Flowering in Bougainvillea

Abstract

Early concepts of the control of reproductive development emphasized the importance of nutritional parameters (7,8,11,14), particularly C/N ratios in the entire plant (12). Many of these ideas were not sustained in subsequent studies (13), and, hence, nutritional hypotheses were assigned a supportive rather than regulatory role in reproductive development. Numerous studies with monocarpic and polycarpic species showed that flower initiation and development have apparently higher light flux requirements than continued leaf initiation (18). There is also considerable evidence, for many photoperiodic species, that high photon flux may replace all or part of the day length requirements for the transition from vegetative to reproductive development (2,3,9,15,18). Since the high light flux is generally in the photosynthetically active range, it seemed as ifchanged levels ofphotosynthesis, or assimilates derived therefrom, played an important role in inductive processes in the leaves and/or as a morphogenetic signal in the shoot apical meristem (5, 10). Bodson (2) obtained evidence for an early increase, before cytological evidence for evocation, in carbohydrate levels in apical buds of Sinapis following induction by LD3 or displaced SD.In a comprehensive review of the effects of nutritional factors, acting as substrates or osmotica, on tissue differentiation and organogenesis, Allsopp (1) assigned a determining, not merely ' Permanent address:

The Influence of 1‐Triacontanol on the Growth, Flowering, and Quality of Potted Bougainvillea Plants (Bougainvillea glabra var. “Elizabeth Angus”) under Natural Conditions

“…The results also showed that the TSS content of leaves was positively correlated with advanced flowering and the increase in flower number of Bougainvillea plants. These findings are in agreement with those of Ramina et al [38], who reported that higher TSS content of leaves stimulates flowering. In the current study, it was also observed that flower weight positively correlated with leaf sugar content in the TRIA-treated plants.…”

Photosynthesis As a Function of Short Day Induction and Gibberellic Acid Treatment in Bougainvillea “San Diego Red”

“…Our finding that SD induction increases PS in mature Bougainvillea leaves lends support to nutritional hypotheses that suggest that increased assimilate supply to the reproductive axis is an important factor in floral initiation in Bougainvillea (19,20,23). This is by no means unequivocal support.…”

“…These findings of GA3-induced inhibition of PS contrast sharply with those for GA3-treated apple and bean leaves (12,13,24) and the general observation of short term dry weight gains in GA3-treated plants. No explanation is available to account for this unexpected GA3 effect on PS rate; one can be reasonably certain that it does not reflect an indirect effect of decreased "sink" activity since the over-all shoot growth rate and '4C assimilate transport to the apical bud in Bougainvillea are increased by BA treatment (8,22,23) and dry weight accumulation as evidenced by per cent dry weight or per cent soluble solids, is unchanged (19).…”

“…Partly as a result of these findings, we proposed that reproductive development in Bougainvillea may depend upon a critical level of assimilates and their transport to the inflorescence axis (19,20 …”

“…Partly as a result of these findings, we proposed that reproductive development in Bougainvillea may depend upon a critical level of assimilates and their transport to the inflorescence axis (19,20). We found evidence for enhanced 14CO2 fixation and transport to the reproductive axes in SD-induced plants (22,23), and wanted to determine whether SD enhanced net PS as well.…”