Structural Traits Research Articles

Isolation of Heavy Metal-Tolerant and Anti-Phytopathogenic Plant Growth-Promoting Bacteria from Soils.

In this study, by isolating multifunctional soil bacteria that can promote plant development, resist heavy metals, exhibit anti-phytopathogenic action against plant diseases, and produce extracellular enzymes, we hope to improve the effectiveness of phytoremediation techniques. To isolate multifunctional soil bacteria, we used soils with diverse characteristics as isolation sources. To look into the diversity and structural traits of the bacterial communities, We conducted amplicon sequencing of the 16S rRNA gene on five types of soils and predicted functional genes using Tax4Fun2. The isolated bacteria were evaluated for their multifunctional capabilities, including heavy metal tolerance, plant growth promotion, anti-phytopathogenic activity, and extracellular enzyme activity. The genes related to plant growth promotion and anti-phytopathogenic activity were most abundant in forest and paddy soils. Burkholderia sp. FZ3 and FZ5 demonstrated excellent heavy metal resistance (≤ 1 mM Cd and ≤ 10 mM Zn), Pantoea sp. FC24 exhibited the highest protease activity (24.90 μmol tyrosine·g-DCW-1·h-1), and Enterobacter sp. PC20 showed superior plant growth promotion, especially in siderophore production. The multifunctional bacteria isolated using traditional methods included three strains (FC24, FZ3, and FZ5) from the forest and one strain (PC20) from paddy field soil. These results indicate that, for the isolation of beneficial soil microorganisms, utilizing target gene information obtained from isolation sources and subsequently exploring target microorganisms is a valuable strategy.

Limited evidence for the influence of the physical structure and floristics of habitat on a boreal forest bird community

Studies conducted at regional and continental scales show that avian richness, community composition, and abundance are associated with variation in the vegetation physical structure and community composition (floristics) within broad habitat types. The relative contributions of physical structure and floristics are contested, and relationships are often taxon-specific. We used 110 microphone arrays deployed across 90 sampling locations and two breeding seasons to survey an avian community in the boreal forest in Labrador, Canada. Our objectives were (1) to describe the avian community of an underrepresented portion of the boreal forest, (2) to estimate the relationships between avian species richness and habitat characteristics, (3) to estimate if species detection at a given location was related to local habitat characteristics, and (4) to investigate the spatial and temporal patterns of the avian community composition. We detected 32 species at our sampling locations; physical structure and floristics were not related to avian species richness, although estimates of richness were higher on warmer days and lower on windier days. Habitat characteristics were associated with the detection of Boreal Chickadee (Poecile hudsonicus), Yellow-rumped Warbler (Setophaga coronata), American Robin (Turdus migratorius), and Black-throated Green Warbler (Setophaga virens). Finally, avian community composition was only moderately consistent among three categorical forest types and between audio sampling periods in two consecutive breeding seasons. Overall, we show that the structural and floristic traits measured at our study site are not related to the detection of most avian species or to species richness.

Shifting trait coordination along a soil‐moisture‐nutrient gradient in tropical forests

Abstract Soil nutrients and water availability are strong drivers of tropical tree species distribution across scales. However, the physiological mechanisms underlying environmental filtering along these gradients remain incompletely understood. Previous studies mostly focused on univariate variation in structural traits, but a more integrative approach combining multiple physiological traits is needed to fully portray species functional strategies. We measured nine leaf functional traits related to trees' resource capture and hydraulic strategies for 552 individuals belonging to 21 tropical tree species across an environmental gradient in Amazonian forests. Our sampling included generalist and specialist species from terra firme (TF) and seasonally flooded (SF) forests. We tested the influence of the topographic wetness index, a proxy for soil moisture and nutrient gradients, on each trait separately and on the trait integration through multivariate indices computed from the eigenvalues of a principal component analysis on the traits of the species. Finally, we evaluated intraspecific trait variability (ITV) for generalists and specialists by calculating the coefficient of variation for each trait. Results showed that (1) the environment had a greater influence on trait syndromes than single trait variation. Moreover, (2) SF specialist species expressed a stronger leaf trait coordination than TF specialist species. Furthermore, (3) the ability of generalist species to occupy a broader range of environments was not reflected by a larger ITV than specialist species but by the capacity to change trait coordination across environments. Our work highlights the need to investigate functional strategies as multidimensional syndromes in physiological trait space to fully understand and predict species distribution along environmental gradients. Read the free Plain Language Summary for this article on the Journal blog.

