The study looked at how different levels of phosphorus and potassium affect the roots of winter wheat plants. They found that increasing phosphorus and potassium levels within a certain range led to more secondary roots, higher root activity, and more sugar in the roots. The combination of moderate phosphorus and potassium levels had the best effects on root growth and activity. When there was not enough phosphorus, adding more potassium helped improve root development. Overall, the quality of root growth improved with higher levels of phosphorus and potassium.