The basis of plant physiology is the process of photosynthesis - the conversion of solar energy into the energy of chemical bonds. The main organ of photosynthesis is the leaf. The surface of the leaf is covered with a thin skin - the epidermis, under which is located chlorenchyma - the same tissue in the cells of which the process of photosynthesis takes place. In some plants, between the epidermis and chlorenchyma, there is another additional layer of cells, which is called the "hypoderm". The cells of the hypodermis are transparent and their main function is to scatter sunlight.
Chlorenchyma cells contain the main organelle that carries out photosynthesis - plastids. We will learn about what plastids are and what color they can be from a school biology course.
What are plastids
Plastids are intracellular organelles surrounded by a double membrane. Inside, each plastid is filled with a special fluid - a matrix. The matrix contains enzymes necessary for the synthesis of glucose, the end product of photosynthesis. With the help of a number of enzymes, 6 molecules of carbon dioxide and 6 water are converted into 2 molecules of glucose. One ofthe main "actors" is a molecule of chloroville - a green pigment, which gives color to the leaves of plants.
Plastid types
If a child asks you what color plastids can be, do not rush to answer that they are certainly green. Everything is not so clear! Plastids are colored by the pigment they contain. Depending on this, several types are distinguished: proplastids, leukoplasts, chloroplasts, chromoplasts. It depends on the type what color plastids are.
Proplastids are colorless organelles from which all other types of plastids are subsequently formed. Leucoplasts are also colorless. Chloroplasts are colored green, and they determine the color of the leaves and stem.
Chromoplasts are the most exotic type of plastids. The matrix of chromoplasts contains carotenoids, and in this case it is they that determine what color plastids can be - orange, yellow, pink, red, burgundy or brown. Chromoplasts give flowers and fruits their characteristic coloration.
Plastid functions
The color of plastids depends on their function. More precisely, from the pigment included in their composition. The main function of plastids is photosynthesis, but not all plastids are capable of photosynthesis, but only chloro- and chromoplasts.
Leucoplasts are "aged" plastids that serve to store substances, mainly starch, and proplastids give rise to everything elseplastid types.
Thus, the functions depend on what colors the plastids can be. Green chloroplasts synthesize new substances, and colored and bright chromoplasts attract pollinating insects to flowers. Colorless leucoplasts store food reserves.
