The dose of 1-naphthaleneacetic acid determines flower-bud regeneration in tobacco explants at a large range of concentrations

Abstract

Short-term applications of very high concentrations of 1-naphthaleneacetic acid (NAA) to expiants from flower stalks of tobacco (Nicotiana tabacum L. cv. Samsun) induced flower-bud regeneration to the same extent as longer or continuous incubation on lower concentrations. The maximum number of flower buds per explant after 15 d of culture was obtained not only by continuous culturing at 1 μmol·l(-1) NAA but also by 12 h of culturing at 22 μmol·l(-1) or 0.5 h at 220 μmol· l(-1), followed by incubation on medium without auxin for the remaining period. Continuous application of such high concentrations resulted in callus formation or caused the death of the explanted tissue. In all experiments in which auxin concentration and time of application were independently varied, the product of concentration and time determined the number of buds formed. Most, but not all, of the NAA taken up by the tissues was converted into conjugates. In expiants which had received a dose which was optimal for regeneration, the internal concentration of free NAA remaining beyond the pulse period was between 1.7 and 6.2 μmol·l(-1). Suboptimal applications led to lower values, supraoptimal treatments to much higher internal concentrations. The physiological effect, which depends on the internal hormone concentration, thus manifested itself as dose-dependent with regard to applied hormone.

Sex expression in monoecious cucumbers micropropagated in vitro

“…Successful in vitro flower formation on media with BA has been reported for bamboo (Nadgauda et al 1997, Singh et al 2000, orchids (Kostenyuk et al 1999, Tee et al 2008) cauliflower (Kumar et al 1995), coriander (Stephen and Jayabalan 1998), maize (Mandal et al 2000), and tobacco (Smulders et al 1990). In this study, supplementation of the culture medium with 4.4 µM BA yielded no flower buds development on the micropropagated shoots.…”

The plant oncogene rolB stimulates the formation of flower and root meristemoids in tobacco thin cell layers

“…The analysis reported here confirms that auxin is the major determinant in rolB expression. In early culture phases, rolB is expressed in the basal pole of TCLs, where auxin accumulates (Smulders, Croes & Wullems, 1988a;Smulders et al, 19906). Later in culture, rolB expression is particularly intense during the neoformation of meristematic cells: as mentioned above, expression of this gene in the meristems is linked to auxin control.…”

In vitro Flowering and Production of Seeds in Oxalis corniculata L. - an Important Medicinal Plant

“…Flower formation was not observed in the combination of BAP-NAA/IAA. In contrast, flowering response was reported in plants like Nicotiana tabacum (Smulders 1990) and Zea Mays (Mandal et al 2000) in the presence of cytokinin such as BAP.…”