Seedling Survivorship of the Beach Morning Glory, Ipomoea pes-caprae (Convolvulaceae)

1998 ◽  
Vol 46 (1) ◽  
pp. 123 ◽  
Author(s):  
Catherine E. Bach
Keyword(s):  
Mortality Rate ◽  
Abiotic Factors ◽  
High Tide ◽  
Fold Increase ◽  
Morning Glory ◽  
Beach Sand ◽  
Seedling Mortality ◽  
Sand Burial ◽  
Seedling Survivorship ◽  
Probability Of Survival

Factors influencing seedling survivorship in the beach morning glory, Ipomoea pes-caprae (L.) Roth, were studied near Townsville, Queensland, Australia. Censuses of recently germinated seedlings revealed an 83% mortality rate over a period of 11 weeks. Seedlings that died occurred significantly further above high-tide line than did seedlings that were still alive at the end of the study. Although distance to the nearest neighbouring plants did not influence the probability of survival, more seedlings survived if their nearest neighbours were monocots than if they were conspecifics. The probability of survival was greater for seedlings which were closer to neighbouring seedlings of I. pes-caprae, but distance to the nearest adult I. pes-caprae did not affect survival. There was 100% mortality of seedlings that were naturally buried by sand. A field experiment manipulated levels of insect herbivory and sand burial, and showed that herbivory caused a seven-fold increase in mortality rate. Although sand burial also increased mortality, this effect was not significant. Overall, seedling mortality appeared to be influenced by both abiotic factors (location on beach, sand burial) and biotic factors (seedling density, neighbour type and herbivory).

scholarly journals Experimental sand burial affects seedling survivorship, morphological traits and biomass allocation of <i>Ulmus pumila var. sabulosa</i> in Horqin Sandy Land

2016 ◽  
Author(s):  
Jiao Tang ◽  
Carlos Alberto Busso ◽  
Deming Jiang ◽  
Ala Musa ◽  
Dafu Wu ◽  
...  
Keyword(s):  
Biomass Allocation ◽  
Morphological Traits ◽  
Seedling Emergence ◽  
Seedling Height ◽  
Horqin Sandy Land ◽  
Sandy Land ◽  
Seedling Mortality ◽  
Ulmus Pumila ◽  
Sand Burial ◽  
Seedling Survivorship

Abstract. As a native tree species, Ulmus pumila var. sabulosa (Sandy elm) is widely distributed in Horqin Sandy Land. However, seedlings of this species have to withstand various depths of sand burial after emergence because of increasing soil degradation. So an experiment was conducted to evaluate the changes in the survivorship, morphological traits and biomass allocation buried with different burial depths (unburied, and seedlings buried vertically up to 33, 67, 100 or 133 % of the initial mean seedling height). The results showed that partial sand burial treatments (i.e., less than 67 % burial) did not influence seedling survivorship, which still reached 100 %. However, seedling mortality increased as sand burial was equal to or greater than 100 %. Seedling height and stem diameter increased at least by 6 to 14 % with partial burial in comparison with control treatment. Whilst seeding taproot length, total biomass, and relative growth rates at least enhanced by 10 %, 15.6 %, and 27.6 %, respectively, with the partial sand burial treatment. Furthermore, sand burial decreased total leaf area and changed biomass allocation on seedlings, transferring more biomass to aboveground rather than belowground parts. Complete sand burial after seedling emergence inhibited its growth, and even lead to death. Our findings indicated that seedling of sandy elm had a certain resistance to partial sand burial and acclimated to sandy environments. The negative effects of common excessive sand burial after seedling emergence help to understand failures in recruitment of sparse elm woodland in the Horqin sandy land.

scholarly journals 1186. Cefazolin inoculum effect predicts reduced susceptibility to other antibiotics and patient outcomes in MSSA endovascular infections

