The researchers studied how different nitrogen fertilizers affect seed yield and nitrogen efficiency in oilseed rape plants. They compared the effects of ammonium nitrate and urea on plant growth and hormone levels. They found that plants fertilized with ammonium nitrate tended to have higher seed yields compared to those fertilized with urea. Ammonium nitrate also increased the movement of nitrogen and hormones within the plants, while urea led to more nitrogen going to the reproductive parts of the plant. Overall, both fertilizers had similar effects on nitrogen uptake and use efficiency in oilseed rape plants.