No abstract

This study compares effects of 2,3,5-triiodobenzoic acid (TIBA) and flavonoid quercetine (Q). In spite of the fact that both these compounds are inhibitors of the polar transport of auxin, a number of experiments demonstrated that their properties are different. If the flax seedlings were decapitated and one cotyledon was removed, the axillary bud of the remaining cotyledon grew up more intensively while TIBA (0.5% applied in the form of a lanolin paste on the remaining cotyledon) induced a correlative reversal so that axillars of removed cotyledons grew up more intensively. However, when Q (0.5%) was applied on the remaining cotyledon in the form of a lanolin paste, this inhibition was not significant. In the lamina-deprived petioles of apple trees TIBA accelerated abscission while Q caused an inhibiting effect similar to that of auxin. TIBA applied on epicotyls of pea seedlings inhibited their growth by 35% while Q only by 15%. As far as the release of ethylene by pea seedlings is concerned, both compounds showed promoting effects similar to the effect of auxin.

No abstract

An increased growth of marginal buds on excised leaves from vegetative plants of Bryophyllum crenatum following transversal separation of leaf blades into three segments (apical, medial and basal) as compared with non-separated leaves, was associated with increased endogeneous cytokinin-like substances. This cycokinin increase can be demonstrated seven days after the separation and before the growth of marginal bud primordia. The level of endogenous cytokinin-like substances increases in a similar direction as the formation and growth of marginal buds, from the base of leaf blade to its apex.Zusammenfassung. Der Anstieg von Marginalknospenbildung an den von den vegetativen Pflanzen Bryophyllum crenatum isolierten Blattern, der durch eine Querteilung der Blattspreiten in drei Segmente (apikales, mittleres und basales) gegeniiber den intakten Kontrollblattspreiten nachweisbar ist, ist mit dem Anstieg der endogenen Zytokininahnlichen Stoffe verkniipft. Diesen Anstieg des Zytokininspiegels in der geteilten Blattspreite, gegenuber der intakten, kann man binnen sieben Tage nach der Querteilung der Blattspreite beweisen, d.h. in der Zeit vor dem Wachstum der Marginalknospenanlagen. Der endogene Zytokininspiegel steigt dabei von der Basis zum Apex der Blattspreite an, 5hnlich wie die MarginaJknospenbildung.