Flowering and Morphogenesis of Kalanchoe in Response to Quality and Intensity of Night Interruption Light

Abstract

The effects of the quality and intensity of night interruption light (NIL) on the flowering and morphogenesis of kalanchoe (Kalanchoe blossfeldiana) ‘Lipstick’ and ‘Spain’ were investigated. Plants were raised in a closed-type plant factory under 250 μmol·m−2·s−1 PPFD white light emitting diodes (LEDs) with additional light treatments. These treatments were designated long day (LD, 16 h light, 8 h dark), short day (SD, 8 h light, 16 h dark), and SD with a 4 h night interruption (NI). The NIL was constructed from 10 μmol·m−2·s−1 or 20 μmol·m−2·s−1 PPFD blue (NI-B), red (NI-R), white (NI-W), or blue and white (NI-BW) LEDs. In ‘Spain’, the SPAD value, area and thickness of leaves and plant height increased in the NI treatment as compared to the SD treatment. In ‘Lipstick’, most morphogenetic characteristics in the NI treatment showed no significant difference to those in the SD treatment. For both cultivars, plants in SD were significantly shorter than those in other treatments. The flowering of Kalanchoe ‘Lipstick’ was not affected by the NIL quality, while Kalanchoe ‘Spain’ flowered when grown in SD and 10 μmol·m−2·s−1 PPFD NI-B. These results suggest that the NIL quality and intensity affect the morphogenesis and flowering of kalanchoe, and that different cultivars are affected differently. There is a need to further assess the effects of the NIL quality and intensity on the morphogenesis and flowering of short-day plants for practical NIL applications.

Daily light integral and/or photoperiod during the young plant and finishing stages influence floral initiation and quality of witchgrass and marigold cut flowers

“…Plants that finished under 10-to 12h photoperiods had faster TVB than those finished under photoperiods ≥ 13 h (Figure 3C). Therefore, the critical photoperiod of marigold 'Xochi' was determined to be ≈12 h. Marigold's flowering responses align with other studies detailing photoperiodic responses of SDPs (Park et al, 2013;Kang et al, 2019). TVB of zinnia 'Dream Land' decreased by 10 d when finished under 9-h SDs instead of 4-h NI (Park et al, 2013).…”

“…TVB of zinnia ‘Dream Land’ decreased by 10 d when finished under 9-h SDs instead of 4-h NI ( Park et al, 2013 ). Similarly, Kang et al (2019) demonstrated that 8-h SDs promoted flowering of kalanchoe ‘Lipstick’ ( Kalanchoe blossfeldiana ), while 16-h photoperiods or 4-h NIs inhibited flowering, regardless of NI TPFDs. Unlike marigold ‘Xochi’, kalanchoe ‘Lipstick’ was ≈45 or 33% taller under SDs compared to plants grown under a 16-h LD or a 4-h NI, respectively ( Kang et al, 2019 ).…”

“…Similarly, Kang et al (2019) demonstrated that 8-h SDs promoted flowering of kalanchoe 'Lipstick' (Kalanchoe blossfeldiana), while 16-h photoperiods or 4-h NIs inhibited flowering, regardless of NI TPFDs. Unlike marigold 'Xochi' , kalanchoe 'Lipstick' was ≈45 or 33% taller under SDs compared to plants grown under a 16-h LD or a 4-h NI, respectively (Kang et al, 2019). However, this may have been due to the absence of stem elongation associated with flowering, as plants grown under LDs or NIs did not transition from vegetative to reproductive growth.…”

Kalanchoë Breeding: Past, Present and Future

“…Although the critical day length of K. blossfeldiana species is 12.5-13 hours, short-day treatment (darkening) is performed for 14 hours in commercial production (Jepsen and Christensen, 2010). The light demand of each species is different in the Kalanchoë genus (Currey and Erwin, 2011) and flowering can also respond to different light quality and intensity of night interruption light (NIL) (Kang et al, 2019). For Kalanchoë, temperature and light quality during the day are also important factors affecting flowering (Mackenzie et al, 2018).…”

Light Emitting Diodes (LEDs) as Agricultural Lighting: Impact and Its Potential on Improving Physiology, Flowering, and Secondary Metabolites of Crops

“…This is explained by the study of Park et al [177], who stated that when the carbon demand linked to plant growth is exceeded by the carbohydrate production, a higher number of flowers per plant is visible due to the fact that vegetative growth is relatively longer. Kang et al [178] reported that two varieties of kalanchoe, namely "lipstick" and "spain", reacted differently to the NI treatments. The "lipstick" variety showed no flowering in any of the photoperiodic treatments, whereas the "spain" variety showed differentially or fully developed flowering in the treatment of NI-B.…”