation to enormous potential for integrating traits into ecological models that estimate productivity-related ecosystem functions across ecological scales and to anticipate the response of terrestrial ecosystems to global change.

EVALUATING THE FUNCTIONAL TRAITS OF THE PIONEERING SPECIES: INSIGHTS TO FOREST RESTORATION

The influence of plant traits on interspecific demographic rates to growth and mortality has recently received an increasing attention because it allows understanding of the underlying determinants of species success especially in open degraded areas. This study examined the trait-based approach in selecting potential species for forest restoration. Five (5) native/indigenous pioneer species were evaluated for functional traits such as plant height, branching architecture, leaf dry matter content, specific leaf area, stem density, and bark thickness. All samples were collected from healthy and well grown mature trees growing in secondary forest of Central Mindanao University. The range of values for the various functional traits as observed by Ostertag and Perez-Harguindeguy were used to evaluate. Based on the result, three species such as Phyllantus albus, Polyscias nodosa, and Buchanania arborescence showed to fit in those values hence we recommend that these species should be considered as primary restoration species in various denuded areas of the Philippines. Our result suggests that multiple functional traits (i.e. Leaf anatomical traits, leaf morphological traits and leaf stomatal traits) are still required to be measured to select appropriate plant species for restoration.

The influence of powdery mildew on chlorophyll a fluorescence and stomatal characteristics of pedunculate oak (Quercus robur L.)

Oak powdery mildew (Erysiphe alphitoides (Griffon and Maubl.) U. Braun and S. Takam.)) is one of the most common foliar pathogenic organism of oaks, exploiting harmful effects, particularly on young seedlings. To assess and evaluate these negative effects, an experiment was conducted under semi-controlled conditions with 20 one-year-old seedlings of Quercus robur L. infected with E. alphitoides, half of them showing 50% of leaf coverage by epiphytic mycelia and the other half a coverage of 75%. The results of the present study have shown that all observed parameters of chlorophyll a fluorescence transient were highly effective in the detection of severe biotic stress. Moreover, the studied parameters of slow fluorescence kinetics were also considerably influenced, with the coefficient of non-photochemical fluorescence quenching and the Stem-Volmer type non-photochemical fluorescence quenching parameters showing the fastest responses. In case of leaf stomatal traits, the decrease of stomata guard cell width coupled with the increase of stomatal density was observed as the protective mechanism of Q. robur against the stressor. The overall results showed the adverse effects of powdery mildew infection on the photosynthesis of pedunculate oak seedlings, which progressed in time and depended on the severity of the infection. The importance of the results of the present study lays in evaluation and monitoring of the effects of powdery mildew development on the photosynthetic apparatus of one-year-old Q. robur seedlings, which is the most vulnerable stage for the infection by the mentioned pathogen.

StomataScorer: a portable and high-throughput leaf stomata trait scorer combined with deep learning and an improved CV model.

To measure stomatal traits automatically and nondestructively, a new method for detecting stomata and extracting stomatal traits was proposed. Two portable microscopes with different resolutions (TipScope with a 40× lens attached to a smartphone and ProScope HR2 with a 400× lens) are used to acquire images of living stomata in maize leaves. FPN model was used to detect stomata in the TipScope images and measure the stomata number and stomatal density. Faster RCNN model was used to detect opening and closing stomata in the ProScope HR2 images, and the number of opening and closing stomata was measured. An improved CV model was used to segment pores of opening stomata, and a total of 6 pore traits were measured. Compared to manual measurements, the square of the correlation coefficient (R 2) of the 6 pore traits was higher than 0.85, and the mean absolute percentage error (MAPE) of these traits was 0.02%–6.34%. The dynamic stomata changes between wild‐type B73 and mutant Zmfab1a were explored under drought and re‐watering condition. The results showed that Zmfab1a had a higher resilience than B73 on leaf stomata. In addition, the proposed method was tested to measure the leaf stomatal traits of other nine species. In conclusion, a portable and low‐cost stomata phenotyping method that could accurately and dynamically measure the characteristic parameters of living stomata was developed. An open‐access and user‐friendly web portal was also developed which has the potential to be used in the stomata phenotyping of large populations in the future.

