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Vegetative growth and flower
initiation of Spathiphyllum cultivars ‘Alfa' and ‘Cervin' were studied
under various climatic conditions over a full year's growth cycle. The four
production cycles started respectively on 18 March, 10th June,
10th September and 26th November 1998. These cycles are referred to as summer,
autumn, winter and spring cultures respectively since the major part of the
experimental period occurred in this specific season. This study indicated
that ‘Alfa' and ‘Cervin' reacted in different ways during the year. Spathiphyllum ‘Alfa' initiated
flowers independently of the attained vegetative biomass and flower initiation
occurred when growth rate was slow or decreased considerably. In the winter
and spring cycles, ‘Alfa' was able to initiate flowers in an early vegetative
stage (12.4 leaves and 7.4 leaves respectively), whereas the summer and autumn
cultured plants were larger (29.5 leaves and 23.2 leaves respectively) at
the start of flower initiation. For ‘Alfa', the absence of temperatures above
26°C seemed to be an initial (essential) condition to start flower initiation.
In addition to non-elevated temperatures, decreasing or low light intensities
and shortening of the photoperiod were associated with the conversion from
the vegetative to the generative stage. For Spathiphyllum ‘Cervin',
however, no linkage of climatic conditions and the start of generative development
was observed. ‘Cervin' required a more extensive vegetative development than ‘Alfa' before
flower initiation could take place. In any of the four culture cycles, flower
initiation did not occur before the plants had formed approximately seven
shoots and 24 leaves.

South African Journal of Botany 2002, 69(2): 129–134