The effect of exposure to enhanced UV-B radiation on the penetration of monochromatic and polychromatic UV-B radiation in leaves of Brassica napus

Cen, Yan‐Ping; Bornman, Janet F.

doi:10.1034/j.1399-3054.1993.870301.x

Cited by 62 publications

(76 citation statements)

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“…A folha diminui a área exposta, mas aumenta a espessura da lâmina, devido ao incremento dos tecidos fotossintéticos e dos espaços intercelulares, garantindo assim o volume da folha (Lewis 1972;Smith et al 1997). Maior espessura também foi reportada para outras espécies estudadas sob a influência da radiação UV-B (Cen & Bornman 1993;Kakani et al 2003a), apesar de resultados contrários serem reportados na literatura (Correia et al 1998;Kakani et al 2003b).…”

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“…Folhas mais espessas possuem um maior número de camadas de células ou células maiores, o que aumenta a área da parede celular, minimizando a ação da radiação UV-B nas camadas do mesofilo fotossinteticamente ativo próximo à face abaxial (Cen & Bornman 1993). O aumento de espessura proporciona também, um maior número de espaços intercelulares, o que afeta a transmitância da luz incidente (luz difusa) no interior da folha (Bornman & Vogelmann 1991).…”

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“…O aumento de espessura proporciona também, um maior número de espaços intercelulares, o que afeta a transmitância da luz incidente (luz difusa) no interior da folha (Bornman & Vogelmann 1991). Entretanto, alguns estudos têm demonstrado que a espessura da folha não é o único fator que pode reduzir a ação da radiação no interior da folha (Cen & Bornman 1993;Day 1993). A composição química da cutícula (Pilon et al 1999), assim como, a presença de compostos fenólicos parece exercer importante função na reflexão da radiação UV-B na superfície da folha (Day et al 1992;Day 1993).…”

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Efeitos da radiação ultravioleta-B sobre a morfologia foliar de Arabidopsis thaliana (L.) Heynh. (Brassicaceae)

Boeger

Poulson

2006

Acta Bot. Bras.

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RESUMO -(Efeitos da radiação ultravioleta-B sobre a morfologia foliar de Arabidopsis thaliana (L.) Heynh. (Brassicaceae)). A redução da camada de ozônio resulta no aumento da radiação ultravioleta que atinge a superfície terrestre, especialmente a radiação ultravioleta-B (UV-B). O aumento da radiação poderá induzir a mudanças estruturais e fisiológicas nas plantas, influenciando no seu crescimento e desenvolvimento. O objetivo deste trabalho foi determinar os efeitos da radiação UV-B ambiente sobre a morfologia das folhas de Arabidopsis thaliana desenvolvidas em condições controladas. As sementes de A. thaliana cresceram em câmaras de crescimento, com 300 µmol m -2 s -1 de radiação fotossinteticamente ativa (PAR) com ou sem 6 kJ m -2 s -1 de radiação UV-B be (UV-B be ; UV-B biologicamente efetiva). Após 21 dias, 10 folhas de cada tratamento (com e sem radiação UV-B) foram coletadas para avaliar área foliar, massa fresca e seca, AEF, densidades estomáticas e de tricomas de ambas as faces da folha, espessura da lâmina foliar e concentração de compostos fenólicos e de clorofila total, a e b. As folhas tratadas com radiação UV-B apresentaram menor área foliar, massa fresca e seca, densidade de tricomas na face adaxial e densidade de estômatos na face abaxial da folha. Entretanto, apresentaram os maiores valores médios de espessura total da lâmina e do mesofilo, maior concentração de clorofila total, clorofila a e clorofila b e compostos fenólicos foliares do que as folhas não tratadas com radiação UV-B. Essas diferenças morfológicas significativas (p < 0,05) entre as folhas tratadas e não tratadas com radiação UV-B indicam que A. thaliana é sensível à radiação e possui mecanismos para minimizar os seus efeitos negativos sobre o desenvolvimento e crescimento foliar. Entretanto, as respostas da planta à radiação UV-B envolvem vários mecanismos fisiológicos que ainda necessitam de investigações mais detalhadas. Palavras-chave : Arabidopsis thaliana, radiação UV-B, morfologia foliar, compostos fenólicos ABSTRACT -(Effects of ultraviolet-B radiation on leaf morphology of Arabidopsis thaliana (L.) Heynh. (Brassicaceae)). Reduction of the ozone layer results in the increase in ultraviolet radiation reaching the earth's surface, especially the ultraviolet-B (UV-B). The increase of radiation may induce structural and physiological changes in plants, influencing their growth and development. This paper evaluates the effects of ambient UV-B radiation upon to the leaf morphology of Arabidopsis thaliana developed under controlled conditions. The seeds of A. thaliana grown in environmental chamber, with 300 µmol m -2 s -1 de photosynthetically active radiation (PAR) with and without 6 kJ m -2 s -1 of radiation UV-B be (UV-B be ; UV-B biologically effective). After 21 days, ten leaves of each treatment (with and without UV-B radiation) were collected to measure leaf area, fresh and dry mass, AEF, stomata and trichome densities of both leaf surfaces, leaf thickness and concentration of phenolic compounds and total chlorophyll, and ...

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Efeitos da radiação ultravioleta-B sobre a morfologia foliar de Arabidopsis thaliana (L.) Heynh. (Brassicaceae)

Boeger

Poulson

2006

Acta Bot. Bras.

