Correlations between leaf economics, mechanical resistance, and drought tolerance across 41 cycad species

2021 ◽  
Author(s):  
Yi-Yi Meng ◽  
Wei Xiang ◽  
Yin Wen ◽  
Dong-Liu Huang ◽  
Kun-Fang Cao ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Functional Divergence ◽  
Leaf Traits ◽  
Climatic Variables ◽  
Future Climate Change ◽  
Leaf Mass Per Area ◽  
Mechanical Resistance ◽  
Economic Traits ◽  
Leaf Trait ◽  
Distribution Ranges

Abstract Background and Aims We conducted a comprehensive analysis of the functional traits of leaves (leaflets) of cycads. This study was aimed to clarify the functional divergence between the earlier-origin Cycadaceae and the later-differentiated Zamiaceae, and the differences in trait associations between cycads and angiosperms. Methods We selected 20 Cycadaceae species and 21 Zamiaceae species from the same cycad garden in South China, and measured their leaf structure, economic traits, mechanical resistance (Fp), and leaf water potential at the turgor loss point (πtlp). In addition, we compiled a dataset of geographical distribution along with climatic variables for these cycad species, and some leaf traits of tropical-subtropical angiosperm woody species from literature for comparison. Key Results The results showed significantly contrasting leaf trait syndromes between the two families, with Zamiaceae species exhibiting thicker leaves, higher carbon investments, and greater Fp than Cycadaceae species. Leaf thickness (LT) and πtlp were correlated with mean climatic variables in their native distribution ranges, indicating their evolutionary adaptation to environmental conditions. Compared to the leaves of angiosperms, the cycad leaves were thicker and tougher, and more tolerant to desiccation. Greater Fp was associated with a higher structural investment in both angiosperms and cycads; however, cycads showed lower Fp at a given leaf mass per area or LT than angiosperms. Enhancement of Fp led to more negative πtlp in angiosperms, but the opposite trend was observed in cycads. Conclusions Our results reveal that variations in leaf traits of cycads are mainly influenced by taxonomy and the environment of their native range. We also demonstrate similar leaf functional associations in terms of economics, but different relationships with regard to mechanics and drought tolerance between cycads and angiosperms. This study expands our understanding of the ecological strategies and likely responses of cycads to future climate change.

Relationships among leaf traits of Australian arid zone plants: alternative modes of thermal protection

2012 ◽  
Vol 60 (6) ◽  
pp. 471 ◽  
Author(s):  
Ellen M. Curtis ◽  
Andrea Leigh ◽  
Scott Rayburg
Keyword(s):  
Water Content ◽  
Structural Damage ◽  
Near Infrared ◽  
Thermal Protection ◽  
Arid Zone ◽  
Leaf Traits ◽  
Leaf Mass Per Area ◽  
Leaf Economics Spectrum ◽  
Leaf Trait ◽  
Leaf Mass

Despite the importance of leaf traits that protect against critically high leaf temperatures, relationships among such traits have not been investigated. Further, while some leaf trait relationships are well documented across biomes, little is known about such associations within a biome. This study investigated relationships between nine leaf traits that protect leaves against excessively high temperatures in 95 Australian arid zone species. Seven morphological traits were measured: leaf area, length, width, thickness, leaf mass per area, water content, and an inverse measure of pendulousness. Two spectral properties were measured: reflectance of visible and near-infrared radiation. Three key findings emerged: (1) leaf pendulousness increased with leaf size and leaf mass per area, the former relationship suggesting that pendulousness affords thermal protection when leaves are large; (2) leaf mass per area increased with thickness and decreased with water content, indicating alternative means for protection through increasing thermal mass; (3) spectral reflectance increased with leaf mass per area and thickness and decreased with water content. The consistent co-variation of thermal protective traits with leaf mass per area, a trait not usually associated with thermal protection, suggests that these traits fall along the leaf economics spectrum, with leaf longevity increasing through protection not only against structural damage but also against heat stress.

scholarly journals Predicted Future Benefits for an Endemic Rodent in the Irano-Turanian Region

