نتایج جستجو برای: uv radiation

تعداد نتایج: 299907  

2013
Marius Hedimbi Shyam Singh A. Kent

The laser induced fluorescence (LIF) spectra from plants give accurate information on the influences of ultraviolet A (UV-A) and ultraviolet B (UV-B) radiation on the growth of maize plants. In this paper, a thorough LIF study has been done on maize plants grown under controlled conditions. The maize (Zea mays) seeds were planted and exposed to UV-A and UV-B radiation from 0 to10 hours. The dec...

2008
K. MAHDAVIAN M. GHORBANLI Kh. M. KALANTARI

Plants have evolved mechanisms to avoid and repair UV radiation damage; it is not surprising that photomorphogenic responses to UV-B and UV-C are often assumed to be adaptations to harmful radiation. Free radicals generated by UV are likely to be involved in the induction of antioxidant defence system. In this study plants were grown for 5 weeks in controlled conditions. Plants were grown in ve...

ژورنال: ارگونومی 2015
حسام, قاسم, علی آبادی, امیر, مرادپور, زهرا,

Introduction: Welding is considered to be one of the main sources of occupational exposure to non ionizing radiations. The present study was conducted to examine the rate of occupational exposure to non-ionizing radiation in common welding processes. Materials and Methods: In the present descriptive analytical study, occupational exposure to different types of non-ionizing radiations in...

Journal: :Applied and environmental microbiology 2000
T A Slieman W L Nicholson

The loss of stratospheric ozone and the accompanying increase in solar UV flux have led to concerns regarding decreases in global microbial productivity. Central to understanding this process is determining the types and amounts of DNA damage in microbes caused by solar UV irradiation. While UV irradiation of dormant Bacillus subtilis endospores results mainly in formation of the "spore photopr...

2005

As a result of stratospheric ozone depletion, more solar ultraviolet-B radiation (UV-B, 280–315 nm) is reaching the Earth’s surface. Enhanced levels of UV-B may, in turn, alter ecosystem processes such as decomposition. Solar UV-B radiation could affect decomposition both indirectly, by changes in the chemical composition of leaves during growth, or directly by photochemical breakdown of litter...

Journal: :Photochemistry and photobiology 2000
A G Ivanov E Miskiewicz A K Clarke B M Greenberg N P Huner

Plectonema boryanum UTEX 485 cells were grown at 29 degrees C and 150 mumol m-2 s-1 photosynthetically active radiation (PAR) and exposed to PAR combined with ultraviolet-A radiation (UV-A) at 15 degrees C. This induced a time-dependent inhibition of photosystem II (PSII) photochemistry measured as a decrease of the chlorophyll a fluorescence ratio, Fv/Fm, to 50% after 2 h of UV-A treatment com...

In this work, photostability, absorption and emission intensity of coated polycarbonate (PC) sheets with optical brightener (OB) as a wavelength converter material have been investigated. In addition, this coated sheet was used as a wall for microalgae culture flask, as a small scale photobioreactor, for studying the spectral conversion of UV-A radiation to blue light region and its effect ...

Journal: :Photochemistry and photobiology 1987
J Lydon A H Teramura C B Coffman

The effects of UV-B radiation on photosynthesis, growth and cannabinoid production of two greenhouse-grown C. sativa chemotypes (drug and fiber) were assessed. Terminal meristems of vegetative and reproductive tissues were irradiated for 40 days at a daily dose of 0, 6.7 or 13.4 kJ m-* biologically effective UV-B radiation. Infrared gas analysis was used to measure the physiological response of...

2017
Tomáš Václavík Michael Beckmann Anna F Cord Anja M Bindewald

Ultraviolet-B (UV-B) radiation is a key but under-researched environmental factor that initiates diverse responses in plants, potentially affecting their distribution. To date, only a few macroecological studies have examined adaptations of plant species to different levels of UV-B. Here, we combined herbarium specimens of Hieracium pilosella L. and Echium vulgare L. with a novel UV-B dataset t...

Journal: :Molecules 2014
Guillaume Marti Sylvain Schnee Yannis Andrey Claudia Simoes-Pires Pierre-Alain Carrupt Jean-Luc Wolfender Katia Gindro

UV-C radiation is known to induce metabolic modifications in plants, particularly to secondary metabolite biosynthesis. To assess these modifications from a global and untargeted perspective, the effects of the UV-C radiation of the leaves of three different model plant species, Cissus antarctica Vent. (Vitaceae), Vitis vinifera L. (Vitaceae) and Cannabis sativa L. (Cannabaceae), were evaluated...

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