Induction of "filamentous structures" in wild type Antirrhinum majus flowers by benzylaminopurine

Abstract

The cytokinin, N 6 -benzylaminopurine (BAP), when applied to young inflorescences of wild-type Antirrhinum majus L., resulted in the formation of chimeric "filamentous structures" in the dorsal region of the third whorl, the position where a stamen primordium is suppressed in wild-type flowers. In addition, BAP induced similar filamentous structures in between the first and second whorls, and this response was concentration dependent. The basal region of the filamentous structures was similar to the filament of a stamen, while the distal portion resembled a petal. These observations suggest that cytokinins may be site-specific factors involved in the regulation of floral organ identity genes or genes that control floral symmetry, i.e., the CYCLOIDEA gene.Résumé : Lorsqu'on applique la cytokinine, N 6 -benzylaminopurine (BAP), sur de jeunes inflorescences du type sauvage de l'Antirrhinum majus, il se forme une « structure filamenteuse » chimérique dans la région dorsale du troisième verticille, la position où un primordium d'étamine supprimé se retrouve chez les fleurs du type sauvage. De plus, la BAP induit une structure filamenteuse similaire entre le premier et le second verticilles, et cette réaction dépend de la concentration. La région basale de la structure filamenteuse était similaire au filament de l'étamine alors que la portion distale est pétaloïde. Ces observations suggèrent que les cytokinines peuvent être des facteurs spécifiques aux sites impliqués dans la modulation des gènes impliqués dans l'identité des organes floraux, ou des gènes qui contrôlent la symétrie florale, i.e., le gène CYCLOIDEA.

The role of cytokinin during Arabidopsis gynoecia and fruit morphogenesis and patterning

“…Other studies have shown that application of BAP to developing inflorescences results in changes in floral organ identity and number, explained by extended meristematic activity (Venglat and Sawhney, 1996;Blahut-Beatty et al, 1998;Lindsay et al, 2006). Interestingly, BAP-treated mature flowers and fruits did not produce ectopic tissue (this study), suggesting that cytokinins have a proliferation-inducing activity in young gynoecia only, where the medial tissues show meristematic characteristics.…”

“…Other studies have shown that application of BAP to developing inflorescences results in changes in floral organ identity and number, explained by extended meristematic activity (Venglat and Sawhney, 1996; Blahut‐Beatty et al. , 1998; Lindsay et al.…”

Influence of metabolic stress on the inheritance of cell determination in the moss,

“…As far as the effect of the transitory action of 10 mM kinetin on expression of apogamy is concerned (Fig. 8), it is relevant to note that in flowering plants, cell-inheritable changes may result not only from habituation (Meins and Binns, 1979) but also by transitory activation of certain homeotic genes (Blahut-Beatty et al, 1998).…”

“…Moreover RNase could depolymerize doublestranded RNA, known to be involved in epigenetic inheritance (Matzke et al, 2001). Treatment with kinetin is known to induce stable epigenetic changes in plants (Meins and Binns, 1979;Blahut-Beatty et al, 1998).…”