Rate of calcium absorption by plant roots and its relation to growth

1969 ◽  
Vol 20 (3) ◽  
pp. 479 ◽  
Author(s):  
JF Loneragan ◽  
K Snowball
Keyword(s):  
Calcium Absorption ◽  
Calcium Deficiency ◽  
Root Weight ◽  
Functional Requirements ◽  
Relative Growth Rates ◽  
Plant Groups ◽  
Plant Group ◽  
Wide Range ◽  
Standard Culture ◽  
Almost All

Rates of calcium absorption per unit root weight were measured for each of three successive weeks for 30 grasses, cereals, legumes, and herbs grown in flowing culture solutions of pH 5.7 with a wide range of calcium concentrations (0.3 to 1000 µM) which were maintained constant. Plants did not absorb calcium from 0.3 µM solutions and absorbed little from 0.8 µM solutions. Increasing solution concentrations from 0.8 to 10 µM increased the average rates of calcium absorption almost linearly in all plant groups: increasing solution concentrations to 100 or 1000 µM increased rates of calcium absorption but with decreasing effectiveness. Rates of absorption generally remained constant during the experiment, except that in grasses and cereals at 100 and 1000 µM calcium they tended to fall with time. At concentrations from 2.5 to 1000 µM, the average rates of calcium absorption by roots of legumes and herbs were generally very much higher than those by equal weights of grass and cereal roots. Individual cultivars within each plant group tended to follow the average behaviour, so that almost all legumes and herbs absorbed calcium very much faster (up to 15 times) than grasses and cereals at all solution concentrations above 2.5 µM. The relationship between rates of calcium absorption and plant growth is discussed. Since excess calcium accumulated in plants is not readily mobilized to developing tissues, plants become calcium-deficient as soon as the rate of calcium absorption falls below the functional requirements of the tissues. Absorption rater of 0.5 µg atom in grasses and cereals, and in herbs and legumes of 1 µg atom per gram fresh roots per day are suggested as minimal to maintain relative growth rates of c. 9% per day. In standard culture solutions legumes and herbs would deplete calcium from solution and hence develop calcium deficiency more quickly than cereals and grasses. By contrast, in flowing culture solutions with low calcium concentrations maintained constant, high rates of calcium absorption by legumes and herbs sometimes offset their high tissue requirements for calcium; this explains why some legumes and herbs are able to grow at lower calcium concentrations than some grasses and cereals. It is suggested that conditions of calcium supply under which deficiency develops in solutions and in soils should be taken into account when assessing the relative susceptibility of plant species to calcium deficiency.

Calcium requirements of plants

1969 ◽  
Vol 20 (3) ◽  
pp. 465 ◽  
Author(s):  
JF Loneragan ◽  
K Snowball
Keyword(s):  
Calcium Concentration ◽  
Dry Weight ◽  
Calcium Deficiency ◽  
Critical Values ◽  
Functional Requirement ◽  
Functional Requirements ◽  
Constant Concentration ◽  
Excess Calcium ◽  
Wide Range ◽  
Calcium Supply