Changes in leaf stomatal traits of different aged temperate forest stands

Stomata control carbon and water vapor exchange between the leaves and the atmosphere, thus influencing photosynthesis and transpiration. Combinations of forest patches with different stand ages are common in nature, however, information of which stomatal traits vary among these stands and how, remains limited. Here, seven different aged forest stands (6, 14, 25, 36, 45, 55, and 100 years) were selected in typical temperate, mixed broadleaf-conifer forests of northeast China. Stomatal density, size and relative area of 624 species, including the same species in stands of different ages were selected. Stomatal density, size and relative area were distributed log-normally, differing across all species and plant functional groups. Stomatal density ranged from 4.2 to 1276.7 stomata mm–2, stomatal size ranged from 66.6 to 8315.7 μm2, and stomatal relative area 0.1–93.3%. There was a significant negative relationship between density and size at the species and functional group levels, while the relative stomatal area was positively correlated with density and size. Stomatal traits of dominant species were relatively stable across different stand ages but were significantly different for herbs. The results suggest that stomatal traits remain relatively stable for dominant species in natural forests and therefore, spatial variation in stomatal traits across forest patches does not need to be incorporated in future ecological models.

Half-Sib Lines of Pedunculate Oak (Quercus robur L.) Respond Differently to Drought Through Biometrical, Anatomical and Physiological Traits

Quercus robur L. is one of the most valued tree species of deciduous temperate forests. However, in the last decade, serious oak declines and loss of adaptation plasticity have been reported throughout Europe as a consequence of drought. Therefore, the aim of the present study was to define the adaptation potential of five Q. robur half-sib lines from the UNESCO Biosphere Reserve Mura-Drava-Danube to drought, using physiological, anatomical and biometrical traits. Half-sib lines that exhibited drought tolerance had particular suites of trait expression regarding biometrical traits (seedling height, root length, root to shoot ratio of dry mass and specific leaf area), leaf stomatal traits (stomatal density per mm2, stomata guard cell length and width, stomatal aperture length and width) and leaf structural traits (adaxial epidermis thickness, palisade parenchyma thickness, spongy parenchyma thickness, lamina thickness). All of the observed parameters of chlorophyll a fluorescence were shown to be good indicators of short-term and severe drought. For the selection of drought-tolerant half-sib lines, all studied chlorophyll a fluorescence parameters associated with the heat dissipation of light energy (coefficient of non-photochemical quenching, quantum yield of regulated energy dissipation, Stern-Volmer type non-photochemical fluorescence quenching) and one parameter related to photochemical dissipation of light energy (effective quantum yield (efficiency) of PS II photochemistry) were proven to be suitable. On the other hand, the coefficient of photochemical quenching, coefficient of photochemical fluorescence quenching assuming interconnected photosystem II antennae and electron transport rate were not suitable for distinguishing the different responses of the studied half-sib lines under drought. The importance of results of the present study is in the selection of drought-tolerant Q. robur half-sib lines for future reforestation programs, particularly in protected areas with sensitive forest management and restricted activities for mitigation of the adverse effects of climate changes.

The use of physiological, biochemical and morpho-anatomical traits in tree breeding for improved water-use efficiency of Quercus robur L.

Aim of study: In the present paper the nature and level of co-dependence between leaf functional traits and intrinsic water-use efficiency (WUEi) were studied in one-year-old Quercus robur L. seedlings, grown in a common garden experiment under moderate drought conditions. The study was established to identify those traits that might potentially be utilized to improve leaf-level WUEi, and therefore be used in breeding programmes to enhance drought adaptation of Q. robur.Area of study: The study was carried out at the common garden site within the UNESCO Biosphere Reserve Mura-Drava-Danube.Material and methods: The study involved one-year-old seedlings of eight half-sib lines of Q. robur. Eighteen leaf parameters were analyzed; i.e. physiological, biochemical, morphological and anatomical. The data were processed using multivariate statistical methods: a) principal component analysis, b) stepwise regression analysis, and c) path coefficient analysis.Main results: The results showed that leaf stomata traits, particularly stomatal density (SD), and leaf dry mass per unit leaf area (LMA) were the most important traits, closely associated with WUEi. Stomatal density achieved the highest score on PC1 (0.825), in which WUEi had the highest loading (0.920), as well. SD was also included first in stepwise regression model.Research highlights: These results demonstrate that under moderate water stress WUEi in Q. robur half-sib lines were mainly the result of the plants’ structural acclimation to surrounding environmental conditions. Keywords: Quercus robur L.; half-sib line; intrinsic water-use efficiency; leaf functional traits.

