Phenological studies of Acrostichum danaeifolium (Pteridaceae, Pteridophyta) at a mangrove site on the Gulf of Mexico

2003 ◽  
Vol 19 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Klaus Mehltreter ◽  
Mónica Palacios-Rios
Keyword(s):  
Life Span ◽  
Leaf Growth ◽  
Leaf Size ◽  
Avicennia Germinans ◽  
Strongly Correlated ◽  
Wet Season ◽  
Leaf Production ◽  
La Mancha ◽  
Spore Release ◽  
The Mean

A population of the giant leather fern Acrostichum danaeifolium was observed during an 18-mo period at La Mancha (19°36′00″N, 96°22′40″W), Veracruz, Mexico. The study site was 230 m from a brackish-water lagoon, in the understorey of the mangroves, which are dominated by Avicennia germinans (Avicenniaceae). Acrostichum danaeifolium showed a clumped distribution pattern, and one third of the population became fertile during this time. Plants had a mean number of 9.4 ± 0.45 sterile leaves, which developed continuously at a rate of 14.6 ± 0.44 leaves y-1. The mean life span of sterile leaves was 7.7 mo. Although soil water was always available, phenological patterns of fertility, leaf production and leaf growth were strongly correlated with the seasonal climate. Individual leaf growth and leaf size increased significantly during the rainy season. Fertile leaves emerged exclusively from April to August and had a mean life span of 4.1 mo. Spore release was restricted to the wet season, when conditions for germination were favourable. Environmental triggers of fertility are discussed and phenological patterns are compared with ferns and angiosperms from other habitats.

scholarly journals Morphology and Anatomy of the Fused Vein Trait in Cucurbita pepo L.

1996 ◽  
Vol 121 (1) ◽  
pp. 6-12
Author(s):  
R. Bruce Carle ◽  
J. Brent Loy
Keyword(s):  
Genetic Background ◽  
Leaf Blade ◽  
Cucurbita Pepo ◽  
Leaf Growth ◽  
Leaf Size ◽  
Leaf Number ◽  
Central Vein ◽  
Vascular Bundles ◽  
Leaf Production ◽  
Leaf Stage

The morphology, growth rate and anatomy of the fused vein trait were characterized in Cucurbita pepo using the inbreds NH2405 (fused vein), NH7210 (moderately fused vein), and NH614 (normal). Morphological analysis showed that the trait is characterized by a partial fusion of the five primary leaf veins. Fusion begins at the distal point of the petiole and extends along the central vein. Branching of the veins is delayed and there is a reduction of the interveinal leaf blade. Consequently, the upper leaf surface appears puckered or wrinkled. Depending on genetic background, the onset of fused vein leaf production starts at the fourth to tenth leaf stage and continues throughout vegetative growth. The extent of fusion increases with leaf number but stabilizes by the twentieth leaf stage maximum extent of vein fusion also varies with genetic background (5-20 cm). Though fused vein and normal inbreds differed in the rate and pattern of leaf growth, examination of F2 and BC populations revealed no significant effect of the fused vein trait on leaf number, leaf size, and rate of leaf initiation. Anatomical examination revealed different vascular patterns in the transition zone between petiole and leaf blade for normal and fused vein leaves. In normal leaves, the vascular bundles of the petiole enlarge and coalesce to form a vascular crescent. The crescent reorganizes and diverges as large vascular columns and pairs of smaller flanking vascular bundles into each vein. In contrast, two cycles of enlargement, coalescence, and dispersal occur in fused vein leaves.

