Summary
Contrary to general concepts, gibberellic acid solution by single foliar spray does
not induce the typical „gibberellin effects” on several drug plants. Refractive to
a single treatment were found in this study Ricinus communis, Pimpinella anisum, Foeniculum vulgäre, Coriandrum sativum, Sesamum
indicum, Plantago spp, Linum usitatissinum, Salvia officinalis, Thymus vulgaris, Lavandula
officinalis, and Carthamus tinctorius.
The responses of two umbelliferous plants, fennel and coriander under controlled greenhouse
conditions are reported in detail. These plants which were refractive to single treatment
received foliar sprays of 100 p.p.m. G.A. twice weekly, eliciting a difference of
cauline length of 200–300 %. No significant differences were found with respect to
yield of fruits, the quality and quantity of volatile oils. The same information has
been given for Ricinus communis.
In seed germination experiments, great inter– and intra–genus variability of response
has been noted.
Since the mode of action of gibberellic acid is presently not completely understood,
except that it differs in several respects from that of the auxins, might it be that
the failure of response of several tested plants is due to a varying natural content
of gibberellin or gibberellin–like substances, so that higher external quantities
are needed for conventional response?
Zusammenfassung
Es wird die Reaktion einiger Arzneipflanzenarten auf zweimal wöchentliches Besprühen
mit Gibberellinsäure beschrieben.
