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1
Volkova, Polina A., Sof'ya A. Kasatskaya, Anna A. Boiko e Alexey B. Shipunov. "Stability of leaf form and size during specimen preparation of herbarium specimens". Feddes Repertorium 121, n. 5-6 (dicembre 2010): 219–25. http://dx.doi.org/10.1002/fedr.201000021.
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Beauvais, Marie-Pierre, Stéphanie Pellerin, Jean Dubé e Claude Lavoie. "Herbarium specimens as tools to assess the impact of large herbivores on plant species". Botany 95, n. 2 (febbraio 2017): 153–62. http://dx.doi.org/10.1139/cjb-2016-0206.
Testo completoAbstract (sommario):
Herbarium specimens can be used to reconstruct spatiotemporal changes in plant morphology caused by environmental pressures. The reliability of herbarium-derived data requires evaluation, because specimen collection is subject to biases. We used herbarium and field data to investigate the impact of large herbivore browsing on the size of a forb. White trillium (Trillium grandiflorum (Michaux) Salisbury) was studied because the impacts of white-tailed deer (Odocoileus virginianus Zimmermann) browsing on this species are well-known. A total of 692 herbarium specimens collected in Quebec (Canada) were used to evaluate leaf area. Leaf area values of herbarium specimens were compared with those of modern (2013, 2014) specimens collected in sites either with >8 deer per square kilometre or without deer. Flowering individuals in modern sites with deer had a significantly lower leaf area than herbarium specimens and modern specimens collected in sites without deer. The distribution of white trillium individuals in deer sites was also skewed towards plants with a smaller leaf area. Herbarium specimens may offer unique and inexpensive data, compared with methods traditionally used to assess the impacts of herbivores on plants, such as exclosures or clipping experiments. Unfortunately, this rich data source is seriously jeopardized by the downtrend in specimen collecting.
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Ahlstrand, Gilbert G., e Richard J. Zeyen. "Bulk Specimen Preparation For X-Ray Microanalysis of Plant Cells". Proceedings, annual meeting, Electron Microscopy Society of America 48, n. 2 (12 agosto 1990): 334–35. http://dx.doi.org/10.1017/s0424820100135277.
Testo completoAbstract (sommario):
Numerous plant pathological investigations have been published where pathologists determined elemental differences between diseased and healthy plant tissue using unfractured bulk specimens and energy dispersive x-ray microanalysis (EDX). In these studies effects of specimen preparation procedures were largely ignored (1). Our objective was to compare bulk specimen preparation procedures using healthy leaf epidermal (surface) cells of barley, Hordeum vulgare, (Fig. 1) to determine advantages and disadvantages of each procedure for reference to future pathological work using EDX. Three preparation procedures were compared: 1) Frozen-hydrated (FH) specimens to maintain soluble and insoluble elements in situ; 2) Freeze-dried (FD) specimens to maintain total soluble and insoluble elements and allow deeper beam penetration than does FH, and; 3) Formalin/acetic acid/ethanol (FAA) fixed specimens, dehydrated in ethanol, and critical point dried (CD) using CO2, for determination of elemental loss in liquid fixatives (2,3).Aluminum specimen stubs were colloidal graphite coated (leaf segments attached to graphite areas) leaving clean Al margins for calibration.
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Corney, David P. A., Jonathan Y. Clark, H. Lilian Tang e Paul Wilkin. "Automatic extraction of leaf characters from herbarium specimens". TAXON 61, n. 1 (febbraio 2012): 231–44. http://dx.doi.org/10.1002/tax.611016.
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Kim, Hyeree, XiaoXuan Du, Sungwook Kim, Pilun Kim, Ruchire Eranga Wijesinghe, Byoung-Ju Yun, Kyung-Min Kim, Mansik Jeon e Jeehyun Kim. "Non-Invasive Morphological Characterization of Rice Leaf Bulliform and Aerenchyma Cellular Regions Using Low Coherence Interferometry". Applied Sciences 9, n. 10 (22 maggio 2019): 2104. http://dx.doi.org/10.3390/app9102104.
Testo completoAbstract (sommario):
Non-invasive investigation of rice leaf specimens to characterize the morphological formation and particular structural information that is beneficial for agricultural perspective was demonstrated using a low coherence interferometric method called swept source optical coherence tomography (SS-OCT). The acquired results non-invasively revealed morphological properties of rice leaf, such as bulliform cells; aerenchyma, parenchyma, and collenchyma layer; and vascular bundle. Beside aforementioned morphologic characteristics, several leaf characteristics associated with cytological mechanisms of leaf rolling (leaf inclination) were examined for the pre-identification of inevitable necrosis and atrophy of leaf tissues by evaluating acute angle information, such as angular characteristics of the external bi-directional angles between the lower epidermis layer and lower mid-vein, and internal angle of lower mid-vein. To further assist the pre-identification, acquired cross-sections were employed to enumerate the small veins of each leaf specimen. Since mutants enlarge leaf angles due to increased cell division in the adaxial epidermis, healthy and abnormal leaf specimens were morphologically and quantitatively compared. Therefore, the results of the method can be used in agriculture, and SS-OCT shows potential as a rigorous investigation method for selecting mutant infected rice leaf specimens rapidly and non-destructively compared to destructive and time consuming gold-standard methods with a lack of precision.
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Kirker, Grant T., Amy Bishell, Jed Cappellazzi, Jonathan Palmer, Nathan Bechle, Patricia Lebow e Stan Lebow. "Role of Leaf Litter in Above-Ground Wood Decay". Microorganisms 8, n. 5 (9 maggio 2020): 696. http://dx.doi.org/10.3390/microorganisms8050696.
Testo completoAbstract (sommario):
The effects of leaf litter on moisture content and fungal decay development in above-ground wood specimens were assessed. Untreated southern pine specimens were exposed with or without leaf litter contact. Two types of leaf litter were evaluated; aged (decomposed) and young (early stages of decomposition). The moisture content of specimens was monitored, and specimens were periodically removed for visual evaluation of decay development. In addition, amplicon-based sequencing analysis of specimens and associated leaf litter was conducted at two time points. Contact with either type of leaf litter resulted in consistently higher moisture contents than those not in contact with leaf litter. Visually, evident decay developed most rapidly in specimens in contact with the aged leaf litter. Analysis of amplicon-based sequencing revealed that leaf litter contributes a significant amount of the available wood decay fungal community with similar communities found in the litter exposed wood and litter itself, but dissimilar community profiles from unexposed wood. Dominant species and guild composition shifted over time, beginning initially with more leaf saprophytes (ascomycetes) and over time shifting to more wood rotting fungi (basidiomycetes). These results highlight the importance of the contributions of leaf litter to fungal colonization and subsequent decay hazard for above-ground wood.
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Petrulaitis, Lukas, e Zigmantas Gudžinskas. "What are We Conserving? A Case Study of Mentha longifolia and Allied Species from Lithuania". Botanica 24, n. 1 (1 giugno 2018): 3–14. http://dx.doi.org/10.2478/botlit-2018-0001.
Testo completoAbstract (sommario):
AbstractAssessment of the conservation status of a species, first, should be based on its clearly defined taxonomic identity. Insufficient knowledge of certain taxonomic groups may lead to misidentifications, misinterpretations and become an obstacle for conservation. Mentha longifolia, listed as a protected plant species of Lithuania since 1981, belongs to a taxonomically complex group of species. The aim of this research was to examine available herbarium specimens of M. longifolia and verify their identification, specify distribution of this species in Lithuania and evaluate its conservation status in the country. The study was based on the analysis of herbarium specimens and information provided in references and databases. We studied a total of 93 specimens initially identified as M. longifolia. Morphological features of 30 leaves (leaf length, leaf width, petiole length, distance from leaf base to the widest place, length of leaf tooth) of both M. longifolia and M. ×villosa were measured on herbarium specimens. After the revision of herbarium specimens, we revealed that 37.6% of specimens initially identified as M. longifolia belong to other species (mostly to M. ×villosa) and 29.0% of specimens cannot be identified precisely because of the early stage of development. Only 33.4% of M. longifolia specimens were identified precisely. Thus, M. longifolia, previously supposed as quite widespread in Lithuania, after the revision appeared to be restricted mainly to the southern and south-eastern parts of the country. Applying the IUCN criteria, M. longifolia was evaluated as data deficient (DD) species. Analysis of leaf morphological traits revealed that M. longifolia and M. ×villosa can be differentiated by the length and the width of leaf blade, the distance from leaf base to the widest part of leaf and by the ratio between the length and the width of middle cauline leaves. This study revealed that taxonomic revision of the genus Mentha in Lithuania is required. Distribution of species, ecology and state of populations, impact of alien species on native congeners should be estimated in the future.
