Why is it necessary for plant seeds to contain food reserves?

Question

Why is it necessary for plant seeds to contain food reserves?

Answer 1

Plant seeds need food reserves because the moment of germination is uncertain and the embryo inside the seed is a living being whom is constantly needing food to grow and develop. Also, it is important to say that the embryo doesnt have an inmediate root system in order to gather food by itself...it takes some few days or hours

Answer 2

For the same reason a new business takes investment capital to get started.

A new plant is generating lots of new tissues and structures at a very rapid rate. New enzymes, cells, cell walls, cell organelles, hormones, etc. all need building blocks - carbohydrates and amino acids - and putting those things together requires energy. This building material and energy is furnished by the mother plant in the form of a seed. It gives the seedling a much-needed advantage in those critical first steps.