Changes in Cytokinin Distribution in the Ovule and Ovary of Taraxacum officinale Web. in Early Stages of Embryogenesis

M. A. Gussakovskaya^* and A. N. Blintsov

Department of Plant Physiology, School of Biology, Lomonosov Moscow State University, Moscow, 119899 Russia; E-mail: radames@mail.ru

^* To whom correspondence should be addressed.

Received May 19, 2000; Revision received July 17, 2000

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Quantitative changes in the hormonal status of the ovules and ovaries were first studied in Taraxacum officinale Web. at the early stages of embryogenesis. The plant material was analyzed by ELISA using labeled anti-rabbit antibodies. A new procedure for differential and quantitative determination of the main endogenous cytokinins based on the estimation of the effective zeatin and zeatin riboside concentrations from calibration curves constructed using zeatin and zeatin riboside as standard antigens was developed. It was shown that, at the three initial stages of embryogenesis examined, the concentration of zeatin uniformly increased in T. officinale ovules. The concentration of zeatin riboside, conversely, uniformly decreased. However, their total concentration changed insignificantly. A gradual increase in the concentration of the active and storage hormone forms from the ovary to the ovule was shown.

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KEY WORDS: Taraxacum officinale, ovule, ovary, endogenous hormones, zeatin, zeatin riboside, ELISA, immunochemical micro method for differential and quantitative determination of zeatin and zeatin riboside

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