Climate ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 16
Author(s):  
Suzanna Meeussen ◽  
Anouschka Hof
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Species Distribution Modelling ◽  
Geographic Range ◽  
Future Climate ◽  
Future Climate Change ◽  
Distribution Ranges ◽  
Bioclimatic Variables ◽  
Suitable Area ◽  
The Impact

Climate change is expected to have an impact on the geographical distribution ranges of species. Endemic species and those with a restricted geographic range may be especially vulnerable. The Persian jird (Meriones persicus) is an endemic rodent inhabiting the mountainous areas of the Irano-Turanian region, where future desertification may form a threat to the species. In this study, the species distribution modelling algorithm MaxEnt was used to assess the impact of future climate change on the geographic distribution range of the Persian jird. Predictions were made under two Representative Concentration Pathways and five different climate models for the years 2050 and 2070. It was found that both bioclimatic variables and land use variables were important in determining potential suitability of the region for the species to occur. In most cases, the future predictions showed an expansion of the geographic range of the Persian jird which indicates that the species is not under immediate threat. There are however uncertainties with regards to its current range. Predictions may therefore be an over or underestimation of the total suitable area. Further research is thus needed to confirm the current geographic range of the Persian jird to be able to improve assessments of the impact of future climate change.

scholarly journals Effect of leaf temperature on the estimation of photosynthetic and other traits of wheat leaves from hyperspectral reflectance

2020 ◽  
Author(s):  
Hammad A Khan ◽  
Yukiko Nakamura ◽  
Robert T Furbank ◽  
John R Evans
Keyword(s):  
Leaf Traits ◽  
Leaf Temperature ◽  
Physiological Traits ◽  
Leaf Mass Per Area ◽  
Hyperspectral Reflectance ◽  
Wheat Varieties ◽  
Unit Leaf ◽  
Temperature Signal ◽  
Wheat Leaves ◽  
Nitrogen Contents

Abstract A growing number of leaf traits can be estimated from hyperspectral reflectance data. These include structural and compositional traits, such as leaf mass per area (LMA) and nitrogen and chlorophyll content, but also physiological traits such a Rubisco carboxylation activity, electron transport rate, and respiration rate. Since physiological traits vary with leaf temperature, how does this impact on predictions made from reflectance measurements? We investigated this with two wheat varieties, by repeatedly measuring each leaf through a sequence of temperatures imposed by varying the air temperature in a growth room. Leaf temperatures ranging from 20 °C to 35 °C did not alter the estimated Rubisco capacity normalized to 25 °C (Vcmax25), or chlorophyll or nitrogen contents per unit leaf area. Models estimating LMA and Vcmax25/N were both slightly influenced by leaf temperature: estimated LMA increased by 0.27% °C–1 and Vcmax25/N increased by 0.46% °C–1. A model estimating Rubisco activity closely followed variation associated with leaf temperature. Reflectance spectra change with leaf temperature and therefore contain a temperature signal.

scholarly journals Linking hydraulic traits to tropical forest function in a size-structured and trait-driven model (TFS v.1-Hydro)

2016 ◽  
Vol 9 (11) ◽  
pp. 4227-4255 ◽  
Author(s):  
Bradley O. Christoffersen ◽  
Manuel Gloor ◽  
Sophie Fauset ◽  
Nikolaos M. Fyllas ◽  
David R. Galbraith ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Water Potential ◽  
Plant Traits ◽  
Coupled Model ◽  
Leaf Traits ◽  
Tree Size ◽  
Leaf Mass Per Area ◽  
Stem Water Potential ◽  
Plant Hydraulics ◽  
Individual Trees