Structural, optical, and thermal traits of Sm³⁺-doped SrB₂O₄ phosphors for solid-state lighting applications

We synthesized Sm³⁺-doped SrB₂O₄ phosphors through a solid-state reaction method, varying the Sm³⁺ doping concentrations. Structural and morphological characteristics of material were investigated using Fourier-transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD) and scanning electron microscopy (SEM). Optical transitions were analyzed by recording the diffuse reflectance spectroscopy, while photoluminescent (PL) spectra were used to evaluate luminescence properties. The PL spectra revealed a strong orange emission at 598 nm under 402 nm excitation. The optimal Sm³⁺ doping concentration was determined to be 0.02 mol, beyond which concentration quenching occurred. This quenching is attributed to exchange-type interactions, which facilitate non-radiative energy relaxation. The CIE color chromaticity coordinates of all the synthesized phosphors fell within the orange region of the chromaticity diagram. Temperature dependent photoluminescence revealed lower activation energy and phonon energy. Thermal quenching temperature was calculated which is inline with commercially available LEDs. All of these results indicate the candidature of SrB2O4 phosphor doped with Sm3+ ions for solid state lighting and optical thermal sensing applications.

A new dimension of leaf economic spectrum: temporal instability of relationships among genotypes.

Leaf economic spectrum (LES) relationships have been studied across many different plant lineages and at different organizational scales. However, the temporal stability of the LES relationships is largely unknown. We used the wild blueberry system with high genotypic diversity to test whether trait-trait relationships across genotypes demonstrate the same LES relationships found in the global database (GLOPNET) and whether they are stable across years. We studied leaf structure, photosynthesis, and leaf nutrients for 16 genotypes of two wild blueberry species semi-naturally grown in a common farm in Maine, USA, across 4 yr. We found substantial variation in leaf structure, physiology, and nutrient traits within and among genotypes, as well as across years in wild blueberries. The LES trait-trait relationships (covariance structure) across genotypes were not always found in all years. The trait syndrome of wild blueberries was shifted by changing environmental conditions over the years. Additionally, traits in 1 yr cannot be used to predict those of another year. Our findings show that LES generally holds among genotypes but is temporally unstable, stressing the significant influence of trait plasticity in response to fluctuating environmental conditions across years, and the importance of temporal dimensions in shaping functional traits and species coexistence.

Enhanced optical and structural traits of irradiated lead borate glasses via Ce3+ and Dy3+ ions with studying Radiation shielding performance

Lead borate glass is the best radiation shielding glass when lead is in high concentration. However, it has low transparency after radiation exposure. Radiation decreases transparency due to chemical and physical changes in the glass matrix, such as creating or healing defects in the glass network. The addition of rare earth elements like cerium and dysprosium oxides to lead borate glasses can improve their transparency and durability as radiation shielding barriers. The newly manufactured glasses’ optical absorption, structural, and radiation shielding properties were measured. The optical characteristics of the generated samples were examined to determine the effect of the cerium/dysprosium ratio on the structural alterations, specifically in the presence of bridging oxygen (BO) and non-bridging oxygen (NBO). Incorporating Ce3+ results in peaks at 195 nm for borate units, 225 nm for Ce3+, and a broadened peak at 393 nm due to overlapping peaks for Ce3+ and Ce4+ in the UV region. By adding Dy, multiple peaks are observed at 825, 902, 1095, 1275, and 1684 nm, corresponding to the transition from 6H15/2 ground state to 6F5/2, 6F7/2, 6F9/2, 6F11/2, and 6H11/2. The samples were also tested before and after exposure to gamma irradiation from a 60Co source at a dose of 75 kGy to assess their stability against radiation. The energy gap value during irradiation shows decreased non-bridging oxygen. The energy gap difference before and after irradiation for the M4 sample shows higher NBO to BO conversion, reducing radiation damage and improving structural stability. Furthermore, X-ray photoelectron spectroscopy was utilized to get insight into the coordination chemistry of the created glass samples. The half-value layer (HVL), radiation protection efficiency (RPE), neutron removal cross-section (FRNCS), mean free path (MFP), mass attenuation coefficients (MAC), and effective atomic numbers (Zef) of the glassy structure were calculated theoretically to assess its radiation shielding qualities. The linear attenuation coefficient order for the prepared samples was M1 > M2 > M3 > M4. The FRNCS values were 0.090, 0.083, 0.081, and 0.079 cm−1 for samples M1, M2, M3, and M4, respectively.

