The physiology of plants is based on the process of photosynthesis - the conversion of solar energy into energy of chemical bonds. The main organ of photosynthesis is the leaf. The surface of the sheet is covered with a thin skin - the epidermis, under which the chlorenchyma is located - the same tissue in which the photosynthesis process takes place. In some plants, between the epidermis and chlorenchyma there is another additional layer of cells called the hypodermis. Hypodermis cells are transparent, and their main function is the diffusion of sunlight.
Chlorenchyma cells contain the main organoid involved in photosynthesis — plastids. We will learn about what color plastids are and what they can be from a school biology course.
What are plastids
Plastids are intracellular organoids 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 final product of photosynthesis. Using a range of enzymes, 6 carbon dioxide molecules and 6 water are converted into 2 glucose molecules. One of the main "actors" is the molecule of chlorovilla - the green pigment, which gives color to the leaves of plants.
Types of Plastids
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! The color of the plastids gives the pigment that they contain. Depending on this, several types are distinguished: proplastids, leukoplasts, chloroplasts, chromoplasts. It depends on the type and what color plastids are.
Proplastids are colorless organelles from which all other types of plastids are subsequently formed. Leukoplasts also have no color. Chloroplasts are colored green, and it is they who determine the color of the leaves and stem.
Chromoplasts are the most exotic type of plastid. Carotenoids are contained in the matrix of chromoplasts, and in this case they determine what color plastids can be - orange, yellow, pink, red, burgundy or brown. Chromoplasts give a characteristic color to flowers and fruits.
Plastid Functions
Their function depends on what color plastids can be. 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.
Leukoplasts are “aged” plastids that serve to store substances, mainly starch, and proplastids give rise to all other types of plastids.
Thus, the functions depend on what colors plastids can be. Green chloroplasts synthesize new substances, and colored and bright chromoplasts attract pollinating insects to flowers. Colorless leukoplasts preserve nutrient reserves.