Question

explain how soaked seeds swell up and burst their seed coats?

Answer 1

I'll tell u basic concept of it, There is a process called osmosis.
As u soak seeds in water ,there is low water concentration inside seeds than the surrounding,and the semi permiable membrane of seeds allows water to come inside seeds so as to maintain water pressure as well as concentration both outside and inside the seeds and thus when water concentration inside seed increases it bursts their seed coats

Answer 2

Explain how soaked seeds swell up and burst open their seed coats. ... This process of entry of water into thesoaked seeds is called as imbibition. Thi imbibition develops large pressure called as imbibition pressure.This imbibition pressure makes the seedlings penetrate the seed coat and germinate out of it.