The growth and development of cowpeas (Vigna unguiculata) under tropical field conditions: 1. Leaf area

1979 ◽  
Vol 93 (2) ◽  
pp. 291-307 ◽  
Author(s):  
E. J. Littleton ◽  
M. D. Dennett ◽  
J. Elston ◽  
J. L. Monteith
Keyword(s):  
Leaf Area ◽  
Leaf Growth ◽  
Leaf Size ◽  
Constant Number ◽  
Area Index ◽  
Number Of Leaves ◽  
The Mean ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance ◽  
Ibadan Nigeria

SUMMARYThe pattern of leaf growth and death was followed in stands of cowpea grown in the field at Ibadan, Nigeria. Temperature affected this pattern. Leaf area index increased quicker and leaf death started sooner during warm seasons. Individual leaves died while pods at the same node were filling. The rate of leaf appearance increased with temperature and the duration of expansion of individual leaves decreased so that a constant number of leaves were expanding at one time. The mean rate of expansion of individual leaves increased with temperature proportionately more than the duration decreased, hence final leaf size increased with temperature. Base temperatures for leaf appearance and leaf expansion were 16 and 20 °C respectively.

Demography and Production of Leptopteris wilkesiana (Osmundaceae), a Tropical Tree-Fern From Fiji

1986 ◽  
Vol 34 (2) ◽  
pp. 207 ◽  
Author(s):  
J Ash
Keyword(s):  
Leaf Size ◽  
Height Growth ◽  
Leaf Longevity ◽  
Primary Forest ◽  
Wet Season ◽  
Tree Fern ◽  
Leaf Production ◽  
Net Production ◽  
Large Plant ◽  
Number Of Leaves

The demography of Leptopteris wilkesiana (Osmundaceae) was studied in an area of undisturbed primary forest near Suva, Viti Levu, Fiji. The tree-fern has a single growth flush of 3-9 new leaves each wet season, and this is apparent as a distinct annual band of stipe scars on the trunk. Trunk ages ranged up to 133 years and trunk height growth averages 1.6 cm year-1. Leaf longevity is normally 2-2½ years. There was a 1% probability that a trunk would fall over, or be knocked over, each year; most trunks produced new roots at the lowest part of the fallen stem and continued growing. Sporangia production commenced in plants 30-45 cm tall and increased with leaf size and the number of leaves. Spore pro- duction ranged up to 17 x 106 spores year-1 on a large plant, and 3 x 108 spores year-1 for a population of 100 plants, while recruitment of sporophytes was estimated at 1 year-1. Annual net production ranged up to 38 g oven-dry tissues on a large plant of which 55% was leaf production and 8% sporangia production.

The Concurrent Validity of the Minnesota Child Development Inventory as a Measure of Young Children's Language Development

1989 ◽  
Vol 54 (1) ◽  
pp. 101-105 ◽  
Author(s):  
J. Bruce Tomblin ◽  
Cynthia M. Shonrock ◽  
James C. Hardy
Keyword(s):  
Child Development ◽  
Language Development ◽  
Expressive Language ◽  
Strong Predictor ◽  
Receptive Language ◽  
Strongly Correlated ◽  
Language Measure ◽  
The Mean ◽  
Child Development Inventory ◽  
Mean Length Of Utterance

The extent to which the Minnesota Child Development Inventory (MCDI), could be used to estimate levels of language development in 2-year-old children was examined. Fifty-seven children between 23 and 28 months were given the Sequenced Inventory of Communication Development (SICD), and at the same time a parent completed the MCDI. In addition the mean length of utterance (MLU) was obtained for each child from a spontaneous speech sample. The MCDI Expressive Language scale was found to be a strong predictor of both the SICD Expressive scale and MLU. The MCDI Comprehension-Conceptual scale, presumably a receptive language measure, was moderately correlated with the SICD Receptive scale; however, it was also strongly correlated with the expressive measures. These results demonstrated that the Expressive Language scale of the MCDI was a valid predictor of expressive language for 2-year-old children. The MCDI Comprehension-Conceptual scale appeared to assess both receptive and expressive language, thus complicating its interpretation.