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Dacuan, Cecielle N., Virgilio Y. Abellana e Hana Astrid R. Canseco. "Assessment and Evaluation of Blended Cement Using Bamboo Leaf Ash BLASH Against Corrosion". Civil Engineering Journal 7, n. 6 (1 giugno 2021): 1015–35. http://dx.doi.org/10.28991/cej-2021-03091707.
Testo completoAbstract (sommario):
Concrete provides a high degree of protection against corrosion of embedded steel reinforcement. Owing to the harsh environmental conditions and the presence of aggressive elements from the marine environment, deteriorating corrosion affects the durability of reinforced concrete structures. This study evaluated the effectiveness of bamboo leaf ash BLASH as a supplementary cementing material or admixture with Portland cement to improve the durability of reinforced concrete structures. Specimens of 0, 10, 15, and 20% BLASH mixtures were prepared using 16, 20, and 25 mm steel reinforcements. A total of 100 cylindrical specimens were cast and used in this study. The specimens were accelerated by corrosion using impressed current techniques and a galvanostatic method in a simulated environment. The results show that specimens with a BLASH content of 10% exhibited superior performance and exhibited longer corrosion initiation and propagation times. It has a higher resistance to acid penetration and lower corrosion rates. The crack parameters of the specimen with BLASH admixtures, such as the crack width and crack frequency, were negligible. The use of BLASH as an admixture strengthens its durability and improves its residual strength and serviceability. Doi: 10.28991/cej-2021-03091707 Full Text: PDF
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Koponen, T. "Taxonomic Results of the BRYOTROP Expedition to Zaire and Rwanda 21. Mniaceae". Bryophyte Diversity and Evolution 8, n. 1 (31 dicembre 1993): 189. http://dx.doi.org/10.11646/bde.8.1.22.
Testo completoAbstract (sommario):
The specimen represents a rather typical African form of this taxon. The marginal teeth of the leaf are small and the leaf cells near isodiametric, but on the basis of the clearly differentiated juxtacostal cells, the specimen belongs to var. rhynchophyrum. Two other tropical African species are Plagiomnium cuspidatum (Hedw.) T. Kop. and P. undulatum (Hedw.) T. Kop. which differ by having an acute or cuspidate leaf apex, which in P. rhynchophorum tends to be emarginate and apiculate, and having sharper and larger projecting marginal teeth on their leaves. The distribution of P. rhynchophyrum is mapped and African specimens listed in Koponen (1981).
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Kozlov, Mikhail V., Irina V. Sokolova, Vitali Zverev e Elena L. Zvereva. "Changes in plant collection practices from the 16th to 21st centuries: implications for the use of herbarium specimens in global change research". Annals of Botany 127, n. 7 (9 febbraio 2021): 865–73. http://dx.doi.org/10.1093/aob/mcab016.
Testo completoAbstract (sommario):
Abstract Background and Aims Herbaria were recently advertised as reliable sources of information regarding historical changes in plant traits and biotic interactions. To justify the use of herbaria in global change research, we asked whether the characteristics of herbarium specimens have changed during the past centuries and whether these changes were due to shifts in plant collection practices. Methods We measured nine characteristics from 515 herbarium specimens of common European trees and large shrubs collected from 1558 to 2016. We asked botanists to rank these specimens by their scientific quality, and asked artists to rank these specimens by their beauty. Key Results Eight of 11 assessed characteristics of herbarium specimens changed significantly during the study period. The average number of leaves in plant specimens increased 3-fold, whereas the quality of specimen preparation decreased. Leaf size negatively correlated with leaf number in specimens in both among-species and within-species analyses. The proportion of herbarium sheets containing plant reproductive structures peaked in the 1850s. The scientific value of herbarium specimens increased until the 1700s, but then did not change, whereas their aesthetic value showed no systematic trends. Conclusions Our findings strongly support the hypothesis that many characteristics of herbarium specimens have changed systematically and substantially from the 16th to 21st centuries due to changes in plant collection and preservation practices. These changes may both create patterns which could be erroneously attributed to environmental changes and obscure historical trends in plant traits. The utmost care ought to be taken to guard against the possibility of misinterpretation of data obtained from herbarium specimens. We recommend that directional changes in characters of herbarium specimens which occurred during the past 150‒200 years, primarily in specimen size and in the presence of reproductive structures, are accounted for when searching for the effects of past environmental changes on plant traits.
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Hill, RS, e MS Pole. "Leaf and shoot morphology of extant Afrocarpus, Nageia and Retrophyllum (Podocarpaceae) species, and species with similar leaf arrangement, from tertiary sediments in Australia". Australian Systematic Botany 5, n. 3 (1992): 337. http://dx.doi.org/10.1071/sb9920337.
Testo completoAbstract (sommario):
A cuticular micromorphological study confirms the separate generic status of Afrocarpus, Nageia and Retrophyllum and increases the number of available diagnostic characters. A re-investigation of fossil species previously assigned to this complex demonstrates that in all cases the generic designation was incorrect. Decussocarpus maslinensis from Eocene sediments at Mash Bay is transferred to the new genus Willungia; specimens from Eocene sediments at Anglesea referred to Decussocarpus brownei are transferred to Smithtonia victoriensis; Prumnopitys lanceolata and specimens assigned to P. aff. tasmanica from Anglesea are combined and transferred to Smithtonia. Previously undescribed fossil specimens from Oligocene sediments in Tasmania are assigned to Smithtonia jonesii and Willungia oppositifolia. Specimens of Retrophyllum are reported from Oligocene sediments in Western Australia and Miocene sediments in the South Island of New Zealand. These new fossil genera and species demonstrate that foliage characters which are now unique to Retrophyllum among the Podocarpaceae were once more widespread, providing further evidence for the hypothesis that many podocarpaceous taxa converged towards the production of flattened short shoots to increase photosynthetic efficiency.
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Annisa, Mutiara, Puteri Aulia Rizqi Kanina, Nur Liyana Binti Hamid e Archadian Nuryanti. "<strong>Effectiveness of green tea, bay leaf, and lime peel extracts as toothpastes active agents for extrinsic stain removal on teeth, artificial teeth, and denture base</strong>". Padjadjaran Journal of Dentistry 34, n. 1 (9 aprile 2022): 47. http://dx.doi.org/10.24198/pjd.vol34no1.32236.
Testo completoAbstract (sommario):
Introduction: Tea consumption causes extrinsic stain formation on teeth and denture surfaces, affecting personal appearance. Herbal plants extract such as green tea, bay leaf, and lime peel are potentially active agents for extrinsic stain removal. This study aimed to analyse the effectiveness of green tea, bay leaf, and lime peel extracts as toothpaste active agents for extrinsic stain removal on teeth, artificial teeth, and denture base. Methods: Twenty-five post-extracted human permanent central incisors, 25 artificial teeth, and 25 heat polymerised acrylic resin denture base (20x20x10mm) were divided into three treatment groups and two control groups. Pictures of all specimens were taken before and after stain induction and after brushing. All specimens were immersed in a tea solution made from 2 grams of tea and 100ml of 100°C boiled water to induce extrinsic stain. The immersion process was repeated every 24 hours for seven days. All specimens were then brushed using an automatic toothbrushing machine for 70 seconds on each surface, 200 grams loads, and five speeds/second. Toothpaste used for brushing were three different active agent toothpaste (treatment groups), no active agent toothpaste, and commercial whitening (control groups). Colour index analysis of the specimen pictures computerised by CIELAB method. The data were analysed by one-way ANOVA (α=0.05). Results: Green tea, bay leaf, and lime peel extract toothpaste and positive control had higher L-values of extrinsic stain removal than essential toothpaste on all specimens. There was a significant difference between green tea, bay leaf, and lime peel extract toothpaste and negative control toothpaste (p<0.05), while no significant difference was found when compared to the positive control toothpaste (p>0.05). Conclusion: Green tea, bay leaf, and lime peel extract toothpaste are effective as extrinsic stain removal on teeth and acrylic resin denture base because of abrasive materials that work together with the active agents such as epigallocatechin-3-gallate (EGCG) in green tea, eugenol in bay leaf, and naringin in lime peel.
