Evidence of cytokinin bases, ribosides and glucosides in roots of Douglas-fir, Pseudotsuga menziesii

Novel cytokinins: The predominant forms in mature buds of Pinus radiata

To elicit the roles of cytokinins in the regulation of maturation of Pinus radiata D. Don, the spectrum of endogenous cytokinins and their concentration in the mature buds were analysed using double-solvent extraction, column complex purification and separation, a novel immunoaffinity purification method, normal and reverse phase high-pressure liquid chromatography, enzymatic treatment, radioimmunoassay and electrospray MS/MS spectrometry. We have isolated two novel cytokinin glycosides whose proposed structures are isopentenyladenine-9-(glucopyranosyl riboside), dihydrozeatin-9-(glucopyranosyl riboside) and confirmed the presence of zeatin-9-(glucopyranosyl riboside). We have also found the presence of novel phosphorylated forms of these 3 cytokinin ribosyl-linked glycosides. Quantitative analyses revealed that the cytokinin ribosyl-linked glycosides predominate in P. radiata mature buds. Although cytokinin free base, riboside and nucleotide forms are also present, we could find no evidence of the traditional cytokinin O- or N-glucosides in the conifer buds. Thus, cytokinin metabolism in mature buds of P. radiata is very different from other species previously examined.

Comparison of oriented and random antibody immobilization in immunoaffinity chromatography of cytokinins

Immunosorbents for the plant hormones cytokinins prepared by random antibody immobilization (to Affi-Gel 10) and by oriented approach via oxidized carbohydrate moieties on the Fc region (to Affi-Gel Hz or hydrazide derivative of Perloza MT 200) have been compared. Both approaches yielded immunosorbents with high dynamic capacity (ca. 5-10 nmol ml gel-1). Oriented antibody immobilization did not exhibit crucial effects in the case of low-molecular-mass cytokinins. Antibodies immobilized via a spacer to Affi-Gel 10 have probably enough conformational freedom to enable good accessibility to cytokinins. The sorbents were used in analysis of endogenous cytokinins in maize seeds. In phosphatase treated samples trans-zeatin and its riboside were predominant.