“Push and Pull”: Biomechanics of the Pollination Apparatus of Oncidium spp.

Comprising ca. 28,000, species the Orchidaceae constitute one of the most species-rich plant families. Orchids differ from other monocotyledons i.a., in the formation of so-called pollinaria, which are entities consisting of pollen grains aggregated into compact pollinia and accessory structures, a viscidium and mostly also a pollinium stalk. The viscidium releases an adhesive material that attaches the pollinarium to a pollinator. Pollinaria are part of a complex pollination apparatus that enables the orchids to colonize niches in which only a few individuals of the respective pollinator occur infrequently. Because the aggregated pollen grains are removed from the flower at once, the development of a mechanical barrier ensuring that only suitable pollinators are able to access the flowers and more importantly to remove the pollen are important selective traits. In this paper we describe the functional morphology of the pollination apparatus in two orchid species, Oncidium wentworthianum and O. otogaya, by experimentally mimicking the pollination process. Furthermore, we analyzed the mechanical resistance of this apparatus by means of force measurements and showed that it most probably constitutes a hierarchical two-stage barrier. The first stage consists of the presence of the anther cap that not only protects the pollinia, but also serves to prevent premature removal of young and unripe pollinaria from the flower. As soon as the pollinaria are ripe, the anther cap sheds and the second stage of the mechanical barrier takes effect, a severable bond between pollinarium and rostellum. This bond can be overcome by a potential pollinator, applying a load of at least 10.8 mN (O. otogaya) or 12.6 mN (O. wentworthianum), respectively, on the viscidium which at the same time disengages the pollinarium from its anchorage. The adhesive material produced by the viscidium creates sufficient adhesive contact between pollinarium and pollinator. Potential pollinators, such as Centris spp. or Trigona spp. bees, should be well able to exert such forces by pushing their head/forebody into the orchid flowers. Thus, whether a pollinator is able to detach the pollinarium depends on both how forcefully it can push and how strongly it can pull the orchid pollination apparatus.

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Genome Size Diversity in Rare, Endangered, and Protected Orchids in Poland

Genes ◽

10.3390/genes12040563 ◽

2021 ◽

Vol 12 (4) ◽

pp. 563

Author(s):

Monika Rewers ◽

Iwona Jedrzejczyk ◽

Agnieszka Rewicz ◽

Anna Jakubska-Busse

Keyword(s):

Genome Size ◽

Species Identification ◽

Dna Content ◽

Size Estimation ◽

Orchid Species ◽

Infraspecific Taxon ◽

2C Dna Content ◽

Plant Families ◽

Liparis Loeselii ◽

Identification And Characterization

Orchidaceae is one of the largest and the most widespread plant families with many species threatened with extinction. However, only about 1.5% of orchids’ genome sizes have been known so far. The aim of this study was to estimate the genome size of 15 species and one infraspecific taxon of endangered and protected orchids growing wild in Poland to assess their variability and develop additional criterion useful in orchid species identification and characterization. Flow cytometric genome size estimation revealed that investigated orchid species possessed intermediate, large, and very large genomes. The smallest 2C DNA content possessed Liparis loeselii (14.15 pg), while the largest Cypripedium calceolus (82.10 pg). It was confirmed that the genome size is characteristic to the subfamily. Additionally, for four species Epipactis albensis, Ophrys insectifera, Orchis mascula, Orchis militaris and one infraspecific taxon, Epipactis purpurata f. chlorophylla the 2C DNA content has been estimated for the first time. Genome size estimation by flow cytometry proved to be a useful auxiliary method for quick orchid species identification and characterization.

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Pollen sources in the Bojanów forest complex identified on honeybee pollen load by microscopic analysis

Acta Agrobotanica ◽

10.5586/aa.1724 ◽

2017 ◽

Vol 70 (4) ◽

Author(s):

Ernest Stawiarz ◽

Beata Żuraw ◽

Agnieszka Marut

Keyword(s):

