Changes in cytokinin activity during flower development in Cosmos sulphureus Cav

Abstract

Endogenous cytokinin activity was determined in the flowers of Cosmos sulphureus Cav. from bud emergence to full bloom using the soybean callus bioassay. Cytokinin activity was low early in flower development but increased prior to full bloom. In Sephadex LH-20 column chromatography of flower extracts, the cytokinins present co-eluted with zeatin, zeatin riboside and glucoside cytokinin. While the former two predominated prior to full bloom, cytokinin glucoside activity appeared to be at a maximum at full bloom. The possible relevance of these findings is discussed in relation to flower development.

Overproduction of Cytokinins in Petunia Flowers Transformed with PSAG12-IPT Delays Corolla Senescence and Decreases Sensitivity to Ethylene

“…An inverse relationship between cytokinin content and senescence occurs in some flowers (Van Staden et al, 1988). Cytokinin content in roses (Mayak et al, 1972), carnation (Van Staden and Dimalla, 1980), and Cosmos sulfureus (Saha et al, 1985) is greatest in young flowers and decreases during corolla opening and development. Article, publication date, and citation information can be found at www.plantphysiol.org/cgi…”

Nutrient remobilization during development and senescence of Petunia x hybrida floral organs

“…Several approaches have been used to study the effect of cytokinins in plant senescence, such as exogenous application of cytokinin solutions, measurement of endogenous cytokinins during senescence, and transgene-encoded cytokinin biosynthesis (McCabe et al, 2001). Cytokinin concentration in roses (Mayak et al, 1972), carnation (Van Staden and Dimalla, 1980), and Cosmos sulfureus (Saha et al, 1985) is greatest in young flowers and decreases during corolla opening and development. Exogenously supplied cytokinin suppresses senescence in cut carnation flowers (Van Staden et al, 1988) and delays senescence of Petunia corollas (Taverner et al, 1999).…”