| 1. |
- Bornman, Janet, et al.
(författare)
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Effects of ultraviolet-radiation on viability of isolated beta-vulgaris and hordeum-vulgare protoplasts
- 1982
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Ingår i: Zeitschrift für Pflanzenphysiologie. - 0044-328X. ; 105:4, s. 297-306
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Tidskriftsartikel (refereegranskat)abstract
- Estimates of viability as measured by vital staining with fluorescein diacetate (FDA) were carried out on freshly isolated and partially aged (16-h-old) B. vulgaris and H. vulgare mesophyll protoplasts following irradiation with UV-B. Damage to the photosynthetic system by UV-B was determined by delayed light emission (DLE). In the case of freshly isolated protoplasts Beta was .apprx. 30% more susceptible than Hordeum following 3 h irradiation, with viability decreasing from 90% to 40%. After storage of protoplasts on ice for 16 h UV-B radiation markedly depressed viability in both species, but in the case of Hordeum there was a substantial initial loss of nearly 70% in viability over the 1st hour of irradiation. The first 10 min of UV-B radiation decreased the intensity of DLE by 40% without appreciably affecting the decay rate. Longer treatment times did not give a proportional effect so that even after 60 min of UV-B the inhibition did not exceed 60%. This suggested that although the enzyme system responsible for FDA hydrolysis may be partially inactivated (viability was 75-80% as compared with 90% in the control), the UV-B did not penetrate the innermost parts of the chloroplasts, but left some thylakoids undamaged.
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| 2. |
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| 3. |
- Andrady, Anthony, et al.
(författare)
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Environmental effects of ozone depletion and its interaction with climate change: Progress report 2007
- 2008
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Ingår i: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-9092 .- 1474-905X. ; 7:1, s. 15-27
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Forskningsöversikt (refereegranskat)abstract
- This year theMontreal Protocol celebrates its 20th Anniversary. In September 1987, 24 countries signed the ‘Montreal Protocol on Substances that Deplete the Ozone Layer’. Today 191 countries have signed and have met strict commitments on phasing out of ozone depleting substances with the result that a 95% reduction of these substances has been achieved. The Montreal Protocol has also contributed to slowing the rate of global climate change, since most of the ozone depleting substances are also effective greenhouse gases. Even though much has been achieved, the future of the stratospheric ozone layer relies on full compliance of the Montreal Protocol by all countries for the remaining substances, including methyl bromide, as well as strict monitoring of potential risks from the production of substitute chemicals. Also the ozone depleting substances existing in banks and equipment need special attention to prevent their release to the stratosphere. Since many of the ozone depleting substances already in the atmosphere are long-lived, recovery cannot be immediate and present projections estimate a return to pre-1980 levels by 2050 to 2075. It has also been predicted that the interactions of the effects of the ozone layer and that of other climate change factors will become increasingly important.
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| 4. |
- Andrady, Anthony, et al.
(författare)
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Environmental effects of ozone depletion and its interactions with climate
- 2009
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Ingår i: Photochemical and Photobiological Sciences. - 1474-9092. ; 8:1, s. 13-22
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Forskningsöversikt (refereegranskat)abstract
- After the enthusiastic celebration of the 20th Anniversary of the Montreal Protocol on Substances that Deplete the Ozone Layer in 2007, the work for the protection of the ozone layer continues. The Environmental Effects Assessment Panel is one of the three expert panels within theMontreal Protocol. This “EEAP” deals with the increase of the UV irradiance on the Earth’s surface and its effects on human health, animals, plants, biogeochemistry, air quality and materials. For the past few years, interactions of ozone depletion with climate change have also been considered. It has become clear that the environmental problems will be long-lasting. In spite of the fact that the worldwide production of ozone depleting chemicals has already been reduced by 95%, the environmental disturbances are expected to persist for about the next half a century, even if the protective work is actively continued, and completed. The latest full report was published in Photochem. Photobiol. Sci., 2007, 6, 201–332, and the last progress report in Photochem. Photobiol. Sci., 2008, 7, 15–27. The next full report on environmental effects is scheduled for the year 2010. The present progress report 2008 is one of the short interim reports, appearing annually.
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| 5. |
- Andrady, Anthony, et al.