How the vertical gradient of light in the understorey and water seasonality affect leaf traits of Vanilla phaeantha (Orchidaceae), a crassulacean acid metabolism (CAM) hemiephyte.

Structural and physiological leaf traits and their plasticity were compared in the hemiepiphyte Vanilla phaeantha . This species grows along a phorophyte reaching different understorey positions and exhibiting diverse responses to environment changes. We analysed three height strata above the ground, establishing a light gradient, and considering seasonal water fluctuations. The upper leaves had higher area and mass and were less pigmented. The dry season induced a reduction of approximately 2h of stomatal opening over the diel 24h crassulacean acid metabolism (CAM) cycle in the leaves at all understorey positions. The leaves more exposed to sunlight were larger with higher titratable acidity during the rainy season, while the leaves near the ground maintained the same rates of stomatal conductance and nocturnal acidification between seasons, with lowest values of carbon isotopes in the rainy season. Our research showed that some structural leaf traits (such as specific leaf mass, biomass, and saturated water content) are sensitive to variation in understorey position. In contrast, other physiological traits (stomatal conductance, transpiration, and fluorescence parameters) are more sensitive to seasonal variations. The results are a novelty in assessing the variation of CAM along the same plant in a height gradient and under field conditions.

Association Between Glaucoma and Brain Structural Connectivity Based on Diffusion Tensor Tractography: A Bidirectional Mendelian Randomization Study.

Glaucoma is a neurodegenerative ocular disease that is accompanied by cerebral damage extending beyond the visual system. Recent studies based on diffusion tensor tractography have suggested an association between glaucoma and brain structural connectivity but have not clarified causality. To explore the causal associations between glaucoma and brain structural connectivity, a bidirectional Mendelian randomization (MR) study was conducted involving glaucoma and 206 diffusion tensor tractography traits. Highly associated genetic variations were applied as instrumental variables and statistical data were sourced from the database of FinnGen and UK Biobank. The inverse-variance weighted method was applied to assess causal relationships. Additional sensitivity analyses were also performed. Glaucoma was potentially causally associated with alterations in three brain structural connectivities (from the SN to the thalamus, from the DAN to the putamen, and within the LN network) in the forward MR analysis, whereas the inverse MR results identified thirteen brain structural connectivity traits with a potential causal relationship to the risk of glaucoma. Both forward and reverse MR analyses satisfied the sensitivity test with no significant horizontal pleiotropy or heterogeneity. This study offered suggestive evidence for the potential causality between the risk of glaucoma and brain structural connectivity. Our findings also provided novel insights into the neurodegenerative mechanism of glaucoma.

Patterns of decomposition and functional traits for flower and leaf litter in tropical woody species.

The variation within and across species has afterlife effects on carbon and nutrient cycling through the alteration of litter decomposability. However, the focus on leaves may not reflect a whole-plant economic spectrum of strategies. Here, we assessed the patterns and predictors of flower and leaf-litter decomposition at the intra- (i.e., flowers and leaves of the same species) and inter-specific (i.e., flowers and leaves from different species) levels for 29 tropical woody species in northeast Brazil. We evaluated nine functional litter traits, including structural and chemical traits. Flower litter decomposed, on average, three times faster than leaf litter (11.9% and 39.4% mass remaining, respectively) and exhibited higher water-holding capacity (WHC), leaching (LEA), and N, P, and K content. Otherwise, leaf litter showed higher density (DEN) and Ca, Mg, and Na content. The average relative differences in decomposition rate and functional traits between flower and leaf litter did not differ at both intra- and inter-specific levels. The predictors of decomposition were mostly similar, explaining 39% and 37% of flower and leaf litter, respectively. Leaching, P, Ca, Mg, and Na predict both flower and leaf-litter decomposition. However, WHC exclusively predicted flower-litter decomposition, and DEN, N, and K exclusively predicted leaf-litter decomposition. The observed differences in decomposition rate and functional traits between flower and leaf litter indicate that the afterlife effects differ between these plant organs and leverage the role of flower litter and its secondary consequences to nutrient and carbon cycling on ecosystems.