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Mustapa, Mohammad Sukri, Saiful Din Sabdin, Abdul Latif M. Tobi, Md Saidin Wahab, Mohd Radzi Mohamed Yunus e Yusri Yusof. "The Effects of Heat and Compression on Moisture Content and Water Absorption of PALF/Sugarcane Bagasse Composition in Disposable Plate Production". Applied Mechanics and Materials 773-774 (luglio 2015): 272–76. http://dx.doi.org/10.4028/www.scientific.net/amm.773-774.272.
Testo completoAbstract (sommario):
This paper presents the results of heat and compression effects on moisture content and water absorption properties in the manufacturing of disposable plate made from Pineapple Leaf Fiber-based material (PALF). The plate was made of PALF and sugarcane bagasse waste as an alternative to polystyrenes, designed to promote the green technology effort on food packaging material. Two different specimens were produced with different compositions of PALF/sugarcane bagasse series N2T8 ( 20 wt% of Pineapple leaf fiber and 80 wt% of sugarcane bagasse ) and series N8T2 ( 80 wt% of Pineapple leaf fiber and 20 wt% of sugarcane bagasse). The specimens were produced using a hot press machine set at compressing temperatures of 50°C, 100°C and 150°C with constant pressure of 0.024 MPa for 10 minutes. Moisture content and water absorption tests were carried out on the specimens to determine the moisture content and water absorption properties. The lower water absorption was obtained for specimen N8T2 because PALF potential to water resistance. This range of properties is expected to be good enough for the requirement of disposable plate and it has the potential as a suitable raw material for strength and lightweight in the manufacturing of disposable plates.
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Kinoshita, Natsuko, Aki Sugita, Barry Lustig, Shigeyuki Betsuyaku, Tetsu Fujikawa e Tatsuji Morishita. "Automating measurements of fluorescent signals in freely moving plant leaf specimens". Plant Biotechnology 36, n. 1 (25 marzo 2019): 7–11. http://dx.doi.org/10.5511/plantbiotechnology.18.1002a.
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Kolesnikov, L. E., E. A. Vlasova e Yu R. Sablina. "Monitoring the development of leaf rust pathogen on common wheat specimens". Russian Agricultural Sciences 34, n. 4 (agosto 2008): 230–33. http://dx.doi.org/10.3103/s106836740804006x.
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CUMMING, ROYCE T., JING V. LEONG e DAVID J. LOHMAN. "Leaf insects from Luzon, Philippines, with descriptions of four new species, the new genus Pseudomicrophyllium, and redescription of Phyllium (Phyllium) geryon Gray, 1843, (Phasmida: Phylliidae)". Zootaxa 4365, n. 2 (17 dicembre 2017): 101. http://dx.doi.org/10.11646/zootaxa.4365.2.1.
Testo completoAbstract (sommario):
Examination of unidentified Phylliidae specimens revealed a number of undescribed species from the island of Luzon, Philippines. Morphological and molecular study of specimens from the obscure phasmid genus Microphyllium Zompro, 2001, revealed a new species, which we describe as Microphyllium haskelli Cumming sp. nov.. It is here described and differentiated from the two other species in the genus, both currently only known from adults of a single sex. Pseudomicrophyllium Cumming gen. nov. is described as a new genus within Phylliidae with the type species Pseudomicrophyllium faulkneri Cumming gen. et sp. nov. as the sole known species in the genus. As is unfortunately often the case in the leaf-mimicking family Phylliidae, this new genus and species is only known from a single specimen. In addition to the new genus, two new Phyllium (Phyllium) species from the siccifolium species-group are named and described as Ph. (Ph.) antonkozlovi Cumming sp. nov. and Ph. (Ph.) bourquei Cumming & Le Tirant sp. nov.. In addition to the newly described species, Phyllium (Phyllium) geryon Gray, 1843 is redescribed from a nearly perfect specimen, completing some of the morphological knowledge gaps currently missing because of the severely damaged holotype specimen. A key to all known species of Phylliidae from Luzon is included. Holotype specimens for all four new species will be deposited in the National Museum of the Philippines type collection and paratype specimens will be deposited into the San Diego Natural History Museum collection or retained within the first author’s collection.
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Mustapa, Mohammad Sukri, Saiful Din Sabdin, Erween Abdul Rahim, Md Saidin Wahab e Yusri Yusof. "Effect of Heat Compression on the Tensile Strength of PALF/Sugarcane Bagasse for Disposable Plate". Applied Mechanics and Materials 660 (ottobre 2014): 362–66. http://dx.doi.org/10.4028/www.scientific.net/amm.660.362.
Testo completoAbstract (sommario):
This paper presents the results of heat compression effect on tensile properties in manufacturing process of disposable plate from Pineapple Leaf Fibers (PALF) based material. The plate was made of PALF and sugarcane bagasse waste as alternatif to polystyrenes to promote the green technology efford on food packaging material. Two different spesimens were produced with different composition of PALF/sugarcane bagasse, N2T8 (20% Pineapple leaf fiber and 80% sugarcane bagasse and N8T2 (80% pineapple leaf fiber and 20% sugarcane bagasse). The specimens were produced on a hot press machine at different compressing temperature, 50°C, 100°C and 150°C with constant pressure of 0.024 MPa at 10 minutes. Tensile and tearing tests were carried out on the specimens to determine the tensile and tearing properties. The results shown that the N2T8 speciment compressed at 50°C gives higher tensile and tearing strength of 22 MPa and 2 MPa ,respectively. This range of properties is expected to be good enough for the requirement of disposable plate and it has a potential as a raw material for strength and lightweight of disposable plate manufacturing.
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HAKIMARA, MAHSA, KAMBIZ MINAEI, SABER SADEGHI e LAURENCE MOUND. "A new species of Liophloeothrips (Thysanoptera, Phlaeothripidae) from leaf litter from Iran". Zootaxa 4571, n. 1 (25 marzo 2019): 138. http://dx.doi.org/10.11646/zootaxa.4571.1.10.
Testo completoAbstract (sommario):
Of the 16 species listed in the genus Liophloeothrips (ThripsWiki 2018), 13 are known only from India, and all of these are phytophagous with some inducing galls in various plant families (Tyagi & Kumar 2011). However, the biology of the type species, L. glaber, as well as that of the other two species, L. hungaricus and L. pulchrisetis, remains in doubt. Each of these three species is from Europe, with L. pulchrisetis known from a single female, L. glaber from two specimens, and hungaricus recorded from Hungary, Finland and Iran on a very few individuals (Minaei & Mound 2014). The record of L. hungaricus from Iran was published without any information concerning the locality, date of collection, or number of specimens (Mortazawiha 1995). However, Minaei and Mound (2014) pointed out that the slide label data of L. hungaricus specimens from Europe suggested that this species is associated with the bark of certain Salicaceae. Moreover, they indicated the possibility that the three names might actually represent a single species, although the male of L. glabrus has a sternal pore plate whereas this is apparently absent in hungaricus. Given the few known specimens, it is not possible to know if these thrips live under bark and feed on fungal hyphae, or if the few specimens collected were actually leaf-feeders that were sheltering under bark. In this paper, a new species of the genus is described from southern Iran, based on both sexes. These specimens were extracted from leaf litter using a Berlese funnel, thus again it is not possible to be certain if the species is part of the community of fungus-feeding litter thrips, or if the specimens were merely sheltering.
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Ellis, R. P. "Leaf anatomy of the South African Danthonieae (Poaceae). XIV. Pentameris dregeana". Bothalia 16, n. 2 (28 ottobre 1986): 235–41. http://dx.doi.org/10.4102/abc.v16i2.1097.