Influence of Platelet Membrane Sialic Acid and Platelet-Associated IgG on Ageing and Sequestration of Blood Platelets in Baboons

1993 ◽  
Vol 70 (04) ◽  
pp. 676-680 ◽  
Author(s):  
H F Kotzé ◽  
V van Wyk ◽  
P N Badenhorst ◽  
A du P Heyns ◽  
J P Roodt ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Life Span ◽  
Blood Platelets ◽  
Senescent Cell ◽  
Platelet Membrane ◽  
Antigen Complex ◽  
The Mean ◽  
Aggregation Of Platelets

SummaryPlatelets were isolated from blood of baboons and treated with neuraminidase to remove platelet membrane sialic acid, a process which artificially ages the platelets. The platelets were then labelled with 111In and their mean life span, in vivo distribution and sites of Sequestration were measured. The effect of removal of sialic acid on the attachment of immunoglobulin to platelets were investigated and related to the Sequestration of the platelets by the spleen, liver, and bone marrow. Removal of sialic acid by neuraminidase did not affect the aggregation of platelets by agonists in vitro, nor their sites of Sequestration. The removal of 0.51 (median, range 0.01 to 2.10) nmol sialic acid/108 platelets shortened their life span by 75 h (median, range 0 to 132) h (n = 19, p <0.001), and there was an exponential correlation between the shortening of the mean platelet life span and the amount of sialic acid removed. The increase in platelet-associated IgG was 0.112 (median, range 0.007 to 0.309) fg/platelet (n = 25, p <0.001) after 0.79 (median, range 0.00 to 6.70) nmol sialic acid/108 platelets was removed (p <0.001). There was an exponential correlation between the shortening of mean platelet life span after the removal of sialic acid and the increase in platelet-associated IgG. The results suggest that platelet membrane sialic acid influences ageing of circulating platelets, and that the loss of sialic acid may have exposed a senescent cell antigen that binds IgG on the platelet membrane. The antibody-antigen complex may then provide a signal to the macrophages that the platelet is old, and can be phagocytosed and destroyed.

Elimination of three doses of gentamicin over three consecutive days using a polyacrylonitrile-derived filter: An in vitro assessment

2021 ◽  
pp. 039139882110322
Author(s):  
Frédéric J Baud ◽  
Vanessa Seif ◽  
Pascal Houzé ◽  
Jean-Herlé Raphalen ◽  
Benoît Pilmis ◽  
...  
Keyword(s):  
Life Span ◽  
Bolus Dose ◽  
Central Compartment ◽  
Daily Session ◽  
Progressive Decrease ◽  
Time Dependency ◽  
Study Results ◽  
In Vitro Assessment ◽  
The Mean

Introduction: Adsorption of gentamicin in a polyacrylonitrile filter was previously evidenced in a session lasting 6 h using the NeckEpur model. We extended the study over three consecutive days to mimic the 72-h life span of a filter. Methods: Prismaflex® monitor and ST150® filter were used in the continuous diafiltration (CDF) mode at a 2.5 L/h flowrate. The daily session started with a 6-h session of CDF. Thereafter, the 5-L central compartment was changed using a bag free of gentamicin to assess gentamicin release over the following 18 h. Experiments were repeated on Day 2 and stopped at the end of the 6-h session of CDF on Day 3. The experiment was performed in duplicate. Results: At a 2.5 L/h diafiltration flowrate, the mean daily clearances of gentamicin were 5.5, 4.0, and 3.3 L/h, respectively. The mean diafiltration and adsorption ratios in the daily elimination of gentamicin were 32/68%, 58/42%, and 88/12%, respectively. During days 1 and 2, the mean amount of gentamicin released from the ST150® filter were 14 and 34 mg, respectively. Conclusion: The pharmacokinetics of gentamicin over 3 days is strongly altered by adsorption in the same filter with a progressive decrease of elimination by adsorption, suggesting saturation of the filter. One limitation of our study results from the mode of administration using a bolus dose instead of an infusion over 30 min. Adsorption adds a clearance to those of diafiltration. The time-dependency of gentamicin clearance precludes using a constant dosage regimen over the filter’s life span.

scholarly journals Two maize cultivars of contrasting leaf size show different leaf elongation rates with identical patterns of extension dynamics and coordination

