The study looked at how different amounts of potassium affected the photosynthesis and potassium levels in tobacco plants. They found that high-efficient potassium improved photosynthesis more than K2SO4. Increasing potassium fertilizer initially raised potassium levels in tobacco leaves, but too much caused levels to drop. Potassium levels in roots and stems increased with more fertilizer, but then decreased later on. Stems consistently had more potassium than roots throughout the growth period.