Calcium concentrations in the tops and roots of 30 grasses, cereals, legumes, and herbs were examined for plants grown over a wide range of calcium concentrations (0.3 to 1000 µM) which were maintained constant in flowing culture solutions of pH 5.7. When plants were grown continuously in solutions of constant concentration, the relation between the calcium concentration in tops and the yield generally showed two regions. Increasing solution calcium concentrations from 0.3 to 2.5 µM increased the yield greatly, while calcium concentrations in the tops remained constant. By contrast, increasing solution concentrations from 10 to 1000 µM markedly increased concentrations in tops but in most species had relatively small effects on yield. At luxury calcium supply the concentrations in herb and legume tops were very much higher than those of grasses and cereals and were surprisingly similar to those of the same species grown in soil in the field. That calcium concentration in plant tops which remained constant while yield increased substantially is believed to indicate the minimal functional requirement of the tops for calcium. The average functional requirements of herb and legume tops (0.1–0.2% dry weight) were generally much lower than previously reported but were about twice those of grasses and cereals (0.05–0.1%). With the exception of Lupinus spp., no legume or herb had functional calcium requirements as low as those of any grass or cereal. When plants were transferred from 1000 to 0.3 µM calcium concentrations, they developed calcium deficiency symptoms and grew less than plants which had one-third to one-tenth the calcium concentrations in their tops but which had been grown continuously in solutions of low and constant concentration (2.5–10 µM). Excess calcium accumulated in the old leaves during luxury calcium supply but was not mobilized when plants were transferred to calcium-deficient solutions. It is suggested that variation in the conditions of calcium supply under which calcium deficiency develops partly accounts for the wide range of critical values used by various workers to diagnose deficiency in plants.

First Detection of Tobacco Mosaic Virus in Tobacco Fields in Northern Lebanon

2020 ◽  
Vol 20 ◽  
Author(s):  
Rami Obeid ◽  
Elias Wehbe ◽  
Mohamad Rima ◽  
Mohammad Kabara ◽  
Romeo Al Bersaoui ◽  
...  
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Viral Genome ◽  
Virus Genome ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Family ◽  
Crop Fields ◽  
Wide Range ◽  
Almost All ◽  
Das Elisa

Background: Tobacco mosaic virus (TMV) is the most known virus in the plant mosaic virus family and is able to infect a wide range of crops, in particularly tobacco, causing a production loss. Objectives: Herein, and for the first time in Lebanon, we investigated the presence of TMV infection in crops by analyzing 88 samples of tobacco, tomato, cucumber and pepper collected from different regions in North Lebanon. Methods: Double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), revealed a potential TMV infection of four tobacco samples out of 88 crops samples collected. However, no tomato, cucumber and pepper samples were infected. The TMV+ tobacco samples were then extensively analyzed by RT-PCR to detect viral RNA using different primers covering all the viral genome. Results and Discussion: PCR results confirmed those of DAS-ELISA showing TMV infection of four tobacco samples collected from three crop fields of North Lebanon. In only one of four TMV+ samples, we were able to amplify almost all the regions of viral genome, suggesting possible mutations in the virus genome or an infection with a new, not yet identified, TMV strain. Conclusion: Our study is the first in Lebanon revealing TMV infection in crop fields, and highlighting the danger that may affect the future of agriculture.

INFLUENCE OF WEATHER ON TEMPORARY AND PERMANENT MIGRATION IN RURAL INDIA

2013 ◽  
Vol 04 (02) ◽  
pp. 1350007 ◽  
Author(s):  
K. S. KAVI KUMAR ◽  
BRINDA VISWANATHAN
Keyword(s):  
National Sample ◽  
Sample Survey ◽  
Urban Migration ◽  
Temporary Migration ◽  
Urban Migrants ◽  
Wide Range ◽  
Permanent Migration ◽  
Sample Survey Data ◽  
Almost All ◽  
Temporary Migrants

While a wide range of factors influence rural–rural and rural–urban migration in developing countries, there is significant interest in analyzing the role of agricultural distress and growing inter-regional differences in fueling such movement. This strand of research acquires importance in the context of climate change adaptation. In the Indian context, this analysis gets further complicated due to the significant presence of temporary migration. This paper analyzes how weather and its variability affects both temporary and permanent migration in India using National Sample Survey data for the year 2007–2008. The paper finds that almost all of the rural–urban migrants are permanent. Only temperature plays a role in permanent migration. In contrast, many temporary migrants are rural–rural and both temperature and rainfall explain temporary migration.

scholarly journals Isolation and Characterization of Bacteriophage ZCSE6 against Salmonella spp.: Phage Application in Milk

