THE EFFECT OF AIR AND SOIL TEMPERATURE ON ASSIMILATE PARTITIONING AND FLOWER BUD INITIATION OF FREESIA.

Time of flower initiation of Freesia ‘Blue Heaven’ depends on the average temperature of soil and air.
Flower initiation is delayed when that temperature is increased irrespective of the separate soil and air temperature.
At 13°C soluble carbohydrate and in particular reducing carbohydrate level in the second leaf is higher than at 21°C. At a low level (21°C) the apex remains vegetative and continues to forme leaves.
Carbohydrate level in the stage considered is mainly regulated by sink-activity of the leaves.
Both higher soil and air temperature enhanced leaf growth, thereby reducing carbohydrate level.
Source strength of the mother corm is not a limiting factor.
Other competing sinks: growth of contractile roots and new corm was little affected by the treatments (contractile roots) or started growth after flower initiation in most treatments (new corm). Further research is outlined to establish the role of assimilates in the process of flower initiation.

V International Symposium on Flower Bulbs

J. Berghoef, A.P. Zevenbergen

https://doi.org/10.17660/ActaHortic.1990.266.21