The Nether Reactor is huge part of Minecraft PE. It is the only known way to get Melon Seeds and Pumkin seeds. I'm not sure about the potato but i got one from the nether reactor this time. This video was made to show you how to build a Nether Reactor and also show you what the 0.8.0 Nether Reactor gives you if your already familiar with the Nether Reactor in from previous PE releases.