caa a22 4500 397522576 CHVBK 20180308164637.0 cr unu---uuuuu 161202e199512 xx s 000 0 eng 10.1093/jxb/46.12.1803 doi (NATIONALLICENCE)oxford-10.1093/jxb/46.12.1803 Organic nitrogen reserves and their mobilization during sprouting of purple nutsedge (Cyperus rotundus L.) tubers [Elektronische Daten] [Andreas Fischer, Renaud Brouquisse, Philippe Raymond] Purple nutsedge is a perennial weed propagating vegetatively by an extended network of rhizomes and tubers. Large quantities of starch are stored in the tubers, but the properties of nitrogen reserves and their importance for early plant growth have received little attention in the past. Organic nitrogen compounds were studied in mature tubers by protein determination, SDS-PAGE and amino acid quantification and separation using reversed-phase HPLC. Changes in these compounds were followed in sprouting tuber pieces fed with a complete nutrient solution (containing nitrate, control) or with a nutrient solution without nitrogen source. As judged by gel electrophoresis or direct protein quantification, some net protein degradation occurred after 2-4 weeks of sprouting in the presence or absence of exogenous N. Amino acids decreased much faster, especially during the first 2 weeks. The major amino acids were arginine and asparagine, which together accounted for 70% of total amino acids at day 0, and which had almost disappeared after 4 weeks of sprouting. Sprout growth depended strongly on the availability of exogenous nitrogen during the second week. The results indicate that amino acids are the main N storage form of purple nutsedge tubers and, essentially, that no storage proteins are present. Future investigations on the N metabolism of sprouting nutsedge should focus on arginine and asparagine metabolism and eventually on nitrogen assimilation, which becomes important in an early phase of plant growth. © Oxford University Press Research Papers nationallicence Cyperus rotundus L nationallicence arginine nationallicence asparagine nationallicence nitrogen assimilation nationallicence storage proteins nationallicence Fischer Andreas Station de Physiologie Végétale, INRA-CR de Bordeaux-BP 81, F-33883 Villenave d'Ornon Cedex, France aut Brouquisse Renaud Station de Physiologie Végétale, INRA-CR de Bordeaux-BP 81, F-33883 Villenave d'Ornon Cedex, France aut Raymond Philippe Station de Physiologie Végétale, INRA-CR de Bordeaux-BP 81, F-33883 Villenave d'Ornon Cedex, France aut Journal of Experimental Botany Oxford University Press 46/12(1995-12), 1803-1808 0022-0957 46:12<1803 1995 46 exbotj https://doi.org/10.1093/jxb/46.12.1803 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1093/jxb/46.12.1803 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Fischer Andreas Station de Physiologie Végétale, INRA-CR de Bordeaux-BP 81, F-33883 Villenave d'Ornon Cedex, France aut NATIONALLICENCE 700 1- Brouquisse Renaud Station de Physiologie Végétale, INRA-CR de Bordeaux-BP 81, F-33883 Villenave d'Ornon Cedex, France aut NATIONALLICENCE 700 1- Raymond Philippe Station de Physiologie Végétale, INRA-CR de Bordeaux-BP 81, F-33883 Villenave d'Ornon Cedex, France aut NATIONALLICENCE 773 0- Journal of Experimental Botany Oxford University Press 46/12(1995-12), 1803-1808 0022-0957 46:12<1803 1995 46 exbotj Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford