Regenerative Capacity of Cacti Schlumbergera and Rhipsalidopsis in Relation to Endogenous Phytohormones, Cytokinin Oxidase/Dehydrogenase, and Peroxidase Activities

0050699 - ÚEB 2007 RIV US eng J - Journal Article
Sriskandarajah, S. - Prinsen, E. - Motyka, Václav - Dobrev, Petre - Serek, M.
Regenerative Capacity of Cacti Schlumbergera and Rhipsalidopsis in Relation to Endogenous Phytohormones, Cytokinin Oxidase/Dehydrogenase, and Peroxidase Activities.
[Regenerační schopnost kaktusů Schlumbergera a Rhipsalidopsis a její vztah k obsahu endogenních fytohormonů a enzymové aktivitě cytokininoxidázy/dehydrogenázy a peroxidázy.]
Journal of Plant Growth Regulation. Roč. 25, č. 1 (2006), s. 79-88. ISSN 0721-7595. E-ISSN 1435-8107
R&D Projects: GA ČR GA206/03/0313
Institutional research plan: CEZ:AV0Z50380511
Keywords : Cytokinin dehydrogenase * Cytokinin oxidase * Endogenous phytohormones * In vitro regeneration * Peroxidase * Rhipsalidopsis * Schlumbergera
Subject RIV: EF - Botanics
Impact factor: 2.107, year: 2006

The recalcitrant nature and increased regenerative capacity in relation to in vitro subcultures in two cactus genera Rhipsalidopsis (Easter cactus) and Schlumbergera (Christmas cactus) were studied by examining the endogenous concentrations of several endogenous phytohormones and enzyme activities. Leaf tissue from greenhouse-grown mother plants, in vitro subcultures 1 and 3, and callus tissues were analyzed and correlated with regenerative ability. The cytokinins present in the two cacti genera were mainly isopentenyl-type derivatives. The total content of isopentenyl-type cytokinins in greenhouse-grown leaves of Rhipsalidopsis was more than twice the amount found in greenhouse-grown leaves of Schlumbergera. The total cytokinin content decreased during subculturing. Cytokinin oxidase/dehydrogenase (CKX, EC 1.4.3.18/1.5.99.12) activity increased during subculturing. In Schlumbergera there is no effect of subculturing on CKX and related cytokinin homeostasis. The total peroxidase (POX, EC 1.11.1.7) activity in greenhouse-grown leaves of both genera was low, and the activity increased significantly during subculturing, more specifically in the tissue of Rhipsalidopsis. The results clearly indicated that an enhanced auxin metabolism (biosynthesis, conjugation/deconjugation, and POX activity), in combination with an enhanced CKX activity, shifts the auxin and cytokinin pool, favoring adventitious shoot formation in Rhipsalidopsis, whereas the low level of POX activity, together with auxin autotrophy/conjugation, makes Schlumbergera more recalcitrant.

Na základě stanovení endogenních koncentrací fytohormonů a aktivit vybraných enzymů zapojených do jejich metabolismu byly studovány rozdíly v regeneraci in vitro kultur u dvou rodů kaktusů Rhipsalidopsis (velikonoční kaktus) a Schlumbergera (vánoční kaktus). U obou rodů lišících se podstatně svou regenerační schopností byla zjištěna výrazná závislost mezi regenerací in vitro kultur, metabolismem endogenních cytokininů a auxinů a enzymovou aktivitou cytokininoxidázy/dehydrogenázy (CKX; EC 1.4.3.18/1.5.99.12) a peroxidázy (POX; EC 1.11.1.7). Zatímco odolnost vůči regeneraci nebo špatná regenerační schopnost kultury Schlumbergera byla spojena s nízkou aktivitou POX a s autotrofií k auxinu, výborná regenerační schopnost a zvýšená produkce adventivních výhonů kultury Rhipsalidopsis souvisela se stimulací metabolismu (biosyntézy, konjugace/dekonjugace a aktivity POX) auxinu a s indukcí aktivity CKX.
Permanent Link: http://hdl.handle.net/11104/0140777