Agriculture Reference
In-Depth Information
Fig. 4.38.
Inflorescence abortion caused by 'competition' from bulbing with
characteristic shrivelling of the flower stalk just below the spathe (from van
Kampen, 1970. Courtesy of
Mededeling Proefstation voor de Groenteteelt in de
Vollegrond, Lelystad
).
Inflorescence initiation in growing seedlings is influenced by photoperiods,
nitrogen nutrition and daily radiant exposure as well as by temperature. Long
photoperiods increase the rate of inflorescence initiation, but a low nitrogen
status can largely replace the requirement for long photoperiods (see Fig. 4.40).
Exposure of seedlings to low light intensities prior to vernalization, resulting in a
low concentration of non-structural carbohydrates in the plants, slows
subsequent inflorescence initiation and increases the critical leaf number
needed to reach the post-juvenile stage by one or two leaves.
Once inflorescences are first initiated within seedlings, subsequent
development through to stage 4 (see Fig. 2.6) and further elongation tends to
be faster as temperature increases in the range 6-12°C, faster with longer
photoperiods at these cool temperatures and faster in high-, rather than low-,
nitrogen status plants. Temperatures of 12-16°C in combination with photo-
periods of 16-17 h have been found satisfactory for inflorescence emergence