The Evolution of Functional Traits in Plants: Is the Giant Still Sleeping?

The Evolution of Functional Traits in Plants: Is the Giant Still Sleeping?

Оцінка ефективності добору морозостійких рослин за стоматографічними ознаками листка

Оцінка ефективності добору морозостійких рослин за стоматографічними ознаками листка

Leaf stomatal traits variation within and among fourteen European beech (Fagus sylvatica L.) provenances

In the present study, variations of leaf stomatal traits for fourteen European beech provenances (Fagus sylvatica L.), originating from six countries (Bosnia and Herzegovina, Croatia, Germany, Hungary, Romania and Serbia), were evaluated at the inter- and intra- provenances levels. Ten stomatal traits (stomatal density (SD), guard cell length (LA) and width (WB), stomatal aperture length (La) and width (Wb ), pore surface of guard cell (SPSLAWB), pore surface of a widely opened pore (SPSLaWb), coefficient (SSC), potential conductance index (PCI) and relative stomatal pore surface (RSPS)) were examined using methods of univariate (ANOVA and Tukey's HSD test) and multivariate statistical analyses (principal component analysis (PCA), discriminant analysis and cluster analysis). The results obtained provide significant insight into the genetic diversity and differentiation of European beech provenances and confirmed high genetic variability within and between examined European beech provenances, according to all examined parameters. Differences at the intra- provenance level had a bigger impact on most of the examined stomatal traits (with 70-80% of total variation), while differences at the inter- provenances level accounted for only 20-30% to the total expected variance. The results of PCA and canonical analysis suggest ecotypic pattern of genetic variability related to seed origin, which influenced leaf stomatal traits in F. sylvatica provenances. Forward stepwise discriminative analysis showed that WB, SD, PCI, SPSLaWb and Wb traits accounted for the same level of discrimination, as all the examined stomatal parameters together. However, the analysis detected considerably small correct allocation of the model that included all examined traits (only 38.85%). In order to discriminate examined beech provenances more precisely, additional phenotypical traits (e.g. morphological, physiological, etc.) should be included in the model.

Variation of stomatal traits from cold temperate to tropical forests and association with water use efficiency

Abstract Stomata control carbon and water vapour exchange between leaves and the atmosphere, thus it can influence water use efficiency (WUE) and reflect plant adaptation to climate. However, the spatial patterns of leaf stomatal traits and relationships between stomatal trait and WUE across natural communities remain unclear. We measured stomatal density, stomatal size and stomatal area fraction for 737 plant species from nine forests ranging from tropical to cold temperate forests. Stomatal density, stomatal size and stomatal area fraction were all log‐normally distributed, and different across species, plant functional groups (trees, shrubs, and herbs), and communities. At the regional scale, variation in stomatal traits was primarily related to species, followed by climate and soil types. The community‐weighted mean of stomatal size increased linearly with latitude, whereas those of stomatal density and stomatal area fraction showed humpbacked relationship. The community‐weighted mean of stomatal area fraction was correlated with climatic aridity, consistent with the adaptation strategies of plant species to achieve high maximum rates of gas exchange in arid regions when water is available. Further, community‐weighted mean of stomatal area fraction was positively correlated with WUE in natural forest communities, indicating that plants have lower stomatal conductance in order to adapt greater aridity conditions. These findings highlight the strong associations of stomatal traits with plant functional group and climate at a regional scale, representing the adaptation strategies of stomatal traits across natural forest communities to climate. A plain language summary is available for this article.

