The Hydraulic Architecture of Petioles and Leaves in Tropical Fern Species under Different Levels of Canopy Openness

2016 ◽  
Vol 177 (2) ◽  
pp. 209-216 ◽  
Author(s):  
M. Klepsch ◽  
A. Lange ◽  
G. Angeles ◽  
K. Mehltreter ◽  
S. Jansen
Keyword(s):  
Canopy Openness ◽  
Hydraulic Architecture ◽  
Fern Species ◽  
Different Levels

scholarly journals Taxonomic, Phylogenetic, and Functional Diversity of Ferns at Three Differently Disturbed Sites in Longnan County, China

Diversity ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 135
Author(s):  
Xiaohua Dai ◽  
Chunfa Chen ◽  
Zhongyang Li ◽  
Xuexiong Wang
Keyword(s):  
Functional Diversity ◽  
Sampling Effort ◽  
Human Disturbances ◽  
Subtropical Zone ◽  
Indicator Group ◽  
Fern Species ◽  
Hill Numbers ◽  
Disturbed Site ◽  
Different Levels ◽  
Biodiversity Analysis

Human disturbances are greatly threatening to the biodiversity of vascular plants. Compared to seed plants, the diversity patterns of ferns have been poorly studied along disturbance gradients, including aspects of their taxonomic, phylogenetic, and functional diversity. Longnan County, a biodiversity hotspot in the subtropical zone in South China, was selected to obtain a more thorough picture of the fern–disturbance relationship, in particular, the taxonomic, phylogenetic, and functional diversity of ferns at different levels of disturbance. In 90 sample plots of 5 × 5 m2 along roadsides at three sites, we recorded a total of 20 families, 50 genera, and 99 species of ferns, as well as 9759 individual ferns. The sample coverage curve indicated that the sampling effort was sufficient for biodiversity analysis. In general, the taxonomic, phylogenetic, and functional diversity measured by Hill numbers of order q = 0–3 indicated that the fern diversity in Longnan County was largely influenced by the level of human disturbance, which supports the ‘increasing disturbance hypothesis’. Many functional traits of ferns at the most disturbed site were adaptive to the disturbance. There were also some indicators of fern species responding to the different disturbance levels. Hence, ferns may be considered as a good indicator group for environmental stress.

Leaf physiological response to light environment of three tree fern species in a Mexican cloud forest

2013 ◽  
Vol 29 (3) ◽  
pp. 217-228 ◽  
Author(s):  
K. Riaño ◽  
O. Briones
Keyword(s):  
Quantum Yield ◽  
Cloud Forest ◽  
Leaf Traits ◽  
Light Sensitivity ◽  
Canopy Openness ◽  
Tree Fern ◽  
Interspecific Differences ◽  
Open Canopy ◽  
Fern Species ◽  
Light Saturation Point

Abstract:Abundance and physiology of three understorey tree fern species were compared in a Mexican cloud forest. We hypothesized that the distribution of species would be associated with canopy openness and leaf physiological characteristics. In gullies (1–2% full sun), Alsophila firma was abundant, Cyathea divergens was distributed in moderately open places (4–9%), and Lophosoria quadripinnata preferred more open canopy (9–30%). Although 11 leaf traits of five plants of each species growing under closed and open canopies over 1 y did not differ within species, there were significant interspecific differences. Alsophila firma had comparatively low maximum electron transport rate ETRmax (26.8 ± 1.81 μmol m−2 s−1) and ETR light saturation point (ETRLSP: 261 ± 36.1 μmol m−2 s−1), high specific leaf area (SLA), thin leaves and decreased quantum yield during a leaf desiccation experiment. Cyathea divergens had relatively high maximum quantum yield (0.84 ± 0.004), ETRmax (37.3 ± 1.8 μmol m−2 s−1) and ETRLSP (409 ± 40.0 μmol m−2 s−1). Lophosoria quadripinnata had comparatively thick leaves, low SLA, high predawn water potential, high density (606 ± 25.5 mm−2) and small length (0.026 ± 0.002 mm) stomata. The results support the hypothesis that light sensitivity shapes tree fern distribution in the cloud forest.

scholarly journals Environmental variables and tree population structures in deciduous forests of central Brazil with different levels of logging

2008 ◽  
Vol 51 (2) ◽  
pp. 419-431 ◽  
Author(s):  
Daniel Luis Mascia Vieira ◽  
Aldicir Scariot
Keyword(s):  
Soil Cover ◽  
Deciduous Forest ◽  
Life Forms ◽  
Deciduous Forests ◽  
Canopy Openness ◽  
Central Brazil ◽  
Tree Population ◽  
Population Structures ◽  
Eugenia Dysenterica ◽  
Different Levels

Population structures of six tree species in three fragments of intact seasonal deciduous forest and three fragments disturbed by logging were studied in the northeastern Goiás. Forty random 400 m² plots were allocated in each fragment to survey plant population structures, number of stumps, cattle feces, burnt logs, and canopy openness. Soil cover by life forms was estimated in 1m² sub-plots. Lianas were abundant in intermediately logged fragments and invasive herbs in the most disturbed fragment. Cattle avoided dense herbaceous strata, such as liana tangles. Cavanillesia arborea, Eugenia dysenterica and Swartzia multijuga trees occurred at very low densities in all the fragments and their seedlings were practically absent, which might endanger their future populations in these fragments. Myracrodruon urundeuva, Tabebuia impetiginosa and Astronium fraxinifolium, the most logged species, had high density of seedlings in all the fragments. However, the highest density of saplings and juvenile individuals occurred in the most disturbed fragment.

