The KOH (potassium hydroxide) test tube placed within the conical flask absorbs the moisture, oxygen, O₂ in the flask and released CO₂ due to which the level of water rises in the tube due to partial vacuum created by absorbed CO₂. An equal volume of water rises. But here, there was no rise in the level of water maybe because of experimental errors like the cork might not have been properly air-tight or maybe the KOH prepared was not fresh or maybe the germinating seeds were not kept moist etc.