(författare)
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Environmental effects of ozone depletion and its interactions with climate change: Progress report, 2016
- 2017
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Ingår i: Photochemical and Photobiological Sciences. - : Springer Science and Business Media LLC. - 1474-9092 .- 1474-905X. ; 16:2, s. 107-145
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Tidskriftsartikel (refereegranskat)abstract
- The Parties to the Montreal Protocol are informed by three Panels of experts. One of these is the Environmental Effects Assessment Panel (EEAP), which deals with two focal issues. The first focus is the effects of UV radiation on human health, animals, plants, biogeochemistry, air quality, and materials. The second focus is on interactions between UV radiation and global climate change and how these may affect humans and the environment. When considering the effects of climate change, it has become clear that processes resulting in changes in stratospheric ozone are more complex than previously believed. As a result of this, human health and environmental issues will be longer-lasting and more regionally variable. Like the other Panels, the EEAPproduces a detailed report every four years; the most recent was published as a series of seven papers in 2015 (Photochem. Photobiol. Sci., 2015, 14, 1–184). In the years in between, the EEAP produces less detailed and shorter Progress Reports of the relevant scientific findings. The most recent of these was for 2015 (Photochem. Photobiol. Sci., 2016, 15, 141–147). The present Progress Report for 2016 assesses some of the highlights and new insights with regard to the interactive nature of the direct and indirect effects of UV radiation, atmospheric processes, and climate change. The more detailed Quadrennial Assessment will bemade available in 2018.
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| 6. |
- Barnes, Paul W., et al.
(författare)
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Ozone depletion, ultraviolet radiation, climate change and prospects for a sustainable future
- 2019
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Ingår i: Nature Sustainability. - : Springer Science and Business Media LLC. - 2398-9629. ; 2:7, s. 569-579
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Forskningsöversikt (refereegranskat)abstract
- © 2019, Springer Nature Limited. Changes in stratospheric ozone and climate over the past 40-plus years have altered the solar ultraviolet (UV) radiation conditions at the Earth’s surface. Ozone depletion has also contributed to climate change across the Southern Hemisphere. These changes are interacting in complex ways to affect human health, food and water security, and ecosystem services. Many adverse effects of high UV exposure have been avoided thanks to the Montreal Protocol with its Amendments and Adjustments, which have effectively controlled the production and use of ozone-depleting substances. This international treaty has also played an important role in mitigating climate change. Climate change is modifying UV exposure and affecting how people and ecosystems respond to UV; these effects will become more pronounced in the future. The interactions between stratospheric ozone, climate and UV radiation will therefore shift over time; however, the Montreal Protocol will continue to have far-reaching benefits for human well-being and environmental sustainability.
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| 7. |
- Black, Lucinda J., et al.
(författare)
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In pursuit of vitamin D in plants
- 2017
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Ingår i: Nutrients. - : MDPI AG. - 2072-6643. ; 9:2
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Tidskriftsartikel (refereegranskat)abstract
- Vitamin D deficiency is a global concern. Much research has concentrated on the endogenous synthesis of vitamin D in human skin following exposure to ultraviolet‐B radiation (UV‐B, 280–315 nm). In many regions of the world there is insufficient UV‐B radiation during winter months for adequate vitamin D production, and even when there is sufficient UV‐B radiation, lifestyles and concerns about the risks of sun exposure may lead to insufficient exposure and to vitamin D deficiency. In these situations, dietary intake of vitamin D from foods or supplements is important for maintaining optimal vitamin D status. Some foods, such as fatty fish and fish liver oils, certain meats, eggs, mushrooms, dairy, and fortified foods, can provide significant amounts of vitamin D when considered cumulatively across the diet. However, little research has focussed on assessing edible plant foods for potential vitamin D content. The biosynthesis of vitamin D in animals, fungi and yeasts is well established; it is less well known that vitamin D is also biosynthesised in plants. Research dates back to the early 1900s, beginning with in vivo experiments showing the anti‐rachitic activity of plants consumed by animals with induced rickets, and in vitro experiments using analytical methods with limited sensitivity. The most sensitive, specific and reliable method for measuring vitamin D and its metabolites is by liquid chromatography tandem mass spectrometry (LC‐MS/MS). These assays have only recently been customised to allow measurement in foods, including plant materials. This commentary focuses on the current knowledge and research gaps around vitamin D in plants, and the potential of edible plants as an additional source of vitamin D for humans.
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| 8. |
- Bornman, Janet, et al.
(författare)
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Action spectrum for inhibition by ultraviolet-radiation of photosystem-II activities in spinach thylakoids
- 1984
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Ingår i: Photobiochemistry and Photobiophysics. - 0165-8646. ; 8:5-6, s. 305-313
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Tidskriftsartikel (refereegranskat)abstract
- The effect of UV radiation (half-band width 10 nm) in the wavelength range 248-340 nm on chlorophyll fluorescence from a thin layer of spinach thylakoid suspension was investigated. The parameter most sensitive to UV radiation was the rise time of variable fluorescence. The increase in rise time was proportional to UV photon fluence and was used for the determination of an action spectrum. The action spectrum falls off from a maximum at .apprx. 275 nm towards longer wavelengths and rises from a minimum at 260 nm towards shorter wavelengths. The UV inhibition apparently is mainly on the PS II oxidizing side. Possibly damage is also inflicted to the PS II reaction center.