Trifolium Repens ◽

Robinia Pseudoacacia ◽

Microscopic Analysis ◽

Pollen Grains ◽

Early Spring ◽

Pollen Load ◽

Pollen Loads ◽

Pollinating Insects ◽

Pollen Traps ◽

Plant Families

The aim of this study was to determine sources of pollen for the honeybee in the Bojanów forest complex, Nowa Dęba Forest District (southeastern Poland). Sampling of pollen loads from bees extended from the beginning of May until the end of September 2016 and was carried out at 7-day intervals using pollen traps mounted at the entrance of beehives. A total of 73 pollen load samples were collected from the study area.Fifty-nine taxa from 31 plant families were identified in the analyzed material. From 4 to 21 taxa (average 9.5) were recorded in one sample. The pollen of Brassicaceae (“others”), Taraxacum type, Solidago type, and Rumex had the highest frequency in the pollen loads examined. Apart from these four taxa, pollen grains of Rubus type, Poaceae (“others”), Calluna, Fagopyrum, Trifolium repens s. l., Phacelia, Aster type, Melampyrum, Quercus, Cornus, and Veronica were recorded in the dominant pollen group. The forest habitat taxa that provided pollen rewards to honeybees in the Bojanów forest complex were the following: Rubus, Calluna, Prunus, Tilia, Frangula alnus, Pinus, Quercus, Cornus, Robinia pseudoacacia, Salix, and Vaccinium. Apart from forest vegetation, the species from meadows and wastelands adjacent to this forest complex, represented by Taraxacum, Rumex, Plantago, Poaceae, Trifolium repens, and Solidago, proved to be an important source of pollen. The study indicates that forest communities are a valuable source of pollen for pollinating insects from early spring through to late fall.

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The carbon and nitrogen ecophysiologies of two endemic tropical orchids mirrors those of their temperate relatives and the local environment

Royal Society Open Science ◽

10.1098/rsos.160427 ◽

2016 ◽

Vol 3 (11) ◽

pp. 160427 ◽

Cited By ~ 2

Author(s):

Nicole A. Hynson

Keyword(s):

Stable Isotope ◽

Evolutionary History ◽

Isotope Composition ◽

Local Environment ◽

Nitrogen Stable Isotope ◽

Orchid Species ◽

Carbon And Nitrogen ◽

Terrestrial Orchids ◽

Nitrogen Concentrations ◽

Plant Families

Orchids are one of the most widely distributed plant families. However, current research on the ecophysiology of terrestrial orchids is biased towards temperate species. Thus, it is currently unknown whether tropical terrestrial orchids belong to similar trophic guilds as their temperate relatives. To examine the ecophysiologies of two tropical terrestrial orchids, I analysed the carbon and nitrogen stable isotope compositions and nitrogen concentrations of the Hawaiian endemics Anoectochilus sandvicensis and Liparis hawaiensis . I compared these values with those of surrounding vegetation and their temperate relatives. I found that A. sandvicensis was consistently enriched in the heavy isotope of nitrogen ( 15 N) and had higher nitrogen (N) concentrations than surrounding vegetation, and these values were even higher than those of its temperate relatives. Carbon stable isotope composition among populations of A. sandvicensis varied by island. These results point to local environment and evolutionary history determining the ecophysiology of this species. Whereas L.hawaiensis was also enriched in 15 N and had on average higher N concentrations than surrounding vegetation, these values were not significantly different from temperate relatives, indicating that evolutionary history may be a stronger predictor of this orchid species' ecophysiology than environment. I suggest that both Hawaiian species are potentially partially mycoheterotrophic.

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Espectro de polen corbicular de Apis mellifera en muestras de Huejotitán, Jalisco, México

Revista Mexicana de Ciencias Pecuarias ◽

10.22319/rmcp.v12i2.4398 ◽

2021 ◽

Vol 12 (2) ◽

pp. 621-632

Author(s):

Roberto Quintero Domínguez ◽

Lino De la Cruz Larios ◽

Diego Raymundo González Eguiarte ◽

José Arturo Solís Magallanes ◽

José Francisco Santana Michel ◽

...

Keyword(s):

Apis Mellifera ◽

Pollen Grains ◽

Wild Plants ◽

Individual Species ◽

Ocular Micrometer ◽

Family Level ◽

Reference Collection ◽

Pollen Traps ◽

Plant Families ◽

The Village

This study examines the different plants visited by the honeybee (Apis mellifera L.) during the honey harvest season (August to November) 2012. The work consisted in identifying the corbicular pollen pellets collected by the bees in one apiary in the village of Huejotitan, municipality of Jocotepec, state of Jalisco, Mexico. Three hives were selected and sampled monthly by means of Ontario modified pollen traps. The samples were tagged and frozen and later processed by acetolysis technique to remove the exine; permanent glycerine slides were made for the preservation and analysis. Identification and counting of pollen grains was performed using an Olympus BH-2® upright microscope equipped with a 100X ocular micrometer to measure each individual species pollen grain, using immersion oil. Wild plants in bloom were also collected monthly, tagged, pressed and taken to the herbarium for identification; the pollen was extracted, processed and identified for a reference collection that served as an ancillary means of identification and as a seasonal reference to the blooming species. In the corbicular pollen, 23 types of plants were identified: 13 at species level, five at genus level and five at family level belonging to 17 plant families. Myrtaceae resulted the most frequently represented family followed by Asteraceae, Fabaceae and Lamiaceae.

