نتایج جستجو برای: uv radiation
تعداد نتایج: 299907 فیلتر نتایج به سال:
Effects of ozone depletion and increase of UV radiation have been studied by many researchers. The aim of this study was to investigate the effects of UV-B radiation on Melissa officinalis L. as well as the impact of salicylic acid and magnetic fields in the reduction of harmful effects of radiation on plants. The Melissa officinalis L. plants were treated with 28 ± 2 Cº for approxi...
objective: on a global scale, stratospheric ozone depletion has caused an increase in uv-b radiation reaching the earth's surface. ultraviolet radiation has long been suspected to be harmful to aquatic organisms. materials and methods: in order to study ionocyte localization (by na+/k+-atpase immunolocalization) and the effects of uv radiation on the ionocytes of skin and gills, the alevins of ...
Studies of the UV-radiation are the most actual ecological problems that are called by ozone depletion increasing the level of biologically active solar UV-B radiation in the biosphere. The air pollution and atmospheric aerosols prevent penetrating appropriate dose UV radiation, which is beneficial for people, specifically due to production of vitamin D3 in skin from its precursor 7dehydrochole...
—Numerous anthropogenic and natural factors affect living organisms in nature. Anthropogenic factors include a wide array of contaminants and processes that alter the habitat on both local and global scales. For example, chlorofluorocarbons (CFCs) and other industrial gases contribute to the depletion of the earth’s protective ozone layer, resulting in increased amounts of cell damaging ultravi...
Although ultraviolet radiation is potentially harmful, it is an important component of terrestrial radiation to which plants have been exposed since invading land. Since then, plants have evolved mechanisms to avoid and repair UV radiation damage. Therefore, it is not surprising that photomorphogenic responses to UV-B and UV-C are often assumed to be adaptations to harmful radiation. Most of th...
Ultraviolet (UV) radiation is part of the electromagnetic spectrum. The biological effects of UV radiation vary enormously with wavelength and for this reason the UV spectrum is further subdivided into three regions: UVA, UVB, and UVC. Quantities of UV radiation are expressed using radiometric terminology. A particularly important term in clinical photobiology is the standard erythema dose (SED...
BACKGROUND AND AIMS Ultraviolet-B (UV-B) radiation effect on reproductive parts of the plants has received little attention. We studied the influence of UV-B radiation on flower and pollen morphology, pollen production and in vitro pollen germination and tube growth of six genotypes of soybean (Glycine max). METHODS Soybean genotypes were investigated by growing them under four levels of biol...
Attenuation of UV-B radiation in the water column occurs due to absorption and scatter but in shallow clear freshwater systems enhanced UV-B radiation might be of importance in affecting aquatic organisms. Two laboratory experiments were performed to determine whether two species of charophytes typical for shallow waterbodies, such as Chara polyacantha and Nitella hyalina, are negatively affect...
UV-B radiation affects crop plants. Growing interest has been shown in studying the effectsof UV-B radiation exclusion on crops since 1993. This article summarized the generalconsequences of UV-B radiation exclusion on crop plants from the aspacts of plant morphology,growth and development. UV-B exlusion has promoting effects on plant height, internodeand leaf size. UV-B exclusion increases roo...
Ultraviolet (UV) radiation can cause stresses or act as a photoregulatory signal depending on its wavelengths and fluence rates. Although the most harmful effects of UV on living cells are generally attributed to UV-B radiation, UV-A radiation can also affect many aspects of cellular processes. In cyanobacteria, most studies have concentrated on the damaging effect of UV and defense mechanisms ...
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