1) Hydroponics is the technique of growing plants in nutrient solution without soil. Significance of hydroponics is as follows: Identification of essential elements Discovery of deficiency symptoms RequirementsFunctionsLightFor photosynthesisSubstrateAs it does not use soil, it requires an alternate substrate for supportWaterPure water to keep plant nutrients in appropriate concentrationNutrientFor proper functioning of plantsAirFor aerobic respiration
2) Lack of proper aeration of water will lead to reduction in dissolvedO2 in the nutrient solution. This will interfere with proper growth and functioning of the plants. Reduction in O2concentration will ultimately lead to the death of the plants.