Leaf trait variation in three species through canopy strata in a semi-evergreen Neotropical forest

2003 ◽  
Vol 81 (4) ◽  
pp. 398-404 ◽  
Author(s):  
Laura Yáñez-Espinosa ◽  
Teresa Terrazas ◽  
Lauro López-Mata ◽  
Juan Ignacio Valdez-Hernández
Keyword(s):  
Environmental Variables ◽  
Forest Canopy ◽  
Structural Changes ◽  
Leaf Shape ◽  
Vapour Pressure Deficit ◽  
Leaf Structure ◽  
Leaf Trait ◽  
Neotropical Forest ◽  
Shade Tolerant Species ◽  
Canonical Variates

Morphological and structural changes among and within leaves of Aphananthe monoica (Hemsley) Leroy, Pleuranthodendron lindenii (Turczaninov) Sleumer, and Psychotria costivenia Grisebach were documented through canopy strata (<10, 10–20, and >20 m high) and related to some environmental variables in a semi-evergreen Neotropical forest. The principal components analysis revealed that two components explained 93% of total variation. The first component (76.4%) denoted leaf structure, whereas the second (16.6%) denoted leaf shape. Anatomical differences in transverse leaf sections among different canopy strata were observed in Aphananthe monoica and Pleuranthodendron lindenii. Variance analyses showed significant differences among strata for leaf characters and light, relative humidity, vapour pressure deficit, and temperature. Canonical correlation analysis revealed that the first pair of canonical variates of leaf characters and environmental variables were closely related. The first environmental variate represented the changes in microclimate along forest canopy strata. Leaf structure observed in Aphananthe monoica and Pleuranthodendron lindenii suggested that they are intermediate shade-tolerant species, and Psychotria costivenia is a shade-tolerant understorey species. Aphananthe monoica and Pleuranthodendron lindenii, which during their life span occupy different positions in the vertical strata, showed the highest leaf variation.Key words: tropical trees, Aphananthe monoica, Pleuranthodendron lindenii, Psychotria costivenia, leaf variation, Veracruz.

scholarly journals Exploring how groundwater buffers the influence of heatwaves on vegetation function during multi-year droughts

2021 ◽  
Vol 12 (3) ◽  
pp. 919-938
Author(s):  
Mengyuan Mu ◽  
Martin G. De Kauwe ◽  
Anna M. Ukkola ◽  
Andy J. Pitman ◽  
Weidong Guo ◽  
...  
Keyword(s):  
Land Surface ◽  
Forest Canopy ◽  
Climate Models ◽  
Root Zone ◽  
Stomatal Closure ◽  
Capillary Rise ◽  
Vapour Pressure Deficit ◽  
Global Climate Models ◽  
Surface Model ◽  
The Impact

Abstract. The co-occurrence of droughts and heatwaves can have significant impacts on many socioeconomic and environmental systems. Groundwater has the potential to moderate the impact of droughts and heatwaves by moistening the soil and enabling vegetation to maintain higher evaporation, thereby cooling the canopy. We use the Community Atmosphere Biosphere Land Exchange (CABLE) land surface model, coupled to a groundwater scheme, to examine how groundwater influences ecosystems under conditions of co-occurring droughts and heatwaves. We focus specifically on south-east Australia for the period 2000–2019, when two significant droughts and multiple extreme heatwave events occurred. We found groundwater plays an important role in helping vegetation maintain transpiration, particularly in the first 1–2 years of a multi-year drought. Groundwater impedes gravity-driven drainage and moistens the root zone via capillary rise. These mechanisms reduced forest canopy temperatures by up to 5 ∘C during individual heatwaves, particularly where the water table depth is shallow. The role of groundwater diminishes as the drought lengthens beyond 2 years and soil water reserves are depleted. Further, the lack of deep roots or stomatal closure caused by high vapour pressure deficit or high temperatures can reduce the additional transpiration induced by groundwater. The capacity of groundwater to moderate both water and heat stress on ecosystems during simultaneous droughts and heatwaves is not represented in most global climate models, suggesting that model projections may overestimate the risk of these events in the future.

