Abstract. In vitro vegetative multiplication of sugarbeet was obtained by culturing of inflorescence explants. Subapical segments or 5-mm-long tips from nine varieties developed axillary shoots (up to 50 per tip) on a medium containing indolebutyric acid (IBA) and benzylaminopurine (BAP). Zeatin was ineffective as cytokinin. Gibberellic acid (GA 3) enhanced the process. Such vegetative shoots were subsequently isolated and were each allowed to develop up to 20 supplementary axillary shoots on a multiplication medium containing IBA, BAP, and naphthaleneacetic acid (NAA). Rooting of shoots was obtained in the absence of growth regulators and plants were established.

Germination capacity, and α‐amylase production in relation to the peroxidase and isoperoxidase activities in the grains of three varieties of wheat have been analysed and compared. A high percentage of germination and α‐amylase producation at 25°C are associated with low peroxidase activity of the isolated embryo. This correlation is lacking when the intact grain is considered. A 2‐day treatment at 4°C which further increases the percentage germination and enhances α‐amylase synthesis, lowers the activity of peroxidase in the embryos. A general decrease in activity of all the isoenzymes is observed. Based on the above data and on differences in the activity of the most cathodic isoperoxidasic bands, a hypothesis is put forward which suggests that a sufficiently low peroxidase activity and a minimum auxin level of the embryo are responsible for the onset of germination.

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