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Pollinium development in Spiranthes sinensis (Pers.) Ames.and Cymbidium pendulum SW: a comparative study

Bangladesh Journal of Botany ◽

10.3329/bjb.v42i2.18035 ◽

2014 ◽

Vol 42 (2) ◽

pp. 307-314 ◽

Cited By ~ 3

Author(s):

Ravi Kant ◽

Mohammad Musharof Hossain ◽

Lucky K Attri

Keyword(s):

Electron Microscopy ◽

Pollen Grains ◽

Anther Development ◽

Anther Wall ◽

Terrestrial Orchid ◽

Orchid Species ◽

Meristematic Cells ◽

Phylogenetic Reconstructions ◽

Spiranthes Sinensis ◽

Scanning Electron

Comparative studies on the early anther development, anther wall differentiation, pollinium development and pollen grains surface features in Spiranthes sinensis (Pers.) Ames. (a terrestrial orchid) and Cymbidium pendulum Sw. (an epiphytic orchid) using light and scanning electron microscopy were described. Anther primordium initiated as a homogenous mass of meristematic cells which developed two thecae, each with a group of archesporial cells of dense cytoplasmic contents. The sporogenous cells of the hypodermal layer formed the anther wall which was 4-5 layered in S. sinensis and 7-layered in C. pendulum. The rare feature of 2-layered endothecium in S. sinensis and a 2-layered tapetum in C. pendulum was reported. Papillate epidermis was observed in C. pendulum. A complete septum of sterile cells in S. sinensis and partial in C. pendulum was observed. Pollen grains were mono-aperturate, reticulate and shed as tetrads in S. sinensis while either monoaperturate or inaperturate, tectate pollen grains and dispersed as hard pollinia in C. pendulum. This is a see-through information for accurate classification and phylogenetic reconstructions of orchid species. DOI: http://dx.doi.org/10.3329/bjb.v42i2.18035 Bangladesh J. Bot. 42(2): 307-314, 2013 (December)

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Materials Having a High Degree of Adhesion for Gripping Elements Designing

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.613.220 ◽

2014 ◽

Vol 613 ◽

pp. 220-225 ◽

Cited By ~ 1

Author(s):

Marcel Horák ◽

František Novotný

Keyword(s):

Rheological Behaviour ◽

Adhesive Contact ◽

Design Solution ◽

New Materials ◽

Level Control ◽

Adhesive Material ◽

Energy Demands ◽

Alternative Approach ◽

High Degree ◽

Plate Type

The paper analyses one of possibilities to use new materials based on polyurethane, polypropylene or silicone having highly adhesive contact surfaces for gripping elements designing. In concrete terms, it is a case of an alternative approach to the solution of designing standard multi-elements vacuum gripping heads with an active control system (vacuum level control) controlling gripping forces in processes of automatic handling flat objects of the plate type. The aim of this new design solution is to replace individual gripping elements (suction cups) by elements, the surfaces of which coming to the contact with the object handled are provided with adhesion materials. The system minimizing energy demands stemmed from this solution, namely in the way that it decreases or even eliminates the pressure air consumption when combined vacuum-adhesive or only adhesive gripping elements are used. Moreover, it is possible to use the adhesive gripping principle profitably in technological processes susceptible to the environment contamination with airflow when manufacturing new products with many functional layers. Besides a general analysis of problems, the paper presents outputs of laboratory tests. Also a computer model of the contact respecting rheological behaviour of the adhesive material basic matrix is given.

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Fracture mechanics implications for apparent static friction coefficient in contact problems involving slip-weakening laws

Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rspa.2015.0271 ◽

2015 ◽

Vol 471 (2180) ◽

pp. 20150271 ◽

Cited By ~ 11

Author(s):

A. Papangelo ◽

M. Ciavarella ◽

J. R. Barber

Keyword(s):

Friction Coefficient ◽

Static Friction ◽

Contact Problems ◽

Adhesive Contact ◽

Small Scale ◽

Force Measurements ◽

Scale Yielding ◽

Static Coefficient Of Friction ◽

Dynamic Slip ◽

Slip Distance

We consider the effect of differing coefficients of static and dynamic friction coefficients on the behaviour of contacts involving microslip. The classic solutions of Cattaneo and Mindlin are unchanged if the transition in coefficients is abrupt, but if it occurs over some small slip distance, the solution has some mathematical similarities with those governing the normal tractions in adhesive contact problems. In particular, if the transition to dynamic slip occurs over a sufficiently small area, we can identify a ‘JKR’ approximation, where the transition region is condensed to a line. A local singularity in shear traction is then predicted, with a stress-intensity factor that is proportional to the square root of the local contact pressure and to a certain integral of the friction coefficient–slip distance relation. We can also define an equivalent of the ‘small-scale yielding’ criterion, which enables us to assess when the singular solution provides a good approximation. One consequence of the results is that the static coefficient of friction determined from force measurements in experiments is significantly smaller than the value that holds at the microscale.

