The characteristics in the physiolelgical response of tomato plants between aeroponics and nutrient film technique (NFT) were compared.
1. There were marked differences in stomatal resistance, water potential of leaves, and temperatures of leaves, root surface and plant body between the two culture systems. It was found that stomatal opening or leaf water potential could be regulated by changing the temperature and ionic strength of the solution. Especially, the temperature fluctuation in the leaves and root surface within±1.5℃ strongly indicated the possibile establishment of an optimal environment.
2. The photosynthetic activity as well as the leaf respiration was significantly higher in the aeroponics than in the NFT.
3. The contents of P,K and Mg in the plants were higher but that of Ca was lower in the aeroponics than in the NFT, while those of Cu, Zn and Fe were similar in the two systems. Carbohydrates/nitrogen ratio was also higher in the aeroponics.
4. The amount of root respiration was lower in the NFT with 606±121.4㎕ O₂/g/hr, while it was 931.2±136.7㎕ O₂/g/hr, 853.9±95.6㎕ O₂/g/hr and 757.2±110㎕ O₂/g/hr in the aeroponics sprayed for 1 minute each at the intervals of 5 min., 10 min. and 20 min., respectively, that is, it was higher in the plots sprayed at shorter intervals among the aeropomcs.
5. In the contents of endogenous growth hormones, in the GA₃ and zeatin riboside were higher in the plants grown in aeroponics, while ABA and IAA were higher in the those grown in NFT. When the hormone contents were compared by organs, roots from the aeroponics contained more GA₃ and zeatin but less ABA and IAA than those from NFT, while the leaves from the aeroponics contained higher amount of zeatin only than those from NFT.
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