AoB Plants ◽  
2021 ◽  
Author(s):  
Tiphaine Vidal ◽  
Hafssa Aissaoui ◽  
Sabrina Rehali ◽  
Bruno Andrieu
Keyword(s):  
Genotypic Variation ◽  
Leaf Size ◽  
High Rate ◽  
Time Interval ◽  
Extension Rate ◽  
Leaf Production ◽  
Maize Cultivars ◽  
Plant Environment ◽  
The Difference ◽  
Leaf Extension

Abstract Simulating leaf development from initiation to maturity opens new possibilities to model plant–environment interactions and the plasticity of plant architecture. This study analyses the dynamics of leaf production and extension along a maize (Zea mays) shoot to assess important modelling choices. Maize plants from two cultivars originating from the same inbred line, yet differing in the length of mature leaves were used in this study. We characterised the dynamics of the blade and sheath lengths of all phytomers by dissecting plants every 2–3 days. We analysed how differences in leaf size were built up and we examined the coordination between the emergence of organs and phases of their extension. Leaf extension rates were higher in the cultivar with longer leaves than in the cultivar with shorter leaves; no differences were found in other aspects. We found that (i) first post-embryonic leaves were initiated at a markedly higher rate than upper leaves; (ii) below ear position, sheaths were initiated at a time intermediate between tip emergence and appearance, while above the ear position, sheaths were initiated at a high rate, such that the time interval between the blade and sheath initiations decreased for these leaves; and (iii) ear position also marked a change in the correlation in size between successive phytomers with little correlation of size between upper and lower leaves. Our results identified leaf extension rate as the reason for the difference in size between the two cultivars. The two cultivars shared the same pattern for the timing of initiation events, which was more complex than previously thought. The differences described here may explain some inaccuracies reported in functional-structural plant models. We speculate that genotypic variation in behaviour for leaf and sheath initiation exists, which has been little documented in former studies.

scholarly journals EFFECT OF CRUDE OIL ON THE DEVELOPMENT OF WHITE MANGROVE SEEDLINGS (Avicennia germinans) IN THE NIGER DELTA, NIGERIA

2008 ◽  
Vol 30 (70/72) ◽  
Author(s):  
A. C. Chindah ◽  
S. A. Braide ◽  
J. O. Amakiri ◽  
J. Onokurhefe
Keyword(s):  
Crude Oil ◽  
Human Life ◽  
T Test ◽  
Avicennia Germinans ◽  
Growth Responses ◽  
Leaf Production ◽  
Wilcoxon Sign Rank ◽  
Mangrove Seedlings ◽  
Growth Attributes ◽  
The Impact

Crude oil is a complex hydrogen whose introduction into the may be hazardous to aquatic and human life, and consequently a threat to natural resources. The severity of the impact of crude oil depends on a variety of factors, including characteristics of the oil itself, natural conditions, such as water temperature and weather, and the sensitivities of receiving or biota. Consequently, various types of biological resources such as mangrove seedlings have different sensitivities to oil spills. The long term persistence of oil in the environment may cause defoliation and possibly death. Recruitment of seedlings into the oiled area may also be affected. This study is designed to evaluate the acute and chronic effects of crude oil (Bonny Light) on the growth performance of mangrove seedlings in a laboratory condition; monitoring critical plant growth attributes such as stem height and diameter, leaf length, width and numbers of leaves (leaf production), senescence and seedlings survival, for sixteen weeks. The study revealed that the mangrove seedlings responded differently in growth attributes with varying treatment. Evidence of crude oil effects were remarkably demonstrated between control and acute (Wilcoxon sign –rank t-test (1.0) > P (0.29)0.05 and chronic (Wilcoxon sign – rank, t-test (1.0) > p (0.47)0.05. The mangrove critical growth responses by mangrove seedlings as a result of the treatments were further explained by the cluster and correspondence analyses.

