## 4 Experimental Section
### Data Collection and Analysis  
The cultivation experiment with all the treatments was repeated twice and, since the results of both experiments showed same trends, only results of the second experiment were presented in this manuscript. At 49 days after the initiation of the photoperiodic treatments, the plant height, number of leaves per plant, chlorophyll content, fresh and dry masses of the shoot and root, percentage of flowering plants, days from treatment initiation to visible buds (DVB), number of flowers and flower buds per plant (mentioned as \"number of flowers hereafter\"), and the expression of important photoreceptor genes were either measured or assessed.  
For the estimation of chlorophyll content, 10 mg of fresh leaf sample was taken from the young fully developed leaves from each biological replicate, and extracted using 80% ice-cold acetone. After centrifugation at 3000 rpm, the absorbance of the supernatant was measured using a spectrophotometer (Biochrom Libra S22, Biochrom Co., Ltd., Holliston, MA, USA) at 663 and 645 nm. Calculation of total chlorophyll was done according to the method described by [PERSON] _et al._[55]. The dry masses of the shoots and roots were determined after drying the samples in an oven (Model FO-450M, Jeio Technology Co., Ltd., Seoul, Korea) at 75 \({}^{\circ}\)C for 3 days.  
Total RNA Isolation, cDNA Synthesis, and Real-Time Polymerase Chain Reaction (PCR) of Selected Genes  
For total RNA extraction, the most recently mature leaf was used which was collected in the morning (9:00 a.m.) at 30 days after the initiation of the photoperiodic light treatments in all treatments when the plants in the SD treatment already started to bloom, those in the inductive NI treatments had flower buds formed, and those in the LD treatment were still vegetative. Total RNA was extracted using an RNA isolation kit according to the manufacturer's instructions (Promega, Madison, WI, USA). The sample collection time (9:00 a.m.) was selected because photosynthetic rates are high, and all plant processes including gene expression are very active at this point of time. One microgram of DNase-treated RNA was reverse transcribed using a reverse transcription kit (Promega, Madison, WI, USA) to synthesize first-strand cDNA, which was used as a template for the polymerase chain reaction (PCR). Real-time PCR was performed using a Rotor-Gene Q 2 plex HRM Platform (Rotor-Gene Q 2 plex HRM Platform, Westburg, The Netherland) and SYBR green from a Qiagen qPCR kit (Qiagen OneStep RT-PCR Kit, Westburg, The Netherland) as a reference dye. Independent real-time PCR reactions with equal amounts of cDNA were performed using the _photochrome A_ (_phyA_), _photochrome B_ (_phyB_), _cryptochrome 1_ (_cry1_), _Anti-forigenic FT/TFL1_ family protein (_AFT_), and _FLOWERING LOCUS T_ (_FTL_) gene primers (the primer sequences are shown in Table 2). _Actin_ was used as an internal control, as it is commonly used to normalize molecular expression studies because of its high level of conservation as an endogenous housekeeping gene. The real-time PCR conditions were as follows: initial denaturation for 5 min at 95 \({}^{\circ}\)C, followed by 25 cycles consisting of 20 s at 95 \({}^{\circ}\)C, 30 s at 60 \({}^{\circ}\)C, and 30 s at 72 \({}^{\circ}\)C, then 10 min at 72 \({}^{\circ}\)C for final extension. To calculate the relative expression levels (treatment/control, SD), the individual expression values of treatment plants were divided by the mean value for SDPs at each sampling date.