Topography consistently drives intra‐ and inter‐specific leaf trait variation within tree species complexes in a Neotropical forest

Oikos ◽  
2020 ◽  
Vol 129 (10) ◽  
pp. 1521-1530 ◽  
Author(s):  
Sylvain Schmitt ◽  
Bruno Hérault ◽  
Émilie Ducouret ◽  
Anne Baranger ◽  
Niklas Tysklind ◽  
...  
Keyword(s):  
Tree Species ◽  
Trait Variation ◽  
Leaf Trait ◽  
Neotropical Forest ◽  
Species Complexes

Modelling stomatal conductance in a northern deciduous forest, Chalk River, Ontario

1994 ◽  
Vol 24 (5) ◽  
pp. 904-910 ◽  
Author(s):  
J. Harry McCaughey ◽  
Antonio Iacobelli
Keyword(s):  
Stomatal Conductance ◽  
Least Squares ◽  
Environmental Variables ◽  
Deciduous Forest ◽  
Vapour Pressure Deficit ◽  
Multiple Linear Regression Model ◽  
Nonlinear Least Squares ◽  
Global Solar Radiation ◽  
White Birch ◽  
Conductance Data

Modelling results of stomatal conductance of trembling aspen (Populustremuloides Michx.) and white birch (Betulapapyrifera Marsh.) are reported. Stomatal conductance for the two species was related to global solar radiation, vapour pressure deficit, and air temperature using both linear and nonlinear least squares approaches. Both approaches provided an equally poor fit when relating the large scatter of stomatal conductance data to each of the environmental variables separately. However, an additive, multiple linear regression model and a multiplicative, nonlinear least squares model were able to explain between 50 and 62% of the variability in stomatal conductance when all three environmental variables were included in the models. The two models were able to track changes in stomatal conductance from one half-hour period to the next.

Combining management based indices with environmental parameters to explain regional variation in soil carbon under dryland cropping in South Australia

Soil Research ◽  
2013 ◽  
Vol 51 (8) ◽  
pp. 738 ◽  
Author(s):  
Lynne M. Macdonald ◽  
Tim Herrmann ◽  
Jeffrey A. Baldock
Keyword(s):  
Environmental Variables ◽  
Explanatory Power ◽  
Regional Scale ◽  
South Australia ◽  
Vapour Pressure Deficit ◽  
Environmental Parameters ◽  
Decomposition Processes ◽  
Historical Management ◽  
Broad Scale

Identifying drivers of variation in soil organic carbon (OC) at a regional scale is often hampered by a lack of historical management information. Focusing on red-brown-earth soils (Chromosol) under dryland agriculture in the Mid-North and Eyre Peninsula of South Australia, our aims were 2-fold: (i) to provide a baseline of soil OC stocks (0.3 m) and OC fractions (mid-infrared predictions of particulate, humus, and resistant OC in 0.1 m samples) in cropping and crop-pasture systems; and (ii) to evaluate whether the inclusion of management-based indices could assist in explaining regional-level variation in OC stocks and fractions. Soil OC stocks in both regions varied ~20 Mg ha–1, with higher OC stocks in the Mid-North (38 Mg ha–1) than the Eyre Peninsula (29.1 Mg ha–1). The humus OC fraction was the dominant fraction, while the particulate OC was the most variable. Environmental variables only partially explained soil OC variability, with vapour pressure deficit (VPD) offering the greatest potential and likely acting as an integrator of temperature and moisture on plant growth and decomposition processes. Differences between broad-scale cropping and crop–pasture systems were limited. In the Mid-North, variability in soil OC stocks and fractions was high, and could not be explained by environmental or management variables. Higher soil OC concentrations (0.1 m) in the Eyre Peninsula cropping than crop–pasture soils were largely accounted for in the particulate OC fraction and are therefore unlikely to represent a long-term stable OC pool. Use of the management data in index format added some explanatory power to the variability in OC stocks over the main environmental variables (VPD, slope) within the Eyre Peninsula cropping soils only. In the wider context, the management data were useful in interpreting differences between regional findings and highlighted difficulties in using uninformed, broad-scale management categories.

A self-perpetuating bamboo disturbance cycle in a neotropical forest

2006 ◽  
Vol 22 (5) ◽  
pp. 587-597 ◽  
Author(s):  
Bronson W. Griscom ◽  
P. Mark S. Ashton
Keyword(s):  
Forest Canopy ◽  
Basal Area ◽  
Size Class ◽  
Tree Canopy ◽  
Physical Damage ◽  
Tree Form ◽  
Madre De Dios ◽  
Neotropical Forest ◽  
The Impact ◽  
Canopy Damage

We investigate a hypothesis for explaining maintenance of forest canopy dominance: bamboo (Guadua weberbaueri and Guadua sarcocarpa) loads and crushes trees, resulting in a self-perpetuating disturbance cycle. Forest inventory data revealed a peculiar pattern of tree form and size class distribution in bamboo-dominated plots within the Tambopata River watershed, Madre de Dios, Peru. Bamboo disproportionately loaded trees 5–29 cm in diameter, and this size class had over seven times more canopy damage than trees in control plots without bamboo. These differences were accompanied by reduced tree basal area and tree density in the 5–29-cm-diameter size class in the presence of bamboo. Elevated tree canopy damage was not apparent for trees ≥30 cm dbh, which are beyond the reach of bamboo. Additional evidence for the impact of bamboo was revealed by an experiment using artificial metal trees. Artificial trees in bamboo-dominated forest plots had nine times higher frequency of physical damage and nine times more plant mass loading as compared with control plots. Our results support the hypothesis that bamboo loading causes elevated physical damage to trees and suppresses tree recruitment, particularly for trees 5–29 cm in diameter.

scholarly journals Map-based cloning and promoter variation analysis of the lobed leaf gene BoLMI1a in ornamental kale (Brassica oleracea L. var. acephala)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Bin Zhang ◽  
Wendi Chen ◽  
Xing Li ◽  
Wenjing Ren ◽  
Li Chen ◽  
...  
Keyword(s):  
Brassica Oleracea ◽  
Promoter Region ◽  
Leaf Shape ◽  
Dominant Gene ◽  
Orthologous Gene ◽  
Snp Markers ◽  
Leaf Trait ◽  
Shape Formation ◽  
Ornamental Kale ◽  
Lobed Leaf

Abstract Background Leaf shape is an important agronomic trait in ornamental kale (Brassica oleracea L. var. acephala). Although some leaf shape-related genes have been reported in ornamental kale, the detailed mechanism underlying leaf shape formation is still unclear. Here, we report a lobed-leaf trait in ornamental kale, aiming to analyze its inheritance and identify the strong candidate gene. Results Genetic analysis of F2 and BC1 populations demonstrate that the lobed-leaf trait in ornamental kale is controlled by a single dominant gene, termed BoLl-1 (Brassica oleracea lobed-leaf). By performing whole-genome resequencing and linkage analyses, the BoLl-1 gene was finely mapped to a 127-kb interval on chromosome C09 flanked by SNP markers SL4 and SL6, with genetic distances of 0.6 cM and 0.6 cM, respectively. Based on annotations of the genes within this interval, Bo9g181710, an orthologous gene of LATE MERISTEM IDENTITY 1 (LMI1) in Arabidopsis, was predicted as the candidate for BoLl-1, and was renamed BoLMI1a. The expression level of BoLMI1a in lobed-leaf parent 18Q2513 was significantly higher compared with unlobed-leaf parent 18Q2515. Sequence analysis of the parental alleles revealed no sequence variations in the coding sequence of BoLMI1a, whereas a 1737-bp deletion, a 92-bp insertion and an SNP were identified within the BoLMI1a promoter region of parent 18Q2513. Verification analyses with BoLMI1a-specific markers corresponding to the promoter variations revealed that the variations were present only in the lobed-leaf ornamental kale inbred lines. Conclusions This study identified a lobed-leaf gene BoLMI1a, which was fine-mapped to a 127-kb fragment. Three variations were identified in the promoter region of BoLMI1a. The transcription level of BoLMI1a between the two parents exhibited great difference, providing new insight into the molecular mechanism underlying leaf shape formation in ornamental kale.

