scholarly journals Ramification has little impact on shoot hydraulic efficiency in the sexually dimorphic genus Leucadendron (Proteaceae)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6835 ◽  
Author(s):  
Adam B. Roddy ◽  
Justin J. van Blerk ◽  
Jeremy J. Midgley ◽  
Adam G. West
Keyword(s):  
Leaf Area ◽  
Hydraulic Resistance ◽  
Leaf Traits ◽  
Sexually Dimorphic ◽  
Hydraulic Efficiency ◽  
Cross Sectional ◽  
In Series ◽  
Males And Females ◽  
Morphological Differences ◽  
The Impact

Despite the diversity of branching architectures in plants, the impact of this morphological variation on hydraulic efficiency has been poorly studied. Branch junctions are commonly thought to be points of high hydraulic resistance, but adjustments in leaf area or xylem conduit abundance or dimensions could compensate for the additional hydraulic resistance of nodal junctions at the level of the entire shoot. Here we used the sexually dimorphic genus Leucadendron (Proteaceae) to test whether variation in branch ramification impacts shoot hydraulic efficiency. We found that branch ramification was related to leaf traits via Corner’s rules such that more highly ramified shoots had smaller leaves, but that branch ramification had little consistent impact on shoot hydraulic efficiency, whether measured on a leaf area or stem cross-sectional area basis. These results suggest that the presumed increase in resistance associated with branching nodes can be compensated by other adjustments at the shoot level (e.g. leaf area adjustments, increased ramification to add additional branches in parallel rather than in series) that maintain hydraulic efficiency at the level of the entire shoot. Despite large morphological differences between males and females in the genus Leucadendron, which are due to differences in pollination and reproduction between the sexes, the physiological differences between males and females are minimal.

scholarly journals Scaling of petiole anatomies, mechanics and vasculatures with leaf size in the widespread Neotropical pioneer tree species Cecropia obtusa Trécul (Urticaceae)

2020 ◽  
Vol 40 (2) ◽  
pp. 245-258 ◽  
Author(s):  
Sébastien Levionnois ◽  
Sabrina Coste ◽  
Eric Nicolini ◽  
Clément Stahl ◽  
Hélène Morel ◽  
...  
Keyword(s):  
Leaf Area ◽  
Leaf Size ◽  
Leaf Traits ◽  
Hydraulic Efficiency ◽  
Cross Sectional ◽  
Leaf Trait ◽  
Key Factor ◽  
Leaf Economic Spectrum ◽  
Geometrical Effect ◽  
Trait Variability

Abstract Although the leaf economic spectrum has deepened our understanding of leaf trait variability, little is known about how leaf traits scale with leaf area. This uncertainty has resulted in the assumption that leaf traits should vary by keeping the same pace of variation with increases in leaf area across the leaf size range. We evaluated the scaling of morphological, tissue-surface and vascular traits with overall leaf area, and the functional significance of such scaling. We examined 1,271 leaves for morphological traits, and 124 leaves for anatomical and hydraulic traits, from 38 trees of Cecropia obtusa Trécul (Urticaceae) in French Guiana. Cecropia is a Neotropical genus of pioneer trees that can exhibit large laminas (0.4 m2 for C. obtusa), with leaf size ranging by two orders of magnitude. We measured (i) tissue fractions within petioles and their second moment of area, (ii) theoretical xylem hydraulic efficiency of petioles and (iii) the extent of leaf vessel widening within the hydraulic path. We found that different scaling of morphological trait variability allows for optimisation of lamina display among larger leaves, especially the positive allometric relationship between lamina area and petiole cross-sectional area. Increasing the fraction of pith is a key factor that increases the geometrical effect of supportive tissues on mechanical rigidity and thereby increases carbon-use efficiency. We found that increasing xylem hydraulic efficiency with vessel size results in lower leaf lamina area: xylem ratios, which also results in potential carbon savings for large leaves. We found that the vessel widening is consistent with hydraulic optimisation models. Leaf size variability modifies scaling of leaf traits in this large-leaved species.