Leaf stomatal traits variation within and among black poplar native populations in Serbia

Populus nigra as a keystone riparian pioneer tree species is one of the rarest and most endangered species in Europe due to the loss of its natural habitats. Genetic diversity existence is a key factor in survival of one species, and stomata as genetically controlled trait could be used for differentiation studies. With the aim of proving stomatal phenotypic variation of the four native populations of Populus nigra located on the banks of three biggest river valleys (Dunabe, Tisa and Sava) in the region of Vojvodina in northern Serbia, we examined various leaf stomatal traits (stomatal length and width, pore length and width, stomatal density, shape coefficient and stomatal and pore area). We tested the differences of stomatal traits among populations, interindividual variability - differences among trees, the intraindividual variability, the differences between sun-exposed and shaded leaves, among leaves nested in exposition and the differences in adaxial and abaxial leaf surface. Based on mixed model ANOVA results, interpopulation variability, as statistically significant differences, observed only for stomatal pore length and shape, while all examined traits showed interindividual variability. On the intraindividual level the results showed differences for stomatal traits, except for stomatal width, stomatal shape coefficient and stomatal density regarding leaf exposure. For better understanding of how morphological and stomatal characteristics vary in black poplar populations, further studies should be necessary involving controlled environmental conditions with the aim of examining phenotypic plasticity to changing climate conditions.

Latitudinal variation of leaf stomatal traits from species to community level in forests: linkage with ecosystem productivity.

To explore the latitudinal variation of stomatal traits from species to community level and their linkage with net primary productivity (NPP), we investigated leaf stomatal density (SDL) and stomatal length (SLL) across 760 species from nine forest ecosystems in eastern China, and calculated the community-level SD (SDC) and SL (SLC) through species-specific leaf area index (LAI). Our results showed that latitudinal variation in species-level SDL and SLL was minimal, but community-level SDC and SLC decreased clearly with increasing latitude. The relationship between SD and SL was negative across species and different plant functional types (PFTs), but positive at the community level. Furthermore, community-level SDC correlated positively with forest NPP, and explained 51% of the variation in NPP. These findings indicate that the trade-off by regulating SDL and SLL may be an important strategy for plant individuals to adapt to environmental changes, and temperature acts as the main factor influencing community-level stomatal traits through alteration of species composition. Importantly, our findings provide new insight into the relationship between plant traits and ecosystem function.

Elevation-related variation in leaf stomatal traits as a function of plant functional type: evidence from Changbai Mountain, China.

Understanding the variation in stomatal characteristics in relation to climatic gradients can reveal the adaptation strategies of plants, and help us to predict their responses to future climate changes. In this study, we investigated stomatal density (SD) and stomatal length (SL) in 150 plant species along an elevation gradient (540–2357 m) in Changbai Mountain, China, and explored the patterns and drivers of stomatal characteristics across species and plant functional types (PFTs: trees, shrubs, and herbs). The average values of SD and SL for all species combined were 156 mm–2 and 35 µm, respectively. SD was higher in trees (224 mm–2) than in shrubs (156 mm–2) or herbs (124 mm–2), and SL was largest in herbs (37 µm). SD was negatively correlated with SL in all species and PFTs (P<0.01). The relationship between stomatal characteristics and elevation differed among PFTs. In trees, SD decreased and SL increased with elevation; in shrubs and herbs, SD initially increased and then decreased. Elevation-related differences in SL were not significant. PFT explained 7.20–17.6% of the total variation in SD and SL; the contributions of CO2 partial pressure (), precipitation, and soil water content (SWC) were weak (0.02–2.28%). Our findings suggest that elevation-related patterns of stomatal characteristics in leaves are primarily a function of PFT, and highlight the importance of differences among PFTs in modeling gas exchange in terrestrial ecosystems under global climate change.

Association genetics, geography and ecophysiology link stomatal patterning in Populus trichocarpa with carbon gain and disease resistance trade-offs.