Morphophysiological Adaptations of Aquatic Macrophytes in Wetland-Based Sewage Treatment Systems: Strategies for Resilience and Efficiency under Environmental Stress

There is a common misconception that aquatic macrophytes face significant challenges in wetland-based sewage treatment systems. This study aims to correct this perception by focusing on the crucial morphophysiological adaptations of aquatic macrophytes that enable them to thrive in wetland-based sewage treatment systems, particularly under environmental stress. These adaptations are vital for improving the efficiency and resilience of wastewater treatment processes, offering sustainable solutions in the face of variable environmental conditions and complex contaminant mixtures. The review emphasizes the role of macrophytes as natural engineers, capable of enhancing pollutant removal and system stability through their unique structural and functional traits. By understanding these adaptations, the review aims to guide the optimization of wetland design and management, ultimately contributing to more sustainable and effective wastewater treatment practices. The findings underscore the importance of species selection and the integration of nature-based solutions in environmental management, advocating for policies that support the use of macrophytes in modern wastewater management.

Fluorescence and Hyperspectral Sensors for Nondestructive Analysis and Prediction of Biophysical Compounds in the Green and Purple Leaves of Tradescantia Plants

The application of non-imaging hyperspectral sensors has significantly enhanced the study of leaf optical properties across different plant species. In this study, chlorophyll fluorescence (ChlF) and hyperspectral non-imaging sensors using ultraviolet-visible-near-infrared shortwave infrared (UV-VIS-NIR-SWIR) bands were used to evaluate leaf biophysical parameters. For analyses, principal component analysis (PCA) and partial least squares regression (PLSR) were used to predict eight structural and ultrastructural (biophysical) traits in green and purple Tradescantia leaves. The main results demonstrate that specific hyperspectral vegetation indices (HVIs) markedly improve the precision of partial least squares regression (PLSR) models, enabling reliable and nondestructive evaluations of plant biophysical attributes. PCA revealed unique spectral signatures, with the first principal component accounting for more than 90% of the variation in sensor data. High predictive accuracy was achieved for variables such as the thickness of the adaxial and abaxial hypodermis layers (R2 = 0.94) and total leaf thickness, although challenges remain in predicting parameters such as the thickness of the parenchyma and granum layers within the thylakoid membrane. The effectiveness of integrating ChlF and hyperspectral technologies, along with spectroradiometers and fluorescence sensors, in advancing plant physiological research and improving optical spectroscopy for environmental monitoring and assessment. These methods offer a good strategy for promoting sustainability in future agricultural practices across a broad range of plant species, supporting cell biology and material analyses.

Evolution of the conformational dynamics of the molecular chaperone Hsp90

Hsp90 is a molecular chaperone of central importance for protein homeostasis in the cytosol of eukaryotic cells, with key functional and structural traits conserved from yeast to man. During evolution, Hsp90 has gained additional functional importance, leading to an increased number of interacting co-chaperones and client proteins. Here, we show that the overall conformational transitions coupled to the ATPase cycle of Hsp90 are conserved from yeast to humans, but cycle timing as well as the dynamics are significantly altered. In contrast to yeast Hsp90, the human Hsp90 is characterized by broad ensembles of conformational states, irrespective of the absence or presence of ATP. The differences in the ATPase rate and conformational transitions between yeast and human Hsp90 are based on two residues in otherwise conserved structural elements that are involved in triggering structural changes in response to ATP binding. The exchange of these two mutations allows swapping of the ATPase rate and of the conformational transitions between human and yeast Hsp90. Our combined results show that Hsp90 evolved to a protein with increased conformational dynamics that populates ensembles of different states with strong preferences for the N-terminally open, client-accepting states.

Stable Isotope Labelling Reveals Water and Carbon Fluxes in Temperate Tree Saplings Before Budbreak.

Despite considerable experimental effort, the physiological mechanisms governing temperate tree species' water and carbon dynamics before the onset of the growing period remain poorly understood. We applied 2H-enriched water during winter dormancy to the soil of four potted European tree species. After 8 weeks of chilling, hydrogen isotopes in stem, twig and bud water were measured six times during 2 consecutive weeks of forcing conditions (Experiment 1). Additionally, we pulse-labelled above-ground plant tissues using 2H-enriched water vapour and 13C-enriched CO2 7 days after exposure to forcing conditions to trace atmospheric water and carbon uptake (Experiment 2). Experiment 1 revealed soil water incorporation into the above-ground organs of all species during the chilling phase and significant species-specific differences in water allocation during the forcing conditions, which we attributed to differences in structural traits. Experiment 2 illustrated water vapour incorporation into all above-ground tissue of all species. However, the incorporation of carbon was found for evergreen saplings only. Our results suggest that temperate trees take up and reallocate soil water and absorb atmospheric water to maintain sufficient above-ground tissue hydration during winter. Therefore, our findings provide new insights into the water allocation dynamics of temperate trees during early spring.