scholarly journals Hydraulic constraints of reproduction do not explain sexual dimorphism in the genus Leucadendron (Proteaceae)

2017 ◽  
Author(s):  
Adam B. Roddy ◽  
Justin van Blerk ◽  
Jeremy J. Midgley ◽  
Adam G. West
Keyword(s):  
Sexual Dimorphism ◽  
Fire Frequency ◽  
Sexually Dimorphic ◽  
Hydraulic Efficiency ◽  
Costs Of Reproduction ◽  
Dioecious Species ◽  
Shoot Architecture ◽  
Males And Females ◽  
And Function ◽  
In Fire

AbstractBecause of the importance of reproduction in plant life history, the physiological costs of reproduction often influence vegetative structure and function. In dioecious species, these effects can be quite obvious, as different costs of male and female reproductive functions are entirely separated among different individuals in a population. In fire-prone ecosystems, in which recruitment is driven by fire frequency, many plants will maintain their seeds in the canopy, only to be released after a fire. The dioecious genus Leucadendron is a notable case of this, as females can maintain their seed cones for years, and, even more interestingly, species in the genus differ substantially in the degree to which males and females are sexually dimorphic. A recent study (Harris and Pannell 2010) argued that the hydraulic costs of maintaining seed cones for many years would effect the degree of sexual dimorphism among species. However, this assumed that shoot hydraulic architecture would be related to traits exhibiting sexual dimorphism. Here we explicitly test this hypothesis on two Leucadendron species. We found (1) that metrics of branch ramification used in the previous study to characterize dimorphism do not conform to known scaling relationships and (2) that sexual dimorphism in shoot architecture has no effect on hydraulic efficiency. Both of these results seriously question the pattern described by Harris and Pannell (2010) and suggest that the hydraulic costs of prolonged seed retention in Leucadendron do not significantly affect branch architecture.

scholarly journals Sex-specific responses to cold in a very cold-tolerant, northern Drosophila species

Heredity ◽  
2021 ◽  
Author(s):  
Darren J. Parker ◽  
Tapio Envall ◽  
Michael G. Ritchie ◽  
Maaria Kankare
Keyword(s):  
Gene Expression ◽  
Cold Tolerance ◽  
Cold Treatment ◽  
Sexually Dimorphic ◽  
Immune Genes ◽  
Cold Tolerant ◽  
Males And Females ◽  
The Impact ◽  
Drosophila Montana ◽  
Harsh Conditions

AbstractOrganisms can plastically alter resource allocation in response to changing environmental factors. For example, in harsh conditions, organisms are expected to shift investment from reproduction toward survival; however, the factors and mechanisms that govern the magnitude of such shifts are relatively poorly studied. Here we compared the impact of cold on males and females of the highly cold-tolerant species Drosophila montana at the phenotypic and transcriptomic levels. Although both sexes showed similar changes in cold tolerance and gene expression in response to cold treatment, indicating that the majority of changes are concordant between the sexes, we identified a clear reduction in sexually dimorphic gene expression, suggesting that preparing for the colder season involves reducing investment in sex-specific traits. This reduction was larger in males than females, as expected if male sexual traits are more condition-dependent than female traits, as predicted by theory. Gene expression changes were primarily associated with shifts in metabolic profile, which likely play a role in increasing cold tolerance. Finally, we found that the expression of immune genes was reduced following cold treatment, suggesting that reduced investment in costly immune function may be important in helping flies survive colder periods.

scholarly journals Prevalence of Small Ruminants Fasciolosis in Mekelle, Tigrai Regional State, Northern Ethiopia

2019 ◽  
pp. 1-8
Author(s):  
Berhe Mekonnen Mengistu ◽  
Abebe Asnake Azbite ◽  
Habtom Kiros Bitsue
Keyword(s):  
Small Ruminants ◽  
Cross Sectional Study ◽  
Northern Ethiopia ◽  
Cross Sectional ◽  
Fecal Samples ◽  
Significant Difference ◽  
Males And Females ◽  
Fasciola Spp ◽  
The Impact ◽  
Important Disease

