For which of the following nutrients does cation exchange NOT increase availability of the nutrient to the plant? Magnesium Nitrogen Calcium Potassium The root nodules of legumes provide a environment for nitrogen-fixing low oxygen, plant cells high oxygen, plant cells low oxygen, fungus high oxygen, bacteria low oxygen, bacteria How does auxin promote cell growth? It is an enzyme that loosens the cell wall allowing for growth. It inhibits the entry of ions into the cell, resulting in water entry into the cell. It stimulates the H + /ATPase, causing the cell wall to become more acidic It stimulates cell division..