Understanding Leaves: Function, Structure and Types of Leaf Bones – Surely you already know that every plant must have leaves. This is because the leaves are one of the important parts or organs of plants. Leaves are able to absorb solar energy which is then used as material for photosynthesis. In other words, leaves greatly affect the survival of plants.
Leaves can be grouped based on the veins of the leaves. In addition to science, we need to study or recognize the bones of the leaves more deeply. Do you already know how many types of leaf bones there are? In this article, we will discuss the types of leaf bones. So, what are you waiting for, immediately read this article until it’s finished.
Definition of Leaf
Leaves are one part of a plant that grows on twigs or stems and usually grows in strands to become thick. The leaves themselves usually have a green color. Why are leaves often green? This is because the leaves contain chlorophyll.
However, the leaves of some plants are less green in color and not even green. Leaves that are less or not green are caused by not much chlorophyll in the leaves.
Not only that, leaves also function as a breathing area for plants. Inside the leaves are organs called stomata. Stomata are the respiratory organs in plants. So, it can be said that if a plant doesn’t have leaves, then it most likely can’t last long.
Leaf Function
The main function of leaves in plants is photosynthesis, but did you know that leaves still have other functions besides photosynthesis? Here are some of the functions of leaves that you need to look at.
1. As a place to store water and food reserves
The function of leaves besides photosynthesis is that the first is a place to store water and food reserves. It is important for us to know the function of these leaves so that plants can continue to survive.
In general, plants store their food in the roots, but in some plants food and water reserves are stored in the leaves. One of the plants whose leaves serve as a place to store food is aloe vera. Therefore, when you open or peel an aloe vera leaf, it will look like jelly.
2. As a breeding tool
As we know that reproduction in plants rarely occurs in leaves. However, in some plants, the leaves become a means of reproduction, such as the Cocor Bebek plant.
In that plant, if the quality of the leaves is not maintained properly, then it could be that the result of the reproduction of the Cocor Bebek plant is not good either. So, if you plant and care for this type of plant, you should always pay attention to the quality of the leaves.
3. As a respirator
Where can plants breathe? Plants can breathe through the leaves because inside the leaves there are organs called stomata. Stomata on leaves can help plants breathe. Likewise, with humans, plants that cannot breathe properly will slowly wither and not even grow anymore.
4. As an evaporation tool
Apart from being a respiratory tool, leaves also function as an evaporation tool. However, in the evaporation process, the leaves are assisted by the cuticle. In fact, in this process the role of the cuticle is greater than that of the stomata.
5. As a guttation site
In general, the process of guttation that occurs in plants through the leaves. Guttation itself means water droplets from the surface of the plant. In this process water droplets will wet the leaves starting from the surface.
Leaf Structure
The leaf structure is divided into two groups, namely the outer leaf structure and the inner leaf structure. In each group of leaf structures there are several more parts. The following describes the structure of the leaf and its parts.
1. Outer Leaf Structure
We can see this leaf structure easily because it is on the outside of the leaf. The outer leaf structure consists of three parts, namely the leaf sheath, petiole, and leaf blade. For more details, let’s look at the explanation as follows.
a) Leaf sheaths
The leaf sheath is the widened part of the leaf base. Leaf sheaths are often known by another name, namely upih daun. The leaf midrib usually serves to wrap the stem of the plant or as a place for the leaves on the stem.
This leaf structure is often found in monocotyledonous plants, especially in the families Musaceae , Graminae , Cyperaceae , and so on.
b) Leaf stalks
The petiole is the part or organ of the leaf that can support or hold the leaf blade so that it does not fall. In each type of leaf, the petiole has a different location and function.
First, a complete leaf, the stalk on this leaf will unite the leaf blade with the leaf midrib. Second, stalked leaves, the petioles on this type of leaf will be attached to the stem nodes. Third, a single leaf, the petiole only supports one leaf.
