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Plants and UVB

Many people say that all plants should not be out in the sun – too much UVB
Some people disagree - and say that plants need UVB

In Pursuit of Vitamin D in Plants - 2017

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UV-A radiation effects on higher plants: Exploring the known unknown - Feb 2017

Plant Sci. 2017 Feb;255:72-81. doi: 10.1016/j.plantsci.2016.11.014. Epub 2016 Nov 30.
Verdaguer D1, Jansen MA2, Llorens L3, Morales LO4, Neugart S5.

Ultraviolet-A radiation (UV-A: 315-400nm) is a component of solar radiation that exerts a wide range of physiological responses in plants. Currently, field attenuation experiments are the most reliable source of information on the effects of UV-A. Common plant responses to UV-A include both inhibitory and stimulatory effects on biomass accumulation and morphology. UV-A effects on biomass accumulation can differ from those on root: shoot ratio, and distinct responses are described for different leaf tissues. Inhibitory and enhancing effects of UV-A on photosynthesis are also analysed, as well as activation of photoprotective responses, including UV-absorbing pigments. UV-A-induced leaf flavonoids are highly compound-specific and species-dependent. Many of the effects on growth and development exerted by UV-A are distinct to those triggered by UV-B and vary considerably in terms of the direction the response takes. Such differences may reflect diverse UV-perception mechanisms with multiple photoreceptors operating in the UV-A range and/or variations in the experimental approaches used. This review highlights a role that various photoreceptors (UVR8, phototropins, phytochromes and cryptochromes) may play in plant responses to UV-A when dose, wavelength and other conditions are taken into account.

PMID: 28131343 DOI: 10.1016/j.plantsci.2016.11.014


Molecular mechanisms involved in adaptive responses to radiation, UV light, and heat -2009

J Radiat Res (Tokyo). 2009 Sep;50(5):385-93. Epub 2009 Jun 13.
Takahashi A, Ohnishi T.
Department of Biology, School of Medicine, Nara Medical University, Nara, Japan.

Viable organisms recognize and respond to environmental changes or stresses. When these environmental changes and their responses by organisms are extreme, they can limit viability. However, organisms can adapt to these different stresses by utilizing different possible responses via signal transduction pathways when the stress is not lethal. In particular, prior mild stresses can provide some aid to prepare organisms for subsequent more severe stresses. These adjustments or adaptations for future stresses have been called adaptive responses. These responses are present in bacteria, plants and animals. The following review covers recent research which can help describe or postulate possible mechanisms which may be active in producing adaptive responses to radiation, ultraviolet light, and heat
PMID: 19525615
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Acute exposure to UV-B sensitizes cucumber, tomato, and Arabidopsis plants to photooxidative stress by inhibiting thermal energy dissipation and antioxidant defense.- 2011

J Radiat Res (Tokyo). 2011;52(2):238-48.
Moon YR, Lee MH, Tovuu A, Lee CH, Chung BY, Park YI, Kim JH.
Advanced Radiation Research Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185, Republic of Korea.

To characterize a change in NPQ upon exposure to ultraviolet-B (UV-B), the xanthophyll cycle-dependent and -independent NPQs were compared in Cucumis sativus, Lycopersicum esculentum, and Arabidopsis thaliana leaves. The xanthophyll cycle-dependent NPQ was dramatically but reversibly suppressed by UV-B radiation. This suppression was correlated more strongly with a marked decrease in photosynthetic electron transport rather than changes in xanthophyll cycle enzymes such as violaxanthin de-epoxidase and zeaxanthin epoxidase. Accordingly, the UV-B-induced suppression of NPQ cannot be attributed to changes in expressions of VDE and ZEP. However, suppression of the xanthophyll cycle-dependent NPQ could only account for the 77 K fluorescence emission spectra of thylakoid membranes and the increased level of (1)O(2) production, but not for the decreased levels of •O(2)(-) production and H(2)O(2) scavenging. These results suggest that a gradual reduction of H(2)O(2) scavenging activity as well as a transient and reversible suppression of thermal energy dissipation may contribute differentially to increased photooxidative damages in cucumber, tomato, and Arabidopsis plants after acute exposure to UV-B radiation.
PMID: 21436613
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The effect of ultraviolet radiation on the accumulation of medicinal compounds in plants - 2009

Fitoterapia. 2009 Jun;80(4):207-18. Epub 2009 Feb 23.
Zhang WJ, Björn LO.
Department of Cell and Organism Biology, Sölvegatan 35, SE-22362 Lund, Sweden.

A review is given of how the production by plants of compounds useful as medicines or raw materials for manufacture of medicines is influenced by ultraviolet radiation, particularly by UV-B radiation (280-315 nm wavelength). The compounds considered in this review are flavonoids and other phenolics, alkaloids (especially indole terpenoid and purine alkaloids), essential oils and other terpenoids, cannabinoids, glucosinolates and isothiocyanates, and compounds having human hormone activity. A short account is also given of ultraviolet signalling in plants. The review concludes with a discussion of the possible evolutionary mechanisms that have led to the evolution of UV-B regulation of secondary metabolite accumulation.
PMID: 19243700


Plant stress and human health: Do human consumers benefit from UV-B acclimated crops? 2008

Marcel A.K. Jansena, , , Kathleen Hectorsb, Nora M. O’Brienc, Yves Guisezb and Geert Pottersd
A Department of Zoology, Ecology and Plant Sciences, University College Cork, Distillery Field, North Mall, Cork, Ireland
B Department of Biology, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
C Department of Food and Nutritional Sciences, University College Cork, College Road, Cork, Ireland
D Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
Received 8 January 2008; revised 29 April 2008; accepted 29 April 2008. Available online 4 May 2008.

Plants are sessile organisms, and consequently cannot avoid exposure to stressful environmental conditions. Exposure to mild stress conditions can induce active acclimation responses, while more severe conditions cause metabolic disruptions. A common plant acclimation response to a variety of environmental stressors is the accumulation of antioxidants and secondary metabolites. For example, ultraviolet-B (UV-B) radiation impacts on the levels of a broad range of metabolites, including phenolic, terpenoid and alkaloid compounds. Our survey of the literature reveals that the levels of some of these metabolites increase following UV-B exposure, while those of others decrease, change transiently or are differently affected by low and high UV-doses. This includes several compounds that are pharmacologically active and/or nutritionally important. We conclude that the complex patterns of stress-induced changes in plant metabolites need to be studied in more detail to determine impacts on the nutritional and pharmacological characteristics of food products. Claims that UV-B acclimated plants have nutritional benefits are currently unproven.


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  • LED Grow Light Spectrum - added Nov 2011

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from Mercola
Short url = http://is.gd/plantsuvb

Attached files

ID Name Comment Uploaded Size Downloads
8244 In Pursuit of Vitamin D in Plants.pdf PDF 2017 admin 03 Aug, 2017 01:44 1.15 Mb 146
2566 Vitamin D3 and plant growth.gif admin 08 Jun, 2013 20:22 10.88 Kb 2353
883 LED-Grow-lights-diy.jpg LED Grow Lights admin 16 Nov, 2011 14:34 33.76 Kb 4401
535 UVB science fair project - 2009.pdf Science Fair admin 20 May, 2011 18:52 14.06 Kb 682
534 Effects of Ultraviolet-B Radiation on Photobiology - 2009.pdf Photobiology admin 20 May, 2011 18:51 159.47 Kb 2075
533 grasses like UVB.PDF GRASSES admin 20 May, 2011 18:50 7.95 Mb 2650
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