Abstract. Forest ecosystem models based on heuristic water stress functions poorly predict tropical forest response to drought partly because they do not capture the diversity of hydraulic traits (including variation in tree size) observed in tropical forests. We developed a continuous porous media approach to modeling plant hydraulics in which all parameters of the constitutive equations are biologically interpretable and measurable plant hydraulic traits (e.g., turgor loss point πtlp, bulk elastic modulus ε, hydraulic capacitance Cft, xylem hydraulic conductivity ks,max, water potential at 50 % loss of conductivity for both xylem (P50,x) and stomata (P50,gs), and the leaf : sapwood area ratio Al : As). We embedded this plant hydraulics model within a trait forest simulator (TFS) that models light environments of individual trees and their upper boundary conditions (transpiration), as well as providing a means for parameterizing variation in hydraulic traits among individuals. We synthesized literature and existing databases to parameterize all hydraulic traits as a function of stem and leaf traits, including wood density (WD), leaf mass per area (LMA), and photosynthetic capacity (Amax), and evaluated the coupled model (called TFS v.1-Hydro) predictions, against observed diurnal and seasonal variability in stem and leaf water potential as well as stand-scaled sap flux. Our hydraulic trait synthesis revealed coordination among leaf and xylem hydraulic traits and statistically significant relationships of most hydraulic traits with more easily measured plant traits. Using the most informative empirical trait–trait relationships derived from this synthesis, TFS v.1-Hydro successfully captured individual variation in leaf and stem water potential due to increasing tree size and light environment, with model representation of hydraulic architecture and plant traits exerting primary and secondary controls, respectively, on the fidelity of model predictions. The plant hydraulics model made substantial improvements to simulations of total ecosystem transpiration. Remaining uncertainties and limitations of the trait paradigm for plant hydraulics modeling are highlighted.

Variation in longevity and traits of leaves among co-occurring understorey plants in a tropical montane forest

2008 ◽  
Vol 24 (2) ◽  
pp. 121-133 ◽  
Author(s):  
Satomi Shiodera ◽  
Joeni S. Rahajoe ◽  
Takashi Kohyama
Keyword(s):  
Life Form ◽  
Census Data ◽  
Condensed Tannin ◽  
Leaf Traits ◽  
Life Forms ◽  
Montane Forest ◽  
Cox Proportional Hazards ◽  
Leaf Longevity ◽  
Tropical Montane Forest ◽  
Leaf Mass Per Area

Abstract:The relationship between leaf longevity and other leaf traits was compared among different life-form categories (trees, herbs, climbers and epiphytes) of 101 plant species in a tropical montane forest on Mt. Halimun, West Java, Indonesia. We applied the Cox proportional hazards regression to estimate the leaf longevity of each species from 30 mo of census data. We examined whether estimated longevity was explained by either species life-form categories, taxonomic groupings (eudicots, monocots, magnoliids and chloranthales, and ferns) or such leaf traits as leaf area, leaf mass per area (LMA), mass-based leaf nitrogen, penetrometer reading, condensed-tannin-free total phenolics and condensed tannin. There was a wide-ranged interspecific variation in leaf longevity, mostly 10–50 mo, similarly across life-form categories. LMA showed a strong positive influence on leaf longevity. We found that relationships between leaf longevity and some leaf traits were different among various life forms. Trees tended to have high LMA, while climbers tended to have low LMA at the same leaf longevity. We hypothesize that such difference among life forms reflects shoot architecture characteristics. Multi-shoot trees with branching architecture need to have self-supporting leaves, whereas semi-epiphytic climbers can maintain relatively low biomass investment to leaves hanging or relying upon the mechanical support from host plants.

scholarly journals Effects of microhabitat on leaf traits in Digitalis grandiflora L. (Veronicaceae) growing at forest edge and interior

2014 ◽  
Vol 66 (2) ◽  
pp. 615-627
Author(s):  
J. Kołodziejek
Keyword(s):  
Soil Moisture ◽  
Leaf Area ◽  
Stomatal Density ◽  
Leaf Traits ◽  
Dry Mass ◽  
Forest Edge ◽  
Leaf Mass Per Area ◽  
Forest Interior ◽  
The Mean ◽  
Shade Leaves

