Structural and Functional Properties of Trichomes of Xeromorphic Leaves

Fahn, A.

doi:10.1093/oxfordjournals.aob.a087146

Cited by 131 publications

(116 citation statements)

References 8 publications

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“…Ten leaves of both species were detached and their adaxial surface was sprayed with a 0.1% (w\v) aqueous solution of fluorescent brightener-20 (Aldrich 29,418-7) (Grammatikopoulus & Manetas, 1994). Fluorescent brightener is an apoplastic tracer (Fahn, 1986) that binds to polysaccharides of the cell wall and emits a strong, pale blue fluorescence under an excitation wavelength of 350 nm (O'Brien & McCully, 1981). After 30 min, the leaves were washed in distilled water.…”

Section: Fluorescence Microscopymentioning

confidence: 99%

Diurnal variations of photosynthesis and dew absorption by leaves in two evergreen shrubs growing in Mediterranean field conditions

1999

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The effects of summer drought, dew deposition on leaves and autumn rainfall on plant water relations and diurnal variations of photosynthesis were measured in two evergreen shrubs, rosemary (Rosmarinus officinalis) and lavender (Lavandula stoechas), grown in Mediterranean field conditions. Withholding water for 40 d caused a similar decrease in predawn shoot water potential (ψ pd ) from c. k0.4 to c. k1.3 MPa in both species, but a 50% decrease in the relative leaf water content in L. stoechas compared with 22% in R. officinalis. A similar decrease in CO # assimilation rates by c. 75% was observed in water-stressed plants of both species, although L. stoechas showed smaller photosynthesis : stomatal conductance ratio than R. officinalis (35 vs 45 µmol CO # : mol H # O). The relative quantum efficiency of photosystem II photochemistry also decreased by c. 45% at midday in waterstressed plants of both species. Nevertheless, neither L. stoechas nor R. officinalis suffered drought-induced damage to photosystem II, as indicated by the maintenance of the ratio F v : F m throughout the experiment, associated with an increase in the carotenoid content per unit of chlorophyll by c. 62% and c. 30%, respectively, in water-stressed plants. Only L. stoechas absorbed dew by leaves. In this species the occurrence of 6 d of dew over a 15-d period improved relative leaf water content by c. 72% and shoot water potential by c. 0.5 MPa throughout the day in water-stressed plants, although the photosynthetic capacity was not recovered until the occurrence of autumn rainfall. The ability of leaves to absorb dew allowed L. stoechas to restore plant water status, which is especially relevant in plants exposed to prolonged drought.

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Section: Fluorescence Microscopymentioning

confidence: 99%

Diurnal variations of photosynthesis and dew absorption by leaves in two evergreen shrubs growing in Mediterranean field conditions

1999

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“…These factors vary in space and time and can be limiting to the establishment and growth of the vegetation. Leaves are the plant organs most exposed to environmental conditions and the changes in their structure have been interpreted as adaptations to specifi c environments (Fahn 1986). The evaluation of anatomical characteristics of the leaves, in widespread species, present in a range of vegetation, being exposed to environmental differences, has the main aim of elucidating the processes of gas exchange and water economy in relation to leaf structure, and purposing to identify predictive ecophysiological responses to environmental stress (Abrams et al 1994).…”

Section: Introductionmentioning

confidence: 99%

Gochnatia polymorpha (Less.) Cabrera (Asteraceae) changes in leaf structure due to differences in light and edaphic conditions

Rossatto

Kolb

2010

Acta Bot. Bras.

