Scanning electron and light microscopy of foliar epidermal characters: A tool for plant taxonomists in the identification of grasses

2017 ◽  
Vol 80 (10) ◽  
pp. 1123-1140 ◽  
Author(s):  
Raees Khan ◽  
Mushtaq Ahmad ◽  
Muhammad Zafar ◽  
Asad Ullah
Keyword(s):  
Light Microscopy ◽  
Electron And Light Microscopy ◽  
Scanning Electron

Chrysophycean stomatocysts from the postglacial sediments of a High Arctic lake

1988 ◽  
Vol 66 (6) ◽  
pp. 1117-1128 ◽  
Author(s):  
Katharine E. Duff ◽  
John P. Smol
Keyword(s):  
Species Composition ◽  
Light Microscopy ◽  
High Arctic ◽  
Ellesmere Island ◽  
Arctic Lakes ◽  
Ecological Research ◽  
Stratigraphic Analysis ◽  
Morphological Detail ◽  
Electron And Light Microscopy ◽  
Scanning Electron

Twenty-six chrysophycean stomatocyst morphotypes were described from the postglacial sediments of a small, rock basin lake near Baird Inlet, Ellesmere Island. Scanning electron and light microscopy were used to classify the stomatocysts, following the guidelines of the International Statospore Working Group. None of the stomatocysts could be related with certainty to the chrysophyte species that produced them, but sufficient morphological detail is present in most of the stomatocysts to allow for taxonomic differentiation. A stratigraphic analysis of the dominant stomatocyst morphotypes revealed that chrysophyte species composition changed most markedly during the lake's early development but then remained relatively constant. This study demonstrated that chrysophycean stomatocysts provide useful paleoecological information in High Arctic lakes, but further taxonomic and ecological research is required to fully exploit these microfossils.

Setal morphology of grooming appendages in blue crabs Callinectes sapidus Rathbun, 1896 and stone crabs Menippe mercenaria (Say, 1818) (Decapoda: Brachyura: Portunidae, Menippidae)

2019 ◽  
Vol 39 (4) ◽  
pp. 357-377
Author(s):  
Jen L Wortham ◽  
Stephanie Pascual
Keyword(s):  
Light Microscopy ◽  
Functional Morphology ◽  
Sensory Input ◽  
Callinectes Sapidus ◽  
Time Budget ◽  
Activity Level ◽  
Body Regions ◽  
Electron And Light Microscopy ◽  
Insight Into ◽  
Scanning Electron

Abstract Respiration, sensory input, movement, and molting rely on crustacean body regions being free of fouling. While the grooming appendages of shrimps have been described, few studies have documented the functional morphology of grooming appendages in brachyuran crabs. Because shrimps and brachyurans have very different body morphology and grooming behaviors, their grooming setae may vary. The morphology of grooming appendages of blue (Callinectes sapidusRathbun, 1896) and stone (Menippe mercenaria (Say, 1818)) crabs were investigated to gain better insight into their efficiencies in decreasing fouling. Callinectes sapidus is an active swimmer, migrates through currents across estuaries, spends less time grooming, and is exposed to more environmental variants in contrast to M. mercenaria, which has a lower activity level and spends more time grooming. To compensate for this higher activity level and lower grooming time budget, C. sapidus was predicted to have more setal types on its grooming appendages as compared to M. mercenaria. Thirteen different body appendages/regions involved in grooming are described in both species by using scanning electron and light microscopy. We documented the morphology, presence or absence of setal patches, and types of setae in 104 different grooming appendages and groomed body regions. Of 25 types of setae, nine are unique to C. sapidus, rejecting the hypothesis that C. sapidus have more diverse grooming setae. Menippe mercenaria has denser setal patches and less fouling than C. sapidus. Nine new setal types are described. Fouling, setal diversities, and functions that correspond to grooming behaviors are discussed.

Apothecial ontogeny in Saccobolus versicolor (Pezizales: Ascomycetes)

1976 ◽  
Vol 54 (17) ◽  
pp. 2055-2060 ◽  
Author(s):  
K. L. O'Donnell ◽  
W. G. Fields ◽  
G. R. Hooper
Keyword(s):  
Light Microscopy ◽  
Basal Cells ◽  
Ectal Excipulum ◽  
Electron And Light Microscopy ◽  
Scanning Electron

Apothecial ontogeny in Saccobolus versicolor was followed by scanning electron and light microscopy from ascogonial coil initiation through spore discharge. Several slender, recurved branches functioned as ascogonia and initiated apothecium formation. Since antheridia were never observed, development was assumed to be parthenogenetic. Soon after ascogonia appeared, slender investing hyphae grew up from nearby vegetative hyphae and from the ascogonium. Subsequently, the basal cells in the ascogonia greatly increased in diameter and their septa broke down. Apothecium ontogeny was either eugymnohymenial with a poorly developed ectal excipulum or paragymnohymenial opening in the prehymenial phase. As a result of the presence of several functional ascogonia, asci developed by typical crozier formation and exhibited a strong positive phototrophic response as they protruded before spore discharge.

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