Capacity of protection against ultraviolet radiation in sun and shade leaves of tropical forest plants

2003 ◽  
Vol 30 (5) ◽  
pp. 533 ◽  
Author(s):  
G. Heinrich Krause ◽  
Alexander Gallé ◽  
Rolf Gademann ◽  
Klaus Winter
Keyword(s):  
Tropical Forest ◽  
Spectral Region ◽  
Cloud Forest ◽  
Leaf Extracts ◽  
Abaxial Epidermis ◽  
Tropical Plants ◽  
Adaxial Epidermis ◽  
Forest Plants ◽  
Shade Leaves ◽  
Sun Leaves

Protection of leaves of tropical forest plants against UV-A and -B radiation was studied in three lowland forests, a montane cloud forest and a mangrove stand in Panama. Leaves were classified as sun or shade leaves according to their chlorophyll a / b ratio, pool size of xanthophyll cycle pigments and α- and β-carotene contents. The capacity of the leaves for protection against UV radiation was assessed by estimating epidermal UV-A shielding, by a non-invasive fluorometric method, and by the absorbance of ethanolic / aqueous leaf extracts in the UV spectral region. In all sun leaves tested, UV-A shielding by the adaxial epidermis was high, usually above 90%, whereas in shade leaves the epidermal UV-A shielding was markedly lower and varied widely between species. In most cases UV-A shielding by the abaxial epidermis was lower than by the adaxial epidermis. UV absorbance of the leaf extracts was generally higher in sun than in shade leaves, and the absorbance was much higher in the UV-B spectral region at 305 nm than in the UV-A region at 375 nm. The data demonstrate that sun leaves of tropical plants are well protected against solar UV-A and UV-B radiation. However, UV-induced damage may occur when shade leaves become exposed to full solar radiation.

scholarly journals Morphological and anatomical aspects of the leaves of Rhizophora mangle L. (Rhizophoraceae) under different lighting conditions / Aspectos morfológicos e anatômicos das folhas de Rhizophora mangle L. (Rhizophoraceae) sob diferentes condições de luz

2016 ◽  
Vol 12 (2) ◽  
pp. 74
Author(s):  
Camilla Reis Augusto da Silva ◽  
Marcelo Dos Santos Silva ◽  
Léa Maria Dos Santos Lopes Ferreira ◽  
Kelly Regina Batista Leite ◽  
Lazaro Benedito da Silva
Keyword(s):  
Stomatal Density ◽  
Rhizophora Mangle ◽  
Palisade Parenchyma ◽  
Abaxial Epidermis ◽  
Lighting Conditions ◽  
Ocular Micrometer ◽  
Significant Difference ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

The basis of differentiation between sun and shade leaves is related to different light intensities. In order to understand the adaptability of the leaves of Rhizophora mangle L., associated with different lighting conditions, leaves were collected from the upper peripheral six individuals (sun leaves) and the lower region of the same internal (shade leaves). The variables analyzed leaf thickness, palisade parenchyma, adaxial and abaxial epidermis, adaxial and abaxial cuticle, stomatal density and index. Measurements were made ??on microscope equipped with ocular micrometer. Sun leaves were lower and with more xeromorphic characteristics, such as increased thickness of the cuticle and the adaxial and abaxial epidermis. The palisade parenchyma and limbus showed up thicker than shade leaves, with no significant difference between the cuticle of the abaxial surface. It was also observed a higher frequency of stomata per mm², an average of 70/mm², while shade leaves showed 47/mm², with no differences between length and width. Differences between the sun leaves and shade leaves indicate adaptive capacity of this species to remain active at different light conditions.

Sun-shade patterns of leaf carotenoid composition in 86 species of neotropical forest plants

2009 ◽  
Vol 36 (1) ◽  
pp. 20 ◽  
Author(s):  
Shizue Matsubara ◽  
G. Heinrich Krause ◽  
Jorge Aranda ◽  
Aurelio Virgo ◽  
Kim G. Beisel ◽  
...  
Keyword(s):  
Woody Species ◽  
Carotenoid Biosynthesis ◽  
Dry Mass ◽  
Daily Basis ◽  
High Irradiance ◽  
Strong Light ◽  
Neotropical Forest ◽  
Forest Plants ◽  
Shade Leaves ◽  
Sun Leaves

A survey of photosynthetic pigments, including 86 species from 64 families, was conducted for leaves of neotropical vascular plants to study sun-shade patterns in carotenoid biosynthesis and occurrence of α-carotene (α-Car) and lutein epoxide (Lx). Under low light, leaves invested less in structural components and more in light harvesting, as manifested by low leaf dry mass per area (LMA) and enhanced mass-based accumulation of chlorophyll (Chl) and carotenoids, especially lutein and neoxanthin. Under high irradiance, LMA was greater and β-carotene (β-Car) and violaxanthin-cycle pool increased on a leaf area or Chl basis. The majority of plants contained α-Car in leaves, but the α- to β-Car ratio was always low in the sun, suggesting preference for β-Car in strong light. Shade and sun leaves had similar β,ε-carotenoid contents per unit Chl, whereas sun leaves had more β,β-carotenoids than shade leaves. Accumulation of Lx in leaves was found to be widely distributed among taxa: >5 mmol mol Chl−1 in 20% of all species examined and >10 mmol mol Chl−1 in 10% of woody species. In Virola elongata (Benth.) Warb, having substantial Lx in both leaf types, the Lx cycle was operating on a daily basis although Lx restoration in the dark was delayed compared with violaxanthin restoration.

