Results of the DFT hydroponic cultivation experiment of mini-bok choy with hyper-oxygenated
nutrient solution created by eco-Bubble®
The DFT hydroponic cultivation system for mini-bok choy with two sets of micro-bubble generators for releasing pure oxygen micro- bubbles in the nutrient solution stored at a pool (640 x 130 x 20 cm) in Experiment.
A typical example of the diurnal DO fluctuations between 14:00 on 14 November and 15:00 on 15 November 2018. They were divided into five different periods (Period 1 to Period 5), and a regression line was interpolated to the data plots in each of them.
【 What the results of the experiment indicate ? 】
Experiment: The cultured plant does not consume dissolved oxygen in the nutrient solution during the daytime when it can carry out photosynthesis even if the nutrient solution in the tank is hyper-oxygenated, while it actively takes in dissolved oxygen in the hyper-oxygenated nutrient solution through the roots during the nighttime when photosynthetic activity has stopped.
The plant has a capacity that can take in dissolved oxygen through the roots in the water and sustain its metabolic activity during the nighttime, if enough oxygen is contained in the water around the roots.
(However, it will be concealed since oxygen is soluble to the water under the present atmosphere of 1 atm that contains about 21 % of oxygen)
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The oxygen intake enables to decompose carbohydrate with oxygen to gain chemical energy (ATP) during the nighttime as does during the daytime.
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The obtained energy enables to take in the nutrients through the roots during the nighttime.
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Oxygen intake through the stomata on the leaves hardly contributes to the oxygen transmission to the roots during the nighttime when the internal oxygen production by photosynthesis has stopped, but it can rely on the DO of the water as an alternative oxygen source if DO of the water is hyper-oxygenated.
Control: The DO concentration of the nutrient solution ranged between 1.50 and 2.55 mg/L. In many cases, the DO of the irrigation water is much lower than the DO saturation level of the water (8 to 10 mg/L) under the atmosphere of 1 atm. The cultured plant can utilize oxygen produced by photosynthesis for the metabolic activity during the daytime, while it has no source of oxygen during the nighttime.
【 Effects of hyper-oxygenated water on the growth of the cultured plant: Mini-bok choy 】
The difference of growth in the experiment
The fresh weight of the aerial parts (leaves) and roots in the experiment increased approximately 2.0 and 1.8 times larger to those of the Control respectively after the cultivation for 30 days.
Sample pictures after cultivation for 30 days
(a) Control: 10.5 g in the aerial parts, 1.8 g in the
roots
(b) Experiment: 20.7 g in the aerial parts, 2.6 g in
the roots.
Research paper
【 How to create the hyper-oxygenated water for crop cultivation 】