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Interaction of milkweed butterflies with egret and jewel orchids: observations on pollinaria attachment to danaid butterflies on east Sulawesi (Indonesia) (Lepidoptera: Nymphalidae: Danainae; Orchidoideae: Habenarinae and Goodyerinae)

Tijdschrift voor Entomologie ◽

10.1163/22119434-20192082 ◽

2019 ◽

Vol 162 (1) ◽

pp. 1-12

Author(s):

Peter H. Roos

Keyword(s):

Morphological Characters ◽

Orchid Species ◽

Orchid Pollination

Species of the butterfly subfamily Danainae visit orchids, resulting in pollinaria being attached to their heads. In several habitats in east Sulawesi a remarkable percentage of Danainae specimens was observed with orchid pollinaria preferentially attached to their eyes. Among the 13 observed native Danainae species, seven carried pollinaria. Pollinaria attachment appears to be selective for Danainae as hundreds of specimens from other butterfly families were negative. Selectivity also concerns the orchid species, as attached pollinaria could be assigned to a Habenaria orchid and in one case only to an Anoectochilus. Efficient pollinaria attachment requires compatible morphological characters of butterfly and orchid. In this respect, the observed high pollinaria load of single butterflies is also important. Comparable investigations in southeast Sulawesi did not reveal danaid–orchid interactions. Further studies are required to prove orchid pollination by Danainae and to clarify the mechanism by which these butterflies are attracted to the orchids.

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Isometric push and pull strengths of agricultural workers from Northeast India

Work ◽

10.3233/wor-213592 ◽

2021 ◽

pp. 1-9

Author(s):

Sentichuba Pongener ◽

Thaneswer Patel ◽

Anubhab Pal ◽

Temjen W

Keyword(s):

Age Groups ◽

Northeast India ◽

Agricultural Workers ◽

Force Measurements ◽

Physical Capability ◽

Pull Strength ◽

Female Data ◽

Student’S T ◽

Push And Pull ◽

Resting Period

BACKGROUND: In agricultural farming operations, the incompatibility between operators’ physical capability and labor demands in the operation of tools and equipment results in a decreased performance, productivity, and safety related measures. OBJECTIVE: The aim of this study was to collect a biomechanical database of push/pull strengths for initiating the development of a human-centered design of equipment that is not available for the intended user group, i.e. Nagaland. METHODS: The sample consisted of 399 male and 271 female agricultural workers from the five districts of Nagaland, aged 18 to 65 years, classified into three age groups. In the process of push and pull force measurements, the elbow angle of the participants were set to 30–120°, 120–130°, and 130–180°. All tests were performed in triplicates with a resting period of two minutes between every consequent recording. RESULTS: The results showed that isometric push and pull strength values (Mean±SD) for males were 18.91±4.67 kg and 17.98±3.97 kg respectively and 13.07±4.06 kg and 11.98±3.33 kg for females respectively. The results of independent samples from student’s t-test demonstrate that there was a substantial variance in the isometric push and pull strength values (p < 0.05) between the genders across the various age spectrum. CONCLUSIONS: With ageing, muscular strength for push-pull strength in males and females reduce. The study reports that the recommended value of male and female isometric push-pull strength for agricultural workers of Nagaland should be 5th percentile of female data i.e. 6.40 and 1.71 kg respectively.

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Tropical orchid mycorrhizae: potential applications in orchid conservation, commercialization, and beyond

Lankesteriana ◽

10.15517/lank.v0i0.11537 ◽

2013 ◽

Author(s):

Joel Tupapac Otero ◽

Ana Teresa Mosquera ◽

Nicola S. Flanagan

Keyword(s):

Mycorrhizal Fungi ◽

Orchid Species ◽

Orchid Conservation ◽

Potential Applications ◽

Pathogenic Interaction ◽

Induce Resistance ◽

Orchid Mycorrhizae ◽

Orchid Mycorrhizal Fungi ◽

Tropical Orchid ◽

Plant Families

Orchid mycorrhizae are unique interactions in the plant kingdom involving all the orchids and a variety of fungi including Rhizoctonia. Orchids are one of the most charismatic plant families and include at least 20,000 species widely appreciated by specialist growers and scientists. They also include Vanilla, source of one of the most traded spices worldwide. Most mycorrhizal fungi belong to a group of basidiomycetes widely known for their pathogenic interaction with many crop plants including potatoes, rice, and beans. The main application of orchid mycorrhizal fungi is in the propagation of endangered and commercial orchid species, but we have recently documented an alternative use. The fungal symbionts of orchids have the ability to induce resistance to Rhizoctonia in rice plants, which opens new possibilities of biological control agents never previously imagined.

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