The interactive effects of UV-B radiation and a herbicide on uptake and allocation of carbon in two strains of the green algaScenedesmus |
| |
Authors: | Fumie Kasai Michael T Arts |
| |
Institution: | (1) National Institute for Environmental Studies, 305 Tsukuba, Ibaraki, Japan;(2) National Hydrology Research Institute, 11 Innovation Blvd., S7N 3H5 Saskatoon, SK, Canada |
| |
Abstract: | We examined the effects of UV B radiation on14C-uptake rates and carbon assimilation into the major end-products of photosynthesis of the green algaScenedesmus in the presence and absence of the triazine herbicide simetryn. Experiments were conducted using both a herbicide-susceptible
and herbicide-tolerant strains ofScenedesmus. Three different UV-B dose rates were used as well as a light control. The lowest dose rate was almost the same level as
in subsurface of ponds and lakes, while the other two were slightly lower and higher than natural sunlight on the surface
of ponds and lakes, respectively. Total uptake rates of14C were not reduced by the UV B irradiation alone even at the highest dose rate. However, in the presence of the herbicide,
uptake rates were clearly reduced by the highest dose rate of UV-B concomitant with increasing herbicide concentrations in
the herbicide-susceptible strain. On the other hand, the proportion of lipid fraction was slightly reduced by all the UV-B
treatments in the herbicide-susceptible strain even in the absence of the herbicide. In the herbicide-tolerant strain, uptake
rates were not affected by UV-B radiation or by the herbicide. These facts indicated that UV-B effects could be smaller than
predicted. It may be important to examine combined effects of UV-B and other anthropogenic and/or natural stresses for assessing
actual UV-B effects in the field. |
| |
Keywords: | sherbicide tolerance photosynthesis phytoplankton simetryn triazine herbicides ultraviolet radiation |
本文献已被 SpringerLink 等数据库收录! |
|