A COMPARARTIVE STUDY OF OXYGENATION TECHNIQUES IN THE HYDROPONIC CULTIVATION OF PELARGONIUM TOMENTOSUM
This aim of this study was to investigate the viability of growing P. tomentosumin deep water culture (DWC) hydroponics and to assess the effects of various methods of oxygenatingthe nutrient solution with regards to growth, development and chlorophyll responses. The experiment was conducted over a period of 74 days. In chapter 3, 16 different methods of oxygenation were applied to 9 replicates. The control had passive aeration. The treatments were madeup of air-pumps, vortex oxygenators and the application of hydrogen peroxide(H2O2)at various frequency intervals; these were combined with each other andrun as separate oxygenation methods. In chapter 3 it was found that the highest chlorophyll content mean value (62.16 mg/m-2) wasachieved through a combination of high frequency application of H2O2, an air-pump and vortex oxygenation (APVHa). This treatment differed significantly (P ≤0.001) from the control and the other treatments. Although high frequency dosage of H2O2alone (Ha) had the highest level of DO(17.96 mg/l), the mean chlorophyll content value was slightly lower than when H2O2was combined with vortex oxygenation and air-pump injection(in treatment 11/APVHa)and had a larger variance. These results indicate that to produce more photosynthetically active Pelargonium tomentosum plants in deep water culture hydroponics it is advisable that application of high frequency dosing of H2O2be combined with other methods of oxygenation.