The researchers studied how the size of the root system affects rice growth and yield. They found that rice varieties with large root systems may have too many roots, which can reduce the amount of nutrients available for shoot growth. By confining the roots in nylon bags of different sizes, they discovered that restricting root growth led to higher surface area for nutrient absorption and increased carbohydrate content in the plant stems. This suggests that having a smaller root system can actually benefit rice plants by improving nutrient uptake and ultimately increasing yield.