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S617-S617
Author(s):  
Dan Smelter ◽  
Sue McCrone ◽  
Warren Rose
Keyword(s):  
Infective Endocarditis ◽  
Mortality Rate ◽  
Patient Outcomes ◽  
Treatment Options ◽  
Fold Increase ◽  
Specific Mechanism ◽  
Research Support ◽  
High Burden ◽  
Low Toxicity ◽  
Inoculum Effect

Abstract Background MSSA Infective endocarditis (IE) is inherently a high-burden infection with up to a 30% mortality rate. Cefazolin is an appealing treatment option for IE with low toxicity and a favorable dosing scheme. However, cefazolin has been associated with treatment failure in IE, attributed to an inoculum effect. The specific mechanism underlying the cefazolin inoculum effect (CIE) remains undetermined, but CIE has been linked to both blaZ expression and agr dysfunction. This study aims to determine whether CIE is linked to reduced susceptibility to other antibiotics and worse outcomes regardless of therapy in MSSA endovascular infections. Methods Sixty-four MSSA strains were collected from patients with endovascular infections not treated with cefazolin. To determine CIE phenotype, strains were cultured and MICs assayed for cefazolin, nafcillin, and vancomycin at 107 CFU/mL for high-inocula (HI) and 105 CFU/mL for standard-inocula (SI). This study defined CIE as a ≥ 4-fold increase in MIC at HI compared to SI, with at least an MIC of 4 mg/L at HI. Nitrocefin disks identified blaZ expression, and beta lysin disks were used to determine hemolysin type and agr function. Patient outcomes of mortality and bacteremia duration were assessed across cohorts. Results Twenty-four strains exhibit a CIE (38%), with 10 strains having an MIC of ≥ 32mg/L at HI. Nafcillin and vancomycin also had an inoculum effect, uncoupled from the CIE and occurring at a lower frequency and amplitude at HI. Presence of CIE had a greater association with blaZ expression (71% vs 25%) than agr dysfunction (38% vs 20%). 50% (9/18) of CIE infections were cleared within 48 hours while 77% (20/26) of CIE-negative infections were cleared within 48 hours (P=0.106). However, presence of CIE was not associated with increased mortality (25% CIE-positive vs 35%; P=0.578) Conclusion Previous studies for CIE failed to enrich for isolates from endovascular sources, where inocula are known to be high. This study presents one of the largest endovascular source cohorts for CIE evaluation. It identifies that CIE prevalence (38%) is higher than reports from diverse infection sources (10-36%). CIE appears to predict bacteremia duration with other MSSA treatment options, suggesting mechanisms independent of blaZ and agr function for this phenomenon. Disclosures Warren Rose, PharmD, MPH, Merck (Grant/Research Support)Paratek (Grant/Research Support)

scholarly journals Experimental sand burial affects seedling survivorship, morphological traits, and biomass allocation of <i>Ulmus pumila</i> var. <i>sabulosa</i> in the Horqin Sandy Land, China

Solid Earth ◽  
2016 ◽  
Vol 7 (4) ◽  
pp. 1085-1094 ◽  
Author(s):  
Jiao Tang ◽  
Carlos Alberto Busso ◽  
Deming Jiang ◽  
Ala Musa ◽  
Dafu Wu ◽  
...  
Keyword(s):  
Biomass Allocation ◽  
Morphological Traits ◽  
Seedling Emergence ◽  
Relative Mass ◽  
Seedling Height ◽  
Horqin Sandy Land ◽  
Sandy Land ◽  
Ulmus Pumila ◽  
Sand Burial ◽  
Seedling Survivorship

