Improving Flower Quality of Cymbidium ‘Red Fire’ by Nutrient Control under Night Interruption Condition

다국어 초록 (Multilingual Abstract)

The effect of night interruption (NI) with potassium (K) and nitrogen (N) supply on flower quality of Cymbidium ‘Red Fire’ was investigated. 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), whereas control plants were grown under 9 hour photoperiod condition without NI treatment. The optimum K and N concentrations for flower initiation and development under NI treatment was evaluated. 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 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 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. The effect of NI with different light intensities was investigated on flower development, color intensity, and anthocyanin concentration of flower in Cymbidium ‘Red Fire’. The changes in petal color were monitored colorimetrically and the concentration of anthocyanins was quantified using UV-spectrophotometer at each flower developmental stages. Inflorescence number and length increased in both LNI and HNI conditions compared to the control. HNI treatment increased the floret number approximately twice more than the control. Days to flowering of the plants decreased in both NI group compared to the control. Color parameters such as lightness (L*) and redness (a*) increased, but yellowness (b*) decreased with the progression of flower development. The most reddish color was observed in the plants under HNI condition as evidenced by high a*, L*, and chroma value along with the high accumulation of anthocyanin. Thus, a NI system for Cymbidium flowering could be used to get great quality and vivid reddish flowers with low energy consumption during the winter season. In conclusion, K at 200 mg∙L-1 under LNI condition during adult vegetative stage and N at 200 mg∙L-1 and 400 mg∙L-1 under LNI and HNI conditions, respectively, after inflorescence emergence could be recommended to improve flower quality when NI is used for forcing. Also, NI strategies could be considered to obtain high quality plants continuously.

목차 (Table of Contents)

• CONTENTS
• ABSTRACT i
• CONTENTS iv
• LIST OF TABLES vi
• LIST OF FIGURES vii
• INTRODUCTION 1
• LITERATURE REVIEW 4
• LITERATURE CITED 8
• CHAPTER 1. Effects of Potassium and Nitrogen on Flower Initiation and Development in Cymbidium ‘Red Fire’ with Night Interruption
• ABSTRACT 14
• INTRODUCTION 16
• MATERIALS AND METHODS 20
• RESULTS 27
• DISCUSSION 35
• LITERATURE CITED 41
• CHAPTER 2. Night Interruption Improves Flower Quality in Cymbidium ‘Red Fire’
• ABSTRACT 47
• INTRODUCTION 49
• MATERIALS AND METHODS 52
• RESULTS AND DISCUSSION 58
• LITERATURE CITED 66
• ABSTRACT IN KOREAN 69