Plant Science - Seed Germination And Growth Essay
The research question: What is the effect of changing the pH of the soil on the germination and growth of mustard peas?
Hypothesis: The greatest number of peas will germinate and will grow the most when the pH is 5 or 7.
Theory: Enzymes play a vital role in the cells of plants (especially when growing) and enzymes work best when at their optimum pH value. Moreover, all chemical reactions have an optimum pH at which they work best (Howard and Loomis, no date). Generally the enzymes in plants work best at a pH of around 5-7. For examples, lipases work best at a pH of between 4-7 (Barros, Fleur and Macedo, 2010). Furthermore, celluloses, which break down specific carbohydrates, have an optimum pH of between 4-5. This leads me to expect that the greatest number of seeds will germinate when the pH is slightly below neutral (7) (SERVA Electrophoresis GmbH, no date). Also germination is stimulated by an uptake of water and due to the shortage of H+ ions in more alkaline solutions this may delay or terminate germination. The pH of soil can affect the spread of important nutrients with in the soil, and unevenness can prevent a plant from absorbing them. Before plants can use a nutrient it must be dissolved in the soil solution. Most minerals and nutrients are most soluble and so more available for plant absorption in a pH of just below 7, rather than in soils with a pH of 7 or higher. For example, phosphorus is most available in soil…