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RESUMO -(Gochnatia polymorpha (Less.) Cabrera modifi ca sua estrutura foliar devido a diferenças na luminosidade e condições edáfi cas). Gochnatia polymorpha (Less.) Cabrera é uma espécie de Asteraceae com ampla distribuição no bioma cerrado, sendo encontrada em diversas fi sionomias fl orestais da região sudeste do Brasil. O presente estudo descreve alguns caracteres anatômicos foliares dessa espécie e os analisa quantitativamente em função de sua ocorrência nas formações fl orestais e também das diferenças de luminosidade. Foram encontradas diferenças quantitativas em todos os parâmetros anatômicos analisados. Os resultados demonstram que a alta plasticidade anatômica foliar nesta espécie pode ser considerada como uma vantagem adaptativa que a permite ocorrer em diversos ambientes do cerrado. Palavras-chave: cerrado, freqüência estomática, mata de galeria, morfologia foliar, plasticidade anatômica ABSTRACT -(Gochnatia polymorpha (Less.) Cabrera (Asteraceae) changes in leaf structure due to differences in light and edaphic conditions). Gochnatia polymorpha (Less.) Cabrera is a widespread Asteraceae species found in different physiognomies of cerrado (Neotropical savanna) and in forest formations of southeast Brazil. This study describes some leaf anatomy characteristics of this species and quantitatively evaluates them in relation to different environments, as well as under different light conditions. We found quantitative differences in all anatomical parameters analyzed. The results demonstrate that high leaf anatomy plasticity is an adaptive advantage that allows this species to occur in diverse cerrado conditions.

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“…O tipo morfológico de ampola e a rugosidade que a cutícula assume nos tricomas tectores, bem como os mesmos serem uni ou pluricelulares, os tornam estruturas epidérmicas características para esta espécie vegetal. Em geral os tricomas são discutidos como anexos epidérmicos capazes de reduzirem a transpiração ao produzirem uma camada de ar parado que retém vapor, além do que, as folhas pubescentes tendem a ser mais efetivas na reflexão da radiação solar (Hallahan et al, 2000;Ricklefs, 1993;Fahn, 1986). Estas considerações vêm ao encontro da ocupação natural de C. glutinosa em locais de campo aberto, ambiente que exige certa proteção em relação à transpiração excessiva e também na reflexão da radiação luminosa intensa.…”

Section: Discussionunclassified

Estudo morfoanatômico das folhas de Cuphea glutinosa Cham. & Schltdl., Lythraceae

Zago¹,

Manfron²,

Morel³

et al. 2010

Rev. bras. farmacogn.

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RESUMO: A determinação de características macro e microscópicas das folhas de Cuphea glutinosaCham. & Schltdl., Lythraceae, foi o objetivo deste trabalho. Esta planta é utilizada tradicionalmente como medicinal. As características macroscópicas das folhas como a forma, a textura e a consistência, bem como o ápice e a base da lâmina foliar são relevantes na determinação da autenticidade de insumos farmacêuticos desta espécie. Microscopicamente a presença de formações epicuticulares, cristais de oxalato de cálcio na forma de drusas, tricomas tectores e glandulares, estômatos do tipo diacítico, células mucilaginosas e floema interxilemático são características úteis no controle botânico de qualidade desta planta como insumo farmacêutico, quando analisados em conjunto.Unitermos: Cuphea glutinosa, farmacobotânica, Lythraceae. ABSTRACT: Morpho-anatomical study of the leaves of Cuphea glutinosa Cham. et Schltdl. (Lythraceae).The determination of macroscopic and microscopic characteristics of Cuphea glutinosa Cham. & Schltdl., Lythraceae, leaves were the aim of this work. This plant is traditionally used as medicinal. The macroscopic characteristics of the leaves as the shape, texture and consistency as well as the apex and the base of the leaf are relevant to determinate pharmaceutical insumes autenticity of this plant. In the leaves microscopy there are epicuticular formations, crystals of calcium oxalate in the form of druses, and glandular trichomes, xerophytytic stoma of the diacytic type, mucilaginous cells, and interxilematic phloem are important characteristics in the botanical quality control of this plant as pharmaceutical insume.

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Structural and Functional Properties of Trichomes of Xeromorphic Leaves

Cited by 131 publications

References 8 publications

Diurnal variations of photosynthesis and dew absorption by leaves in two evergreen shrubs growing in Mediterranean field conditions

Diurnal variations of photosynthesis and dew absorption by leaves in two evergreen shrubs growing in Mediterranean field conditions

Gochnatia polymorpha (Less.) Cabrera (Asteraceae) changes in leaf structure due to differences in light and edaphic conditions

Estudo morfoanatômico das folhas de Cuphea glutinosa Cham. & Schltdl., Lythraceae

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