The seed of a plant is also the plant embryo, which occurs when a pollen grain gets to an ovule and fertilizes it. The fertilized plant embryo contains the seed and nutrient tissues needed to feed the embryo while it begins to grow into a plant.
The nutrients inside the seed are also called the endosperm, which are generally made of proteins, fats or carbohydrates. The ovules are located with the ovary of a mature flowering plant. The ovary is a large round structure located at the very base of the flower. In conifers and other nonflowering plants, the ovules are located inside the scales of a seed cone, which is often referred to as a pine cone. In apples, the ovary of the plant is the fruit that grows after the ovules have been fertilized, and all that is left of the flower are the leaves that are still attached to the fruit.
Some seeds lay in a state of dormancy until the conditions are right for growth. This protects the plant from growing too early and being unable to survive the elements. Horticulturists use a technique called stratification to subject seeds to both moist and cold conditions.