Testo completoAbstract (sommario):
Transverse sections and abaxial epidermal scrapes of leaf blades of Pentameris dregeana Stapf, both of herbarium specimens and of freshly fixed material, were examined by light microscopy. The anatomical structure was found to be basically uniform in a representative sample. A few somewhat atypical specimens, how'ever, showed epidermal similarities with Pentaschistis colorata (Steud.) Stapf. A comparison with other danthonoid grasses revealed some specimens identified as Pentaschistis colorata var. polytricha Stapf which resemble Pentameris dregeana very closely in leaf anatomy. A definite gradation in leaf anatomy between Pentameris dregeana and Pentaschistis colorata appears to exist and. consequently, it is proposed that the affinities of Pentameris dregeana lie with this group of Pentaschistis species rather than close to any of the other Pentameris species.
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Jordan, Gregory J. "Uncertainty in Palaeoclimatic Reconstructions Based on Leaf Physiognomy". Australian Journal of Botany 45, n. 3 (1997): 527. http://dx.doi.org/10.1071/bt96035.
Testo completoAbstract (sommario):
There are several methods of predicting terrestrial palaeoclimates from the size and shape of fossil leaves (foliar physiognomy). The assumptions and sources of uncertainty of these methods are considered and used to determine the true uncertainty. Their ability to predict mean annual temperature (MAT) is poor. The approximate standard errors for samples of living vegetation in North America are in the range of 1.7˚C to 2.5˚C, but the true uncertainty for fossil samples is higher. Specimens with very different physiognomy to typical specimens in the model have higher uncertainties. Besides these uncertainties, the processes of fossilisation, the allocation of specimens to taxa, and the effects of other factors on foliar physiognomy all increase the uncertainty of the predictions. Overall uncertainties in the predictions of MAT are equivalent to standard errors of about 3–5˚C depending on the nature of the fossil site and flora. Other factors affect foliar physiognomic predictions significantly because predicted MAT does not change as rapidly with altitude as true MAT, and floras from different parts of the world with similar temperatures give different temperature predictions. Mean annual temperature and one precipitation parameter (probably mean annual precipitation or the growing season precipitation) can be predicted more or less independently, although the predictions of precipitation are weak. Physiognomic signals for other climatic parameters are weak or apparently non-existent, and previously published predictions of past equability are primarily based on correlations with modern MAT, rather than physiognomy.
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Guerin, Greg R., Haixia Wen e Andrew J. Lowe. "Leaf morphology shift linked to climate change". Biology Letters 8, n. 5 (4 luglio 2012): 882–86. http://dx.doi.org/10.1098/rsbl.2012.0458.
Testo completoAbstract (sommario):
Climate change is driving adaptive shifts within species, but research on plants has been focused on phenology. Leaf morphology has demonstrated links with climate and varies within species along climate gradients. We predicted that, given within-species variation along a climate gradient, a morphological shift should have occurred over time due to climate change. We tested this prediction, taking advantage of latitudinal and altitudinal variations within the Adelaide Geosyncline region, South Australia, historical herbarium specimens ( n = 255) and field sampling ( n = 274). Leaf width in the study taxon, Dodonaea viscosa subsp. angustissima , was negatively correlated with latitude regionally, and leaf area was negatively correlated with altitude locally. Analysis of herbarium specimens revealed a 2 mm decrease in leaf width (total range 1–9 mm) over 127 years across the region. The results are consistent with a morphological response to contemporary climate change. We conclude that leaf width is linked to maximum temperature regionally (latitude gradient) and leaf area to minimum temperature locally (altitude gradient). These data indicate a morphological shift consistent with a direct response to climate change and could inform provenance selection for restoration with further investigation of the genetic basis and adaptive significance of observed variation.
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Wilf, Peter, Shengping Zhang, Sharat Chikkerur, Stefan A. Little, Scott L. Wing e Thomas Serre. "Computer vision cracks the leaf code". Proceedings of the National Academy of Sciences 113, n. 12 (7 marzo 2016): 3305–10. http://dx.doi.org/10.1073/pnas.1524473113.
Testo completoAbstract (sommario):
Understanding the extremely variable, complex shape and venation characters of angiosperm leaves is one of the most challenging problems in botany. Machine learning offers opportunities to analyze large numbers of specimens, to discover novel leaf features of angiosperm clades that may have phylogenetic significance, and to use those characters to classify unknowns. Previous computer vision approaches have primarily focused on leaf identification at the species level. It remains an open question whether learning and classification are possible among major evolutionary groups such as families and orders, which usually contain hundreds to thousands of species each and exhibit many times the foliar variation of individual species. Here, we tested whether a computer vision algorithm could use a database of 7,597 leaf images from 2,001 genera to learn features of botanical families and orders, then classify novel images. The images are of cleared leaves, specimens that are chemically bleached, then stained to reveal venation. Machine learning was used to learn a codebook of visual elements representing leaf shape and venation patterns. The resulting automated system learned to classify images into families and orders with a success rate many times greater than chance. Of direct botanical interest, the responses of diagnostic features can be visualized on leaf images as heat maps, which are likely to prompt recognition and evolutionary interpretation of a wealth of novel morphological characters. With assistance from computer vision, leaves are poised to make numerous new contributions to systematic and paleobotanical studies.
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Franco, Celeste de Jesus Pereira, Oberdan Oliveira Ferreira, Ângelo Antônio Barbosa de Moraes, Everton Luiz Pompeu Varela, Lidiane Diniz do Nascimento, Sandro Percário, Mozaniel Santana de Oliveira e Eloisa Helena de Aguiar Andrade. "Chemical Composition and Antioxidant Activity of Essential Oils from Eugenia patrisii Vahl, E. punicifolia (Kunth) DC., and Myrcia tomentosa (Aubl.) DC., Leaf of Family Myrtaceae". Molecules 26, n. 11 (29 maggio 2021): 3292. http://dx.doi.org/10.3390/molecules26113292.
Testo completoAbstract (sommario):
Essential oils (EOs) were extracted from Eugenia patrisii, E. punicifolia, and Myrcia tomentosa, specimens A and B, using hydrodistillation. Gas chromatography coupled with mass spectrometry (GC/MS) was used to identify the volatile constituents present, and the antioxidant capacity of EOs was determined using diphenylpicryl-hydrazyl (DPPH) and trolox equivalent antioxidant capacity (TEAC) assays. For E. patrisii, germacrene D (20.03%), bicyclogermacrene (11.82%), and (E)-caryophyllene (11.04%) were identified as the major constituents of the EOs extracted from specimen A, whereas specimen B primarily comprised γ-elemene (25.89%), germacrene B (8.11%), and (E)-caryophyllene (10.76%). The EOs of E. punicifolia specimen A contained β-Elemene (25.12%), (E)-caryophyllene (13.11%), and bicyclogermacrene (9.88%), while specimen B was composed of (E)-caryophyllene (11.47%), bicyclogermacrene (5.86%), β-pinene (5.86%), and γ-muurolene (5.55%). The specimen A of M. tomentosa was characterized by γ-elemene (12.52%), germacrene D (11.45%), and (E)-caryophyllene (10.22%), while specimen B contained spathulenol (40.70%), α-zingiberene (9.58%), and γ-elemene (6.89%). Additionally, the chemical composition of the EOs was qualitatively and quantitatively affected by the collection period. Furthermore, the EOs of the studied specimens, especially specimen A of E. punicifolia, showed a greater antioxidant activity in DPPH rather than TEAC, as represented by a significantly high inhibition percentage (408.0%).
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Oza, Kavi K., Rinku J. Desai e Vinay M. Raole*. "Digital Morphometrics: A Tool for Leaf Morpho-Taxonomical Studies". Indian Journal of Botany 1, n. 2 (10 ottobre 2021): 1–7. http://dx.doi.org/10.35940/ijb.b2001.101221.