scholarly journals 111In-oxine platelet survivals in thrombocytopenic infants

Blood ◽  
1987 ◽  
Vol 70 (3) ◽  
pp. 652-656
Author(s):  
V Castle ◽  
G Coates ◽  
JG Kelton ◽  
M Andrew
Keyword(s):  
Life Span ◽  
Function Analysis ◽  
Screening Tests ◽  
Severe Thrombocytopenia ◽  
Common Occurrence ◽  
Platelet Volume ◽  
Platelet Destruction ◽  
Percent Recovery ◽  
The Mean ◽  
Full Body

Thrombocytopenia is a common occurrence (20%) in sick neonates, but the causes have not been well studied. In this report we demonstrate that thrombocytopenia in the neonate is characterized by increased platelet destruction as shown by shortened homologous 111In-oxine-labeled platelet life spans. Thirty-one prospectively studied thrombocytopenic neonates were investigated by measuring the 111In-labeled platelet life span, platelet-associated IgG (PAIgG), and coagulation screening tests. In every infant, the thrombocytopenia was shown to have a destructive component since the mean platelet life span was significantly shortened to 65 +/- 6 (mean +/- SEM) hours with a range of one to 128 hours compared with adult values (212 +/- 8; range, 140 to 260; gamma function analysis). The platelet survival was directly related to the lowest platelet count and inversely related to both the highest mean platelet volume and duration of the thrombocytopenia. In 22 infants the percent recovery of the radiolabeled platelets was less than 50%, which suggested that increased sequestration also contributed to the thrombocytopenia. Infants with laboratory evidence of disseminated intravascular coagulation (n = 8) or immune platelet destruction evidenced by elevated levels of PAIgG (n = 13) had even shorter platelet survivals and a more severe thrombocytopenia compared with the ten infants in whom an underlying cause for the thrombocytopenia was not apparent. Full-body scintigraphic images obtained in 11 infants showed an increased uptake in the spleen and liver, with a spleen-to- liver ratio of 3:1. This study indicates that thrombocytopenia in sick neonates is primarily destructive, with a subgroup having evidence of increased platelet sequestration.

scholarly journals Investigation of Heavy Metals Level in selected Boreholes around the Vicinity of some Cemeteries in Benin City, Nigeria

2021 ◽  
Vol 25 (5) ◽  
pp. 841-845
Author(s):  
C.A.E. Ibhadode ◽  
I.R. Ilaboya
Keyword(s):  
Heavy Metals ◽  
Pollution Index ◽  
Mean Value ◽  
Dry Season ◽  
Wet Season ◽  
Monthly Basis ◽  
Benin City ◽  
Standard Procedures ◽  
The Mean ◽  
Mean Concentration

Groundwater pollution by heavy metals such as lead, copper, nickel and iron is one of the major environmental issues of concern which has developed into a widely studied area. In this study, attempt was made to investigate the level of heavy metals in selected boreholes around the vicinity of cemeteries in Benin City. Seventy-two (72) samples of groundwater were taken from boreholes in 9 stations around the three cemeteries in Benin City on monthly basis. The samples were analysed for 7 heavy metals, in accordance with standard procedures. The heavy metals include; Zinc, Lead Iron, Copper, Cadmium, Nickel and Mercury. From the results of the study, a variation in the mean concentration of zinc was observed. The mean concentration of zinc in site 1 was 0.450mg/l, for site 2, it was 0.140mg/l and for site 3, it was 1.0533mg/l. For iron, mean concentration was 0.072mg/l in site 1. For site 2, mean concentration of iron was 2.140mg/l and for site 3, mean concentration of iron was 0.560mg/l. It was further revealed based on the results that mean value of heavy metals in groundwater around cemeteries in Benin City were generally lower during dry season compared to wet season. In addition, result of computed pollution index (Pi) revealed that the heavy metal with the highest potential to pollute groundwater is Cadmium, with Pi of 0.5333 and 0.400 representing dry season and wet season respectively.

Sign in / Sign up

Export Citation Format

Share Document