Biologics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 164-176
Author(s):  
Abdallah S. Abdelsattar ◽  
Anan Safwat ◽  
Rana Nofal ◽  
Amera Elsayed ◽  
Salsabil Makky ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Raw Milk ◽  
Salmonella Spp ◽  
Isolation And Characterization ◽  
Food Borne ◽  
Wide Range ◽  
Almost All ◽  
And Control ◽  
Milk And Dairy Products

Food safety is very important in the food industry as most pathogenic bacteria can cause food-borne diseases and negatively affect public health. In the milk industry, contamination with Salmonella has always been a challenge, but the risks have dramatically increased as almost all bacteria now show resistance to a wide range of commercial antibiotics. This study aimed to isolate a bacteriophage to be used as a bactericidal agent against Salmonella in milk and dairy products. Here, phage ZCSE6 has been isolated from raw milk sample sand molecularly and chemically characterized. At different multiplicities of infection (MOIs) of 0.1, 0.01, and 0.001, the phage–Salmonella interaction was studied for 6 h at 37 °C and 24 h at 8 °C. In addition, ZCSE6 was tested against Salmonella contamination in milk to examine its lytic activity for 3 h at 37 °C. The results showed that ZCSE6 has a small genome size (<48.5 kbp) and belongs to the Siphovirus family. Phage ZCSE6 revealed a high thermal and pH stability at various conditions that mimic milk manufacturing and supply chain conditions. It also demonstrated a significant reduction in Salmonella concentration in media at various MOIs, with higher bacterial eradication at higher MOI. Moreover, it significantly reduced Salmonella growth (MOI 1) in milk, manifesting a 1000-fold decrease in bacteria concentration following 3 h incubation at 37 °C. The results highlighted the strong ability of ZCSE6 to kill Salmonella and control its growth in milk. Thus, ZCSE6 is recommended as a biocontrol agent in milk to limit bacterial growth and increase the milk shelf-life.

An Absorption Assessment of Eggshell Calcium Citrate Treated by PEF in Mice

2013 ◽  
Vol 634-638 ◽  
pp. 1413-1416 ◽  
Author(s):  
Song Yi Lin ◽  
Tong Shen ◽  
Hai Qing Ye
Keyword(s):  
Acid Phosphatase ◽  
Electric Field ◽  
Calcium Absorption ◽  
Calcium Deficiency ◽  
Control Group ◽  
Tartrate Resistant Acid Phosphatase ◽  
Calcium Citrate ◽  
Male Mice ◽  
Normal Range ◽  
Calcium And Phosphorus

Eggshell calcium citrate (ESCC) prepared by pulsed electric field (PEF) may be a new calcium resource to help treat and prevent calcium deficiency. An absorption assessment of ESCC prepared by PEF was performed in male mice with apparent calcium absorption. Compared with control group, ESCC prepared by PEF at doses of 133.0 mg/(kg•d) significantly improved the alkalinity phosphatase (ALP) activity (P < 0.05) and decreased the levels of tartrate-resistant acid phosphatase (TRAP) (P < 0.05). The ratio of calcium and phosphorus were in the normal range. Therefore, ESCC prepared by PEF could promote the absorption of calcium in mice.

Actual Challenges, Risks and Security Safety

2020 ◽  
Vol 1 (1) ◽  
pp. 65-83
Author(s):  
Božidar Forca ◽  
Dragoljub Sekulović ◽  
Igor Vukonjanski
Keyword(s):  
National Security ◽  
Modern World ◽  
Security Strategy ◽  
Theoretical Understanding ◽  
National Security Strategy ◽  
Security Challenges ◽  
Wide Range ◽  
The Subject ◽  
Almost All ◽  
The Relationship

Security is one of the most common terms in the modern world. This statement is supported by the fact that the term security is used in a wide range of areas. The subject of this paper is national security and the challenges, risks and threats to that security in contemporary international relations. The purpose of the work is twofold. First, to show the diversity of theoretical understanding of the term challenge, risk and threat by various authors. On the other hand, the overriding goal is to analyze the relationship to the challenges, risks and threats in different countries. When it comes to national security, challenges, risks and threats, most often, are identified in a document called the national security strategy. This document, as one of the highest in the hierarchy of political acts of every state, when it comes to security, is passed by almost all modern states of the world. The analysis of numerous national security strategies has revealed that it is possible to identify: 1) the challenges, risks and threats that appear in all strategies, 2) the challenges, risks and threats of security that appear in most strategies, and 3) the challenges, risks and threats of security which are country specific.

