Seasonal influence on vegetative growth and flower initiation of Spathiphyllum

Abstract

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 th March, 10 th June, 10 th September and 26 th 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.