Articles
EFFECT OF SEASON ON GROWTH AND DEVELOPMENT OF CHRYSANTHEMUM IN THE VEGETATIVE PHASE
Measurements were carried out on the fresh weight increases from 1 to 10 g.
The leaf initiation rate was determined by microscope during the same period.
During this growth phase the length of the stem was also measured.
The leaf area index was maintained at lower than 2.0 by the removal of sample plants.
The relative growth rate from 1 to 10 g fresh weight was constant, being appr. 25% daily between the end of April and mid August.
Here after the RGR decreased linearly to appr. 8% in the middle of the winter and increased linearly to 25% again in the spring.
Under Dutch meteorological conditions the radiation increase between the end of April and 21 June is appr. 50%, but it had no apparent effect on growth rate.
The leaf initiation rate was constant during the same summer period at a rate of 1.0 leaf.day -1. Just as with RGR the leaf initiation rate decreased linearly to midwinter (0.3 leaf.day -1), and increased linearly again to the end of April.
Stem length reacted in the same manner.