The morphological, anatomical and biochemical traits of the leaves of yellow foxglove (Digitalis grandiflora Mill.) from two microhabitats, forest interior (full shade under oak canopy) and forest edge (half shade near shrubs), were studied. The microhabitats differed in the mean levels of available light, but did not differ in soil moisture. The mean level of light in the forest edge microhabitat was significantly higher than in the forest interior. Multivariate ANOVA was used to test the effects of microhabitat. Comparison of the available light with soil moisture revealed that both factors significantly influenced the morphological and anatomical variables of D. grandiflora. Leaf area, mass, leaf mass per area (LMA), surface area per unit dry mass (SLA), density and thickness varied greatly between leaves exposed to different light regimes. Leaves that developed in the shade were larger and thinner and had a greater SLA than those that developed in the half shade. In contrast, at higher light irradiances, at the forest edge, leaves tended to be thicker, with higher LMA and density. Stomatal density was higher in the half-shade leaves than in the full-shade ones. LMA was correlated with leaf area and mass and to a lesser extent with thickness and density in the forest edge microsite. The considerable variations in leaf density and thickness recorded here confirm the very high variation in cell size and amounts of structural tissue within species. The leaf plasticity index (PI) was the highest for the morphological leaf traits as compared to the anatomical and biochemical ones. The nitrogen content was higher in the ?half-shade leaves? than in the ?shade leaves?. Denser leaves corresponded to lower nitrogen (N) contents. The leaves of plants from the forest edge had more potassium (K) than leaves of plants from the forest interior on an area basis but not on a dry mass basis; the reverse was true for phosphorus.

scholarly journals Predicting Leaf Trait Variability as a Functional Descriptor of the Effect of Climate Change in Three Perennial Grasses

Diversity ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 233
Author(s):  
Marwa Hamdani ◽  
Khouloud Krichen ◽  
Mohamed Chaieb
Keyword(s):  
Functional Traits ◽  
Leaf Traits ◽  
Perennial Grasses ◽  
Arid Ecosystems ◽  
Leaf Trait ◽  
Grassland Species ◽  
Dimensional Shrinkage ◽  
Potential Link ◽  
Dehydration Avoidance ◽  
Stipa Lagascae

Aims of the study: The most important trends of the current climate variability is the scarcity of rains that affects arid ecosystems. The aim of this study was to explore the variability of leaf functional traits by which grassland species survive and resist drought and to investigate the potential link between resource use efficiency and water scarcity resistance strategies of species. Methods: Three grasses (Cenchrus ciliaris (C4), Stipa parviflora and Stipa lagascae (C3)) were established in a randomized block consisting of eleven replications. The seedlings were kept under increasing levels of water stress. In addition to their functional leaf traits, the rate of water loss and dimensional shrinkage were also measured. Key Results: Thicker and denser leaves, with higher dry matter contents, low specific leaf area and great capacity of water retention are considered among the grasses’ strategies of dehydration avoidance. Significant differences between the means of the functional traits were obtained. Furthermore, strong correlations among leaf traits were also detected (Spearman’s r exceeding 0.8). Conclusions: The results provide evidence that the studied grasses respond differently to drought by exhibiting a range of interspecific functional strategies that may ameliorate the resilience of grassland species communities under extreme drought events.

scholarly journals Leaf Photosynthetic Capacity of Sunlit and Shaded Mature Leaves in a Deciduous Forest

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 318
Author(s):  
Guangman Song ◽  
Quan Wang ◽  
Jia Jin
Keyword(s):  
Close Relationships ◽  
Deciduous Forest ◽  
Photosynthetic Capacity ◽  
Leaf Gas Exchange ◽  
Nitrogen Concentration ◽  
Leaf Traits ◽  
Leaf Nitrogen ◽  
Leaf Mass Per Area ◽  
Clear Understanding ◽  
Equivalent Water Thickness

