수직농장 내 인공광과 야간 증기압차가 ‘금실’ 딸기의 발달단계별 생육에 미치는 영향 = Effects of Artificial Lighting and Nighttime Vapor Pressure Deficit on Developmental Stage-Specific Growth of Strawberry ‘Kuemsil’ in a Vertical Farm

다국어 초록 (Multilingual Abstract)

Artificial light vertical farms enable the tight regulation of irradiance, spectrum, temperature, relative humidity, and CO2, providing a controlled platform for stable year-round strawberry production. However, optimal developmental stage-specific environmental control guidelines for indoor strawberry cultivation remain poorly defined in terms of yield and quality stability. This study aimed to develop stage-specific cultivation strategies for the Korean strawberry ‘Kuemsil’ (Fragaria × ananassa Duch.) by assessing the effects of light conditions, nighttime vapor pressure deficit (VPD), and flower load across the acclimation, nursery, vegetative, and reproductive stages in an artificial light vertical farm. During the acclimation stage, plant morphological development under low daily light integral (DLI) was predominantly modulated by light quality, wherein red-enriched light stimulated shoot elongation and increased shoot dry matter accumulation. Blue-enriched light suppressed seedling elongation while increasing chlorophyll content (as measured by SPAD), resulting in compact plants. During the nursery stage, a balanced R:B light ratio, combined with an intermediate DLI, promoted uniform root and crown development, whereas the lowest DLI limited biomass accumulation. In the vegetative stage, before leaf thinning, optimal vegetative growth and the lowest incidence of tip burn occurred under a low nighttime vapor pressure deficit (VPD) of 0.2 kPa. After leaf thinning, shoot growth was maximized under the combination of 0.2 kPa VPD and retention of 6–8 leaves. Although tip burn incidence was generally lower at 0.2 kPa, it was explicitly minimized under the condition of retaining four leaves and a nighttime VPD of 0.4 kPa. These results suggest that a moderate nighttime VPD effectively balances water status and calcium transport under specific levels of leaf retention. Gas exchange analysis revealed that low VPD increased transpiration and stomatal conductance during the day, without enhancing photosynthetic rate. In contrast, a nighttime VPD of 0.4 kPa minimized water loss while maintaining carbon assimilation. During the reproductive stage, DLI was the primary factor influencing shoot growth, fruit weight, and soluble solids content (SSC). Adjusting the number of residual flowers between 3 and 7 had a minimal impact on vegetative growth. However, fewer flowers resulted in higher SSC. Overall, these findings provide empirical guidelines for optimizing vertical farming of the strawberry ‘Kuemsil’. Stage-specific control of light spectrum, nighttime VPD, and crop load can be effectively integrated to establish practical environmental setpoints that ensure stable yields and enhanced fruit quality in artificial light vertical farming systems.

목차 (Table of Contents)

• General Introduction 1
• Literature Review 4
• Chapter Ⅰ. Effects of Combined Daily Light Integral and R:B Light Ratio on the Growth of Micropropagated Strawberry 'Kuemsil' Plantlets in Vertical Farm 14
• 1. Abstract 14
• 2. Introduction 16
• 3. Materials and Methods 20
• 3-1. Plant Materials and Growth Conditions 20
• 3-2. Environmental Data Collection 29
• 3-3. Growth Measurements 31
• 3-4. Statistical Analysis 32
• 4. Results and Discussion 33
• 4-1. Growth Responses to Daily Light Integral and Light Quality during the Acclimation Phase 33
• 4-2. Growth Responses to Daily Light Integral and Light Quality during the Pre-Vertical Farm Phase 40
• 4-3. Growth Responses to Daily Light Integral and Light Quality during the Vertical Farm Phase 45
• 5. Conclusion 50
• 6. Literature Cited 52
• Chapter Ⅱ. Effects of Nighttime Vapor Pressure Deficit and Leaf Thinning on Growth and Tip Burn Incidence of Strawberry 'Kuemsil' in Vertical Farm 56
• 1. Abstract 56
• 2. Introduction 58
• 3. Materials and Methods 61
• 3-1. Plant Materials and Growth Conditions 61
• 3-2. Environmental Data Collection 64
• 3-3. Growth Measurements 71
• 3-4. Statistical Analysis 75
• 4. Results and Discussion 76
• 4-1. Vegetative Growth and Tip Burn before Leaf Thinning 76
• 4-2. Vegetative Growth and Tip Burn after Leaf Thinning 84
• 4-3. Effects of Nighttime Vapor Pressure Deficit on Morning Stomatal Conductance and Transpiration after leaf thinning 93
• 5. Conclusion 97
• 6. Literature Cited 99
• Chapter Ⅲ. Effects of Daily Light Integral and Flower Thinning on Fruit Yield and Quality of Strawberry 'Kuemsil' in Vertical Farm 101
• 1. Abstract 101
• 2. Introduction 103
• 3. Materials and Methods 107
• 3-1. Plant Materials and Growth Conditions 107
• 3-2. Environmental Data Collection 110
• 3-3. Growth Measurements 112
• 3-4. Statistical Analysis 114
• 4. Results and Discussion 115
• 4-1. Reproductive Growth Responses of Strawberry 'Kuemsil' to Daily Light Integral and Number of Flowers 115
• 4-2. Fruit Weights and Soluble Solids Content under Daily Light Integral and Flower Thinning 125
• 5. Conclusion 130
• 6. Literature Cited 132
• General Conclusion 134
• Abstract in Korean 138
• Literature Cited 140