What was the significance of the seeds Yamato had? They took some time to show them, and they're definitely part of his equipment. At first I thought he snuck it into the food they ate. 3 seeds, 3 team members, and he kinda looked at the food/Sai funny when they all finished. Maybe that was just him restraining himself to ask Sakura about Sasori though. If those seeds weren't used in the food, then the most likely thing is that's probably the source of his power, using seeds to perform wood techniques.