Testo completoAbstract (sommario):
Leaves are most important part of the plant and can be used for the identification of a taxon. An appropriate understanding of leaf development in terms of shape and responsible abiotic factors is necessary for improvement in plant. Leaf shape variation could be evaluated successfully, and the symmetrical and asymmetrical elements of the overall shape variation could be detected. The aim of the present study was to establish a quantitative analysis method of leaf shape by elliptic Fourier descriptors and principal component analysis (EF-PCA). EF-PCA describes an overall shape mathematically by transforming coordinate information concerning its contours into elliptic Fourier descriptors (EFDs) and summarizing the EFDs by principal component analysis. We can be able to extract six variables by using leaf specimen images from field and herbarium specimens. In the present study, total leaf area with respect to notch area is more variable within species. Within a species the major source of the symmetrical elements may be governed by genotypic features and the asymmetrical elements are strongly affected by the environment. We could discuss the value of morphometrics to detect subtle morphological variation which may be undetectable by human eye.
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Oza, Kavi K., Rinku J. Desai e Vinay M. Raole. "Digital Morphometrics: A Tool for Leaf Morpho-Taxonomical Studies". Indian Journal of Advanced Botany 1, n. 2 (10 ottobre 2021): 1–7. http://dx.doi.org/10.54105/ijab.b2001.101221.
Testo completoAbstract (sommario):
Leaves are most important part of the plant and can be used for the identification of a taxon. An appropriate understanding of leaf development in terms of shape and responsible abiotic factors is necessary for improvement in plant. Leaf shape variation could be evaluated successfully, and the symmetrical and asymmetrical elements of the overall shape variation could be detected. The aim of the present study was to establish a quantitative analysis method of leaf shape by elliptic Fourier descriptors and principal component analysis (EF-PCA). EF-PCA describes an overall shape mathematically by transforming coordinate information concerning its contours into elliptic Fourier descriptors (EFDs) and summarizing the EFDs by principal component analysis. We can be able to extract six variables by using leaf specimen images from field and herbarium specimens. In the present study, total leaf area with respect to notch area is more variable within species. Within a species the major source of the symmetrical elements may be governed by genotypic features and the asymmetrical elements are strongly affected by the environment. We could discuss the value of morphometrics to detect subtle morphological variation which may be undetectable by human eye.
26
Kabíček, J. "Broad Leaf Trees as Reservoirs for Phytoseiid Mites (Acari: Phytoseiidae)". Plant Protection Science 39, No. 2 (25 novembre 2011): 65–69. http://dx.doi.org/10.17221/3828-pps.
Testo completoAbstract (sommario):
The possibility that broad leaf trees can be reservoirs for phytoseiid mites was investigated by determining their occurrence and species diversity on common deciduous tree species. No phytoseiid mites were found on Betula pendula and Populus tremula. Altogether 280 specimens of phytoseiids belonging to six species (Neoseiulella ace-ri, N. tiliarum, Paraseiulus soleiger, Euseius finlandicus, Phytoseius severus, Typhlodromus rhenanus) were found on Acer platanoides, Fagus sylvatica, Quercus robur and Salix caprea. Ph. severus was the dominant phytoseiid species on S. caprea, while N. aceri was most abundant on A. platanoides. The greatest abundance and species diversity of phytoseiids were found on S. caprea that can thus constitute an excellent reservoir for some phytoseiid mites, particularly Phytoseius spp.
27
Catarino, Michel F., e Jansen Zuanon. "Feeding ecology of the leaf fish Monocirrhus polyacanthus (Perciformes: Polycentridae) in a terra firme stream in the Brazilian Amazon". Neotropical Ichthyology 8, n. 1 (marzo 2010): 183–86. http://dx.doi.org/10.1590/s1679-62252010000100022.
Testo completoAbstract (sommario):
Monocirrhus polyacanthus (Polycentridae) is a remarkable leaf-mimicking fish that inhabits streams, lake and river margins along the Amazon basin. Despite its obvious predatory habits and being frequently present in the international aquarium trade, little is known about its diet under natural conditions. We examined 35 specimens of leaf fish (28.5-82.0 mm SL), of which 19 had food the stomach. Thirty-three preys were found in the stomach contents, 19 of which were measured (2.0-33.0 mm total length). Up to five preys were found in the stomach contents of a single leaf fish specimen. The diet of the leaf fish was constituted by fish (63.15% FO, n = 12) and invertebrates (36.3% FO, n = 4); fish and invertebrate preys occurred together in three stomachs (15.8% FO). Of the 33 prey found in the stomachs, 21 were fish and 12 invertebrates. Among the consumed prey fishes, Characiformes and Perciformes represented 76.1% and 14.2% respectively. Characidae was the most commonly recorded prey family, followed by Lebiasinidae. Invertebrates were represented by shrimps (Decapoda) and insects (Coleoptera, Hymenoptera, Ephemeroptera and Odonata). There was a positive relation between the size of the leaf fish specimens and of its consumed preys. The combination of leaf fish's visually effective body camouflage and the reduced activity of the characids at crepuscular hours probably allow the capture of such fast moving preys. The coiled position of the fishes found in the stomach of M. polyacanthus possibly allowed the accommodation of more than one prey simultaneously, which seems to be important for predators that consume proportionally large preys that are captured only occasionally.
28
Chandra, Shaila, e K. J. Singh. "On Euryphyllum Feistmantel and its epidermal features". Journal of Palaeosciences 45 (31 dicembre 1996): 7–14. http://dx.doi.org/10.54991/jop.1996.1213.
Testo completoAbstract (sommario):
The leaf form genus Euryphyllum Feistmantel 1879 is known by two species, viz., E. whittianum Feistmantel 1879 E. obovatum Maithy 1970 from the Karharbari bed of Giridih Coalfield, India. Both these species are based on the external morphology only. For the first time epidermal features of this leaf are reported from the Early Permian beds of Talchir Coalfield and a new species– E. maithyi has been established. Besides, three specimens assignable to the type species of the genus E. whittianum are also recorded. All the specimens hitherto described and or transferred under this leaf genus have also been re-examined alongwith its possible affinities and affiliation.
29
Everill, Peter H., Richard B. Primack, Elizabeth R. Ellwood e Eli K. Melaas. "Determining past leaf-out times of New England's deciduous forests from herbarium specimens". American Journal of Botany 101, n. 8 (agosto 2014): 1293–300. http://dx.doi.org/10.3732/ajb.1400045.
Testo completo
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STUART, BRYAN L., e UWE FRITZ. "Historical DNA from museum type specimens clarifies diversity of Asian leaf turtles (Cyclemys)". Biological Journal of the Linnean Society 94, n. 1 (29 aprile 2008): 131–41. http://dx.doi.org/10.1111/j.1095-8312.2008.00966.x.
Testo completo
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Evarte-Bundere, Gunta, e Pēteris Evarts-Bunders. "Use of leaf morphometric parameters for identification of the most common cultivated intraspecific taxa of Tilia platyphyllos". Botanica Lithuanica 19, n. 2 (1 dicembre 2013): 83–90. http://dx.doi.org/10.2478/botlit-2013-0011.
Testo completoAbstract (sommario):
Abstract Evarte-Bundere G., Evarts-Bunders P., 2013: Use of leaf morphometric parameters for identification of the most common cultivated intraspecific taxa of Tilia platyphyllos [Morfometrinių požymių panaudojimas dažniausiems kultūriniams Tilia platyphyllos vidurūšiniams taksonams apibūdinti]. - Bot. Lith., 19(2): 83-90. To determine variation of the most important morphological parameters of Tilia platyphyllos Scop., we studied four most frequently found in Latvia taxa: T. platyphyllos subsp. platyphyllos, T. platyphyllos subsp. cordifolia (Besser) C.K.Schneid., T. platyphyllos ‘Rubra’, T. platyphyllos ‘Obliqua.’ Morphometric measurements (length of petioles, width and length of leaf blades, pubescence and margin of leaves) were performed for 10 different specimens of every selected taxon measuring five typical leaves from each specimen. The cultivated intraspecific taxa of Tilia platyphyllos differed by the following morphometric parameters - the pubescence of leaves, the margin of leaves and the length of leaf blades. No significant differences were ascertained between taxa in such morphometric parameters as the width of leaf blades and the length of petioles.
