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Sensors (Basel, Switzerland) Aug 2016Efforts to predict the germination ability of acorns using their shape, length, diameter and density are reported in the literature. These methods, however, are not...
Efforts to predict the germination ability of acorns using their shape, length, diameter and density are reported in the literature. These methods, however, are not efficient enough. As such, a visual assessment of the viability of seeds based on the appearance of cross-sections of seeds following their scarification is used. This procedure is more robust but demands significant effort from experienced employees over a short period of time. In this article an automated method of acorn scarification and assessment has been announced. This type of automation requires the specific setup of a machine vision system and application of image processing algorithms for evaluation of sections of seeds in order to predict their viability. In the stage of the analysis of pathological changes, it is important to point out image features that enable efficient classification of seeds in respect of viability. The article shows the results of the binary separation of seeds into two fractions (healthy or spoiled) using average components of regular red-green-blue and perception-based hue-saturation-value colour space. Analysis of accuracy of discrimination was performed on sections of 400 scarified acorns acquired using two various setups: machine vision camera under uncontrolled varying illumination and commodity high-resolution camera under controlled illumination. The accuracy of automatic classification has been compared with predictions completed by experienced professionals. It has been shown that both automatic and manual methods reach an accuracy level of 84%, assuming that the images of the sections are properly normalised. The achieved recognition ratio was higher when referenced to predictions provided by professionals. Results of discrimination by means of Bayes classifier have been also presented as a reference.
Topics: Bayes Theorem; Color; Germination; Image Processing, Computer-Assisted; Light; Seeds
PubMed: 27548173
DOI: 10.3390/s16081319 -
Agricultural and Forest Meteorology Aug 2020We explored the inter-individual variability in bud-burst and its potential drivers, in homogeneous mature stands of temperate deciduous trees. Phenological observations...
We explored the inter-individual variability in bud-burst and its potential drivers, in homogeneous mature stands of temperate deciduous trees. Phenological observations of leaves and wood formation were performed weekly from summer 2017 to summer 2018 for pedunculate oak, European beech and silver birch in Belgium. The variability of bud-burst was correlated to previous' year autumn phenology (i.e. the onset of leaf senescence and the cessation of wood formation) and tree size but with important differences among species. In fact, variability of bud-burst was primarily related to onset of leaf senescence, cessation of wood formation and tree height for oak, beech and birch, respectively. The inter-individual variability of onset of leaf senescence was not related to the tree characteristics considered and was much larger than the inter-individual variability in bud-burst. Multi-species multivariate models could explain up to 66% of the bud-burst variability. These findings represent an important advance in our fundamental understanding and modelling of phenology and tree functioning of deciduous tree species.
PubMed: 32817727
DOI: 10.1016/j.agrformet.2020.108031 -
BMC Genomics Jan 2024Local adaptation is a key evolutionary process that enhances the growth of plants in their native habitat compared to non-native habitats, resulting in patterns of...
BACKGROUND
Local adaptation is a key evolutionary process that enhances the growth of plants in their native habitat compared to non-native habitats, resulting in patterns of adaptive genetic variation across the entire geographic range of the species. The study of population adaptation to local environments and predicting their response to future climate change is important because of climate change.
RESULTS
Here, we explored the genetic diversity of candidate genes associated with bud burst in pedunculate oak individuals sampled from 6 populations in Poland. Single nucleotide polymorphism (SNP) diversity was assessed in 720 candidate genes using the sequence capture technique, yielding 18,799 SNPs. Using landscape genomic approaches, we identified 8 F outliers and 781 unique SNPs in 389 genes associated with geography, climate, and phenotypic variables (individual/family spring and autumn phenology, family diameter at breast height (DBH), height, and survival) that are potentially involved in local adaptation. Then, using a nonlinear multivariate model, Gradient Forests, we identified vulnerable areas of the pedunculate oak distribution in Poland that are at risk from climate change.
CONCLUSIONS
The model revealed that pedunculate oak populations in the eastern part of the analyzed geographical region are the most sensitive to climate change. Our results might offer an initial evaluation of a potential management strategy for preserving the genetic diversity of pedunculate oak.
Topics: Humans; Quercus; Biological Evolution; Genomics; Forests; Poland; Adaptation, Physiological
PubMed: 38243199
DOI: 10.1186/s12864-023-09897-y -
Environmental and Experimental Botany Jun 2017Gypsy moth ( L., Lymantriinae) is a major pest of pedunculate oak () forests in Europe, but how its infections scale with foliage physiological characteristics, in...
Disproportionate photosynthetic decline and inverse relationship between constitutive and induced volatile emissions upon feeding of leaves by large larvae of gypsy moth ().