Fasciolosis is one of the most economically important and widespread parasitic diseases of domestic animals. Accordingly, a cross sectional study was conducted in Mekelle, northern Ethiopia to assess the prevalence of small ruminants Fasciolosis. Fecal samples were collected from a total of 384 small ruminants comprising of 245 sheep and 139 goats and were examined by using the sedimentation technique to find out the eggs of Fasciola species. Out of the total, 384 examined fecal samples, 67 were found to be positive for Fasciolosis with an overall prevalence rate of 17.5 percent. The prevalence of Fasciolosis was higher in sheep (24.1%) as compared to goats (5.8%). There was a statistically significant difference (P=.00) among sheep and goats as regards to the occurrence of Fasciola spp. With body condition scores of the animals, Fasciolosis was statistical significant (P=.00) which was higher in animals with poor body scores followed by medium and good body conditions, respectively. However, the prevalence of Fasciolosis between males and females (P=.19) as well as young and adult animals (P=.92) was not statistically significant difference. The result among the origins of the animals also revealed that no statistically significance difference (P=.81). In conclusion, the burden of Fasciolosis still remains a great problem in the study area. Thus, we need for further investigation to study the impact of the disease on animal production and its economic values and requires integrated interventional strategies to be implemented to tackle such an economically important disease of small ruminants.

scholarly journals Sex-specific responses to cold in a very cold-tolerant, northern Drosophila species

2020 ◽  
Author(s):  
Darren J. Parker ◽  
Tapio Envall ◽  
Michael G. Ritchie ◽  
Maaria Kankare
Keyword(s):  
Gene Expression ◽  
Cold Tolerance ◽  
Cold Treatment ◽  
Sexually Dimorphic ◽  
Immune Genes ◽  
Cold Tolerant ◽  
Males And Females ◽  
The Impact ◽  
Drosophila Montana ◽  
Harsh Conditions

AbstractOrganisms can plastically alter resource allocation in response to changing environmental factors. For example, in harsh conditions organisms are expected to shift investment from reproduction towards survival, however, the factors and mechanisms that govern the magnitude of such shifts are relatively poorly studied. Here we compared the impact of cold on males and females of the highly cold-tolerant species Drosophila montana at the phenotypic and transcriptomic levels. Although both sexes showed similar changes in cold tolerance and gene expression in response to cold treatment, indicating that the majority of changes are concordant between the sexes, we identified a clear reduction in sexually dimorphic gene expression, suggesting that preparing for colder season also involves reducing investment in sex-specific traits. This reduction was larger in males than females, as expected if male sexual traits are more condition-dependent than female traits, as predicted by theory. Gene expression changes were primarily associated with shifts in metabolic profile which likely play a role in increasing cold tolerance. Finally, we found that the expression of immune genes was reduced following cold treatment, suggesting that reduced investment in immunity may be important in helping flies survive colder periods.

Evidence that branches of evergreen angiosperm and coniferous trees differ in hydraulic conductance but not in Huber values

2007 ◽  
Vol 85 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Christopher H. Lusk ◽  
Mylthon Jiménez-Castillo ◽  
Nicolás Salazar-Ortega
Keyword(s):  
Leaf Area ◽  
Rain Forest ◽  
Temperate Forests ◽  
Hydraulic Conductance ◽  
Structure And Function ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Hydraulic Efficiency ◽  
Cross Sectional ◽  
And Function

