Sclerenchyma

Jarvis, Michael C.; His, Isabelle

doi:10.1002/9780471743989.vse6313.pub2

Cited by 2 publications

(1 citation statement)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We observed sclerenchymatous bundle cap mainly outside the phloem both in the stem and leaf of H. odorus, which physically protects the inner tissues of these plant parts. This type of tissue as bundle cap is widely distributed in dicotyledonous plants and it is common as bundle sheath in monocotyledonous plants (Jarvis and His 2007).…”

Section: Discussionmentioning

confidence: 99%

Ethnobotanical, historical and histological evaluation of Helleborus L. genetic resources used in veterinary and human ethnomedicine

Balázs

Filep

Ambrus

et al. 2020

Genet Resour Crop Evol

View full text Add to dashboard Cite

The use of hellebore (Helleborus) species for medical purposes has a long-standing tradition. Our work aimed at providing a historical survey of their medicinal application in Europe, and data on current ethnobotanical use of H. purpurascens Waldst. et Kit. in Transylvania (Romania), compared with earlier records of this region and other European countries. While the chemistry and pharmacology of hellebores have been researched extensively, little is known about their anatomical traits. Thus, we intended to provide a detailed histological analysis of Helleborus odorus Waldst. et Kit., H. purpurascens, and H. niger L., based on transverse sections of aerial parts and root. Our survey revealed that H. purpurascens is known for immunotherapy, wounds, and as antiemetic drug in ethnoveterinary medicine, but not in human therapy in the study area. Distinctive histological characters included diverse stele structure in the root; sclerenchymatous bundle caps around compound vascular bundles in the stem and the main leaf veins of H. odorus; and amphistomatic leaves in H. purpurascens. Quantitative vegetative traits also revealed significant differences among species, but they may reflect environmental influences, too. In all three species the sepal was hypostomatic with mesomorphic stomata, while the modified petal comprised a proximal nectar-producing and a distal non-secretory part. Distinctive floral traits included shape of modified petal, presence of papillae and thickness of nonsecretory part; as well as ornamentation of tricolpate pollen grains. Our findings suggest that the anatomy of various plant parts varies slightly with each species, including ethnomedicinally known H. purpurascens, even though the basic structure is the same within the genus.

show abstract

Section: Discussionmentioning

confidence: 99%

Ethnobotanical, historical and histological evaluation of Helleborus L. genetic resources used in veterinary and human ethnomedicine

Balázs

Filep

Ambrus

et al. 2020

Genet Resour Crop Evol

View full text Add to dashboard Cite

show abstract

Hierarchical levels of organization of the Brazil nut mesocarp

Sônego

Fleck

Pessan

2020

Sci Rep

View full text Add to dashboard Cite

Aiming to understand Nature´s strategies that inspire new composite materials, the hierarchical levels of organization of the Brazil nut (Bertholletia excelsa) mesocarp were investigated. Optical microscopy, scanning electron microscopy (SEM), microtomography (MicroCT) and small-angle X-ray scattering (SAXS) were used to deeply describe the cellular and fibrillary levels of organization. The mesocarp is the middle layer of the fruit which has developed several strategies to avoid its opening and protect its seed. Fibers have a different orientation in the three layers of the mesocarp, what reduces the anisotropy of the structure. Sclereids cells with thick cell walls fill the spaces between the fibers resembling a foam-filled structural composite. The mesocarp has several tubular channels and fractured surfaces which may work as sites for crack trapping and increase toughness. The thick and lignified cell wall of sclereids and fibers and the weak interface between cells can promote a longer and tortuous intercellular crack path. Additionally, fibers with high strength and stiffness due to microfibrils oriented along the main cell axis (µ = 0° to 17°) were identified in the innermost layer of the mesocarp. Such an understanding of each hierarchical level can inspire the development of new cellular composites with improved mechanical behaviorThe mesocarp layer of Bertholletia excelsa fruit, the seed of which is known as brazil nut, is an impressive structure. It is a shell capable to resist falls as high as 50 m and compression forces higher than 10 kN 1 . Such a strong natural structure has great potential as a source for bioinspiration to produce new high performance composites 1,2 . The impressive properties of the mesocarp arise from its hierarchical structure, which emerged from millions of years of evolution.This hierarchy is the main factor to explain how relatively weak components organized in a complex way can result in a system with outstanding properties 3 . Four hierarchical levels of structuring have been described for plants: macroscopic, cellular, fibrillar, and molecular 3 . Each hierarchical level has its own contribution to the overall properties of the natural composite.On the largest length-scale, the "macroscopic" level, trunk, leaves, roots, flowers, and fruit are distinguished, and it is analyzed how the association of different tissues leads to different geometries and functions in the plant. At this level, the mesocarp is described as a spherical or elliptical shell of 10-12 cm diameter with a wall thickness of approximately 1 cm. Its function is to protect the seeds against predators and impact on the ground when the fruit falls from the tree 1,4,5 . The mesocarp has a rough surface with a peduncle and an opercular opening on opposite sides of the fruit. The opening is a hole with a diameter of approximately 2 cm, which is, however, not large enough to allow the dispersion of the seeds, as it was millions of years ago.On the cellular hierarchical level, the cells and vegetable tissues are ...

show abstract

Sclerenchyma

Cited by 2 publications

References 12 publications

Ethnobotanical, historical and histological evaluation of Helleborus L. genetic resources used in veterinary and human ethnomedicine

Ethnobotanical, historical and histological evaluation of Helleborus L. genetic resources used in veterinary and human ethnomedicine

Hierarchical levels of organization of the Brazil nut mesocarp

Contact Info

Product

Resources

About