What Kind of Friction Model Is Needed to Predict Brake Squeal?

2012 ◽  
Author(s):  
Tore Butlin ◽  
Jim Woodhouse
Keyword(s):  
Large Scale ◽  
Dynamic Properties ◽  
Theoretical Work ◽  
Friction Model ◽  
Coupled Systems ◽  
Brake Squeal ◽  
Model Framework ◽  
Wide Range ◽  
Pin On Disc ◽  
Almost All

Predictive models of friction-induced vibration have proved elusive despite decades of research. There are many mechanisms that can cause brake squeal; friction coupled systems can be highly sensitive to small perturbations; and the dynamic properties of friction at the contact zone seem to be poorly understood. This paper describes experimental and theoretical work aimed at identifying the key ingredients of a predictive model. A large-scale experiment was carried out to identify squeal initiations using a pin-on-disc test rig: approximately 30,000 squeal initiations were recorded, covering a very wide range of frequencies. The theoretical model allows for completely general linear systems coupled at a single sliding point by friction: squeal is predicted using a linearised stability analysis. Results will be presented that show that almost all observed squeal events can be predicted within this model framework, but that some subsets require innovative friction modelling: predictions are highly dependent on the particular choice of friction model and its associated parameters.

scholarly journals Two Populations of Glucocorticoid Receptor-Binding Sites in the Male Rat Hippocampal Genome

Endocrinology ◽  
2013 ◽  
Vol 154 (5) ◽  
pp. 1832-1844 ◽  
Author(s):  
J. Annelies E. Polman ◽  
E. Ronald de Kloet ◽  
Nicole A. Datson
Keyword(s):  
Receptor Binding ◽  
Binding Sites ◽  
Glucocorticoid Receptors ◽  
Full Range ◽  
Male Rat ◽  
Motif Analysis ◽  
Wide Range ◽  
Neuronal Processes ◽  
Almost All

Abstract In the present study, genomic binding sites of glucocorticoid receptors (GR) were identified in vivo in the rat hippocampus applying chromatin immunoprecipitation followed by next-generation sequencing. We identified 2470 significant GR-binding sites (GBS) and were able to confirm GR binding to a random selection of these GBS covering a wide range of P values. Analysis of the genomic distribution of the significant GBS revealed a high prevalence of intragenic GBS. Gene ontology clusters involved in neuronal plasticity and other essential neuronal processes were overrepresented among the genes harboring a GBS or located in the vicinity of a GBS. Male adrenalectomized rats were challenged with increasing doses of the GR agonist corticosterone (CORT) ranging from 3 to 3000 μg/kg, resulting in clear differences in the GR-binding profile to individual GBS. Two groups of GBS could be distinguished: a low-CORT group that displayed GR binding across the full range of CORT concentrations, and a second high-CORT group that displayed significant GR binding only after administering the highest concentration of CORT. All validated GBS, in both the low-CORT and high-CORT groups, displayed mineralocorticoid receptor binding, which remained relatively constant from 30 μg/kg CORT upward. Motif analysis revealed that almost all GBS contained a glucocorticoid response element resembling the consensus motif in literature. In addition, motifs corresponding with new potential GR-interacting proteins were identified, such as zinc finger and BTB domain containing 3 (Zbtb3) and CUP (CG11181 gene product from transcript CG11181-RB), which may be involved in GR-dependent transactivation and transrepression, respectively. In conclusion, our results highlight the existence of 2 populations of GBS in the rat hippocampal genome.