scholarly journals An experimental study of generating electricity from urban tropical forest plants

2021 ◽  
Vol 1825 (1) ◽  
pp. 012099
Author(s):  
M. Muladi ◽  
M. F. A. Jalil ◽  
R. F. Arifin ◽  
A. Aripriharta ◽  
I. A. E. Zaini ◽  
...  
Keyword(s):  
Experimental Study ◽  
Tropical Forest ◽  
Forest Plants

scholarly journals Seasonal Variation of Tannin and Nutrient in Aegiceras corniculatum Leaves in Zhangjiang Mangrove Ecosystem

2015 ◽  
Vol 9 (1) ◽  
pp. 143-148
Author(s):  
Minshen Huang ◽  
Lihua Zhang ◽  
Shudong Wei ◽  
Qi Zeng ◽  
Haichao Zhou ◽  
...  
Keyword(s):  
Condensed Tannins ◽  
Insect Pests ◽  
Mangrove Ecosystem ◽  
Plant Diseases ◽  
The Sun ◽  
Aegiceras Corniculatum ◽  
Significant Difference ◽  
Sun And Shade ◽  
Shade Leaves ◽  
Sun Leaves

Seasonal dynamics of total phenolics (TP), extractable condensed tannins (ECT), protein-bound condensed tannins (PBCT), fiber-bound condensed tannins (FBCT), total condensed tannins (TCT) and nitrogen contents in sun and shade leaves of Aegiceras corniculatum were studied in the Zhangjiang Estuary, Fujian Province, China. The contents of TP, ECT and TCT in the sun leaves were significantly higher than those in the shade leaves through the season. The N content in sun leaves was higher than that in shade leaves in the autumn, while it was lower in the summer, and there was no significant difference in the winter and spring. With the respect to the P through the year, P content in the sun leaves was different between seasons, with the highest in winter and the lowest in summer. In addition, the TP:N and ECT:N ratios in sun leaves were significantly higher than those in shade leaves except in autumn. High tannin levels and TP:N and ECT:N ratios in the sun leaves not only can reduce oxidative stress, but also improve the ability of resisting plant diseases and insect pests.

scholarly journals Comparative Foliar Epidermal Studies in Coix lacryma-jobi L. andCoix aquatica Roxb. (Poaceae)

2009 ◽  
Vol 1 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Rinku Jitendrakumar DESAI ◽  
Vinay Madhukar RAOLE ◽  
Arun Omprakash ARYA
Keyword(s):  
Light Microscopy ◽  
Species Identification ◽  
Foliar Analysis ◽  
Abaxial Epidermis ◽  
Diagnostic Characters ◽  
Pointed Apex ◽  
Adaxial Epidermis ◽  
The Cross ◽  
Micromorphological Characters ◽  
Diagnostic Importance

As micromorphological knowledge was not available for Coix aquatica Roxb., the foliar epidermal studies were carried out for Coix lacryma-jobi L. and Coix aquatica Roxb. with the aim of determining the patterns of variation in their epidermal characteristics and assessing their value in species identification. Comparative foliar analysis was carried out by using light microscopy, after following routine scraping method. The characters of diagnostic importance in the identification of C. aquatica are the sparsely distributed prickle hairs with long pointed apex in the abaxial epidermis and dumbbell shaped silica cells in both the epidermises. The diagnostic characters for C. lacryma-jobi are the cross shaped silica cells and dumbbell shaped on the abaxial and adaxial epidermis respectively. The observed differences in certain micromorphological characters helps in identification of presently studied two species of Coix.

scholarly journals Carbon gain optimization in five broadleaf deciduous trees in response to light variation within the crown: correlations among morphological, anatomical and physiological leaf traits

2015 ◽  
Vol 74 (1) ◽  
pp. 71-94 ◽  
Author(s):  
Rosangela Catoni ◽  
Loretta Gratani ◽  
Francesco Sartori ◽  
Laura Varone ◽  
Mirko U. Granata
Keyword(s):  
Phenotypic Plasticity ◽  
Deciduous Forest ◽  
Light Variation ◽  
Stress Factors ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Carbon Gain ◽  
Deciduous Species ◽  
Shade Leaves ◽  
Sun Leaves

