Hye Ryun An

Flower initiation and development in Cymbidium by night interruption with potassium and nitrogen

This study was conducted to investigate the effects of potassium (K) and nitrogen (N) on flower initiation and development when applied in conjunction with night interruption (NI) in Cymbidium ‘Red Fire’. The experimental plants were grown with NI at a low light intensity (LNI) of 3–7 μmol·m−2·s−1 and at a high light intensity NI (HNI) of 120 μmol m−2·s−1 for 4 hours (22:00 to 02:00 HR), whereas control plants were grown under 9 hours photoperiod condition. The concentrations of K and N used in each experiment were 0, 100, 200, and 400 mg·L−1. The plants grown under LNI conditions had 75% inflorescence emergence when 200 mg·L−1 K was supplied, while no inflorescence emerged in control plants, despite the application of K fertilizer. Flower diameter, as well as inflorescence length and diameter increased with an increasing N application up to 200 mg·L−1 under LNI and 400 mg·L−1 under HNI conditions. K fertilization during the adult vegetative stage in Cymbidium grown under LNI artificially induced inflorescence, but the flower quality of the plants decreased relative to those grown under HNI. To improve the flower quality, maintaining N at 200 mg·L−1 and 400 mg·L−1 for plants grown under LNI and HNI conditions, respectively, after inflorescence emergence is recommended.

High temperature promotes growth and flowering in Sophrolaeliocattleya

This study investigated the effects of temperature on vegetative growth and flowering in Sophrolaeliocattleya ‘Red Doll’ and ‘Grace’. Plants were grown at constant temperatures of 8, 13, 18, or 23°C for 12 weeks in environmentally controlled growth chambers. Photosynthetic efficiency was measured four weeks after the start of the temperature treatment. The shoot length, leaf length, leaf width, and the number of new shoots increased in plants from both cultivars that were grown at 18 and 23°C, respectively; whereas the number of days to visible buds and flowering were reduced compared to plants grown at 8 and 13°C. The number of flowering florets and the flower diameter were greater in plants grown at 18 and 23°C than at 8 and 13°C. High photosynthetic efficiency was observed in plants grown at 23°C, which was measured as increased PSII quantum yield, photochemical quenching, and electron transport rate; and decreased non-photochemical quenching. These results indicate that temperatures of 18-23°C promote growth and stimulate earlier production of high-quality flowers in Sophrolaeliocattleya.

Night interruption improves subsequent cut flower quality in Cymbidium ‘Red Fire’

The influence of night interruption (NI) on cut flower quality was examined during subsequent Cymbidium flowering. Forty-two-month old Cymbidium ‘Red Fire’ plants were subjected to first-flower cutting and were regrown for subsequent flowering in the following year. The plants were exposed to 9 hour natural light (control) or 9 hour natural light plus NI from 22:00–02:00 HR with low light intensity (LNI) at 3–7 µmol·m−2·s−1 or high light intensity (HNI) at 120 µmol·m−2·s−1. NI treatments accelerated subsequent flowering and increased the number of inflorescences, the number of flowers per inflorescence, and the inflorescence length compared with those of control plants. The red coloration of petals increased under both LNI and HNI conditions compared with that of control plants, which was represented by increases in a* and total anthocyanin content. These results indicate that NI lighting enhances the cut flower quality and accelerates the subsequent flowering time of Cymbidium for cut flower production. NI could be an effective method for maintaining long-term productivity of high-quality Cymbidium flowers.