Stomata are essential for diffusive entry of gases to support photosynthesis, but may also expose internal leaf tissues to pathogens. To uncover trade-offs in range-wide adaptation relating to stomata, we investigated the underlying genetics of stomatal traits and linked variability in these traits with geoclimate, ecophysiology, condensed foliar tannins and pathogen susceptibility in black cottonwood (Populus trichocarpa). Upper (adaxial) and lower (abaxial) leaf stomatal traits were measured from 454 accessions collected throughout much of the species range. We calculated broad-sense heritability (H(2) ) of stomatal traits and, using SNP data from a 34K Populus SNP array, performed a genome-wide association studies (GWAS) to uncover genes underlying stomatal trait variation. H(2) values for stomatal traits were moderate (average H(2) = 0.33). GWAS identified genes associated primarily with adaxial stomata, including polarity genes (PHABULOSA), stomatal development genes (BRASSINOSTEROID-INSENSITIVE 2) and disease/wound-response genes (GLUTAMATE-CYSTEINE LIGASE). Stomatal traits correlated with latitude, gas exchange, condensed tannins and leaf rust (Melampsora) infection. Latitudinal trends of greater adaxial stomata numbers and guard cell pore size corresponded with higher stomatal conductance (gs ) and photosynthesis (Amax ), faster shoot elongation, lower foliar tannins and greater Melampsora susceptibility. This suggests an evolutionary trade-off related to differing selection pressures across the species range. In northern environments, more adaxial stomata and larger pore sizes reflect selection for rapid carbon gain and growth. By contrast, southern genotypes have fewer adaxial stomata, smaller pore sizes and higher levels of condensed tannins, possibly linked to greater pressure from natural leaf pathogens, which are less significant in northern ecosystems.

Variation in leaf stomatal traits of 28 tree species in relation to gas exchange along an edaphic gradient in a Bornean rain forest

Quantifying variation in functional traits associated with shifts in the species composition of plant communities along resource gradients helps identify environmental attributes important for community assembly. Stomates regulate the balance between carbon assimilation and water status in plants. If environmental attributes affecting photosynthetic water-use efficiency govern species distribution along an edaphic gradient, then adaptive variation in stomatal traits of plant species specializing on different soils should reflect belowground resource availability. • We tested this hypothesis by quantifying stomatal trait variation in understory saplings of 28 Bornean tree species in relation to gas exchange and water-use efficiency (WUE). • Comparisons between congeneric specialists of the more fertile, moister clay and the less fertile, well-drained sandy loam revealed little evidence of similar shifts in stomatal traits across genera, nor was stomatal pore index correlated with g(max), A(max), or WUE (A(max)/g(max) or Δ(13)C), suggesting that stomates may be overbuilt in these shaded juveniles. A(max) was higher on sandy loam, likely due to higher understory irradiance there, but there were no other significant differences in gas exchange or WUE. • Despite substantial diversity in stomatal anatomy, there were few strong relationships between stomatal, photosynthetic, and WUE traits in relation to soil resources. Routine differences in water availability therefore may not exert a dominant control on the distributions of these Bornean tree species. Furthermore, the clades represented by these 12 genera may possess alternative functional designs enabling photosynthetic WUE that is sufficient to these humid, understory environments, due to whole plant-functional integration of stomatal traits with other, unmeasured traits influencing gas exchange.

Inter and intra-population variation of leaf stomatal traits of Quercus robur L. in Northern Serbia

The research involved the examination of inter- and intra-population variation of stomatal traits: stomatal density, stomatal length and width, stomatal pore surface, potential conductance index and stomatal shape coefficient, in Quercus robur L. leaves. The research was conducted in northern Serbia and included five populations (?Ada Ciganlija?, ?Bojcinska suma?, ?Subotica?, ?Sombor? and ?Vrsac?). The stomatal characteristics were examined in fully expanded leaves, from two leaf positions - the sun-exposed and shaded side of the tree. The leaf position in the tree crown, forming a part of the phenotypic variance, was relevant for the stomatal dimension traits. Within populations, the differences between the genotypes (i.e. trees), were relevant for all analyzed traits. On the basis of the analysis of the inter-populational differences, the ?Bojcinska suma? population had a statistically significantly lower stomatal density in comparison to the other populations.