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RÊGO, MÉRCIA DE CARVALHO ALMEIDA, ANGELA CELIS DE ALMEIDA LOPES, ROSELI FARIAS MELO DE BARROS, ALONSO MOTA LAMAS, MARCONES FERREIRA COSTA e REGINA LUCIA FERREIRA-GOMES. "MORPHOLOGICAL CHARACTERIZATION AND GENETIC DIVERSITY IN ORNAMENTAL SPECIMENS OF THE GENUS SANSEVIERIA". Revista Caatinga 33, n. 4 (ottobre 2020): 985–92. http://dx.doi.org/10.1590/1983-21252020v33n413rc.
Testo completoAbstract (sommario):
ABSTRACT The aim of this study was to characterize and estimate genetic divergence among twelve specimens of the Sansevieria genus from the collection of the Universidade Federal do Piauí (UFPI). A completely randomized experimental design was used with three replicates, and the plot consisted of four plants. In morphological characterization, qualitative and quantitative descriptors of leaves were evaluated. Genetic divergence among the specimens was determined by the Tocher clustering method and the hierarchical UPGMA. There is genetic variation among specimens evaluated, which was also expressed by the variability of colors, shapes, and sizes of the leaves. The Tocher clustering method and the hierarchical UPGMA were effective in differentiation of the specimens from multi-categorical qualitative descriptors, as the Tocher method grouped the accessions in two groups and the UPGMA in seven different groups. We highlight the accessions SSV 09 and SSV 10 as exhibiting the highest mean values in weekly leaf growth and in leaf height, important characteristics for local sale and for export.
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Puspitasari, Dewi, Maharani Laillyza Apriasari, Dewi Rahayu e Priyawan Rachmadi. "THE EFFECT OF Musa acuminata AND Ocimum basilicum MIXED EXTRACTS TO THE SURFACE HARDNESS OF BIOACTIVE COMPOSITE RESIN". Dentino : Jurnal Kedokteran Gigi 5, n. 2 (15 agosto 2020): 172. http://dx.doi.org/10.20527/dentino.v5i2.8970.
Testo completoAbstract (sommario):
ABSTRACTBackgrounds: The use of mouthwash daily may influence the mechanical properties of bioactive composite resin as a dental restoration, one of the mechanical properties is surface hardness. Herbal mouthwash can be used to minimize the side effect of mouthwash that contain alcohol. Mauli banana stem and basil leaf extracts can be produced into herbal mouthwash. Methods: Thirty specimens (10mm diameter x 2mm thick; n=5/group) bioactive composite resins were immersed in a mixed solution of Mauli banana and basil leaf extracts with concentration of 25%, 50%, 75 %%, 100%, the control group of chlorhexidine gluconate 0.2% and aquadest for 7 days in 37oC. Measurement of the surface hardness was using the Vickers Microhardness Tester with 100 gf load for 15 seconds. Results: One Way ANOVA and Post Hoc Bonferroni exhibited the significant differences (p <0.05) in hardness values between the specimens that immersed in the mixed solution Mauli banana and Basil leaf extracts, which in the concentration of 100% (4,49 ± 4,61 VHN) compared with 25% (38,20 ± 2,58 VHN), 50% (41,40 ± 3,84 VHN) and 75% concentration (40,40 ± 3,55 VHN). There was no siginificant difference (p >0.05) between specimens immersed in CHX, aquadest and the mixed solution of mauli banana and basil leaf extracts in all concentration. Conclusion: There is no change in bioactive composite resin surface hardness after immersed in the mixed solution of Mauli Banana stem (Musa acuminata) and Basil leaf (Ocimum basilicum) extracts.Keywords: Basil leaf extract, Bioactive resin, Mauli Banana stem extract, Surface hardness
34
Oh, Se Doo, Won Wook Jung, Dong Ho Bae e Young Ze Lee. "Friction and Wear Characteristics for Automotive Leaf Spring Materials due to the Influence of the Residual Stress". Key Engineering Materials 297-300 (novembre 2005): 1388–94. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.1388.
Testo completoAbstract (sommario):
In this paper, the effects of the residual stresses on the life of structural engineering components were investigated to predict the wear-life. Residual stresses are usually created by the surface treatment, such as shot peening or deep rolling. The objective of the experimental investigation was focused on the influence of friction and wear characteristics due to the residual stress under dry sliding condition and the measurement of the interleaf friction. Test specimens were made of SUP9, the leaf spring material. The residual stresses were created on their surface by shot peening treatment. Residual stress profiles were measured on the surface and subsurface by means of X-ray diffraction method. Also, the sliding tests were carried out under the different contact pressure and the same sliding velocity of 0.035m/s in order to investigate the friction and wear characteristics of leaf surfaces. Leaf spring assembly tests were performed by the ultimate tensile machine with sticking strain gauges on the leaf surfaces in order to evaluate interleaf friction characteristics. We compared friction coefficients, wear volumes and wear rates of the shot-peened specimens with those of the unpeened specimens, and evaluated the effects of residual stress on the tribological characteristics. We obtained the load-displacement curves, and measured interleaf friction force and interleaf friction coefficient of leaf spring assembly from these curves.
35
Bergo, Maria C. J., Tereza C. M. Pastore, Vera T. R. Coradin, Alex C. Wiedenhoeft e Jez W. B. Braga. "NIRS IDENTIFICATION OF SWIETENIA MACROPHYLLA IS ROBUST ACROSS SPECIMENS FROM 27 COUNTRIES". IAWA Journal 37, n. 3 (7 settembre 2016): 420–30. http://dx.doi.org/10.1163/22941932-20160144.
Testo completoAbstract (sommario):
Big-leaf mahogany is the world’s most valuable widely traded tropical timber species and Near Infrared Spectroscopy (NIRS) has been applied as a tool for discriminating its wood from similar species using multivariate analysis. In this study four look-alike timbers of Swietenia macrophylla (mahogany or big-leaf mahogany), Carapa guianensis (crabwood), Cedrela odorata (cedar or cedro) and Micropholis melinoniana (curupixá) have been successfully discriminated using NIRS and Partial Least Squares for Discriminant Analysis using solid block and milled samples. Species identification models identified 155 samples of S. macrophylla from 27 countries with a correct classification rate higher than 96.8%. For these specimens, the NIRS spectrum variation was more powerful for species identification than for determining provenance of S. macrophylla at the country level.
36
Ehleringer, James R., John F. Casale, Janet E. Barnette, Xiaomei Xu, Michael J. Lott e Janet Hurley. "14C Calibration Curves for Modern Plant Material from Tropical Regions of South America". Radiocarbon 53, n. 4 (2011): 585–94. http://dx.doi.org/10.1017/s0033822200039060.
Testo completoAbstract (sommario):
Two Δ14C calibration curves have been produced that allow determination of the statistical average age of coca leaf and cocaine base specimens produced for the time period 1979–2009. These calibration curves are based on field collections of specimens in Bolivia, Colombia, Ecuador, and Peru. The coca leaf F14C and Δ14C calibration curves can be used to predict the ages of botanical tissues collected in tropical South America and possibly extended to other tropical locations. The cocaine F14C and Δ14C calibration curves can be used to predict the ages of seized cocaine specimens. Because the Δ14C of the atmosphere is diminishing, the precision of this approach for age determinations will continue to get less precise over time as atmospheric 14C content continues to decline.
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HE, XIAOLAN, e YU SUN. "Rare sporophyte found in Europe for Herbertus sendtneri with a range expansion to Africa and Malesia". Phytotaxa 324, n. 1 (6 ottobre 2017): 42. http://dx.doi.org/10.11646/phytotaxa.324.1.2.
Testo completoAbstract (sommario):
The sporophytes of the genus Herbertus are rare or completely absent in some areas. The first discovery of the sporophyte of Herbertus in Europe, on H. sendtneri from a herbarium specimen collected in Austria in 1851, is reported here. We report that finely papillose spores characterize Herbertus species which have originated in the Northern Hemisphere, whereas the spores of the species which have originated in the Southern Hemisphere are tuberculate or shortly spinulose. Based on morphological studies of over 600 herbarium specimens of Herbertus, supported by previously published molecular phylogenetic studies, H. armitanus and H. circinatus are new synonyms of H. sendtneri. It is distinct from other Northern Hemisphere species by its coarsely toothed leaf base, despite large variation in leaf size and shape, and leaf apex cilia. The range of H. sendtneri is now extended to east Africa (Tanzania) and Malesia (Papua New Guinea and the Solomon Islands).