Abstract. As a native tree species, Ulmus pumila var. sabulosa (sandy elm) is widely distributed in the Horqin Sandy Land, China. However, seedlings of this species have to withstand various depths of sand burial after emergence because of increasing soil degradation, which is mainly caused by overgrazing, climate change, and wind erosion. An experiment was conducted to evaluate the changes in its survivorship, morphological traits, and biomass allocation when seedlings were buried at different burial depths: unburied controls and seedlings buried vertically up to 33, 67, 100, or 133 % of their initial mean seedling height. The results showed that partial sand burial treatments (i.e., less than 67 % burial) did not reduce seedling survivorship, which still reached 100 %. However, seedling mortality increased when sand burial was equal to or greater than 100 %. In comparison with the control treatment, seedling height and stem diameter increased at least by 6 and 14 % with partial burial, respectively. In the meantime, seedling taproot length, total biomass, and relative mass growth rates were at least enhanced by 10, 15.6, and 27.6 %, respectively, with the partial sand burial treatment. Furthermore, sand burial decreased total leaf area and changed biomass allocation in seedlings, partitioning more biomass to aboveground organs (e.g., leaves) and less to belowground parts (roots). Complete sand burial after seedling emergence inhibited its re-emergence and growth, even leading to death. Our findings indicated that seedlings of sandy elm showed some resistance to partial sand burial and were adapted to sandy environments from an evolutionary perspective. The negative effect of excessive sand burial after seedling emergence might help in understanding failures in recruitments of sparse elm in the study region.

scholarly journals Nutrition Status and the Risk of Mortality in Children 6–36 Months Old in Tanzania

1991 ◽  
Vol 13 (4) ◽  
pp. 1-6 ◽  
Author(s):  
Olivia Yambi ◽  
Michael C. Latham ◽  
Jean-Pierre Habicht ◽  
Jere D. Haas
Keyword(s):  
Fold Increase ◽  
Nutrition Status ◽  
Registration System ◽  
Fourfold Increase ◽  
Probability Of Survival ◽  
Low Weight ◽  
One Year ◽  
Increase In Risk ◽  
Height For Age ◽  
Weight For Age

Anthropometric measurements were taken on 2,452 children between 6 and 36 months of age at baseline and at two-month intervals thereafter in rural Tanzania. The children were followed for one year. All deaths occurring in this group were recorded using a village registration system introduced as part of a village nutrition status monitoring system. The relationship between the anthropometric indicators (weight for age, height for age, and weight for height, as well as weight increment) and subsequent mortality was assessed. The results indicate that over the one-year period, nutrition status was a significant predictor of mortality, with the probability of survival lower in children of low nutrition status. Low weight for age (<60% of the standard) was associated with a nine-fold increase in risk compared to weight for age above 80%; low weight for height (<80%) earned an almost fourfold increase in risk compared to weight for height>90%; and low height for age had a twofold increase in risk compared to the normal categories. An overall linear relationship was found between nutrition status and mortality, suggesting a gradual increase in mortality as nutrition status deteriorates. Incremental weight appears to be a good short-term predicator of mortality.

scholarly journals Soil pH Affects Nutrient Balance in Cherry Rootstock Leaves

HortScience ◽  
2001 ◽  
Vol 36 (5) ◽  
pp. 916-917 ◽  
Author(s):  
H. Melakeberhan ◽  
G.W. Bird ◽  
A.L. Jones
Keyword(s):  
Soil Ph ◽  
Abiotic Factors ◽  
Nutrient Balance ◽  
Stone Fruit ◽  
Plant Nutrient ◽  
Seedling Mortality ◽  
Biotic And Abiotic Factors ◽  
Nutrient Imbalance

This study was conducted as part of a stone fruit decline project to determine the effects of soil pH (3.9 to 7.0) on soil and plant nutrient imbalance and mortality of standard (Mazzard and Maheleb) and new (GI148-1 and GI148-8) rootstocks. Seedling mortality and soil Ca in all rootstocks and soil K and leaf Ca, K, Al, and Mn contents in all rootstocks but GI148-8 were higher at below optimum than at optimum soil pH. The nutrient imbalance suggests that the adaptation of these rootstocks to biotic and abiotic factors needs to be considered.

scholarly journals The Resistance of Scots Pine (Pinus sylvestris L.) Half-sib Families to Heterobasidion annosum

