may be due to the use of different B light intensities. For instance,
Shimizu et al. (2006) applied B light interruption at a lower intensity
(1.7 mol m−2 s−1) compared to the light-level used in the current
study (100 mol m−2 s−1). In general, low photon intensities of
light are related to the accumulation of less dry matter (Goins et al.,
1997). Furthermore, Khattak and Pearson (2006) reported that B
light suppressed plant height under low light-level conditions.
In conclusion, supplemental B light was shown to promote
internode extension in the cut chrysanthemum ‘Zembla’. However,
bud formation might be associated with mixed RB light duration.
Our results indicate that supplemental monochromatic B lighting
for 4 h after 11 h of mixed RB light promotes internode extension,
but does not interrupt flower bud formation. Supplemental B light
irradiance, at least in part, may reduce the number of LDs required
to obtain sufficient stem length during SD induction. The results of
this study present a useful practical technique for optimizing cut
chrysanthemum production in greenhouse horticulture.
Acknowledgements
This research was supported by National Research Foundation
of Korea (KRF–2009–352–F00013) and the Dutch Technology Foundation
STW.