Gypsy moth ( L., Lymantriinae) is a major pest of pedunculate oak () forests in Europe, but how its infections scale with foliage physiological characteristics, in particular with photosynthesis rates and emissions of volatile organic compounds has not been studied. Differently from the majority of insect herbivores, large larvae of rapidly consume leaf area, and can also bite through tough tissues, including secondary and primary leaf veins. Given the rapid and devastating feeding responses, we hypothesized that infection of leaves by leads to disproportionate scaling of leaf photosynthesis and constitutive isoprene emissions with damaged leaf area, and to less prominent enhancements of induced volatile release. Leaves with 0% (control) to 50% of leaf area removed by larvae were studied. Across this range of infection severity, all physiological characteristics were quantitatively correlated with the degree of damage, but all these traits changed disproportionately with the degree of damage. The net assimilation rate was reduced by almost 10-fold and constitutive isoprene emissions by more than 7-fold, whereas the emissions of green leaf volatiles, monoterpenes, methyl salicylate and the homoterpene (3)-4,8-dimethy-1,3,7-nonatriene scaled negatively and almost linearly with net assimilation rate through damage treatments. This study demonstrates that feeding by large insect herbivores disproportionately alters photosynthetic rate and constitutive isoprene emissions. Furthermore, the leaves have a surprisingly large capacity for enhancement of induced emissions even when foliage photosynthetic function is severely impaired.
PubMed: 29367792
DOI: 10.1016/j.envexpbot.2017.03.014 -
The Indian Medical Gazette Aug 1933
PubMed: 29009470
DOI: No ID Found -
Molecular Plant-microbe Interactions :... Sep 2014Rhizobacteria are known to induce defense responses in plants without causing disease symptoms, resulting in increased resistance to plant pathogens. This study...
Rhizobacteria are known to induce defense responses in plants without causing disease symptoms, resulting in increased resistance to plant pathogens. This study investigated how Streptomyces sp. strain AcH 505 suppressed oak powdery mildew infection in pedunculate oak, by analyzing RNA-Seq data from singly- and co-inoculated oaks. We found that this Streptomyces strain elicited a systemic defense response in oak that was, in part, enhanced upon pathogen challenge. In addition to induction of the jasmonic acid/ethylene-dependent pathway, the RNA-Seq data suggests the participation of the salicylic acid-dependent pathway. Transcripts related to tryptophan, phenylalanine, and phenylpropanoid biosynthesis were enriched and phenylalanine ammonia lyase activity increased, indicating that priming by Streptomyces spp. in pedunculate oak shares some determinants with the Pseudomonas-Arabidopsis system. Photosynthesis-related transcripts were depleted in response to powdery mildew infection, but AcH 505 alleviated this inhibition, which suggested there is a fitness benefit for primed plants upon pathogen challenge. This study offers novel insights into the mechanisms of priming by actinobacteria and highlights their capacity to activate plant defense responses in the absence of pathogen challenge.
Topics: Ascomycota; Cyclopentanes; Ethylenes; Gene Expression Regulation, Plant; Gene Ontology; High-Throughput Nucleotide Sequencing; Host-Pathogen Interactions; Oxylipins; Photosynthesis; Plant Diseases; Plant Growth Regulators; Plant Immunity; Plant Leaves; Plant Roots; Quercus; Salicylic Acid; Secondary Metabolism; Sequence Analysis, RNA; Signal Transduction; Streptomyces
PubMed: 24779643
DOI: 10.1094/MPMI-10-13-0296-R -
The New Phytologist Sep 2014The root-rot pathogen Phytophthora quercina is a key determinant of oak decline in Europe. The susceptibility of pedunculate oak (Quercus robur) to this pathogen has...
The root-rot pathogen Phytophthora quercina is a key determinant of oak decline in Europe. The susceptibility of pedunculate oak (Quercus robur) to this pathogen has been hypothesized to depend on the carbon availability in roots as an essential resource for defense. Microcuttings of Q. robur undergo an alternating rhythm of root and shoot growth. Inoculation of mycorrhizal (Piloderma croceum) and nonmycorrhizal oak roots with P. quercina was performed during both growth phases, that is, root flush (RF) and shoot flush (SF). Photosynthetic and morphological responses as well as concentrations of nonstructural carbohydrates (NSC) were analyzed. Infection success was quantified by the presence of pathogen DNA in roots. Concentrations of NSC in roots depended on the alternating root/shoot growth rhythm, being high and low during RF and SF, respectively. Infection success was high during RF and low during SF, resulting in a significantly positive correlation between pathogen DNA and NSC concentration in roots, contrary to the hypothesis. The alternating growth of roots and shoots plays a crucial role for the susceptibility of lateral roots to the pathogen. NSC availability in oak roots has to be considered as a benchmark for susceptibility rather than resistance against P. quercina.
