Energy Dispersive X-Ray Analysis

Heslop-Harrison, J. S.

doi:10.1007/978-3-642-83611-4_9

Cited by 4 publications

(1 citation statement)

References 37 publications

(28 reference statements)

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“…druse-rich zones of the millet stigma was demonstrated by energydispersive X-ray analysis using a Philips 505 scanning electron microscope with Tracor Northern TN5500 X-ray analyser (see Heslop-Harrison 1990). Fresh stigmas were mounted above a carbon stub by partially crushing the base of the ovule onto the stub; the cytoplasm released was both sticky and conductive enough that about 30% of preparations remained physically stable and uncharged over the 5 -10 min required for analysis.…”

Section: Methodsmentioning

confidence: 99%

The pollen tube activated abscission zone in the stigma of pearl millet: structural and physiological aspects

Heslop‐Harrison¹,

Heslop‐Harrison²

1997

Can. J. Bot.

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Abscission of the stigmas of pearl millet (Pennisetunl typhoides (Burman) Stapf et Hubbard) after pollination results from the activation of a specialized zone of tissue near the base. This abscission zone comprises a well-defined stretch of the basal column made up of thin-walled cells lacking a cuticularized epidermis. The penetration of the first few pollen tubes following a compatible pollination results in loss of turgor throughout the tissue, followed by loss of adhesion between the cells and ultimately disruption of the whole zone. Pectolytic enzymes are released concomitantly, but the cellulosic skeletons of the cells persist. Numerous calcium oxalate druses, identified cytochemically and by energy-dispersive X-ray analysis, are present in the cells of the abscission zone; these undergo dissolution after activation of the zone, while simultaneously the druse population in the stigma stump and the upper ovary wall increases. The barrier formed by the degenerating abscission zone tissues excludes pollen tubes arriving after the initial activation and prevents the penetration of pathogens such as ergot and so has a prophylactic role. We suggest that the collapsed abscission zone forms not only a physical barrier but also a chemical one. Dissolution products of the numerous calcium oxalate druses during the breakdown of the tissue are likely to raise the calcium ion concentrations beyond the optimum for pollen-tube growth, thereby preventing further penetration. Inhibited tubes swell at the tips and may show growth disorientation before arrest, responses similar to those seen in pearl millet tubes in culture when exposed to higher than normal calcium ion concentration.Resum6 : L'abscission des stigmates du millet perlt (Penniseturn typhoides (Burman) Stapf et Hubbard), aprks la pollinisation, rtsulte de I'activation d'une zone sptcialiste du tissus situC a sa base. Cette zone d'abscission comporte une portion bien dCfinie de la colonne basale, constitute de cellules i paroi mince dCpourvues d'Cpiderme cuticularist.La penetration du premier grain de pollen, i la suite d'une pollinisation compatible, conduit i une perte de turgescence dans l'ensernble du tissus, suivi par une perte de cohtsion entre les cellules et tventuellement d'une dCsorganisation de I'ensemble de la zone. Des enzymes pectolytiques sont reldchtes i ce moment mais le squelette cellulosique des cellules persiste. De nombreux cristaux d'oxalate de calcium, identifiCs cytochimiquement et par I'tnergie dispersive des rayons X, sont prtsents dans les cellules de la zone d'abscission; ceux-ci subissent une dissolution aprks l'activation de la zone, alors que simultanCment la population de cristaux dans la base du stigmate et dans la partie suptrieure de l'ovaire augmente. La barrikre formte par les tissus de la zone d'abscission en dCgtntrescence exclut les tubes polliniques qui arrivent aprks l'activation initiale et prtvient la ptnttration par des organismes pathogknes tels que I'ergot, comportant ainsi des proprittts prophylactiques. Les auteur...

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Section: Methodsmentioning

confidence: 99%

The pollen tube activated abscission zone in the stigma of pearl millet: structural and physiological aspects

Heslop‐Harrison¹,

Heslop‐Harrison²

1997

Can. J. Bot.

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Rapid detection of metals in red mangrove Rhizophora mangle leaves in a polluted environment in Brazil

Victório,

dos Santos,

Alves

et al. 2023

Int. J. Environ. Sci. Technol.

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Rhizophora mangle L. (Rhizophoraceae) is a halophyte from two mangroves in the municipality of Rio de Janeiro in Rio de Janeiro state, Brazil. This work aimed to determine the presence of environmental contaminants in the leaf of R. mangle through morphological and chemical analyses. We collected samples in Coroa Grande mangrove (CG), near an industrial park, and Pedra de Guaratiba mangrove (PG), which is currently under threat of anthropization by domestic occupation. Energy Dispersive X-Ray Spectroscopy (EDS) coupled to Scanning Electron Microscopy (SEM) revealed the presence of chemicals and their relative quantities in leaves. Light microscopy and Scanning Electron Microscopy (SEM) were used to examine leaf tissue. Na, Ca and Cl were found in both CG and PG. Speci c leaf area was signi cantly lower in PG. Leaves from CG also presented the three heavy metals Mn, Zn and Cu. R. mangle presents succulent, hypostomatic leaves with dorsiventral structure. Abundant mucilage and crystals in idioblasts were observed. Slight differences in anatomical qualitative traits between leaves from both sites were detected. Leaves from CG were slightly thicker than those examined from PG, especially on main vein vascular system, and a high quantity of stomata was observed in abaxial surface of leaves from PG. Collectively, these ndings indicate that R. mangle is resilient and tolerant to the environmental pollutants and presents functional traits related with saline environments; therefore, the morphoanatomical variations are probably related to abiotic factors. Highlights-The main minerals detected by EDS were Na, Ca and Cl.-Zn and Cu were the only heavy metals detected in R. mangle leaves in samples from CG.-A large number of stomata in leaves were observed in plants from PG.-Differences in spongy parenchyma and stomata were noted between leaves of PG and CG.-No anatomical changes related to pollution were noted.

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Structural, optical, and thermoluminescence characterizations of 1 mol% Dy3+ion-activated Fluro Boro-phosphate glass for photonic devices

Murugasen,

Dhavamurthy,

Anthoniammal

et al. 2024

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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Energy Dispersive X-Ray Analysis

Cited by 4 publications

References 37 publications

The pollen tube activated abscission zone in the stigma of pearl millet: structural and physiological aspects

The pollen tube activated abscission zone in the stigma of pearl millet: structural and physiological aspects

Rapid detection of metals in red mangrove Rhizophora mangle leaves in a polluted environment in Brazil

Structural, optical, and thermoluminescence characterizations of 1 mol% Dy3+ion-activated Fluro Boro-phosphate glass for photonic devices

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