Why do plants grow flowers

Science in dialogue

How do flowers grow?

At the beginning of a flower there is a small seed, a plant embryo. When it is warm and humid at the same time, such as in spring, the seeds begin to germinate. It swells up because water seeps through its shell.

The seed coat breaks open and the first cotyledons come out of the soil. The cotyledons serve the young plant, also known as the seedling, as a food store. While the cotyledons later dry out, roots, shoots and leaves develop from the seedling, and later also the flowers.

From a microscopic point of view, plants grow in two different ways: When the cell enlarges, the volume of the cell simply becomes larger and larger. But that only works up to a certain point, at some point it will end. During cell division (mitosis), the cell divides, thereby increasing the number of cells. The mother cell divides in such a way that it creates two identical daughter cells. These are initially half the size of the mother cell and later grow to the size of the mother cell. As the individual parts of the flowers (the cells) get bigger and bigger, the whole flower gets bigger too.

The roots give the plant support in the earth. The water is sucked out of the earth through fine root hairs. Nutrient salts are dissolved in the water - they are the breakfast, lunch and dinner of a plant. The water reaches all parts of the plant in long tubes, especially the leaves. Thanks to the nutrient salt meals, the plant can grow.

The sprout grows above the earth. Leaves and side shoots form from it, the main shoot grows into a strong stalk. At some point a flower will develop at its tip. Each plant species has a different flower shape and the colors of the flowers are very different, often even the flowers of the same plant species have different colors. Now they bloom for a couple of weeks. You can pick the flowers and put them in a vase at home or you can let them grow and be happy that the garden is so beautifully colorful.

The question was answered by Prof. Dr. Albert-Dieter Stevens, director of the Berlin-Dahlem Botanical Garden.