AbstractLeaf trait variations in five deciduous species (Quercus robur, Corylus avellana, Populus alba, Acer campestre, Robinia pseudoacacia) growing in an old broadleaf deciduous forest in response to light variation within the tree crown was analyzed. Net photosynthetic rate (PN), leaf respiration rate (R) and the photosynthetic nitrogen use efficiency were, on average, more than 100% higher in sun than in shade leaves. A. campestre and C. avellana sun leaves had the highest specific leaf area (SLA, 156.0 ± 17.9 cm2 g-1) and the lowest total leaf thickness (L, 101.9 ± 8.8 μm) underlining their shade-tolerance. Among the shade-intolerant species (Q. robur, P. alba and R. pseudoacacia), Q. robur had the lowest SLA and the highest L in sun leaves (130.6 ± 10.0 cm2 g-1 and 160.8 ± 9.6 μm, respectively) since shade-intolerant species typically have thicker leaves. The higher PN decrease in respect to R decrease from sun to shade leaves attested the higher sensitivity of PN than R to light variations within the crown. This determined a 69% lower R/PN in sun than in shade leaves. This result is further attested by the significant correlation between PN and the relative photosynthetic photon flux density. The shade-tolerant species have a 76% higher R/PN ratio than the shade-intolerant ones. The measured leaf phenotypic plasticity (PI = 0.35) was in the range of broadleaf deciduous species. Plasticity is a key trait useful to quantify plant response to environmental stimuli. It is defined as the ability of a genotype to produce different phenotypes depending on the environment. Among the considered species, Q. robur showed the highest PI (0.39) and P. alba the lowest (0.29). Knowledge on phenotypic plasticity is important in making hypotheses about the dynamics of the studied forest in consideration of environmental stress factors, including invasive species competition and global climate change.

Human Impacts on Pollination, Reproduction, and Breeding Systems in Tropical Forest Plants

2011 ◽  
pp. 173-194 ◽  
Author(s):  
Mauricio Quesada ◽  
Fernando Rosas ◽  
Ramiro Aguilar ◽  
Lorena Ashworth ◽  
Víctor M. Rosas-Guerrero ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Human Impacts ◽  
Breeding Systems ◽  
Forest Plants

Clausospicula, a new Australian genus of grasses (Poaceae, Andropogoneae)

1991 ◽  
Vol 4 (2) ◽  
pp. 391
Author(s):  
M Lazarides ◽  
J Lenz ◽  
L Watson
Keyword(s):  
Cell Walls ◽  
Transverse Section ◽  
Northern Territory ◽  
Vascular Bundles ◽  
Monotypic Genus ◽  
Prominent Feature ◽  
Abaxial Epidermis ◽  
Diagnostic Characters ◽  
Adaxial Epidermis

Clausospicula, a new monotypic genus from the Darwin and Gulf District, Northern Territory, Australia, is described and illustrated. Its diagnostic characters include cleistogamous spikelets, reduced panicles, racemes and spikelets, and pedicelled spikelets which are poorly developed and deciduous, or suppressed. Also, the glumes of the bisexual spikelet are awned and slightly keeled or without keels. A prominent feature is the extension of the peduncle into an appendage to which the callus of the bisexual spikelet is attached. The epidermis is notable for its distinct costal and intercostal zones, rectangular intercostal long-cells with tessellated, pitted cell walls, stomata inserted beneath the overlapping interstomatals and arranged in definite rows bordering the costal zones, the presence of macrohairs, narrow microhairs 39–46.5 µm long, silica-celllcork-cell pairs with dumbbell-shaped silica bodies costally and butterfly-shaped silica bodies intercostally. The transverse section shows a distinct midrib with the vascular bundles arranged in a conventional arc abaxially and colourless tissue adaxially, and a symmetrically ordered lamina. The primary vascular bundles are accompanied by sclerenchyma as girders abaxially and adaxially; the adaxial epidermis is extensively bulliform and the abaxial epidermis is of bulliform-like cells.

scholarly journals Phytochemical Screening of Leaf Extracts of Eleven selected Tropical Plants Species from Eastern and Southern Nigeria

2019 ◽  
Vol 23 (10) ◽  
pp. 1867-1873
Author(s):  
C.J. Nwandu ◽  
B.L. Nyananyo ◽  
C.O. Ozimede
Keyword(s):  
Traditional Medicine ◽  
Plant Species ◽  
Leaf Extract ◽  
Phytochemical Screening ◽  
Leaf Extracts ◽  
Tropical Plants ◽  
Southern Nigeria ◽  
Standard Techniques

The pyhtochemical constituents of butanol and acid leaf extracts of eleven (11) plant species from three different families (Annonaceae, Apocynaceae and Euphorbiaceae) obtained from various locations in eastern and southern Nigeria were made following standard techniques. Results obtained show that the leaf extracts contain alkaloids, flavonoids and saponins. This paper provides evidence that alcoholic and acid leaf extract of the selected plant species studied contains medicinally important metabolites that justifies their usage as traditional medicine for treatment of various ailments.Keywords: Tropical plants, Phytochemicals, Ethno-medicine, Extracts

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