| Light-emitting diode(LED) is a solid-state semiconductor devices and it can be directly put electricity into light. LED lighting systems have several unique advantages over traditional lighting, including the ability to maintain useful light output for years without replacement, spectral composition pure, low consumption, the ability of environmental protection. So they are widely used in the study of plant growth. Led light source as the most promising and development prospect in the field of artificial light source for future factilities, using its regulation of plant morphogenesis and plant growth is an important technology in the field of greenhouse cultivation. Now most studies of light qualities of strawberries using sun light transmittance of similar filter membrane and they can’t accurate quantitative modulation spectral energy distribution, light unit and light intensity are not unified, so affect the accuracy of research. The study mainly explores the LED as light source of photoperiod and light qualities on photosynthetic characteristic, fruit production and quality of strawberry, in order to provide reference of photoperiod and light qualities environmental regulation of strawberry in the facility cultivation.The study use LED as light source set two trials, taking ‘miao xiang No.7’ strawberry as material, photoperiodic study set four treatment, 8 h·d-1, 12 h·d-1, 16 h·d-1 and 20 h·d-1; light quality treatment including full red light, full blue light, full yellow light, full white light, red/blue/yellow(7/2/1), red/blue(7/2) light generated by light emitting diode(LED) was applied to accurately modulate with white light generated as control. The results showed that:1. Photoperiod had significant effect on growth and development of strawberry. Plant height, leaf area, root activity, dry and fresh weight of plant under 16 h·d-1 were superior to other treatments. The result showed that extend photoperiod can effectively promote the growth of strawberry.2. Photoperiod had different effect on photosynthetic characteristic of strawberry. Photosynthetic parameters(Pn, Tr, Gs) and pigment contents were increased at first and then decreased with the extension of photoperiod, got a peak at 16 h·d-1. Visibly, extend photoperiod can effectively improve photosynthesis, pigment contents and fluorescence yield of strawberry.3. Photoperiod had significant effect on fruit quality of strawberry. The soluble solids content, titratable acid, vitamin C and sugar-acid ratio were increased at first and then decreased with the extension of photoperiod, got a peak at 16 h·d-1, while the protein content was decreased. In conclusion, as compared with other photoperiod, 16 h·d-1 photoperiod was more beneficial to the growth and some qualities of strawberry.4. Different light quality had significant effect on photosynthetic characteristic of strawberry. The red light could increase photosynthetic parameters(Pn, Tr), while blue light has inhibitory effect. Fo, Fm and ΦPSⅡ were the highest under red light, but values of the maximal photochemical efficiency of PS II(Fv/Fm), Fv/Fo and Fm/Fo, pigment contents of leaves were highest under red/blue/yellow(7/2/1). Blue light can improve intercellular CO2 concentration(Ci) and conductance(Gs).5. Light quality had different effect on material distribution of strawberry. The dry weight and fresh weight of aerial part were the highest under red light, while minimal under blue light. The dry weight and fresh weight of underground part were the highest under white light, while minimal under red/blue(7/2) light. Light quality had different response to aboveground and underground of plant.6. Different light quality had significant effect on production and quality of fruit. Fruit production was highest under red/blue/yellow(7/2/1). In addition, the soluble solids content and vitamin C were highest under red light. The blue light could increase protein content and titratable acid, while sugar-acid ratio was highest under red/blue/yellow(7/2/1). Comprehensive analysis indicated that red/blue/yellow(7/2/1) was more beneficial to the increase of pigment contents of leaves, fruit production and some qualities of strawberry. |
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