A developmental approach expanding the knowledge of inflorescence diversity in subtribe Eleusininae (Chloridoideae: Poaceae)

2020 ◽  
Author(s):  
Sebastián E Muchut ◽  
Vanesa Pilatti ◽  
Andrea G Reutemann ◽  
Abelardo C Vegetti ◽  
Renata Reinheimer
Keyword(s):  
Flower Development ◽  
Current Knowledge ◽  
Morphological Diversity ◽  
Main Axis ◽  
Inflorescence Meristem ◽  
Developmental Approach ◽  
Developmental Patterns ◽  
Inflorescence Structure ◽  
Scanning Electron ◽  
Transition To Flowering

Abstract Subtribe Eleusininae (Chloridoideae, Poaceae) comprise 237 species with little morphological diversity in inflorescence structure. This diversity may be explained by an evolution from complex (pyramidal, highly branched) to simpler (digitate, barely branched) morphologies. However, only mature specimens have been studied; the developmental analyses of the inflorescences are rare. We analysed the inflorescence, spikelet and flower development of 17 species of Eleusininae using scanning electron microscopy. In the early stages of the transition to flowering of the studied species, the inflorescence meristem elongates initiating primary branches acropetally. The differentiation of these branches along the main axis is either basipetal or amphipetal. Although the initiation of secondary branches along primary branches may be acropetal or amphipetal, their differentiation follows an amphipetal direction. The florets in spikelets are initiated acropetally. We found abnormal orientation of stamens and gynoecium in florets of Leptochloa chloridiformis. The analysis of the ontogeny has enriched current knowledge of inflorescences in the subtribe. In addition, the developmental patterns revealed the existence of more than one developmental pattern leading to similar mature inflorescence forms. The results will support future efforts on postulating trends of developmental patterns across Poaceae.

Oxidation of Manganese-Containing Aluminum Alloys Studied by SEM

2014 ◽  
Vol 794-796 ◽  
pp. 1095-1100
Author(s):  
Shawn C. Wilson ◽  
Anne Kvithyld ◽  
Thorvald Abel Engh ◽  
Gabriella Tranell
Keyword(s):  
Electron Microscope ◽  
Chemical Composition ◽  
Scanning Electron Microscope ◽  
Oxide Film ◽  
Current Knowledge ◽  
Sem Analysis ◽  
Muffle Furnace ◽  
Mn Content ◽  
Small Clusters ◽  
Scanning Electron

During remelting of aluminum manganese-containing alloys, some industrial experience has indicateda tendency toward increased oxidation losses when compared to unalloyed Al. A goal of thiswork is to increase current knowledge of oxidation of Mn-containing aluminum. An oxidation studywas performed on 99.99% Al, Al-1%Mn and Al-5%Mn materials in a muffle furnace in air. Theseoxidized materials were analyzed in the Scanning Electron Microscope using Energy Dispersive xraySpectroscopy (EDS) both for chemical composition and to analyze the structure of the oxide thatwas formed. The main findings from the SEM analysis of the oxidized 99.99% Al, Al1%Mn andAl5%Mn materials are: 1) The oxides formed on the Al1Mn and Al5Mn materials contained onlyminute amounts of Mn. However, small clusters of Mn metal were found among the Al2O3 particleson the surface of the Al1Mn and Al5Mn samples. 2) Dissolved Mn increased from the surface to theinterior, and Mn-rich particles were present in the interior of the Al1Mn and Al5Mn samples. 3) Theoxide layer thickness increases with Mn content, and the oxide film is more fragmented.

scholarly journals Branching System of the Mexican Hawthorn “Tejocote” (Crataegus Spp.)

