ISHS Acta Horticulturae 399: Greenhouse Environment Control and Automation
EFFECT OF VERTICAL AIR FLOWING ON LETTUCE GROWING IN A PLANT FACTORY |
| Authors: | T. Shibata, K. Iwao, T. Takano |
| Keywords: | Lettuce, vertical air flowing, stomatal conductance, tip-burn, plant factory |
| Abstract:
An air flowing method was investigated for promoting photosynthesis, transpiration, and nutrient uptake of crops. Lettuce (Lactuca sativa L. var. capitata L. cv. Red-fire-W, butter-head type) plants were cultured in a plant factory with fluorescent lamps. Stomatal aperture closed by water stress caused by vertical air flowing at 60 % RH. Vertical air flowing (0.7 m s-1) at high humidity (80 % RH) decreased the diffusion resistance of gases without stomatal closing. Vertical air flowing lowered leaf temperature as compared with ambient temperature by 0.5 °C. Therefore, the yield by vertical air flowing at 80 % RH got 130 % compared with horizontal air flowing. Furthermore, vertical air flowing to a meristem suppressed an occurrence of tip-burn disorder. The growth promotion by vertical air flowing at 0.7 m s-1 and 80 % RH in a closed system was recognized to be more effective than that in an open system. As the results, high transpiration rate is proved to be obtained by vertical air flowing at 0.7 m s-1 and 80 % RH. | |
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