Stem Elongation in Tulip and Narcissus: The Influence of Floral Organs and Growth Regulators

Abstract

SUMMARY Decapitation of tulips early in extension growth resulted in a 59% reduction in stem length at flowering. Selective removal of the floral parts showed that the gynoecium controlled stem extension. The upper internodes were most affected, and the effect was largely reversed by the application of indol‐3‐ylacetic acid (IAA) but not by gibberellic acid (GA). Soil drenches of ancymidol also reduced tulip stem extension, but in this case the lower internodes were most affected and this effect was reversed by GA. The result of flower removal in narcissus was similar to that in tulip, although the narcissus scope and the tulip stem differ morphologically. Scape extension of narcissus was reduced by decapitation; this was due entirely to the removal of the gynoecium and could be reversed by IAA but not GA. In narcissus, spathe removal led to earlier flowering. Flower blasting in tulip (a drying out of the flower which occurs commercially under some conditions) resulted from a number of treatments, including floral surgery, injections and ancymidol soil drenches. The incidence of flower blasting was reduced by injecting GA or kinetin. The results are discussed in relation to commerical flower production, the control of pot‐plant height, and the prevention of flower blasting.

Endogenous Auxin Profile in the Christmas Rose (Helleborus niger L.) Flower and Fruit: Free and Amide Conjugated IAA

“…5). A similar effect of flower stalk growth inhibition upon bud decapitation or emasculation was observed in the miniature Cymbidium orchid (Ohno and Kako 1991), the tulip (Hanks and Rees 1977;Saniewski and De Munk 1981), and the daffodil (Edelbluth and Kaldewey 1976;Hanks and Rees 1977).…”

“…It is in agreement with results obtained on Cymbidium flowers (Ohno and Kako 1991), which suggested that the peduncle is supplied mostly by auxins from the developing flower buds, especially from the anthers. Furthermore, selective removal of the floral parts in tulip and narcissus showed that gynoecium controls stem extension (Hanks and Rees 1977).…”

“…It was observed that removal of the flower or floral organs inhibits the elongation of the floral stalk or peduncle (Op den Kelder and others 1971;Hanks and Rees 1977). Treatment of emasculated or decapitated flowers with auxins (Edelbluth and Kaldewey 1976;Hanks and Rees 1977;De Munk 1979;Kohji and others 1979;Saniewski and De Munk 1981;Ohno and Kako 1991), as well as treatments of isolated stalk explants (Gabryszewska and Saniewski 1983), led to the conclusion that these plant hormones originating in anthers, gynoecium, or developing fruit are largely responsible for peduncle elongation. Identification of endogenous hormones during flowering in the tulip (Okubo and Uemoto 1985;Xu and others 2008) and barley (Wolbang and others 2004) confirm that diffusible auxins from floral organs, in the first place, and in coordination with gibberellins are responsible for stalk elongation.…”

Effects of growing environments, planting date, and stem treatments on sandersonia tuber weight and secondary tuber development

“…Auxins play a major role in controlling plant growth and are produced in areas of rapid cell (Hanks & Rees 1977). Stem treatments which significantly reduced secondary tuber production in sandersonia were pruning, tipping plus flower removal, and tipping plus pruning 4 weeks later.…”

The hot, the cold and the tulip : the regulation of flowering time and dormancy release

“…In addition to these developmental constrains, environmental cues are interfering regularly with cut flower production. For example, floral bud blasting caused by high temperature during development in spring and summer has been occurring more frequently over the last decade ( Fig.1A-B) (Hanks and Rees, 1977). These high temperatures coincide with climate change and can lead to reoccurring events of floral bud blasting in the future, especially when these sensitive cultivars are used for breeding purposes.…”