Fourth, compound leaves, leaf stalks can grow branches to form new leaf stalks (child stalks). This child stalk serves to support the children of the leaves.
c) Leaf blade
Although the shape is very diverse, but the leaf blade becomes a very important outer leaf structure because it is in the leaf blade that photosynthesis occurs. The shape of the leaf blade is thick and some are thin and the color and size are also very diverse.
The diversity in the leaves, then we can identify the types of plants that we are looking at, caring for, or even cultivating. The leaf blade in ferns has a function as a spore carrier.
Plants that have an outer leaf structure consisting of leaf sheaths, petioles, and leaf blades, these leaves can be called complementary leaves. Meanwhile, plants that do not have all three outer leaf structures are called incomplete leaves.
Which leaves are included in the incomplete leaf type? The following is an incomplete explanation of the leaves below.
a) Stemmed leaves
A stalked leaf is a leaf that only consists of a petiole and a leaf blade. You can see examples of stalked leaves in mango leaves, jackfruit leaves, and others.
b) Sitting leaves
Sitting leaves are leaves that only have leaf blades. Sitting leaves are found in biduri plants ( Calotropis gigantea ). These leaves usually have a base that is wide enough to even look like it is hugging the stem.
c) Corrugated leaves
Berupih leaves are leaves that only consist of leaf blades and upih leaves. Usually, these puffy leaves can be seen in the grass family ( Graminae ), such as corn leaves, rice leaves, and so on.
d) Pseudo leaves
Pseudo leaves are leaves that only consist of stalks. In general, the stalks on pseudo leaves are flat. While the leaves are slightly widened like a leaf blade. For example, Oxalis bupleurifolis, Acasia auriculiformis, and others.
2. Inner Leaf Structure
After discussing the outer leaf structure, the next discussion is the inner leaf structure. This inner structure consists of two parts, namely the epidermis and mesophyll tissue. Let’s look at the two parts.
a) Epidermis
The epidermis is the layer of tissue that is under the lower surface of the leaf. The epidermis in higher plants has a different thickness. The epidermis of higher plants is only one layer thick. Meanwhile, in lower plants, the epidermis is thin and generally does not have chlorophyll.
There are lots of cells in the epidermis on leaves that study it. This is because, these epidermal cells have physiological characteristics. One of the epidermal cells that is often studied is stomata.
b) Mesophyll tissue
Mesophyll is a network formed from photosynthetic parenchyma cells and is on the inside of the leaf. The mesophyll tissue consists of several parts, namely palisade tissue and spongy tissue or spongy tissue .
First, mast tissue is a network that has a lot of chloroplasts. The function of this network is as a food maker. Second, spongy tissue is a network whose cavities are useful for storing food reserves.
Types of Leaf Bones Based on the Size
There are 3 types of leaf bones which are grouped based on their size.
1. Mother bone or costa
The mother bone is the leaf bone which is a continuation of the petiole and is in the middle which is longitudinal and divides the leaf. . This mother bone can be said to be the leaf bone which is generally the largest compared to the other leaf bones.
The leaves on the mother’s side of the bone are usually divided into two types, namely there are symmetrical and symmetrical parts and those that are not symmetrical or asymmetrical.
The symmetrical part is the mother of the bone which is located in the middle of the leaf blade so that the left and right leaf sides become symmetrical or symmetrical. Meanwhile, the parts that are not symmetrical are the mother bones that are not located in the middle of the leaf so that the left and right sides of the leaf are not symmetrical or asymmetrical.
2. Branches or lateral nerves
Branch bones or lateral nerves are the bones in the leaves and are smaller in shape than the mother leaf bones. The bones of these branches are at the base of the mother of the bones or are between the branches of these bones.
The names of the bones of this branch are based on how close they are to the mother bone. In short, the branch bones that originate from the mother bone are called the first level branch bones, then this level one branch will branch out, then it is called the second level branch, the naming continues onwards.
Thus, it can be said that each of the branch bones will depend heavily on the mother bone. If the mother bones are not symmetrical or asymmetrical, then it is possible that the bones of this branch will also be asymmetrical.
