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Advance in histochemistry, ultrastructure and secretion of glandular trichomes in Salvia dolomitica Codd.
No full textIn order to have better knowledge of African sages, we begun the study of some Salvia species (Serrato Valenti, 1997; Bisio et al., 1998; Bisio et al., 2001) belonging to the G species-group according to Hedge classification (1974). In the present work we examined the ultrastructure and the histochemistry of the glandular trichomes, and the essential oil and the exudate products of Salvia dolomitica Codd., a shrub, native of Transvaal, South Africa.
The leaves of S. dolomitica appeared covered by uniseriate non-glandular trichomes and glandular trichomes. The latter occurred as peltate and capitate (Bisio et al., 2001).
The histochemistry of peltate hairs evidenced a secretion with abundant hydrophobic substances, but also small quantities of hydrophilic substances (polysaccharides, flavonoids, phenols, essential oil, triterpenoids). The ultrastructural observations are consistent with the histochemical ones; indeed, the former showed abundant plastids and smooth endoplasmic reticulum (SER), typical organelles of lipophilic secreting cells, as observed in many other trichomes secreting lipophilic substances. SER can also be responsible for flavonoid secretion, as indicated also by Schopker et al. (1995).
Two types of capitate hairs, depending on the number of the secreting and stalk cells, were observed. The cytoplasm of type I presented numerous Golgi stacks, plastids and dilated ER, that are organelles respectively responsible for secretion of polysaccharides, terpenes and also flavonoids. Indeed, histochemical observations indicated a complex secretion, in which phenolic compounds, polysaccharides and terpenes were present. Also in type II trichomes the histochemical and ultrastructural observations indicated a complex secretion with phenolic compounds, polysaccharides and terpenes, but probably the release of secretion occurs in a different way and at a different time.
In S. dolomitica the essential oil was mainly constituted by monoterpene hydrocarbons, followed by oxigenated monoterpenes and sesquiterpene hydrocarbons. The main components of the oil were represented by substances that are often described for other Salvia species, 1,8-cyneol, limonene, -3-carene, -pinene and -caryophyllene.
The analysis of leaf surface extract identified abietane diterpenoids: carnosol and 7-methoxirosmanol suggesting that these products could be good taxonomic markers.
BISIO A, FONTANA N, ROMUSSI G, DE TOMMASI N. 1998. Pharmazie 53: 210-211.
BISIO A, ROMUSSI G, MALECI L, CORALLO A, ZAPPA E, PROFUMO P. 2001. 96°Congresso della Società Botanica Italiana – Varese 26-28 settembre 2001. 145.
HEDGE IC. 1974. Notes from the Royal Botanic Garden, Edinburgh. 33: 1-118.
SCHÖPKER H, KNEISEL M, BEERHUES L, ROBENEK H, WIERMANN R. 1995. Planta 196: 712-719.
SERRATO-VALENTI G, BISIO A, CORNARA L, CIARALLO G. 1997. Annals of Botany 79: 329-336
The chromium issue in soils of the leather tannery district in Italy
No full textAmong heavy metals, up to now chromium has received little attention. The reasons for this lack of interest are diverse. One is that Cr was considered a “ local source ” contaminant, thus constituting a non-widespread environmental problem. A second reason is that the dominant naturally occurring form of chromium, Cr2 O3, is considered essentially immobile in the environment, in
contrast with the highly mobile and toxic Cr(VI).
Based on these assumptions, we have started a research program aimed at assessing the actual chromium accumulation in soils and plants of a tannery industrial district in NE Italy.
Further objectives of our study were:
- to highlight possible contamination of soils, plants and waters;
- to ascertain the potential risk to human health.
Large differences in Cr concentration were observed in the area investigated, with a very scattered distribution. Mean Cr concentration in soils is 210 mg/kg (range 50 – 10,000). Most of the investigated sites present surface Cr concentrations higher than subsurface, suggesting local sources of Cr to be responsible for soil contamination.
Chromium concentrations in selected plants ( Taraxacum officinale , Plantago lanceolata) present wide ranges in both the species examined, with little translocation from roots to leaves (barrier effect).
To determine the groundwater pollution hazard in the surveyed district, we have compared the soil Cr concentration with the soil vulnerability map. Surface soils having the highest Cr concentration correspond to sites with very high to high vulnerability.
Therefore, considering the present soil Cr concentrations and the pollution hazard, precaution and control acts are needed, in order to avoid more damage to land and waters. Moreover, considering all the above items, hazard for human health by direct contact with soil, ingestion, and inhalation should be taken in consideration by decision makers
Comparative observations on Thymus striatus Vahl and Thymus striatus var. ophioliticus Lacaita in Central Italy
No full textThe Chromium issue in soils of the leather tannery district in Italy.
No full textpubblicato su CD-Rom (EGU06-A-02354
Effect of heavy metals on morphological characteristics of Taraxacum officinale Web growing on mine soils in NE Italy. J. Geochem. Explor., 123, 101-108.
No full textPlants growing on metal contaminated soils can uptake heavy metals and accumulate them in their tissues; the accumulation of potentially toxic elements can produce adverse effects on plant morphology and health. In this study, plants of Taraxacum officinale Web growing on mixed sulphides (Cu, Fe, Pb, Zn) mine waste in NE Italy were studied in order to assess the levels of potentially toxic heavy metals (Cd, Cr, Cu, Fe, Pb, Zn) in plants in relation to soil, and to investigate the accumulation ability and morphological response to environmental stress. T. officinale accumulates relatively high amounts of different metals in both shoots and roots, with positive translocation factor (TF. ≥. 1). Micromorphological observations on the leaf anatomy of contaminated plants revealed significant reduction in the leaf thickness, changes in intercellular spaces and in cell structural organization in comparison to plants grown on unpolluted soil. The recorded morphological changes appear to be related to contamination levels in soils. © 2012 Elsevier B.V
Glandular trichomes and secreted material in Salvia wagneriana Polak.
No full textSalvia wagneriana is a shrub of the subgenus Calosphace, growing in Central America, particularly in Mexico and Costa Rica, frequently cultivated in the gardens of the warm-temperate regions for his beautiful, red inflorescences.
The subject of this work is a study of the glandular trichomes present on the plant and of their type of secretion. The leaves of Salvia wagneriana bear numerous glandular trichomes both on abaxial and adaxial sides. They occur as peltate and capitate. The peltate trichomes consist of one basal epidermal cell, a stalk cell and a broad head of 4 secretory cells. Three types of capitate trichomes are present: capitate type I, consisting of one basal epidermal cell, one stalk cell and a round head of one single broad cell; capitate type II, consisting of one basal epidermal cell, one stalk cell and an elongated head of one cell; capitate type III, consisting of a basal epidermal cell, 1-6 stalk cells and a single rounded head cell. All these types of trichomes are present on the leaf, although type III is rare; however it is frequent on the flowers, particularly on the calix. The histochemical and ultrastructural observations evidence in peltate hairs a lipophylic secretion constituted mostly of essential oil and in capitate type I hairs a mainly hydrophilic secretion. The other two types of capitate hairs show a lipophylic secretion constituted mainly of essential oil. Flavonoids have been evidenced in all the hair types.
In the essential oil, obtained by hydrodistillation of the leaves, twenty nine components, have been identified by GC-MS: monoterpene hydrocarbons account for 0.3%, oxigenated monoterpenes 6.3%, sesquiterpene hydrocarbons 47.1%, oxygenated sesquiterpenes 2.9%, non-terpenoidic compounds 13.2%
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Markers fitognostici utili per l'identificazione di possibili sofisticazioni di Hypericum perforatum L. con specie congeneri
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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