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 287 ◽  
Author(s):  
Adas Marčiulynas ◽  
Vaida Sirgedaitė-Šėžienė ◽  
Povilas Žemaitis ◽  
Virgilijus Baliuckas
Keyword(s):  
Phenolic Compounds ◽  
Mortality Rate ◽  
Pinus Sylvestris ◽  
Incidence Rate ◽  
Scots Pine ◽  
Heterobasidion Annosum ◽  
Total Phenolic ◽  
Total Phenolic Compounds ◽  
Seedling Mortality ◽  
Sib Families

This study observed the genotypic variation among Scots pine (Pinus sylvestris L.) half-sib families’ susceptibility to Heterobasidion annosum. Scots pine susceptibility was tested in 12 half-sib families by inoculating them with four different H. annosum strains. At two, six, and ten months after the inoculations, the susceptibility indicators (incidence rate, pathogen spread, and mortality rate) were compared and the total phenolic compounds (TPC) in the inoculated and control groups determined using the Folin–Ciocalteu method. Among half-sib families, significant differences were found for seedling mortality (range: 1.3%–21.2%); however, the differences in incidence rate (range: 54%–77%) and pathogen spread (range: 24–53 mm) were not significant. The incidence rate among half-sib families correlated positively and significantly (r = 0.72, p < 0.05) with the mortality rate, while the pathogen spread correlated negatively with mortality, although the correlation was not significant (r = −0.29, p > 0.05). The TPC comparison with susceptibility indicators showed that the half-sib families with lower susceptibility were characterized by the ability to increase TPC after inoculation compared to the control group. This tendency was most apparent in stems and roots six and two months after inoculation, respectively. Correlation analyses revealed that higher TPC in stems six months after inoculation determined a lower incidence rate (r = −0.32, p < 0.05), while higher Change in concentration of total phenolic compounds (TPCΔ) indicated a lower pathogen spread (r = −0.60, p < 0.05). The lowest incidence of the pathogen was determined in half-sib families with the highest TPCΔ in the roots two months after inoculation. The lower susceptibility of Scots pine half-sib families is based on a combination of enhanced constitutive and inducible phenolic defense mechanisms. The data may facilitate the selection of Scots pine half-sib families with low susceptibility for breeding programs and forest management strategies.

PERSISTENCE OF OIL IN BEACH SAND FOLLOWING A CATASTROPHIC RELEASE OF NO. 2 FUEL OIL

1997 ◽  
Vol 1997 (1) ◽  
pp. 409-413 ◽  
Author(s):  
Michael J. Mulhare ◽  
Paula-Jean Therrien
Keyword(s):  
Natural Attenuation ◽  
High Tide ◽  
Bird Species ◽  
Fuel Oil ◽  
Beach Sand ◽  
The North ◽  
The World ◽  
The Impact ◽  
The Town ◽  
High Tide Line

ABSTRACT Contamination of beach sand from two large releases of no. 2 fuel oil was found to persist for years in intertidal sand and for months in sand at the storm high tide line. This information on the unexpected persistence of this light, volatile fuel oil in the beach environment is invaluable in determining whether active remediation or natural attenuation is appropriate for the restoration of a contaminated beach. The major receptors of the impact of this contamination are a driving force in deciding what remedial approach should be taken. The two releases reported had different receptors. The major impact from the World Prodigy spill was to a public bathing beach. The oil contamination was of primary importance to residents of the town of Jamestown. Active remediation was conducted to restore an important socioeconomic resource. The major impact from the North Cape spill was to a beach in a wildlife refuge that is a protected nesting area for the threatened bird species, the piping plover. Active remediation was not conducted because of concern over disturbing the plover habitat, but would have been conducted had this been a public bathing beach.

Abiotic factors affect leaf litter mass loss more strongly than initial litter traits under sand burial conditions

CATENA ◽  
2021 ◽  
Vol 196 ◽  
pp. 104900
Author(s):  
Hao Qu ◽  
Xueyong Zhao ◽  
Shaokun Wang ◽  
Jie Lian ◽  
Xia Tang ◽  
...  
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Abiotic Factors ◽  
Sand Burial ◽  
Litter Mass ◽  
Litter Traits ◽  
Litter Mass Loss
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