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MOHAMEDSAID, MOHAMED S. "Aplosonyx amorphophallus, an interesting new species of Galerucinae from Timor, Indonesia (Coleoptera: Chrysomelidae)". Zootaxa 1910, n. 1 (20 ottobre 2008): 53–58. http://dx.doi.org/10.11646/zootaxa.1910.1.5.
Testo completoAbstract (sommario):
Aplosonyx amorphophallus, a new species of chrysomelid beetle of the subfamily Galerucinae is described and illustrated from Timor, Indonesia. An aroid plant, Amorphophallus muelleri Blume, is identified as the host plant. Live specimens of the new species are shiny bright yellow, whereas dried preserved specimens are dull, brownish, or yellowish. The feeding behaviour of the new species differs from other Aplosonyx that have been reported, where it feed from the leaf margin resulting semicircular cuts, not as round holes on the leaf of the host plant. Information on bionomics is provided.
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Milković, Matija, Mihajlo Stanković, Tatjana Gogić, Sara Rodić e Aleksandra Konjević. "The first record on Xanthium strumarium and Helianthus decapetalus as host plants of ragweed leaf beetle (Ophraella communa L.) in Serbia". Biljni lekar 50, n. 1 (2022): 40–47. http://dx.doi.org/10.5937/biljlek2201040m.
Testo completoAbstract (sommario):
So far, the confirmed host plants of the ragweed leaf beetle in Serbia belonged to the genus Ambrosia (Ambrosia artemisifolia, A. trifida). At one locality Tošin bunar (Bežanija, Belgrade, Serbia) the first case of Ophraella communa adults feeding on leaves of Xanthium strumarium and Helianthus decapetalus was recorded in Serbia. The number of specimens of O. communa on H. decapetalus was ranging between 1 and 18 specimens per plant, while on X. strumarium it was up to 10 adult specimens. While the plants of ragweed had up to 100% damaged leaves, the leaves of X. strumarium and H. decapetalus had leaf damage less than 10-15% per plant. Considering our findings of the insect feeding on spontaneous allochthonous plant species H. decapetalus, seasonal monitoring of O. communa is recommended especially in the fields where the sunflower (Helianthus annus) is widely cultivated. Monitoring of O. communa on the other plant species of Astereae, especially on allochthonous species originating from North America which share the same natural habitats with the ragweed leaf beetle is also recommended.
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Deranja, Maks, Niko Kasalo, Karmela Adžić, Damjan Franjević e Josip Skejo. "Lepocranus and Valalyllum gen. nov. (Orthoptera, Tetrigidae, Cladonotinae), endangered Malagasy dead-leaf-like grasshoppers". ZooKeys 1109 (1 luglio 2022): 1–15. http://dx.doi.org/10.3897/zookeys.1109.85565.
Testo completoAbstract (sommario):
Only two leaf-like pygmy grasshopper species and specimens are known from Madagascar: the Leatherback Pygmy Grasshopper (Lepocranus fuscus Devriese, 1991) —which has a relatively low median carina of the pronotum; and the Malagasy Litterhopper (Valalyllum foliumgen. et. sp. nov.), herein described — which has a high median carina. Lepocranus fuscus is known from the rainforests around Tampolo, Manakambahiny, and Mahavelona (Foulpointe). The new taxon, Valalyllum foliumgen. et. sp. nov. is known only from the Belanono forest. Both species inhabit northeastern Madagascar. The new species could be rare or not-easy-to-spot in the rainforest leaf litter, where it most probably lives. A new tribe, Valalyllinitrib. nov., is described for the two mentioned genera because its members are different from the Caribbean leaf-like Choriphyllini Cadena-Castañeda & Silva, 2019, from the African leaf-like Xerophyllini Günther, 1979, and from the Asian leaf-like Cladonotini Bolívar, 1887. A tabular key to the tribes of Cladonotinae with leaf-like representatives is provided, together with photographs of type specimens of both species belonging to the newly described tribe. The holotype of the new species belongs to the Muséum national d’Histoire naturelle Orthoptera collection, Paris.
41
XU, DONG-XIAN, e QUAN-RU LIU. "Lectotypification of Spiraea yunnanensis Franchet var. siccanea W. W. Smith (Rosaceae)". Phytotaxa 267, n. 4 (13 luglio 2016): 289. http://dx.doi.org/10.11646/phytotaxa.267.4.5.
Testo completoAbstract (sommario):
Spiraea yunnanensis Franchet (1890: 200) var. siccanea W. W. Smith (1917: 69) was described on the basis of two collections, G. Forrest 9912 and 9972, from Yunnan province, China, but without indicating the type. These specimens should be treated as syntypes in accordance with Article 9.5 of the ICN (McNeill et al. 2012). Rehder (1933: 205) treated it as a distinct species and considered it could be easily distinguished from S. yunnanensis by the leaf blades being adaxially glabrous (vs. pilose) and abaxially sparsely pilose (vs. densely white tomentose). Although this treatment is accepted by latter botanists, its type is still not designated (Yu & Lu 1974, Wu 1984, Lu & Crinan 2003, Zhou & Xu 2006, Businský 2011). We traced nine specimens that fit the protologue, i.e. five duplicate specimens labeled “G. Forrest 9972” (barcodes A00033520, BM000622233, E000385320, K000737489, PE00703468) and four duplicate specimens labeled “G. Forrest 9912” (A00033519, BM000622232, E00385319, K000737490). The specimen (G. Forrest 9972, barcode E000385320) is better preserved and more complete, and W. W. Smith worked at E as deputy keeper in 1911–1922 (Stafleu & Cowan 1985), therefore we designate it as the lectotype for this taxon.
42
LI, QIANSHENG, JIE ZHANG e ALLEN COOMBES. "Quercus lineata (Fagaceae): new distribution records from China and Vietnam and its leaf anatomical features". Phytotaxa 266, n. 3 (24 giugno 2016): 226. http://dx.doi.org/10.11646/phytotaxa.266.3.7.
Testo completoAbstract (sommario):
Quercus lineata is native to Malaysia and Indonesia. During our studies on herbarium collections and field collections, two new distribution records of Q. lineata were found in Hainan island, South China and Central Vietnam. All the key diagnostic features of the specimens from China and Vietnam were consistent with the specimens collected from Malaysia. The leaf anatomical features of the populations of different regions were compared. We also addressed the conservation status and biogeographic implications of the distribution of Q. lineata.
43
Aras, Sümer, Ahmet Duran e Gülay Yenilmez. "Isolation of DNA for RAPD analysis from dry leaf material of someHesperis L. specimens". Plant Molecular Biology Reporter 21, n. 4 (dicembre 2003): 461–62. http://dx.doi.org/10.1007/bf02772597.
Testo completo
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Li, Yaoqi, Dongting Zou, Nawal Shrestha, Xiaoting Xu, Qinggang Wang, Wen Jia e Zhiheng Wang. "Spatiotemporal variation in leaf size and shape in response to climate". Journal of Plant Ecology 13, n. 1 (2 dicembre 2019): 87–96. http://dx.doi.org/10.1093/jpe/rtz053.
Testo completoAbstract (sommario):
Abstract Aims Morphological variation of leaves is a key indicator of plant response to climatic change. Leaf size and shape are associated with carbon, water and energy exchange of plants with their environment. However, whether and how leaf size and shape responded to climate change over the past decades remains poorly studied. Moreover, many studies have only explored inter- but not intraspecific variation in leaf size and shape across space and time. Methods We collected >6000 herbarium specimens spanning 98 years (1910–2008) in China for seven representative dicot species and measured their leaf length and width. We explored geographical patterns and temporal trends in leaf size (i.e. leaf length, leaf width and length × width product) and shape (i.e. length/width ratio), and investigated the effects of changes in precipitation and temperature over time and space on the variation in leaf size and shape. Important Findings After accounting for the effects of sampling time, leaf size decreased with latitude for all species combined, but the relationship varied among species. Leaf size and shape were positively correlated with temperature and precipitation across space. After accounting for the effects of sampling locations, leaf size of all species combined increased with time. Leaf size changes over time were mostly positively correlated with precipitation, whereas leaf shape changes were mostly correlated with temperature. Overall, our results indicate significant spatial and temporal intraspecific variation in leaf size and shape in response to climate. Our study also demonstrates that herbarium specimens collected over a considerable period of time provide a good resource to study the impacts of climate change on plant morphological traits.
