关键词: 流苏石斛, LED, 光质, 生理特性, 叶绿素荧光

Abstract: To cultivate high⁃quality commercial seedlings of Dendrobium fimbriatum，six different light quality treatments were set up，including 100% red light（R），100% blue light（B），80% red light+20% blue light（8R∶2B），70% red light+30% blue light（7R∶3B），and 50% red light+50% blue light（5R∶5B），with white fluorescent lamp as the control（CK）. After 60 days，growth indicators（plant height，leaf number，leaf length，stem diameter，fresh weight，dry weight），antioxidant indicators［superoxide dismutase（SOD）activity，malondialdehyde（MDA）content，ascorbate peroxidase（APX）activity，peroxidase（POD）activity，catalase（CAT）activity］，photosynthetic indicators（chlorophyll a content，chlorophyll b content，chlorophyll a+b content，chlorophyll a/b ratio，and carotenoid content），chlorophyll fluorescence indicators［potential activity of PS Ⅱ in plants（Fv/Fo），maximum photochemical efficiency（Fv/Fm），actual photochemical efficiency（Φ_PSⅡ），photochemical quenching coefficient（qP），electron transfer rate（ETR Ⅱ），and non⁃photochemical quenching coefficient（qN）］，as well as the content of nutrients（soluble proteins and soluble sugars）and other related indices，totaling 24 indexes were measured in order to screen the LED light quality ratio for the healthy growth of D. fimbriatum test⁃tube seedlings.The results indicated that monochromatic red light was beneficial for the height and elongation of test⁃tube seedlings，while monochromatic blue light was beneficial for increasing soluble protein content. 8R∶2B treatment was beneficial for leaf elongation，leaf number，and stem thickness increase of test⁃tube seedlings of D.fimbriatum.The overall antioxidant index was best when they were treated with 5R∶5B，and the dry and fresh weight，soluble sugar content，chlorophyll content，and chlorophyll fluorescence of test⁃tube seedlings were also best when they were treated with 5R∶5B.There was a significant correlation between growth indicators，antioxidant indicators，nutritional indicators，chlorophyll fluorescence parameters，and chlorophyll content.The results of principal component analysis indicated that the physiological and biochemical indicators of Dendrobium fimbriatum test⁃tube seedlings under 5R∶5B treatment showed the best performance，with the highest comprehensive score.In summary，the light environment of 50% red light+50% blue light（5R∶5B）LED is the most conducive to the growth and development of the test⁃tube seedlings of D.fimbriatum，and is the most suitable light environment for cultivating strong seedlings.

Key words: Dendrobium fimbriatum, LED, Light quality, Physiological characteristic, Chlorophyll fluorescence