Topics: Biomass; Carbohydrates; DNA; Disease Susceptibility; Photosystem II Protein Complex; Phytophthora; Plant Diseases; Plant Leaves; Plant Roots; Plant Stems; Quercus; Solubility; Starch
PubMed: 24902781
DOI: 10.1111/nph.12876 -
Journal of Cardiology Dec 2012There is no clear consensus about antithrombotic treatment in atrial fibrillation (AF) patients at low-intermediate thromboembolic risk. Transesophageal echocardiography...
Clinical and transesophageal echocardiographic variables for prediction of thromboembolic events in patients with nonvalvular atrial fibrillation at low-intermediate risk.
BACKGROUND
There is no clear consensus about antithrombotic treatment in atrial fibrillation (AF) patients at low-intermediate thromboembolic risk. Transesophageal echocardiography (TEE) is useful for prediction of thromboembolic events in AF.
METHODS AND RESULTS
Of 498 patients with nonvalvular AF, incidence of stroke, cardiac events, and mortality was investigated in 280 patients with CHADS(2) score 0 or 1 (mean age 64 years, mean follow-up 6.4 ± 3.1 years). Left atrial abnormality (low left atrial appendage flow, spontaneous echo contrast, or thrombi), complex aortic plaque (mobile, ulcerated, pedunculate, or thickness ≥ 4mm), or both were defined as TEE risk. The incidences of ischemic stroke, cardiovascular events, and death were higher in patients with TEE risk than in those without the risk (2.0%/year vs. 0.5%/year, p<0.05; 4.7%/year vs. 1.9%/year, p<0.01; and 4.7%/year vs. 2.0%/year, p<0.01, respectively). This was also true for patients with CHADS(2) score of 0 (1.7%/year vs. 0.3%/year, p<0.05; 4.1%/year vs. 1.6%/year, p<0.05; and 3.9%/year vs. 1.4%/year, p<0.01; respectively). On multivariate analysis, TEE risk predicted ischemic stroke, cardiovascular events, and mortality independently of clinical variables or CHADS(2) score.
CONCLUSIONS
TEE could be useful for further stratification of patients with nonvalvular AF stratified at low-intermediate risk (CHADS(2) score 0 or 1) and could indicate who should receive anticoagulation treatment.
Topics: Aged; Atrial Fibrillation; Cardiovascular Diseases; Echocardiography, Transesophageal; Female; Forecasting; Humans; Incidence; Male; Middle Aged; Multivariate Analysis; Risk; Stroke; Thromboembolism
PubMed: 23063013
DOI: 10.1016/j.jjcc.2012.09.001 -
The New Phytologist Nov 2018Insect herbivores cause substantial changes in the leaves they attack, but their effects on the ecophysiology of neighbouring, nondamaged leaves have never been...
Insect herbivores cause substantial changes in the leaves they attack, but their effects on the ecophysiology of neighbouring, nondamaged leaves have never been quantified in natural canopies. We studied how winter moth (Operophtera brumata), a common herbivore in temperate forests, affects the photosynthetic and isoprene emission rates of its host plant, the pedunculate oak (Quercus robur). Through a manipulative experiment, we measured leaves on shoots damaged by caterpillars or mechanically by cutting, or left completely intact. To quantify the effects at the canopy scale, we surveyed the extent and patterns of leaf area loss in the canopy. Herbivory reduced photosynthesis both in damaged leaves and in their intact neighbours. Isoprene emission rates significantly increased after mechanical leaf damage. When scaled up to canopy-level, herbivory reduced photosynthesis by 48 ± 10%. The indirect effects of herbivory on photosynthesis in undamaged leaves (40%) were much more important than the direct effects of leaf area loss (6%). If widespread across other plant-herbivore systems, these findings suggest that insect herbivory has major and previously underappreciated influences in modifying ecosystem carbon cycling, with potential effects on atmospheric chemistry.
Topics: Animals; Butadienes; Hemiterpenes; Herbivory; Models, Theoretical; Moths; Photosynthesis; Plant Leaves; Quercus
PubMed: 30047151
DOI: 10.1111/nph.15338 -
PhytoKeys 2020is described from northern Chile. The new species is morphologically similar to the discoid caespitose Andean species and belongs to the subgroup displaying yellow...
is described from northern Chile. The new species is morphologically similar to the discoid caespitose Andean species and belongs to the subgroup displaying yellow corollas and yellowish anthers and style branches. It is characterized by a weak, not self-supporting stem, narrowly linear leaves, long pedunculate capitula with (17-)21 involucral bracts, and minutely papillose achenes. Among other characters, the color of the corollas, anthers, and style branches and the number of involucral bracts differentiate it from , which is the morphologically closest species. The new species thrives in the desertic Puna ecoregion and grows amongst tufts of (Poaceae). Detailed pictures of living plants are provided, as well as a distribution map and a dichotomous key to the discoid caespitose species from northern Chile.
PubMed: 32549746
DOI: 10.3897/phytokeys.149.52297