Plant diversity of Ghorkhod Protected Area, NE Iran

Phytotaxa ◽  
2016 ◽  
Vol 249 (1) ◽  
pp. 118 ◽  
Author(s):  
FARSHID MEMARIANI ◽  
MOHAMMAD REZA JOHARCHI ◽  
HOSSEIN AKHANI
Keyword(s):  
Plant Species ◽  
Protected Area ◽  
Life Form ◽  
Vascular Plant ◽  
Floristic Composition ◽  
Transitional Zone ◽  
Plant Groups ◽  
Wide Range ◽  
Plant Families ◽  
Ne Iran

Ghorkhod Protected Area (GPA) is located in a transitional zone among different biogeographical units in North Khorassan Province, NE Iran. The study area is mainly a mountainous region in western extensions of Khorassan-Kopet Dagh floristic province. We investigated the floristic composition, life form spectrum and phytogeography of the study area through several random collection efforts and 200 vegetation samples (reléves) in selected vegetation types during 2007–2012. A total of 663 vascular plant species belonging to 367 genera and 81 families are recorded as native and naturalized in GPA. Angiosperms and Dicots are among the most diverse plant groups. The richest plant families are Asteraceae (88 species), Poaceae (78), Lamiaceae (45), Brassicaceae (43), Fabaceae (38), and Caryophyllaceae (32). The genera Allium L. (17 species), Astragalus L. (15) and Cousinia Cass. (12) are the richest ones, however, the majority of the species belongs to oligotypic and monotypic genera. Life form spectrum of the study area is dominated by hemicryptophytes (38.9%) and therophytes (23.4%). Allium transvestiens Vved., Agropyron desertorum Schult., Helictotrichon turcomanicum Czopanov and Piptatherum latifolium (Roshev.) Nevski are recorded as new to Iran. The core flora of the area has the Irano-Turanian origin. However, the wide-range and widespread elements are also well represented in the study area. GPA is inhabited by several endemic, rare and narrow-range plant species, indicating the biodiversity importance of the study area in NE Iran.

scholarly journals DNA methylation-based sex classifier to predict sex and identify sex chromosome aneuploidy

2020 ◽  
Author(s):  
Yucheng Wang ◽  
Eilis Hannon ◽  
Olivia A Grant ◽  
Tyler J Gorrie-Stone ◽  
Meena Kumari ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Sex Chromosome ◽  
Klinefelter Syndrome ◽  
Association Studies ◽  
Gene Expression Omnibus ◽  
Sex Chromosome Aneuploidy ◽  
Chromosome Aneuploidy ◽  
Wide Range ◽  
Almost All ◽  
Methylation Patterns

AbstractSex is an important covariate of epigenome-wide association studies due to its strong influence on DNA methylation patterns across numerous genomic positions. Nevertheless, many samples on the Gene Expression Omnibus (GEO) frequently lack a sex annotation or are incorrectly labelled. Considering the influence that sex imposes on DNA methylation patterns, it is necessary to ensure that methods for filtering poor samples and checking of sex assignment are accurate and widely applicable. In this paper, we presented a novel method to predict sex using only DNA methylation density signals, which can be readily applied to almost all DNA methylation datasets of different formats (raw IDATs or text files with only density signals) uploaded to GEO. We identified 4345 significantly (p < 0.01) sex-associated CpG sites present on both 450K and EPIC arrays, and constructed a sex classifier based on the two first components of PCAs from the two sex chromosomes. The proposed method is constructed using whole blood samples and exhibits good performance across a wide range of tissues. We further demonstrated that our method can be used to identify samples with sex chromosome aneuploidy, this function is validated by five Turner syndrome cases and one Klinefelter syndrome case. The proposed method has been integrated into the wateRmelon Bioconductor package.

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