Premium
Influence of senescence and of carbohydrate levels on the pattern of leaf proteases in purple nutsedge ( Cyperus rotundus )
Author(s) -
Fischer Andreas,
Brouquisse Renaud,
Raymond Philippe
Publication year - 1998
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1998.1020307.x
Subject(s) - biology , senescence , perennial plant , botany , proteases , weed , cyperus rotundus , protease , proline , biochemistry , enzyme , microbiology and biotechnology , horticulture , amino acid
Cyperus rotundus L. is a monocotyledonous perennial weed, which forms large numbers of tubers during its vegetative growth. Since these tubers represent major sinks, source/sink interactions are more complex, and leaf senescence and proteolytic processes in this species may be different from the situation in the well‐investigated annual crop plants characterized by monocarpic senescence. Judged by native PAGE and by inhibitor studies, three different aminopeptidases, one iminopeptidase, two or more carboxypeptidases and two or more different endopeptidases were present in mature green leaves. Exo‐ and endoproteolytic activities increased during the senescence of excised leaf segments. A marked change was observed in the endopeptidase pattern, since a cysteine proteinase activity was strongly induced during senescence of the segments. This endopeptidase was also found in naturally senescing leaves and may, therefore, participate in nitrogen salvage from these organs. An increase of different protease activities was demonstrated in leaf segments of C. rotundus in the presence of high carbohydrate levels. The mechanisms involved, and the importance of this phenomenon for the interaction between source/sink relations and senescence, remain to be demonstrated.