Spore Germination of Three Tree Fern Species in Response to Light, Water Potential, and Canopy Openness

2015 ◽  
Vol 105 (2) ◽  
pp. 59-72 ◽  
Author(s):  
Karolina Riaño Ospina ◽  
Oscar Briones ◽  
Blanca Pérez-García
Keyword(s):  
Water Potential ◽  
Spore Germination ◽  
Canopy Openness ◽  
Tree Fern ◽  
Light Water ◽  
Fern Species

scholarly journals The predominant role of soil in determining species composition of fern communities in subtropical coastal forest ecosystems

2019 ◽  
Vol 14 (4) ◽  
pp. 559-575
Author(s):  
Amanda Angélica Carmes ◽  
Michele de Sá Dechoum ◽  
Pedro Fiaschi
Keyword(s):  
Species Richness ◽  
Species Composition ◽  
Atlantic Forest ◽  
Vegetation Structure ◽  
Environmental Variables ◽  
Abiotic Factors ◽  
Canopy Openness ◽  
Vegetation Types ◽  
Edaphic Conditions ◽  
Fern Species

Ferns are an important component in the understorey of tropical forests and their distribution is influenced by several biotic and abiotic factors. At a regional scale, soil characteristics and canopy openness play an important role in fern species composition and richness, as well as in the abundance of individuals. Our objective was to compare the influence of edaphic conditions and vegetation structure on the abundance and distribution of fern communities in Atlantic forest and restinga forest. Our hypotheses were that fern species richness and diversity are higher in Atlantic forest than in restinga due to limiting conditions in this habitat and the composition of fern species in Atlantic forest differs from restinga, especially due to differences in edaphic conditions. A principal coordinates analysis was applied to ordinate sampling units in relation to the environmental variables and a permutational multivariate analysis of variance was used to test that environmental variables did not differ between the two vegetation types. Species richness was compared using rarefaction curves. The influence of abiotic variables in species composition and abundance was verified using canonical correspondence analysis. No differences were observed in species richness, diversity or dominance between vegetation types, although abundance was higher in restinga. Fern communities respond to edaphic conditions and vegetation structure variations between vegetation types, the soil playing a major role. A greater variety of habitats resulting from differences in soil drainage in restinga facilitates the co-existence of species with different ecological tolerance, increasing local diversity and compensating for limiting conditions in restinga.

Leaf hydraulic architecture and water relations of three ferns from contrasting light habitats

2010 ◽  
Vol 37 (6) ◽  
pp. 566 ◽  
Author(s):  
Maria A. Lo Gullo ◽  
Fabio Raimondo ◽  
Alessandro Crisafulli ◽  
Sebastiano Salleo ◽  
Andrea Nardini
Keyword(s):  
Water Potential ◽  
Hydraulic Resistance ◽  
Water Relations ◽  
The Other ◽  
Vascular Bundles ◽  
Hydraulic Architecture ◽  
Turgor Loss Point ◽  
Leaf Osmotic Potential ◽  
Fern Species ◽  
Xylem Conduits

Leaf hydraulic architecture and water relations of three fern species were measured. The species selected were adapted either to deeply shaded (Woodwardia radicans), moderately shaded (Dryopteris affinis) or moderately sunny (Polystichum setiferum) habitats, as confirmed by microclimatic measurements performed in the field. Leaf water potential (Ψleaf) was lower and leaf conductance to water vapour (gL) was higher in P. setiferum than in the shade-adapted ferns. Leaf osmotic potential and water potential at the turgor loss point were lower in the sun-adapted species than in the other ferns. Leaf hydraulic resistance (Rleaf) was lowest in P. setiferum and Rleaf was correlated with gL across species. Low Rleaf was coordinated with low rachis hydraulic resistance (Rrachis). Low values of Rrachis in P. setiferum were not due to the presence of wide xylem conduits as checked on the basis of anatomical measurements, but to increased radial permeability of vascular bundles. This was a consequence of the absence of endodermis surrounding the vascular bundles in P. setiferum, which was observed in the rachis of shade-adapted species. We conclude that hydraulic adjustment of fern fronds is a key component of adaptation of pteridophytes to contrasting light habitats.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

Memory Processes, Aging, Cognitive Decline, and Neurodegenerative Diseases

2006 ◽  
Vol 11 (4) ◽  
pp. 304-311 ◽  
Author(s):  
Lars-Göran Nilsson
Keyword(s):  
Cognitive Impairment ◽  
Cognitive Decline ◽  
Neurodegenerative Disease ◽  
Genetic Markers ◽  
Brain Activity ◽  
Memory Performance ◽  
Modeling And Simulations ◽  
Aging And Health ◽  
Explained Variance ◽  
Different Levels

This paper presents four domains of markers that have been found to predict later cognitive impairment and neurodegenerative disease. These four domains are (1) data patterns of memory performance, (2) cardiovascular factors, (3) genetic markers, and (4) brain activity. The critical features of each domain are illustrated with data from the longitudinal Betula Study on memory, aging, and health ( Nilsson et al., 1997 ; Nilsson et al., 2004 ). Up to now, early signs regarding these domains have been examined one by one and it has been found that they are associated with later cognitive impairment and neurodegenerative disease. However, it was also found that each marker accounts for only a very small part of the total variance, implying that single markers should not be used as predictors for cognitive decline or neurodegenerative disease. It is discussed whether modeling and simulations should be used as tools to combine markers at different levels to increase the amount of explained variance.

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