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KMID : 1161519980020040455
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Animal Cells and Systems
1998 Volume.2 No. 4 p.455 ~ p.462
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Influence of light regime on nitrate reductase activity and organic and inorganic solute composition of four sedges (carex spp.)
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Choo Yeon-Sik
Albert Roland
Song Seung-Dal
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Abstract
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A survey was conducted on the inorganic and organic solute patterns of plants in connection with nitrate metabolism according to different light regimes (1.9, 16.0, 91.5 Wm?2). Besides measuring in vivo NRA, we also quantitatively analyzed water?soluble inorganic ions, organic acids, low molecular weight carbohydrates, amino acids and total N (% DW). Among 4 Carex species, C. pilosa is known as a shade?adapted species and the others as half (C. gracilis) to full (C. rostrata & C. distans) light?adapted specjes. Compared to species adapted to high light intensity, shade?adapted C. pilosa showed reduced productivity under the highest light intensity. In general, nitrate and amino acid levels decreased at higher light intensity, while sugar and organic acid concentrations increased. In C. pilosa osmolality tended to rise with increasing light intensity, while in the other species it tended to fall. Under low light intensity, the drop in soluble carbohydrate contents is osmotically compensated for by an enhanced nitrate concentration. It is concluded that competition between nitrate and CO2 reduction for reductants and ATP from photosynthesis may have important ecological consequences for the adaptation of plants to low or high light conditions. Additionally, the patterns of ionic changes due to Increased light intensities were essentially the same in all selected species, indicating similar characteristics of their mineral ion and organic acid metabolism as well as in field?grown Carex species.
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KEYWORD
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Light regime, Nitrate reductase activity (NRA), Carex, Mineral metabolism, Organic solutes, Ionic balance
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