Production of flowering photoperiodic plants in plant factories by using quality, quality shifting, and positioning of night interruption light for control of flowering and morphogenesis

Abstract

Feasibility of using light quality, a shift in light quality, and positioning of night interruption light (NIL), provided at 10 μmol m-2 s-1 PPFD, for control of flowering and morphogenesis was investigated in three model plants, chrysanthemum (qualitative short-day plant, SDP), geranium (day-neutral plant), and petunia (qualitative long-day plant). All model species tested showed the well-known photoperiodic responses, but only results in the chrysanthemum are described here. Morphogenesis, flowering, and transcriptional factors of the chrysanthemum plant were greatly affected by NIL quality and its positioning. The night interruption-blue (NI-B) light was imported for photomorphogenesis and flowering. The expression level of phyA, phyB, and cry1 in the NI-R and NI-Fr treatments increased for initial flower initiation, which was also observed in morphological characteristics of chrysanthemum. Results also indicate that NI-B onto the old leaves has potential applicability for the production of potted SDPs such as chrysanthemum due to its subsequent effect for height suppression. The results demonstrated that these techniques may be useful for controlling flowering as an alternative method of using black-out curtains and photoperiodic lighting seasonally. ? 2022 International Society for Horticultural Science. All rights reserved.