3. Leaf veins or veins
Basically, leaf veins or veins are part of the branch bones, only with smaller sizes. In addition, between the veins of the leaves have a finer texture than the bones of the branches. This finer texture will be difficult to see with our eyes.
One leaf vein with the other leaf veins will form an arrangement like a road or path. In the process of this formation, leaf veins are assisted by larger branch bones.
Thus, the mother bones, branch bones, and leaf veins are related to each other. In fact, it can be said that the growth or formation of these parts is mutually determining.
Kinds of Leaves Based on the Arrangement
After discussing the bones of the leaves based on their size, the next discussion is about the bones of the leaves based on their arrangement. The leaves are classified based on their arrangement and are divided into four, viz
1. Bone Leaf Pinnate or Penninervis
The pinnate leaves are the leaf bones whose arrangement is shaped like the fins of a fish. The arrangement of the pinnate leaf bones is very neat, even this neat arrangement can be seen from the petiole to the tip of the leaf blade.
We can usually see pinnate leaf bones in plants that have dicotyledonous seeds ( Dicotyledoneae ). As for dicot seed plants, such as mango leaves, guava leaves, and rambutan, durian leaves, melinjo leaves, jackfruit leaves, and others.
2. Bone Leaves Menjari or Palminervis
Finger leaf bones are leaf bones that have a fairly large shape. Just as the name suggests, this leaf bone is shaped like a stretched or widened finger.
The number of finger leaf bones is usually an odd number and the bones in the middle have the longest and largest shape.
Have you ever seen a plant with finger bones? Chances are you’ve seen finger bones in plants because these plants are often used as cooking ingredients. Plants that have finger bones, such as cassava leaves, papaya leaves, and the like.
3. Curved Leaf Bones or Cervinervis
Curved leaf veins are leaf bones that can be said to have several large bones in the middle of the leaf. The large bones will open or make paths on the edges of the leaves. If seen at a glance with our eyes, these leaf bones form a curved line or the ends of the leaves look like they are merging.
If you want to see these curved leaf bones, then you can see them in hibiscus leaves, genjer leaves, betel leaves, gadung leaves, and the like. Have you seen these curved leaf bones?
4. Parallel Leaf Bones or Rectinervis
Parallel veins are leaves that are straight like parallel. This parallel shape makes the leaf shapes look like they are blending together. Parallel leaf bones can be said to be small, but long.
Plants that have parallel leaf veins, such as sugarcane plants, corn plants, coconut leaves, rice leaves, and the like.
5. Spiny Leaves
The last leaf bone is the spiny bone. In general, this spiny leaf bone is included in the type of conifer plant. You can see these thorny leaf-boned plants in fir trees, pine trees, and similar trees.
Functions of Leaf Bones
Leaf bones in plants have functions, including:
1. Strengthen the leaves
Just like the function of bones in other living things that function as strength. Likewise, the bones in the leaves also provide strength to the leaves. These leaf bones will be able to hold or support the leaves from the brunt of the wind. Because of its strength, the bones in leaves are called leaf skeletons or skeletons .
2. The route of transport of substances
The function of the next leaf bone is to transport nutrients. The transportation of nutrients consists of two parts. First, the part for transporting nutrients from the soil, such as water and dissolved salts.
Second, the part for transporting assimilation leftovers originating from the place of manufacture. In other words, the remnants of the assimilation come from the leaves and are distributed to other parts that are in need of these substances.
Also read articles related to “Definition of Leaves” :
- Characteristics of Living Things
- Definition of Mammals
- Functions of the Lungs and Their Parts
- Process of Metamorphosis
- Greenhouse effect
- Source of Motion Energy
- Source of Heat Energy
- Natural Mineral Resources
- Acid rain
- The process of rain
- Mosquito Life Cycle
- Frog Life Cycle
- Tropical climate
Conclusion
The function of leaves in plants cannot be underestimated because without leaves, plants can die. Therefore, when caring for plants, the condition of the leaves must continue to be considered.
The leaf itself has constituent bones consisting of pinnate leaf bones, finger leaf bones. curved veins, parallel veins, and spiny veins.