The hydraulic efficiency conferred by vessels is regarded as one of the key innovations explaining the historical rise of the angiosperms at the expense of the gymnosperms. Few studies, however, have compared the structure and function of xylem and their relationships with foliage traits in evergreen representatives of both groups. We measured sapwood cross-sectional area, conduit diameters, hydraulic conductance, and leaf area of fine branches (2.5–7.5 mm diameter) of five conifers and eight evergreen angiosperm trees in evergreen temperate forests in south-central Chile. Conductance of both lineages was higher at Los Lleuques, a warm temperate site with strong Mediterranean influence, than in a cool temperate rain forest at Puyehue. At a common sapwood cross-sectional area, angiosperm branches at both sites had greater hydraulic conductance (G) than conifers, but similar leaf areas. Branch conductance normalized by subtended leaf area (GL) at both sites was, therefore, higher in angiosperms than in conifers. Hydraulically weighted mean conduit diameters were much larger in angiosperms than in conifers, although this difference was less marked at Puyehue, the cooler of the two sites. Conduits of the vesselless rain forest angiosperm Drimys winteri J.R. & G. Forst were wider than those of coniferous associates, although narrower than angiosperm vessels. However, GL of D. winteri was within the range of values measured for vesselbearing angiosperms at the same site. The observed differences in xylem structure and function correlate with evidence that evergreen angiosperms have higher average stomatal conductance and photosynthetic capacity than their coniferous associates in southern temperate forests. Comparisons of conifers and angiosperm branches thus suggest that the superior capacity of angiosperm conduits is attributable to the development of higher gas-exchange rates per unit leaf area, rather than to a more extensive leaf area. Results also suggest that the tracheary elements of some vesselless angiosperms differ in width and hydraulic efficiency from conifer tracheids.

Normalization criteria determine the interpretation of nitrogen effects on the root hydraulics of pine seedlings

2020 ◽  
Vol 40 (10) ◽  
pp. 1381-1391
Author(s):  
Andrei Toca ◽  
Pedro Villar-Salvador ◽  
Juan A Oliet ◽  
Douglass F Jacobs
Keyword(s):  
Leaf Area ◽  
Pinus Halepensis ◽  
Distinct Species ◽  
Pinus Nigra ◽  
Hydraulic Conductance ◽  
Specific Conductance ◽  
N Availability ◽  
Hydraulic Efficiency ◽  
Cross Sectional ◽  
Plant Hydraulics

Abstract Plant hydraulics is key for plant survival and growth because it is linked to gas exchange and drought resistance. Although the environment influences plant hydraulics, there is no clear consensus on the effect of nitrogen (N) supply, which may be, in part, due to different hydraulic conductance normalization criteria and studied species. The objective of this study was to compare the variation of root hydraulic properties using several normalization criteria in four pine species in response to three contrasting N fertilization regimes. We studied four closely related, yet ecologically distinct species: Pinus nigra J.F. Arnold, Pinus pinaster Ait., Pinus pinea L. and Pinus halepensis Mill. Root hydraulic conductance (Kh) was measured with a high-pressure flow meter, and values were normalized by total leaf area (leaf specific conductance, Kl), xylem cross-section area (xylem specific conductance, Ks), total root area (root specific conductance, Kr) and the area of fine roots (fine root specific conductance, Kfr). Controlling for organ size differences allowed comparison of the hydraulic efficiency of roots to supply or absorb water among fertilization treatments and species. The effect of N on the root hydraulic efficiency depended on the normalization criteria. Increasing N availability reduced Kl and Ks, but increased Kh, Kr and especially Kfr. The positive effect of N on Kr and Kfr was positively related to seedling relative growth rate and was also consistent with published results at the interspecific level, whereby plant hydraulics is positively linked to photosynthesis and transpiration rate and fast growth. In contrast, normalization by leaf area and xylem cross-sectional area (Kl and Ks) reflected opposite responses to Kr and Kfr. This indicates that the normalization criteria determine the interpretation of the effect of N on plant hydraulics, which can limit species and treatment comparisons.

