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Like any animal, phanerogamic plants also emerge from an embryo in successive stages of development. The first sheet arising from a plant embryo in the early development of a plant, is called a cotyledon.
In this Green Ecologist article we will learn what is a cotyledon, what are their characteristics, their importance and their functions, as well as the types that exist or their classification.
What is a cotyledon: definition
Within botany, the primordial leaves of flowering plants are called cotyledon (phanerogams) and that develop with the seed germination, where they form the first leaf of the embryo. In botany, the number of cotyledons present in the seed is used as a way of classifying phanerogamic plants. The cotyledons, shoots and roots of the plant are structures that develop in the embryogenesis process prior to germination.
In addition, for the cotyledons to be able to differentiate themselves from the rest of the leaves of the plant, their size and how many nutrients they have, such as oil, starch or starch, also contribute.
Cotyledon characteristics
Some cotyledon characteristics are:
- They are the first leaf to emerge from the embryo of the plant.
- They can be differentiated from other leaves due to their size.
- Their number serves as a method of classifying plants.
- The cotyledon is capable of digesting the albumen (tissue that surrounds the embryo) and that after germination, it is used as food. If you want to see this process, we encourage you to do the experiment at home. Learn how to create a germinator and how to use it with this other Green Ecologist article.
- Cotyledons have various nutrients in their tissue
- Cotyledons have a short half-life because when plants develop the leaves with which they get energy, the cotyledons eventually fall off.
- They also have different nutrients.
- It is also important to know that cotyledons are short-lived, because when the plant already manages to develop the leaves that really serve to obtain energy, the cotyledons fall off.
Cotyledon functions and their importance
Cotyledons are very important structures in plants, since provide the nutrients suitable and necessary so that the seeds can germinate. Another function of the cotyledon is to absorb and reserve nutrients that are stored in the seed until the moment when the seedling be able to generate your own true leaves that are capable of carrying out the photosynthesis process.
In addition to the aforementioned, cotyledons are also important for the coloration of plants, because thanks to them the chloroplasts appear with which the ability to carry out photosynthesis is obtained.
Monocots and dicots
Plants can be classified according to number of cotyledons in:
Monocots
Monocots include angiosperm plants that are characterized by having a single cotyledon in the seed, so that after germination they only have a single primitive leaf instead of two. These plants do not have a true secondary growth, that is, they do not have a true trunk nor do they have a cambium (plant tissue made up of embryonic cells. Monocotyledonous plants are unable to generate wood and their stature increases by widening the internodes as the plant grows.
The typical example of monocotyledonous plants are grasses (or cereals), such as wheat, corn or sugar cane, but lilies, palm trees, jonquil, tulips, onion or orchids are also monocots.
Dicotyledons
Dicotyledonous plants are the most common group and the embryo found in its seed has two cotyledons that, when germination occurs, generate two primitive leaves that will serve as food for the new seedling. The leaves of dicotyledonous plants can take various forms, there are heart-shaped, ribbon-shaped or compound and can have serrated or simple edges. The branches of these plants are composed of annual rings and made up of phloem and xylem as conductive tissues. In addition, they are capable of forming wood or firewood.
Dicotyledonous plants are the majority and up to 170,000 species are known. Rosaceae, legumes and Rutaceae belong to this group. As species, we have tobacco, beans, soybeans, peas, chickpeas, daisies, sunflowers, coffee, carob, roses, avocado or cherries.
If you want to read more articles similar to What is a cotyledon, we recommend that you enter our Biology category.
