Abstract: To investigate the effects of different LED red（R）and blue（B）light cycles on the growth and development，photosynthesis，and nutrient accumulation of Dendrobium officinale tissue culture seedlings，tissue culture seedlings of D.officinale were used as experimental material.Based on the previously screened optimal LED red and blue combination light（R∶B=5∶5），five different light cycle treatments were set up［ white light control group（CK），treatment group A（3 h/d），treatment group B（6 h/d），treatment group C（9 h/d） and treatment group D（12 h/d）］.After 120 days of illumination，growth parameters（plant height，number of leaves，leaf length，stem diameter，fresh weight，dry weight），antioxidant parameters［superoxide dismutase（SOD） activity，malondialdehyde（MDA）content，ascorbate peroxidase（APX）activity，peroxidase（POD） activity，catalase（CAT）activity］，photosynthetic pigment parameters（chlorophyll a content，chlorophyll b content，chlorophyll a+b content，chlorophyll a/b，and carotenoid content），chlorophyll fluorescence parameters［PSⅡ maximum photochemical efficiency（Fv/Fm），PSⅡ potential activity（Fv/Fo），actual quantum efficiency（Φ_PSⅡ），electron transport rate（ETR Ⅱ），photochemical quenching coefficient（qP），non⁃photochemical quenching coefficient（qN）］ and nutrient content（amino acids，alkaloids，polysaccharides，flavonoids） were determined.The results showed that the plant height，stem diameter，fresh weight and dry weight of the seedlings reached the peak in treatment D，while the leaf length and number of leaves reached the peak in treatment C. APX，CAT and POD activities peaked in treatment B，SOD activity peaked in treatment C，and the MDA content was the lowest in treatment C. Overall，the nutrient content，photosynthetic pigment indicators and chlorophyll fluorescence parameters of the seedlings were the best in treatment B.There were significant or extremely significant correlations between growth indicators，antioxidant indicators，nutrient indicators and chlorophyll fluorescence parameters and photosynthetic pigment indicators.The principal component analysis results showed that the comprehensive performance of Dendrobium officinale in treatment B was the best in terms of growth indicators，antioxidant indicators，photosynthetic indicators and nutrient accumulation，with a comprehensive score of 3.35.In conclusion，when the red and blue light ratio is 5∶5，LED light exposure for 6 h has the best promoting effect on the growth and development and nutrient accumulation of Dendrobium officinale.

Key words: Dendrobium officinale, LED photoperiod, Physiology and biochemistry, Nutrient, Chlorophyll fluorescence

摘要： 为探究不同LED红（R）蓝（B）光周期对铁皮石斛试管苗生长发育、光合作用及营养成分积累的影响，以铁皮石斛试管苗为材料，以前期筛选出的最优LED红蓝组合光（R∶B=5∶5）为基础，设置5种不同的光周期处理［白光对照组（CK）、处理组 A（3 h/d）、处理组B（6 h/d）、处理组C（9 h/d）和处理组D（12 h/d）］，光照120 d后测定生长指标（株高、叶片数、叶长、茎粗、鲜质量、干质量）、抗氧化指标［超氧化物歧化酶（SOD）活性、丙二醛（MDA）含量、抗坏血酸过氧化物酶（APX）活性、过氧化物酶（POD）活性、过氧化氢酶（CAT）活性］、光合色素指标（叶绿素a含量、叶绿素b含量、叶绿素a+b含量和叶绿素a/b及类胡萝卜素含量）、叶绿素荧光指标［PSⅡ最大光化学效率（Fv/Fm）、PSⅡ潜在活性（Fv/Fo）、实际光量子效率（Φ_PSⅡ）、电子传递速率（ETRⅡ）、光化学淬灭系数（qP）、非光化学淬灭系数（qN）］及营养成分（氨基酸、生物碱、多糖、类黄酮）含量。结果表明，试管苗株高、茎粗、鲜质量和干质量在D处理达到峰值，叶长和叶片数在C处理达到峰值。APX、CAT和POD活性在B处理达到峰值，SOD活性在C处理时达到峰值，MDA含量在C处理时最低。试管苗营养物质和光合色素指标及叶绿素荧光参数等指标整体上以B处理最优。生长指标、抗氧化指标、营养指标与叶绿素荧光参数和光合色素指标间存在显著或极显著相关关系。主成分分析结果显示，B处理铁皮石斛在生长指标、抗氧化指标、光合指标及营养物质成分积累等方面综合表现最优，综合得分达3.35。综上，采用红蓝光比为5∶5、LED光照射6 h/d，促进铁皮石斛生长发育及营养成分积累的效果最好。

关键词: 铁皮石斛, LED光周期, 生理生化, 营养物质, 叶绿素荧光