45
Loganathan, T. G., R. Krishna Murthy e Chandrasekaran Kesavan. "Effect of Cyclic Loading Frequency on Flexural Modulus of GFRP Laminates with Resin Rich Intermediate Layers". Applied Mechanics and Materials 787 (agosto 2015): 543–47. http://dx.doi.org/10.4028/www.scientific.net/amm.787.543.
Testo completoAbstract (sommario):
The flexural modulus of composite laminates subjected to cyclic loads of varying cycle periods are experimentally investigated in this work. GFRP composite laminate specimen of configuration 0/R/0/0/0, 0/R/30/60/0, 0/R/90/90/0 and 0/R/45/-45/0 are prepared by hand lay-up technique with a uniquely processed resin-rich intermediate layer for the testing. Specimens are exposed to constant amplitude cyclic loading of frequencies 4.6 Hz and 8.6 Hz. A cantilever configuration of specimen with cyclic tip loading is considered to simulate the conditions of a leaf of a laminated automobile leaf spring. The flexural response of the laminate is measured using three point bend test as per ASTM D 790 and damping by hysteresis loop. The observed reduction in flexural modulusand the increase in damping factor after loading are compared with virgin. Minimised flexural modulus deviations between the loading frequencies are favoured by the cushioning of resin rich intermediate layer in the lay-up.
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TUNGMUNNITHUM, DUANGJAI, THAWEESAKDI BOONKERD, SIRIPORN ZUNGSONTIPORN e NORIO TANAKA. "Morphological variations among populations of Monochoria vaginalis s.l. (Pontederiaceae) in Thailand". Phytotaxa 268, n. 1 (15 luglio 2016): 57. http://dx.doi.org/10.11646/phytotaxa.268.1.4.
Testo completoAbstract (sommario):
Monochoria vaginalis s.l. is an annual aquatic herb belonging to the family Pontederiaceae and having an extensive distribution in tropical and subtropical Asia, Africa, and Australia. The taxon is extremely variable and morphologically complicated. In Thailand, it is recognized as a monotypic species but displays great variations not only in vegetative but also in reproductive structures. Because of these variations, its taxonomic status and species boundary remain uncertain. Morphological investigation was conducted on 244 living specimens of M. vaginalis s.l. covering the current distribution in Thailand together with a detailed observation of 80 herbarium specimens. The holotype of M. vaginalis var. angustifolia and its related specimens were also re-examined. The present study points out that M. vaginalis can be separated into 2 morphological forms: based on leaf shapes, leaf base, number of flowers/raceme, flower arrangements, seed shapes and its longitudinal ridges. Furthermore, the living specimens were used for two cluster and one canonical discriminant analyses in a phenetic study to collect additional data for new taxonomic insights. A total of 22 quantitative and 12 qualitative characters were employed. The first cluster analysis using only quantitative characters and the second cluster analysis using both quantitative and qualitative characters displayed the same trends. The specimens separated into two distinct groups. Likewise, canonical discriminant analysis also indicated that there were two groups. The two groups can be distinguished by the petiole length of floral-leaf and peduncle length. In conclusion, the results from morphological and phenetic studies support the segregation of M. vaginalis s.l. in Thailand into two taxa.
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Adwan, Rania, Ekhlas Edan Kader e Lutfi Yousuf Zedan. "Experimental analysis of composite materials leaf spring used in automotive". Diyala Journal of Engineering Sciences 14, n. 4 (6 dicembre 2021): 26–36. http://dx.doi.org/10.24237/djes.2021.14403.
Testo completoAbstract (sommario):
product modifications or replacement of old products with new and improved material items. Vehicle suspension systems are another area where these developments are carried out on a regular basis. More efforts are being made to improve the user's comfort. Appropriate combination of comfort riding attributes and economics in leaf spring production becomes an evident requirement. Many changes have been made to the suspension system throughout time in order to enhance it. Some of the most recent suspension system innovations include the invention of the parabolic leaf spring and the usage of composite materials for these springs. The implementation of composite materials by replacing steel in conventional leaf springs of a suspension system. Composite material having a lot of good properties like simple fabrication, low weight and low cost to performance .The purpose of this study is to investigate the structural properties of a hybrid leaf spring consisting of 95% Epoxy, 5% carbon, 5% glass fiber, and 5% hybrid carbon-glass fiber composite. The various specimens were produced using the manual layup method, specimen were subjected to tensile, hardness, and fatigue tests, with all data reported and compared. The experimental results showed an increase in Hardness, Tensile, and fatigue life when the reinforcing fibers are applied. The best results of the mechanical test obtained when hybrid reinforcement was applied.
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MINAEI, KAMBIZ, MAHMOOD ALICHI, LIDA FEKRAT, MARYAM ALEOSFOOR e JALIL ALAVI. "Leaf-feeding Mycterothrips: two new species from southern Iran (Thysanoptera: Thripidae)". Zootaxa 4243, n. 1 (13 marzo 2017): 195. http://dx.doi.org/10.11646/zootaxa.4243.1.11.
Testo completoAbstract (sommario):
Mycterothrips doostii sp. n. and Mycterothrips zagrosi sp. n. are described and illustrated from Fars province, southern Iran, on the basis of specimens collected on green leaves of Juglans regia and Amygdalus scoparia respectively. M. doostii is closely related to M. aureus and M. weii, whereas M. zagrosi resembles M. sanubari and M. glycines in color and structure.
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Collins, Timothy L., Rose L. Andrew, Ben W. Greatrex e Jeremy J. Bruhl. "Reliable analysis of volatile compounds from small samples of Eucalyptus magnificata (Myrtaceae)". Australian Systematic Botany 31, n. 3 (2018): 232. http://dx.doi.org/10.1071/sb18005.
Testo completoAbstract (sommario):
Phytochemistry is a source of data for plant systematics. This tool has much more value if herbarium specimens can be used without major damage and if results are comparable with fresh samples. A modified method for the solvent extraction of eucalypt leaf oils for phytochemical analysis and chemotaxonomy studies, including historical herbarium samples by gas chromatography–mass spectrometry (GC-MS), has been statistically assessed using Eucalyptus magnificata L.A.S.Johnson & K.D.Hill leaves. Leaf sample size was reduced by a factor of 250 to minimise damage to herbarium specimens, reduce solvent volume and simplify preparation of solvent extract before analysis. Leaf sampling treatments assessed the effects of the number of leaves and post-harvest air-drying on variation in components in the solvent extract. The results showed no statistically significant effect of leaf mass or the number of leaves used in GC-MS analyses on the precision of the measurements, but a significant difference among treatments for some oil constituents, particularly 1,8-cineole. Most differences in terpenoid concentration were due to variation among plants rather than extraction treatments. Extracts from air-dried herbarium leaves up to 44 years old were directly comparable with those from fresh leaves. Solvent extraction in 2 mL GC-MS vials of ~0.5 cm2 (16 mg) of leaf material, using fragments of fresh or air-dried leaves, drastically reduced sample and solvent volumes and showed that sampling from E. magnificata herbarium specimens for chemotaxonomy and chemotyping is a valid method, enabling broader sampling with much lower costs than for traditional fieldwork collections.
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Jaworska, Maria. "Some Remarks on the Ivy Leaf Lamp Found in Ptolemais". Studies in Ancient Art and Civilisation 22 (31 gennaio 2019): 191–201. http://dx.doi.org/10.12797/saac.22.2018.22.08.
Testo completoAbstract (sommario):
During the Polish excavations in Ptolemais (Libya), a unique terracotta lamp top of the Cretan Ivy Leaf type was found. It is one of only few known specimens of that kind found on the site. The article provides a brief discussion on the Cretan influences seen in the lychnological material found in Ptolemais. It also draws attention to the problem of studying the relations between the two parts of the Roman province Crete and Cyrenaica.