2013 ◽  
Vol 21 (1) ◽  
pp. 47-59
Author(s):  
Sergio A. Pérez-Ortega ◽  
Antonio H. Méndez-Santiago ◽  
Raúl Nieto-Angel ◽  
Leszek S. Jankiewicz
Keyword(s):  
Apical Dominance ◽  
Calcareous Soils ◽  
Morphological Diversity ◽  
Fruit Trees ◽  
Dry Period ◽  
Inflorescence Axis ◽  
Long Shoots ◽  
Inflorescence Structure ◽  
The Common ◽  
Common Character

Abstract The architecture of the tejocote (pronounciation: tehocote) - a Mexican fruit trees is described. There is a great morphological diversity among the tejocote clones growing in Germplasm Bank of the Autonomic University of Chapingo, Mexico. The common character of all hawthorns in this bank is that the inflorescence axis dies after shedding the reproductive parts (flowers or fruits) but remains on the tree, and the growth continues from the bud situated below the dead part. The growth and ramification habit were described as long shoots showing marked apical dominance and as the complex of shoots showing week apical dominance. The non-pruned trees of tejocote clones used as fruit trees form strong natural crown. The architecture of it is similar to the “Troll’s model” of Hallé and Oldeman (1970). Metamorphosis and reiteration are relatively frequent. The inflorescence structure was described, as well as the types of thorns in clones, which have thorns. Tejocote hawthorn may probably be an interesting fruit tree for countries with warm climate and a long dry period. It is also well adapted to shallow calcareous soils.

scholarly journals Morphological diversity and evolution of Centrolepidaceae (Poales), a species-poor clade with diverse body plans and developmental patterns

2015 ◽  
Vol 102 (8) ◽  
pp. 1219-1249 ◽  
Author(s):  
Dmitry D. Sokoloff ◽  
Margarita V. Remizowa ◽  
Matthew D. Barrett ◽  
John G. Conran ◽  
Paula J. Rudall
Keyword(s):  
Morphological Diversity ◽  
Developmental Patterns

scholarly journals Cavefish and the basis for eye loss

2017 ◽  
Vol 372 (1713) ◽  
pp. 20150487 ◽  
Author(s):  
Jaya Krishnan ◽  
Nicolas Rohner
Keyword(s):  
Embryonic Development ◽  
Convergent Evolution ◽  
Current Knowledge ◽  
Morphological Diversity ◽  
Astyanax Mexicanus ◽  
Genomic Resources ◽  
Evolutionary Forces ◽  
Different Populations ◽  
Entire World ◽  
Evo Devo

Animals have colonized the entire world from rather moderate to the harshest environments, some of these so extreme that only few animals are able to survive. Cave environments present such a challenge and obligate cave animals have adapted to perpetual darkness by evolving a multitude of traits. The most common and most studied cave characteristics are the regression of eyes and the overall reduction in pigmentation. Studying these traits can provide important insights into how evolutionary forces drive convergent and regressive adaptation. The blind Mexican cavefish ( Astyanax mexicanus ) has emerged as a useful model to study cave evolution owing to the availability of genetic and genomic resources, and the amenability of embryonic development as the different populations remain fertile with each other. In this review, we give an overview of our current knowledge underlying the process of regressive and convergent evolution using eye degeneration in cavefish as an example. This article is part of the themed issue ‘Evo-devo in the genomics era, and the origins of morphological diversity’.

Holopothrips diversity—a Neotropical genus of gall-inducing insects (Thysanoptera, Phlaeothripidae)

Zootaxa ◽  
2018 ◽  
Vol 4494 (1) ◽  
pp. 1 ◽  
Author(s):  
MARIANA F. LINDNER ◽  
AUGUSTO FERRARI ◽  
LAURENCE A. MOUND ◽  
ADRIANO CAVALLERI
Keyword(s):  
New Species ◽  
Phylogenetic Relationships ◽  
Host Plants ◽  
Current Knowledge ◽  
Morphological Diversity ◽  
Biological Information ◽  
Key To Species ◽  
Future Studies ◽  
Plant Galls

