This article throws light upon the top five theories of ion uptake by plants. The theories are: 1. Lundegardh Theory 2. Contact Exchange Theory 3. Carbonic Acid Exchange Theory 4. Bennet-Clark’s Protein Lecithin Theory 5. Donnans’ Equilibrium Theory. 1. Lundegardh Theory (Electro-Chemical Theory) of Ion Uptake: Lundegardh (1945) proposed that an electrical potential gradient existing […]