The researchers studied how different cutting angles affect the growth of grafted watermelon seedlings. They used watermelon and pumpkin plants in their experiments. The angle at which the plants were cut did not affect the survival rate of the grafts, but it did impact the growth of the plants after grafting. A larger cutting angle for the plants led to better growth in both the scion (watermelon) and the root (pumpkin). This information can help improve the design of cutting mechanisms for robots that perform grafting, making the process more precise.