The genus Holopothrips represents the main Neotropical group of thrips associated with plant galls, and several of the 36 currently described species are known to induce or invade galls of other organisms. The existence of several Holopothrips specimens in collections that do not belong to any of the already described species, allied to the absence of basic biological information for several species, such as host plants and habit, shows that the current knowledge on the genus is severely lacking. Here we start addressing these problems, by describing 24 new species: H. acrioris, H. atlanticus, H. bicolor, H. brevicapitatum, H. cardosoi, H. curiosus, H. flavisetis, H. graziae, H. inconspicuus, H. infestans, H. irregularis, H. johanseni, H. kaminskii, H. longihamus, H. longisetus, H. magnus, H. maiae, H. nigrisetis, H. nigrum, H. punctatus, H. reticulatus, H. singularis, H. spermathecus, H. varicolor. This study also includes information on galls for several species; an updated and illustrated key to species; and comments on the morphological diversity of the group. With that, we hope to lay the taxonomic and morphological bases for future studies in this group, focusing on its diversity, ecology and phylogenetic relationships. 

scholarly journals Spinnerets and silk-producing system of Segestria senoculata (Araneae, Araneomorphae, Segestriidae)

2016 ◽  
Vol 48 (3) ◽  
pp. 388 ◽  
Author(s):  
S. Karschová ◽  
J. Hajer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Microscopy ◽  
Current Knowledge ◽  
The Other ◽  
Sem Study ◽  
First Time ◽  
Scanning Electron

The spinning apparatus and silk of <em>Segestria senoculata</em> were studied with the use of scanning electron microscopy and light microscopy, which confirmed the presence of four categories of spigots connected with four types of spinning glands (<em>i.e</em>., <em>Glandulae ampullaceae major, Glandulae ampullaceae minor, Glandulae piriformes and Glandulae pseudaciniformes</em>). New data about the morphology of spinnerets and spigots were obtained for both the adults and nymphal stages of both sexes. For the first time the silken threads of retreats, signal threads and attachment discs of the members of <em>Segestria</em> were subjected to a detailed SEM study. The data resulting from studying the spinning apparatus of <em>S. senoculata</em> was compared to current knowledge of the silk producing systems of families belonging to the Dysderoidea superfamily. Silks that are emitted from spigots in the course of retreat construction are not (similarly to the other dysderoids) processed by the spider’s legs during the subsequent process of hardening. Apart from the major ampullate glands/spigots, segestriids also possess developed minor ampullate glands. Minor ampullate threads are used by <em>S. senoculata</em> spiders when making their signal threads.

scholarly journals Comparative anatomy and phylogeny of the Forcipulatacea (Echinodermata: Asteroidea): insights from ossicle morphology

2019 ◽  
Vol 189 (3) ◽  
pp. 921-952 ◽  
Author(s):  
Marine Fau ◽  
Loïc Villier
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Phylogenetic Analysis ◽  
Comparative Anatomy ◽  
Morphological Diversity ◽  
Consensus Tree ◽  
Sea Stars ◽  
Extant Species ◽  
Tree Resolution ◽  
Scanning Electron

Abstract A new phylogenetic analysis of the superorder Forcipulatacea is presented. Forcipulatacea is one of the three major groups of sea stars (Asteroidea: Echinodermata), composed of 400 extant species. The sampled taxa are thought to represent the morphological diversity of the group. Twenty-nine forcipulate taxa were sampled belonging to Asteriidae, Stichasteridae, Heliasteridae, Pedicellasteridae, Zoroasteridae and Brisingida. Specimens were dissected with bleach. Detailed description of the skeleton and the anatomy of the ossicles were investigated using scanning electron microscopy. Comparative anatomy allowed the scoring of 115 phylogenetically informative characters. The consensus tree resulting from the analysis recovers Asteriidae, Stichasteridae, Zoroasteridae and Brisingida as monophyletic. All types of morphological features contribute to tree resolution and may be appropriate for taxon diagnosis. The synapomorphies supporting different clades are described and discussed. Brisingida and Zoroasteridae are the best-supported clades. The potentially challenging position of Brisingida in the tree may be explained by homoplastic changes, but also by the presence of numerous non-applicable characters.

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