The stem is the aerial part of the plant in charge of, among other functions, give support and structure to it. However, although we have mentioned that we know it, in general, as an aerial part of the plant, there are also types of stems that grow underground.
In this Ecology Text, we bring you all the information you need to understand the importance of the stem in plants. Here we will talk about the parts of the stem and their functionsas well as the differentiation that exists between the various types of stems present in the plant kingdom.
What is the stem
We can define the stem as the part of the plant that grows to the opposite direction of the root. In addition, he is in charge of carrying the Water, nutrients and mineral salts to all parts of the plant to facilitate the energy exchange that occurs during photosynthesis. These are more Plant stem characteristics:
- The stem originates in the ajemula or plumula of the embryo of a seed.
- It is the plant support organ, responsible for supporting not only the leaves, but also to flowers and fruits.
- The stems have terminal buds that flow from both flowers and new ramifications.
- In addition, it has a negative geotropism, that is, they are in the opposite direction to the earth, and positive phototropism, that is to say that they go in a positive sense towards the light. This is what causes them to grow up and unlike roots.
The main parts of the stem and the functions of each
The stem structure It is divided into several parts. In general and orderly, there are the following parts of a stem:
- Neck: This part is located right in the union between the root and the beginning of it.
- Knots: They are small nodules that appear along the stem and indicate the birth of the leaves.
- School: They are the spaces between two consecutive knots. Usually the enterprises decrease as we approach the stem.
- Armpit: It is the exact point of union between the branch or the leaf.
- Vegetative apex: Located at the end of the stem, it is a set of Meristematic cells in constant separation process and protected by a cluster of leaves that gives rise to what is known as terminal yolk. From it the flower and fruit will be born.
- YEMAS: They are the small outbreaks that appear in each armpit and that indicate the growth of a new branch. The yolks are held by an insertion point between the leaf and the armpit and there are several types: the terminal buds, located at the upper end, the lateral yolks, generally located between the knots, and the adventitious yolks, which are found throughout the plant.
Plants stem functions
After knowing the parts of the stem and the specific functions of each one, we can address the subject of the functions that the stem has in the structure of a plant.
- Hold the entire aerial part of the plant.
- Transport nutrients and substances inside the plant. Here you can better know the issue of plant nutrition.
- Transport from the gross sap from the root until it reaches the leaves thanks to the use of the stem ducts, where it is enriched with carbon dioxide and the so -called elaborated sap is created, the main food of the plant.
We recommend you learn more about the stem and other parts of the plants with this other post about the parts of a plant and their functions.
Types of stem
In general, we can classify stems for their consistency, duration and average in which they live.
Types of stem according to your consistency
- Woody: typical of trees and shrubs.
- Semileñosa: typical of floral or rivera plants.
- Herbaceous: typical of vegetables and wild plants.
Types of stem according to its duration
- Annual: Own plants with a year of life.
- Biannuals: typical of plants with two years of life.
- Perennes: typical of trees and big bushes.
Types of stem according to the medium in which they live
- Aerial stems.
- Underground stems.
- Aquatic stems.
Aerial stems
This type of stem is divided into four types.
- Stem: He who offers consistency to herbaceous
- Trunk: woody stem that generally takes cylindrical shape and is present in trees and shrubs.
- Caña: semileum -type stem, also with cylindrical shape, formed by knots and training that sometimes are usually hollow and present crowding leaves.
- Estipite: cylindrical shape that usually ends in a plume of leaves and with a single terminal. Name by which the stem of the palm trees is known.
Underground stems
They are classified into rhizomes, tubers and bulbs. Sometimes they are confused with roots.
- Rizomas: horizontal growth stems, have yolks on their upper face and in turn manufacture air organs to facilitate storage reserve substances.
- Tubers: swelling stems with stored reserve substances that also have yolks capable of causing a new plant.
- Bulbos: stems composed of a single structure that widens to produce several yolks in the upper part, and with adventitious roots in the lower part. Usually spherical and covered by a bed of squamous leaves to protect the seed.
Aquatic stems
They are the ones that make up the aquatic plants, whether fixed, floating or submerged. They are normally very intense green and fleshy texture.
We invite you to discover this topic with more details with this other ecology article about the different types of stems.
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