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“…The decrease of AET, even moderately, may interfere with the protection and prevention of tissue water loss (Bukovac et al, 1990). However, its increase determines prevention from sweating, being an important factor to mitigate the penetration of radiation inside the leaf, protecting the layers of the photosynthetically active mesophyll (Cen and Bornman, 1993). Môro et al (1999) have noticed anatomical changes such as significant increase in number, size and shape of bulliform cells, besides the almost complete disappearance of key epidermal cells of Zea mays submitted to herbicide nicosulfuron.…”

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Structural Evaluation of Damage Caused by Herbicide Clomazone in Leaves of Arborescent Species Native to Brazil

et al. 2017

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Herbicide clomazone is highly soluble in water, which increases the risk of leaching, resulting in contamination of sources of groundwater and waterways, affecting non-target organisms, with possible degradation of riparian areas. The objective of this work was to investigate the possible anatomical modifications of the leaf tissue of twelve arborescent species native to Brazil grown in soil contaminated by clomazone, in order to microscopically characterize leaf damage caused by the herbicide, and investigate whether the structural damage precedes visible damage. Through micro morphometrics, the thickness and the area occupied by the tissues were measured in a cross section of the leaves of the forest species: adaxial and abaxial epidermis, palisade and spongy parenchyma. It has been found that the species evaluated were affected by the presence of the pesticide in the soil, and the variable with the largest negative changes was the spongy parenchyma. Among the species, Inga marginata, Schizolobium parahyba and Handroantus. serratifolius had higher tolerance to the herbicide, demonstrating potential for studies on the mechanism by which these plants exert such tolerance. Overall, the results revealed that the forest species studied demonstrate significant alterations in leaf anatomy in response to the presence of residues of herbicide clomazone in the soil, even in leaves with no visible lesions.

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“…1/3 of the epidermal cell layers warned that there was a limit to this tolerance. Teramura and Sullivan (1994) listed maize as a species sensitive to UV-B radiation.The responses of plants to more intense UV-B radiation occur mostly at the physiological and biochemical level (Hollósy, 2002), resulting in a reduction in radiation absorption on the leaf surface (Cen and Bornman, 1993). Morphological changes (such as leaf area reduction, leaf thickening, decrease in the number of stomata, etc.)…”

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Effect of increased UV-B radiation on the anthocyanin content of maize ( Zea mays L.) leaves

Pintér

Kósa

Hadi

et al. 2007

Acta Agronomica Hungarica

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The level of UV-B radiation reaching the surface of the earth is increasing due to the thinning of the ozone layer in the stratosphere over recent decades. This has numerous negative effects on living organisms.Some of the Hungarian inbred maize lines examined under the climatic conditions in Chile exhibited an unusually high proportion of pollen mortality, flowering asynchrony and barrenness. The evidence suggests that this can be attributed to the approx. 30% greater UV-B radiation in Chile.The investigation of this problem within the framework of abiotic stress breeding programmes is extremely important in the light of the global rise in UV-B radiation, which may make it necessary to elaborate a selection programme to develop inbred lines with better tolerance of this type of radiation.In the course of the experiment the same ten inbred lines, having different maturity dates and genetic backgrounds, were tested for five years in Chile and Hungary. The tests focussed on anthocyanin, a flavonoid derivative involved in the absorption of damaging UV-B radiation.Averaged over years and varieties, the total anthocyanin content in the leaf samples was significantly higher in Chile than in Hungary. This was presumably a response at the metabolic level to the negative stress represented by higher UV-B radiation.In the five early-maturing flint lines the anthocyanin contents were more than 45% greater than those recorded in Hungary. This suggests that these genotypes, originating from northern regions, were not sufficiently adapted to the higher radiation level. In these samples higher UV-B caused a sharp rise in the quantity of anthocyanin, which absorbs the dangerous radiation. In late-maturing genotypes the initial content of the protective compound anthocyanin was higher at both locations, so in these types the high radiation level was not a problem and did not cause any substantial change.Similar conclusions were drawn from the results of fluorescence imaging. The F440/F690 ratio indicative of the stress level was higher in late lines with a high anthocyanin content, good tolerance and good adaptability.Key words: Zea mays L., inbred line, ultraviolet-B radiation, flavone, anthocyanin, stress acclimation, fluorescence imaging J. PINTÉR et al. Hungarica, 55, 2007 8 Acta Agronomica IntroductionOne negative consequence of global climate change is the thinning of the ozone layer in the stratosphere, which functions as a shield against dangerous radiation. This has been caused in part by human activities, especially by the ozone-antagonistic gases emitted by heavy industry (Anderson et al., 1991;McFarland and Kaye, 1992;McKenzie et al., 1999;Reddy and Hodges, 2000).A decrease of 1% in the ozone level may result in a 1.3-1.8% rise in the UV-B radiation (280-320 nm), the most biologically active form of ultraviolet radiation, with the most damaging effect on living organisms (Madronich, 1993). Naturally, the level of dangerous radiation depends on many factors, such as the latitude and altitude of the given location, ...

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The effect of exposure to enhanced UV-B radiation on the penetration of monochromatic and polychromatic UV-B radiation in leaves of Brassica napus

Cited by 62 publications

References 3 publications

Efeitos da radiação ultravioleta-B sobre a morfologia foliar de Arabidopsis thaliana (L.) Heynh. (Brassicaceae)

Efeitos da radiação ultravioleta-B sobre a morfologia foliar de Arabidopsis thaliana (L.) Heynh. (Brassicaceae)

Structural Evaluation of Damage Caused by Herbicide Clomazone in Leaves of Arborescent Species Native to Brazil

Effect of increased UV-B radiation on the anthocyanin content of maize ( Zea mays L.) leaves

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