A clear understanding of the dynamics of photosynthetic capacity is crucial for accurate modeling of ecosystem carbon uptake. However, such dynamical information is hardly available and has dramatically impeded our understanding of carbon cycles. Although tremendous efforts have been made in coupling the dynamic information of photosynthetic capacity into models, using “proxies” rooted from the close relationships between photosynthetic capacity and other available leaf parameters remains the popular selection. Unfortunately, no consensus has yet been reached on such “proxies”, leading them only applicable to limited cases. In this study, we aim to identify if there are close relationships between the photosynthetic capacity (represented by the maximum carboxylation rate, Vcmax) and leaf traits for mature broadleaves within a cold temperature deciduous forest. This is based on a long-term in situ dataset including leaf chlorophyll content (Chl), leaf nitrogen concentration (Narea, Nmass), leaf carbon concentration (Carea, Cmass), equivalent water thickness (EWT), leaf mass per area (LMA), and leaf gas exchange measurements from which Vcmax was derived, for both sunlit and shaded leaves during leaf mature periods from 2014 to 2019. The results show that the Vcmax values of sunlit and shaded leaves were relatively stable during these periods, and no statistically significant interannual variations occurred (p > 0.05). However, this is not applicable to specific species. Path analysis revealed that Narea was the major contributor to Vcmax for sunlit leaves (0.502), while LMA had the greatest direct relationship with Vcmax for shaded leaves (0.625). The LMA has further been confirmed as a primary proxy if no leaf type information is available. These findings provide a promising way to better understand photosynthesis and to predict carbon and water cycles in temperate deciduous forests.

Within-species leaf trait variation and ecological flexibility in resprouting tropical trees

2012 ◽  
Vol 28 (5) ◽  
pp. 527-530 ◽  
Author(s):  
Carl F. Salk
Keyword(s):  
Leaf Area ◽  
Tree Species ◽  
Environmental Changes ◽  
Functional Trait ◽  
Leaf Mass Per Area ◽  
Trait Variation ◽  
Leaf Functional Traits ◽  
Leaf Trait ◽  
Neotropical Tree ◽  
Ecological Flexibility

Plants have an inherent flexibility to respond to different environmental conditions. One axis of plant ecophysiological strategy is seen in the spectrum of leaf functional traits. Flexibility in these traits would be suggestive of plants’ phenotypic plasticity in response to environmental changes. This research seeks to identify differences between leaves of sprout and non-sprout shoots of a broad ecological range of neotropical tree species. Using a functional-trait approach, this study assesses a large pool of species for within-species physiological flexibility. Leaf mass per area (LMA) and leaf area were measured for plants of sprout and non-sprout origin for 26 tree species grown in a reforestation plantation in Panama. Sprouts had a consistently lower LMA than non-sprouts, but there was no consistent pattern for leaf area. These trends show that sprouts are more like pioneer species than conspecific saplings, a finding in general agreement with fast sprout growth seen in previous studies. Further, later-successional (high LMA) species showed a greater reduction of LMA in sprouts. These results show that tropical tree species adjust physiologically to changing ecological roles and suggest that certain species may be more resilient than realized to changing climate and disturbance patterns.

Interspecific covariation between stomatal density and other functional leaf traits in a local flora

Botany ◽  
2010 ◽  
Vol 88 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Jessy Loranger ◽  
Bill Shipley
Keyword(s):  
Chlorophyll Content ◽  
Stomatal Density ◽  
Leaf Traits ◽  
Functional Ecology ◽  
Leaf Trait ◽  
Leaf Chlorophyll ◽  
Sun And Shade Leaves ◽  
Angiosperm Species ◽  
Sun And Shade ◽  
Shade Leaves

Despite the importance of stomata in leaf functioning, and despite the recent interest in interspecific leaf trait covariation in functional ecology, little is known about how stomatal density relates to other leaf traits in a broad interspecific context. This is especially important because stomatal density has been widely used to deduce temporal variation in atmospheric CO2 concentrations [CO2atm] from fossilized or herbarium leaves. We therefore measured stomatal density, specific leaf area (SLA) and its components, leaf thickness, and leaf chlorophyll content in both sun and shade leaves of 169 individuals from 52 angiosperm species in southwestern Quebec. Using mixed models, we show that stomatal density decreases allometrically with increasing SLA and chlorophyll content, and increases allometrically with increasing lamina thickness. The sun–shade contrast changes the intercepts, but not the slopes, of these relationships. It is important to take into consideration these relations when correlating stomatal density with [CO2], to avoid spurious interpretations.

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