Non-senescent species are not immortal: Stress and decline in two planaria species.

Potential immortality is observed in several species (e.g. prickly pear cactus, hydra and flatworms) and is indicative of their negligible or even negative senescence rates. Unlike in senescent species, which experience reduced individual performance with age due to physiological degradation, species with negligible or negative senescence display mortality rates that remain constant or decline with age, respectively. These rates vary across taxa and are correlated with life history traits. Yet, the extent to which variable resource availability, a key driver of variation in life history traits, impacts species that show negligible or negative senescence is currently unknown. Here, we examine whether and how variation in the quantity, quality and feeding interval of resources impact population structure, population performance and life history trait trade-offs in two long-lived planaria that do not senesce: Schmidtea mediterranea and Dugesia tahitiensis. In a full factorial design, different combinations of resource quantity (reduced intake, standard intake and high intake) and quality (high and low quality) were provided in two different feeding intervals (7-day and 14-day intervals) for 19 weeks. We show that variability in resource availability, via decreases in quantity, quality and frequency of resources, does not diminish population viability in either species but does result in suboptimal conditions of stress in S. mediterranea. The high population viability we report can be attributed to two different mechanisms: increased reproduction or increased investment into maintenance at the expense of reproduction. Moreover, which mechanism was responsible for said high population viability was context-dependent and modulated by the specific life history strategy of the two planaria species. We show that suboptimal conditions can cause stress responses that have significant impacts on non-senescent species. The context-dependent response we observe suggests that species that do not senesce but are subject to suboptimal conditions of stress may ultimately exhibit declines in performance and ultimately die. A clearer understanding of the impact of suboptimal conditions of resource availability on non-senescent species is needed to determine the extent of stress experienced and ultimately whether a species can truly be immortal.

Cooperation of rhamnolipid and thermophilic bacteria modifies proteinic structure, microbial community, and metabolic traits for efficient solubilization and acidogenesis of mariculture solid wastes

Anaerobic fermentation combined with thermophilic bacteria (TB) pretreatment is a promising method to realize effective waste management and carbon resource recovery. However, undesirable properties of high-strength mariculture solid wastes (MSW) such as high solids concentration, excessive salinity and poor bioavailability limited the overall solubilization and acidogenic efficiency. This study innovatively introduced rhamnolipid (RL) to alleviate this adverse effect, and unveiled its cooperation with TB on enhancing organic matter dissolution and volatile fatty acids (VFAs) production. The results showed that VFAs yield from pretreated MSW was improved by 9.4-15.1 folds with enriched acetate (81.4%-94.4%) in the TB+RL groups. The co-pretreatment of RL and TB disintegrated substrate structure for efficient release of electron shuttles and biodegradable organics. This was because introducing RL reconstructed solid-liquid interfacial charge and molecular arrangement, improved thermophilic enzyme activity, and reduced apoptosis and necrosis cells of TB. Substrate bioavailability was further improved with proteinic structure shifted from α-helix and β-sheet to random coil and aggregated strands, and amide II and carboxyl groups interacted with RL molecules. These changes induced the selective enrichment of hydrolytic and acidogenic bacteria, and the upregulated expression of encoding genes responsible for transmembrane transport, protein hydrolysis, carbohydrate metabolism and acetate biosynthesis. This study provides a new strategy to overcome the bottlenecks of acidogenesis from high-strengthen organic wastes and deciphers the underlying mechanism.

A comparative study of Nd and Sm doping on the structural, magnetic, and electromagnetic traits of Mg-Zn spinel nanoferrites

A comparative study of Nd and Sm doping on the structural, magnetic, and electromagnetic traits of Mg-Zn spinel nanoferrites

Grass leaf structural and stomatal trait responses to climate gradients assessed over the 20th century and across the Great Plains, USA.