Tardigrades in the Canopy: Associations with Tree Vole Nests in Southwest Oregon

2020 ◽  
Author(s):  
John Villella ◽  
Jesse E. D. Miller ◽  
Alexander Young ◽  
Greg Carey ◽  
Andrew Emanuels ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Environmental Variables ◽  
Forest Canopy ◽  
Coniferous Forests ◽  
Forest Canopies ◽  
Species Numbers ◽  
The Pacific ◽  
Southwest Oregon ◽  
East West ◽  
Local Dispersal

Tardigrades live in many ecosystems, but local dispersal mechanisms and the influence of ecological gradients on tardigrade communities are not fully understood. Here we examine tardigrade communities in nests of the red tree vole (Arborimus longicaudus True), an arboreal mammal occupying the canopy of coniferous forests in western Oregon and northwestern California. We found 12 species of tardigrades from resin ducts sampled from 43 nests along a transect that spanned the east-west range of the tree vole in southern Oregon. Tardigrade occurrence was more likely in larger trees and species numbers were significantly higher in areas that received more precipitation. At sites where they occurred, tardigrades were more abundant in tree vole nests at greater heights within the forest canopy. Of the 12 species of tardigrades that were found, seven have not been previously reported in Oregon. Our results suggest that tardigrades in forest canopies in the Pacific Northwest are impacted by regional precipitation gradients as well as local environmental variables, and that nest building by small mammals may facilitate dispersal of tardigrades within the forest canopy.

The interpretation of the variations in leaf water potential and stomatal conductance found in canopies in the field

1976 ◽  
Vol 273 (927) ◽  
pp. 593-610 ◽  
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Vapour Pressure ◽  
Environmental Variables ◽  
Turgor Pressure ◽  
Radiant Energy ◽  
Vapour Pressure Deficit ◽  
Leaf Water ◽  
Scatter Diagram

Attempts to correlate values of stomatal conductance and leaf water potential with particular environmental variables in the field are generally of only limited success because they are simultaneously affected by a number of environmental variables. For example, correlations between leaf water potential and either flux of radiant energy or vapour pressure deficit show a diurnal hysteresis which leads to a scatter diagram if many values are plotted. However, a simple model may be adequate to relate leaf water potential to the flow of water through the plant. The stomatal conductance of illuminated leaves is a function of current levels of temperature, vapour pressure deficit, leaf water potential (really turgor pressure) and ambient CO 2 concentration. Consequently, when plotted against any one of these variables a scatter diagram results. Physiological knowledge of stomatal functioning is not adequate to provide a mechanistic model linking stomatal conductance to all these variables. None the less, the parameters describing the relationships with the variables can be conveniently estimated from field data by a technique of non-linear least squares, for predictive purposes and to describe variations in response from season to season and plant to plant.

scholarly journals Leaf shape influences spatial variation in photosynthetic function in Lomatia tinctoria

2014 ◽  
Vol 41 (8) ◽  
pp. 833 ◽  
Author(s):  
Andrea Leigh ◽  
Ross Hill ◽  
Marilyn C. Ball
Keyword(s):  
Leaf Shape ◽  
Leaf Tissue ◽  
Vapour Pressure Deficit ◽  
Photochemical Quenching ◽  
Water Delivery ◽  
Minor Vein ◽  
Dimensional Shape ◽  
Use Efficiency ◽  
Non Photochemical Quenching ◽  
The Relationship

A relationship exists between the two-dimensional shape of leaves and their venation architecture, such that broad or broad-lobed leaves can have leaf tissue far from major veins, potentially creating stronger gradients in water potential – and associated photosynthetic function – than found across narrow counterparts. We examined the spatial patterns of photosynthetic efficiency (ΔF/Fm′) and non-photochemical quenching (NPQ) in response to increased vapour pressure deficit (VPD) using two morphs of Lomatia tinctoria (Labill.) R.Br: those with broad-lobed and those with narrow-lobed leaves. Stomatal conductance (gs), instantaneous water use efficiency (WUE), stomatal and minor veins density also were measured. ΔF/Fm′ decreased with stress but was higher and less spatially heterogeneous across broad than narrow lobes. The strongest depression in ΔF/Fm′ in broad lobes was at the edges and in narrow lobes, the tips. Non-photochemical quenching was spatially more varied in broad lobes, increasing at the edges and tips. Variation in photosynthetic function could not be explained by gs, WUE or minor vein density, whereas proximity to major veins appeared to mitigate water stress at the tips only for broad lobes. Our findings indicate that the relationship between venation architecture and water delivery alone can partially explain the spatial pattern of photosynthetic function.

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