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| 9. |
- Buffoni Hall, Roberta, et al.
(författare)
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UV-induced changes in pigment content and light penetration in the fruticose lichen Cladonia arbuscula ssp. mitis
- 2002
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Ingår i: Journal of Photochemistry and Photobiology, B: Biology. - 1011-1344. ; 66:1, s. 13-20
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Tidskriftsartikel (refereegranskat)abstract
- The response of the lichen, Cladonia arbuscula (Wallr.) Flot. ssp. mitis (Sandst.) Ruoss to enhanced UV-B (280-315 nm) radiation was investigated with respect to: (a) changes in phenolic content; (b) differential pigment accumulation under visible and UV radiation with increasing distance from thallus apices; and (c) the internal distribution of UV-B radiation within the thallus measured with quartz optical fibres. In a short-term experiment, lichens were exposed for 7 days in a growth chamber to visible light with or without additional UV-B radiation. For a longer term experiment, lichens were grown outdoors under both natural UV radiation, and supplemental UV-A (315–400 nm)+UV-B provided by lamps. Controls were placed under filters that removed the radiation below 290 nm from the natural sunlight. The concentration of total phenolic compounds was measured spectrophotometrically at the termination of the experiments, in different parts of the lichen podetia. UV-exposed lichens showed increased accumulation of phenolics compared to those not grown under UV. At the termination of the long-term experiment, fibre optic measurements of the penetration of radiation into lichen thallus reflected the influence of growth under UV radiation, whereby UV was more strongly attenuated as compared to that in lichens not exposed to enhanced levels of UV-B radiation. Results indicated that in Cladonia, UV-B radiation induces the accumulation of phenolic compounds that may have a protective role. In addition, the morphological distribution of phenolic compounds was different under visible and supplemental UV-B radiation. Internal radiation measurements served to visualise the attenuation of radiation with thallus depth for different wavelengths in the UV-B waveband.
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| 10. |
- Buffoni Hall, Roberta, et al.
(författare)
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Water- and temperature-dependence of DNA damage and repair in the fruticose lichen Cladonia arbuscula ssp mitis exposed to UV-B radiation
- 2003
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317. ; 118:3, s. 371-379
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Tidskriftsartikel (refereegranskat)abstract
- The induction of cyclobutane pyrimidine dimers (CPDs) by ultraviolet-B radiation (UV-B, 280-315 nm) and repair mechanisms were studied in the lichen Cladonia arbuscula ssp. mitis exposed to different temperatures and water status conditions. In addition, the development and repair of CPDs were studied in relation to the different developmental stages of the lichen thallus podetial branches. Air-dried lichen thalli exposed to UV-B radiation combined with relatively high visible light (HL, 800 mumol m(-2) s(-1); 400-700 nm) for 7 days showed a progressive increase of CPDs with no substantial repair, although HL was present during and after irradiation with UV-B. Fully hydrated lichen thalli, that had not been previously exposed to UV-B radiation for 7 days, were given short-term UV-B radiation treatment at 25degreesC, and accumulated DNA lesions in the form of CPDs, with repair occurring when they were exposed to photoreactivating conditions (2 h of 300 mumol m(-2)s(-1), 400-700 nm). A different pattern was observed when fully hydrated thalli were exposed to short-term UV-B radiation at 2degreesC, in comparison with exposure at 25degreesC. High levels of CPDs were induced at 2degreesC under UV-B irradiation, without significant repair under subsequent photoreactivating light. Likewise, when PAR (300 mumol m(-2)s(-1) ) and UV-B radiation were given simultaneously, the CPD levels were not lowered. Throughout all experiments the youngest, less differentiated parts of the lichen thallus - namely 'tips', according to our arbitrary subdivision - were the parts showing the highest levels of CPD accumulation and the lowest levels of repair in comparison with the older thallus tissue ('stems'). Thus the experiments showed that Cladonia arbuscula ssp. mitis is sensitive to UV-B irradiation in the air-dried state and is not able to completely repair the damage caused by the radiation. Furthermore, temperature plays a role in the DNA damage repairing capacity of this lichen, since even when fully hydrated, C. arbuscula ssp. mitis did not repair DNA damage at the low temperatures.
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