An overview of Afrotropical canopy-dwelling Orchestina (Araneae, Oonopidae), with a wealth of remarkable sexual dimorphic characters

Zootaxa ◽  
2012 ◽  
Vol 3284 (1) ◽  
pp. 1 ◽  
Author(s):  
ARNAUD HENRARD ◽  
RUDY JOCQUÉ
Keyword(s):  
New Species ◽  
Sexually Dimorphic ◽  
Afrotropical Region ◽  
Males And Females ◽  
Morphological Differences

Eighteen new species of the genus Orchestina are described on the basis of specimens obtained from fogging samples inthe Afrotropical region. They are O. acaciae, O. ampulla, O. clavigera, O. communis, O. cornuta, O. crypta, O. debakkeri,O. fannesi, O. fractipes, O. gibbotibialis, O. gigabulbus, O. intricata, O. kasuku, O. lanceolata, O. macrofoliata, O. mi-crofoliata, O. probosciformis and O. saaristoi. Excepted for O. intricata, they are all known from males and females, al-though those of O. debakkeri and O. probosciformis cannot be separated. One species (O. crypta) was recognized afterDNA-analysis and was found to show morphological differences with O. communis. The study revealed a series of re-markable sexually dimorphic characters most of which had not been documented so far: modified leaf shaped setae on thelabium in some species arranged asymmetrically, endites with hook shaped excrescences and rows of spectacular flattenedsetae, remarkable cheliceral setae and outgrowths, a modified clypeus, modified front legs, a preocular carapace swellingand the infra-ocular gutter. Spectacular modifications of the endites were already known from other Oonopidae. The function of the modifications is discussed.

scholarly journals COMPARATIVE STUDY OF EXERCISE STRESS TEST ON CARDIOVASCULAR AUTONOMIC FUNCTIONS BETWEEN MALES AND FEMALES - A CROSS SECTIONAL STUDY

2021 ◽  
pp. 14-16
Author(s):  
Tamil Sudar S ◽  
S. Kannan
Keyword(s):  
Stress Test ◽  
Exercise Stress Test ◽  
Cross Sectional Study ◽  
Exercise Stress ◽  
South Indian Population ◽  
Sectional Study ◽  
Autonomic Functions ◽  
Cross Sectional ◽  
Males And Females ◽  
The Impact

Background: Exercise stress test is a simple, reliable and noninvasive test which detects the coronary artery disease even before the symptoms arise among both males and females.Hence this test was used to assess the impact of exercise stress test on cardiac autonomic function among males and females. Objectives: To compare the cardiac autonomic functions between the males and females among normal, overweight and obese individuals in South Indian population. Methods:A cross sectional study in department of Cardiology and Master Health Checkup in Chennai medical College and hospital, Trichy, a tertiary care teaching hospital during December 2015 to December 2016. Study population includes healthy participants aged between 18-70 years of age from both genders with BMI more than 20 kg/m2. Participants who gave history of alcohol consumption,smoking,hypertension,diabetes mellitus,pregnant and lactating mothers and cases with psychiatric disorders were excluded from the study.Total participants included were 135.Data was entered and analyzed using Statistical Package for Social Sciences version 18.Descriptive statistics and analysis of variance tests were used,appropriately to test the statistical significance. Results: Overweight females had significantly low duration of exercise and MET and obese females had significantly low hear rate at peak of the exercise, duration of exercise, MET and HRR at one and three minutes compared to the individuals with similar BMI categories.Females with normal BMI were found to show no significant difference in any of the observed parameters. Conclusion: Overweight and obese females were comparative at higher risk of developing cardiac disorders compared to overweight and obese males.To reduce the burden of cardiovascular disease in the population,these high risk populations should be targeted first by health education and promoting weight reduction

Gender determination of caucasoid hair using image analysis

1993 ◽  
Vol 51 ◽  
pp. 216-217
Author(s):  
T.B. Ball ◽  
W.M. Hess
Keyword(s):  
Image Analysis ◽  
Cross Sections ◽  
Scalp Hair ◽  
The Body ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Hair Samples ◽  
Length Width ◽  
Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

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