Morphological Plasticity in the Endemic Isoëtes Species from Serra dos Carajás, Amazonia, Brazil

AbstractIntertidal sea stars often function in environments with extreme hydrodynamic loads that can compromise their ability to remain attached to surfaces. While behavioral responses such as burrowing into sand or sheltering in rock crevices can help minimize hydrodynamic loads, previous work shows that sea stars also alter body shape in response to flow conditions. This morphological plasticity suggests that sea star body shape may play an important hydrodynamic role. In this study, we measured the fluid forces acting on surface-mounted sea star and spherical dome models in water channel tests. All sea star models created downforce, i.e., the fluid pushed the body towards the surface. In contrast, the spherical dome generated lift. We also used Particle Image Velocimetry (PIV) to measure the midplane flow field around the models. Control volume analyses based on the PIV data show that downforce arises because the sea star bodies serve as ramps that divert fluid away from the surface. These observations are further rationalized using force predictions and flow visualizations from numerical simulations. The discovery of downforce generation could explain why sea stars are shaped as they are: the pentaradial geometry aids attachment to surfaces in the presence of high hydrodynamic loads.

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Morphological Characterization of Root System Architecture in Diverse Tomato Genotypes during Early Growth

International Journal of Molecular Sciences ◽

10.3390/ijms19123888 ◽

2018 ◽

Vol 19 (12) ◽

pp. 3888 ◽

Cited By ~ 2

Author(s):

Aurora Alaguero-Cordovilla ◽

Francisco Gran-Gómez ◽

Sergio Tormos-Moltó ◽

José Pérez-Pérez

Keyword(s):

Root System ◽

System Architecture ◽

Lateral Root ◽

Morphological Plasticity ◽

Root System Architecture ◽

Morphological Characterization ◽

Early Growth ◽

Soil Conditions ◽

Wild Tomato Species ◽

Local Soil

Plant roots exploit morphological plasticity to adapt and respond to different soil environments. We characterized the root system architecture of nine wild tomato species and four cultivated tomato (Solanum lycopersicum L.) varieties during early growth in a controlled environment. Additionally, the root system architecture of six near-isogenic lines from the tomato ‘Micro-Tom’ mutant collection was also studied. These lines were affected in key genes of ethylene, abscisic acid, and anthocyanin pathways. We found extensive differences between the studied lines for a number of meaningful morphological traits, such as lateral root distribution, lateral root length or adventitious root development, which might represent adaptations to local soil conditions during speciation and subsequent domestication. Taken together, our results provide a general quantitative framework for comparing root system architecture in tomato seedlings and other related species.

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Aboveground growth habits of two Vaccinium species in relation to habitat

Canadian Journal of Botany ◽

10.1139/b95-047 ◽

1995 ◽

Vol 73 (3) ◽

pp. 465-473 ◽

Cited By ~ 24

Author(s):

Anne Tolvanen

Keyword(s):

Morphological Plasticity ◽

Vaccinium Myrtillus ◽

Open Habitat ◽

Branching Angle ◽

Below Ground ◽

Growth Habits ◽

Intercepted Radiation ◽

Shoot Mass ◽

Aboveground Growth ◽

Vaccinium Myrtillus L

Ramet morphology in the deciduous Vaccinium myrtillus L. and the evergreen Vaccinium vitis-idaea L. was compared between the forest and open, clear-felled habitats. Growth habits were measured in terms of branching, shoot mass, bud type, branching angle, and vertical elevation of ramets. New ramets of both species were produced from buds on the below-ground stem. Branching occurred from buds on 1-year-old shoots in young ramets. Aging and flowering induced rejuvenation, i.e., production of new shoots from buds on older shoot generations within the ramets. Sympodial V. myrtillus ramets were more branched than the predominantly monopodial V. vitis-idaea ramets. In ramets of both species, vegetative shoots grew primarily from distal buds in the forest, whereas a greater number of lower buds were activated in the ramets in the open habitat. Vaccinium myrtillus ramets grew more horizontally and had wider branching angles to increase the intercepted radiation in the forest, whereas compact, vertically growing ramets prevailed in the open habitat, where light was not limited. No difference in branch orientation was observed between habitats in V. vitis-idaea. Production of flowers was greater in the open habitat than in the forest in both species. The observed differences in growth habits between forest and open habitat were assumed to indicate high morphological plasticity in both species, allowing the plants to respond rapidly to changed environmental conditions. Key words: architecture, branching, growth habit, shrub, Vaccinium.

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Nothing in (sponge) biology makes sense – except when based on holotypes

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315415000521 ◽

2015 ◽

Vol 96 (2) ◽

pp. 305-311 ◽

Cited By ~ 10

Author(s):

Dirk Erpenbeck ◽

Merrick Ekins ◽

Nicole Enghuber ◽

John N.A. Hooper ◽

Helmut Lehnert ◽

...

Keyword(s):

New Species ◽

Reference Material ◽

Species Identification ◽

Dna Sequences ◽

Morphological Plasticity ◽

Morphological Characters ◽

Molecular Techniques ◽

Reference Sequences ◽

Species Descriptions ◽

Preservation History

Sponge species are infamously difficult to identify for non-experts due to their high morphological plasticity and the paucity of informative morphological characters. The use of molecular techniques certainly helps with species identification, but unfortunately it requires prior reference sequences. Holotypes constitute the best reference material for species identification, however their usage in molecular systematics and taxonomy is scarce and frequently not even attempted, mostly due to their antiquity and preservation history. Here we provide case studies in which we demonstrate the importance of using holotype material to answer phylogenetic and taxonomic questions. We also demonstrate the possibility of sequencing DNA fragments out of century-old holotypes. Furthermore we propose the deposition of DNA sequences in conjunction with new species descriptions.

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Taxonomic application of macro and micro morphological characters of seeds in Astragalus L. (Galegeae, Fabaceae) in India

Phytotaxa ◽

10.11646/phytotaxa.502.2.8 ◽

2021 ◽

Vol 502 (2) ◽

pp. 191-207

Author(s):

SHIVANI KASHYAP ◽

CHANDAN KUMAR SAHU ◽

ROHIT KUMAR VERMA ◽

LAL BABU CHAUDHARY

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Light Microscopy ◽

Seed Coat ◽

Morphological Plasticity ◽

Morphological Characters ◽

Individual Species ◽

Large Size ◽

The Individual ◽

Scanning Electron

Due to large size and enormous morphological plasticity, the taxonomy of the genus Astragalus is very complex and challenging. The identification and grouping of species chiefly based on macromorphological characters become sometimes difficult in the genus. In the present study, the micromorphology of the seeds of 30 species belonging to 14 sections of Astragalus from India has been examined applying scanning electron microscopy (SEM) along with light microscopy (LM) to evaluate their role in identification and classification. Attention was paid to colour, shape, size and surface of seeds. The overall size of the seeds ranges from 1.5–3.2 × 0.8–2.2 mm. The shape of the seeds is cordiform, deltoid, mitiform, orbicular, ovoid and reniform. The colour of seeds varies from brown to blackish-brown to black. Papillose, reticulate, ribbed, rugulate and stellate patterns were observed on the seed coat surface (spermoderm) among different species. The study reveals that the seed coat ornamentations have evolved differently among species and do not support the subgeneric and sectional divisions of the genus. However, they add an additional feature to the individual species, which may help in identification in combination with other macro-morphological features.

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