Abstract. Using herbarium specimens spanning 133 years and field-collected measurements, we assessed intraspecific trait (leaf structural and stomatal) variability from grass species in the Great Plains of North America. We focused on two widespread, closely related grasses from the tribe Paniceae: Dichanthelium oligosanthes subsp. scribnerianum (C3) and Panicum virgatum (C4). Thirty-one specimens per taxon were sampled from local herbaria from the years 1887 to 2013 to assess trait responses across time to changes in atmospheric [CO2] and growing season precipitation and temperature. In 2021 and 2022, the species were measured from eight grasslands sites to explore how traits vary spatially across natural continental precipitation and temperature gradients. Δ13C increased with atmospheric [CO2] for D. oligosanthes but decreased for P. virgatum, likely linked to increases in precipitation in the study region over the past century. Notably, this is the first record of decreasing Δ13C over time for a C4 species illustrating 13C linkages to climate. As atmospheric [CO2] increased, C:N increased and δ15N decreased for both species and %N decreased for D. oligosanthes. Across a large precipitation gradient, D. oligosanthes leaf traits were more responsive to changes in precipitation than those of P. virgatum. In contrast, only two traits of P. virgatum responded to increases in temperature across a gradient: specific leaf area (increase) and leaf dry matter content (decrease). The only shared significant trend between species was increased C:N with precipitation. Our work demonstrates that these closely related grass species with different photosynthetic pathways exhibited various trait responses across temporal and spatial scales, illustrating the key role of scale of inquiry for forecasting leaf trait responses to future environmental change.

Corporate governance and financial distress in China a multi-dimensional nonlinear study based on machine learning

Promoting governance efficiency is crucial for preventing corporate financial distress. However, previous research has been constrained by limited dimensions of governance predictors and insufficient linear estimations to predict financial distress. To address this issue, this study gathers 37 corporate governance indicators of Chinese publicly listed firms from 2009 to 2022 in the dimensions of ownership structure, board features and executive traits. The LightGBM machine learning approach is then used to compare the predicting power of these individual indicators, as well as the predicting power of the dimensions. The SHAP (SHapley Additive exPlanations) method is further adopted to conduct an in-depth interpretability analysis upon the established prediction. Our approach identifies the nonlinear effects of important corporate governance indicators on financial distress and prioritizes those indicators based on their impact levels. Our results show that the most influential indicator is institutional ownership, followed by managerial ownership and executive compensation disparity. In addition, the dimension of ownership structure has the highest predicting power among the three. Overall, our study provides new insights into how firms can optimize their corporate governance mechanisms to prevent financial distress.

Chronosequence and Temporal Changes in Soil Conditions, Vegetation Structure and Leaf Traits in a Tropical Dry Forest in Brazil

Chronosequence and Temporal Changes in Soil Conditions, Vegetation Structure and Leaf Traits in a Tropical Dry Forest in Brazil

ScaLing of cotyledon and primary leaf mass and area in Acer platanoides seedLings under different light conditions

Abstract Cotyledons play an important role in early seedLing establishment. However, relative to primary leaves, cotyledons tend to have a different investment on return strategy. To detect the potential differences in the mass (M) vs. area (A) scaLing relationships between cotyledons and primary leaves in different light environments, a total of 75 Acer platanoides L. seedLings were sampled at an open site (n = 52; light availability: 74 ± 5%) and a shaded site (n = 23; light availability: 4.2 ± 1.2%). Reduced major axis regression protocols were used to fit the M vs. A scaLing relationships of primary leaves and cotyledons. The bootstrap percentile method was used to test the significance of the differences in the scaLing exponents of M vs. A between the two light environments. The scaLing exponents of cotyledons at both two sites, as well as the primary leaves at the shade site, were greater than unity indicating “diminishing returns”, while the scaLing exponent of primary leaves at the open site was smaller than unity indicating “increasing returns”, and the data collectively indicated light-dependent shifts in support investments, and differences in function of cotyledons and primary leaves. Average leaf structural traits displayed significant differences between the two light environments in accordance with the premium in enhancing photosynthetic capacity in high light and light interception in low light. Although the trait responses to light availability were similar for primary leaves and cotyledons, primary leaves were more responsive to light availability, indicating lower plasticity of cotyledons in response to light levels. These results advance our understanding of the roles of cotyledons and primary leaves in the life-history of seedLings in different forest light environments.