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.
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.
Some cotyledon characteristics are:
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.
Plants can be classified according to number of cotyledons in:
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.
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.
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