Cytokinins and leaf development in sweet pepper (Capsicum annuum L.)

Abstract

Immunoaffinity purification of zeatin, dihydrozeatin and isopentenyl-type cytokinins from expanding leaves of sweet pepper was accomplished using a single immobilized monoclonal antibody. Isopentenyl adenosine, zeatin, zeatin riboside and the N9-glucosides of zeatin and isopentenyl adenine were found to be the dominating endogenous cytokinins while the dihydrozeatin cytokinins were either absent or constituted a very minor group of cytokinin metabolites in pepper. Leaves were selected for analysis at an age where a range of developmental stages exist within a single leaf. The spatial distribution of endogenous cytokinins in rapidly expanding leaves at this stage was markedly different from the almost uniform distribution in expanded leaves. The distribution of zeatin and zeatin riboside in rapidly expanding leaves was found to be correlated with the rate of leaf expansion which is high (∼40%/24 h) in the basal leaf tissue and low (∼10%/24 h) near the leaf tip. Applied growtn factors supported a rate of expansion of excised discs comparable to the growth rates observed in situ, but did not affect the ability of the tissue to retain assimilated amino acids. The results are discussed in relation to sink-strength stimultation as a potential mode of cytokinin action in leaf development.

Levels of endogenous cytokinins, indole‐3‐acetic acid and abscisic acid during the cell cycle of synchronized tobacco BY‐2 cells

“…After centrifugation (24000×g, 4°C, 20 min), organic solvent from the supernatant was evaporated in vacuo and the pH of the resulting water phase was adjusted to 7. This extract was loaded on a combination of a pre-immune serum column, an IAA immunoaffinity column [19] and an ABA immunoaffmity column [20]. The effluent, containing the cytokinins, was then further purified on a combination of a DEAE sephadex (2 ml, HCO3-form) and a RP-C18 column.…”

Analysis of Cytokinin Metabolism in ipt Transgenic Tobacco by Liquid Chromatography-Tandem Mass Spectrometry

“…The eluate was concentrated in vacuo until the water phase and applied to a combination of a nonimmune column (1 mL), an immunoaffinity column (0.5 mL), and an RP C,, column. The immunoaffinity columns were prepared with monoclonal anti-ZR antibodies, which were able to bind a broad spectrum of CKs, including a11 major isoprenic and aromatic CK free bases, ribosides, and Nglucosides (Ulvskov et al, 1992; P. Redig, unpublished results). They had a binding capacity of more than 7000 pmol ZR/ mL gel.…”

“…They had a binding capacity of more than 7000 pmol ZR/ mL gel. The nonimmune columns were prepared with bovine y-globulins as described by Ulvskov et al (1992). After washing with 10 mL of water the immunoaffinity column was eluted with 4 mL of ice-cold methanol and immediately reconditioned with water.…”

Changes in expression of two cytokinin-repressed genes, CR9 and CR20, in relation to aging, greening and wounding in cucumber

“…In various plant species, exogenously applied cytokinins delay senescence of leaves (for review, see Hall 1973). It has also been known for a number of plants that levels of endogenous cytokinins are high in young leaves and decrease with the progress of aging (Hewett and Wareing 1973;Henson and Wareing 1976;Singh et al 1992; Ulvskov et al 1992). Both CR9 and CR20 tran-393 scripts accumulated in mature and senescent leaves, while their levels were quite low in young leaves and apical buds, the CR9 transcript being almost undetectable in apical buds (Figs.…”