The flat and expanded portion of the leaf in its entirety is known as the lamina. In short, the blade of the leaf or the leaf blade is called the lamina of a leaf. It is the main part of the leaf, as all the chloroplasts, which are the reaction centres of the photosynthetic process carried out by the leaves for making their own nutrition, are present in the leaf lamina. The lamina plant leaf produces food as the expanded form allows it to gather and absorb photons from the sunlight which further is utilised in the process of photosynthesis for making available the essential energy and nutrition to the plants.
A leaf is the principal component of all the lateral structures that a plant contains. It is the kitchen of the plant best known for carrying out photosynthesis, thus making the most important vascular organs of the plant. This also means that they are autotrophic as the capture sunlight and the chloroplasts present in the leaf turn the sunlight into chemical energy and nutrients. These nutrients and the energy molecules are then supplied to the entire plant through the vascular network of xylem and phloem. To carry out different functions, the leaf can be divided into various segments. The different parts of a simple leaf are shown below:
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From the above diagram, the lamina plant leaf is clearly visible and understandable. Taking note from above the lamina plant leaf is the expanded and flat portion of the leaf that is above the ground and is responsible for photosynthesis process. The flat and thin area (with different varying degrees) of the lamina botany provides an advantage as the plants can gather significant amounts of sunlight required for the resulting growth and development of the plant. The wide expanse of the lamina botany provides more exposure to the chloroplasts present in the chlorenchyma of the plant leaf. This feature of the lamina plant leaf provides access to the sunlight deep inside the tissue as the sunlight is able to fully penetrate through the leaf.
Different parts of the leaf of a simple plant such as the apex, veins, etc. are the parts of the lamina botany. They are very briefly explained below:
Apex: The tip of the leaf is known as the apex.
Midvein or Primary Vein: The main vascular bundle passing usually through the centre of the leaf is known as the midvein or primary vein.
Secondary Vein: These are the extensions of the primary vein in the lamina plant leaf, covering the entire leaf blade. These veins along with the midvein are responsible for the transport of nutrients, water and food to and from the leaves to the plants.
Leaf Margin: The boundary area following the edge of the leaf is called the leaf margin.
Apart from these structures present in the leaf lamina, the lamina botany is also divided into the ventral (upper or facing towards the stem) and dorsal (lower or facing away from the stem) surfaces of the leaf. The ventral surface is botanically known as adaxial and the dorsal surface is known as abaxial. A common distinction between the two surfaces is that the ventral surface is slightly darker than the dorsal surface although it may not be true for all cases. Apart from differences in the colour, there is also difference in the hairiness and the amount and structure of epicuticular wax. The epicuticular wax is a type of hydrophobic organic compound found on the surface of the lamina plant leaf that keeps the lamina from becoming wet with water and to avoid any moisture loss.
As can be recalled from above, the primary leaf lamina function is the absorption of sunlight for photosynthesis. Different types of lamina are found in different plants. But in almost all of them, either slender or wide, the lamina botany is a flat structure enabling it to take in the photons present in different wavelengths of the sunlight. These photons are then utilised by the chlorophyll present in the chloroplasts of the lamina manufacturing nutrients and food and then passing it to different parts of the plant through the vascular network.
Along with the chloroplasts the leaf stomata are also a part of the lamina botany. The stomata are pores present in the epidermis of the plant leaves, stems and other body organs that control the exchange of gases between the plant and the atmosphere. Specifically the carbon dioxide which is utilised in photosynthesis is absorbed via the stomata into the leaves. The stomata also controls the diffusion of oxygen and water vapour from the leaf to the surrounding atmosphere. This exchange of water vapour and other gases are major contributors for the changes in the plant and surrounding temperature. Thus, another one of the leaf lamina functions is to control the temperature fluctuations through the stomata.
The expanse of the leaf lamina is controlled by the YABBY genes. These genes affect the final extension or expansion of the leaf lamina, thus regulating the eventual amount of the intake of gases and the sunlight, giving every plant a distinct characteristic as the area of the leaf lamina although vital is an important factor in plant growth and development. Depending upon the ecosystem, the leaf lamina area plays an important role in sustaining the viability of plant life via controlling the leaf lamina function.
In Biology we learn about the Plants as living things from a very young age. In higher Classes we get to study the various parts of a tree or Plant such as root, stem, branch, Leaf, flowers, fruit and seed. In this topic we will learn in detail about the various parts of the Leaf such as petiole, Lamina, mid rib, etc and its functions.
Leaf is known as the kitchen of the Plant having Chloroplast which imparts the green colour to it. The flat surface of the Leaf is known as the Lamina which is attached to the Plant through the petiole. The Lamina is the major body of the Leaf having a network of stomata for the intake and exhaustion of Carbon dioxide and Oxygen. These stomata open and close as the requirement of the Plant for preparing the food and are interconnected by primary and secondary veins. Midrib and other lateral ribs provide the structure and shape to the Lamina. Lamina contains the Chlorophyll which carries out the function of trapping the energy obtained from sunlight. This energy trapped in turn is used for production of glucose by the combination of water and carbon dioxide. The glucose produced is the food for the Plant which is translocated through the phloem or the vascular tissue also present in the Lamina to various parts of the Plant. The whole process is called photosynthesis and is the main function of the green leaves.
Botanically, Lamina is also differentiated as the dorsal part and the ventral part. The dorsal part is the surface of the Leaf facing away from the stem. This surface is the visible part of the Leaf in normal position. The ventral part is the other surface facing the stem. This surface is rarely visible from a normal position.
It is quite well-known that a leaf is a significant part of the plant. It is popularly known as the plant's kitchen as it is the main source of food for the plant and going up the food chain to various other organisms as well. The flat and usually thin region of the leaf, the leaf lamina has an important role in giving the special status to the leaf. The lamina plant leaf, as clear from the above article, consists of the chloroplasts and stomata, crucial for photosynthesis and gaseous exchange respectively. The area of the leaf lamina botany controls the number of stomata and the photosynthetic reaction centres thus, controlling the nutrient production and release of water vapour and oxygen.
1. What is the lamina of a leaf?
The lamina of the leaf is a flat and thin structure of the leaf that contains the chloroplast and the stomata. It is made up of the mesophyll tissue surrounded by an upper and lower epidermis. Apart from the chloroplasts and stomata, it also contains the veins which are part of the vascular tissue network of plants responsible for the transport of water, nutrients and food.
2. What is the difference between leaf lamina and leaf blade?
Plant leaf lamina is the flat region of the leaf containing the chloroplasts, veins and the stomata. On the other hand, the leaf blade, in botanical terms, is the entire flat and thin part that is connected to the stem (petiole). Thus, leaf lamina is simply the flat area, whereas the leaf blade is the entire structural aspect of the joined lamina with the stem.
3. What is leaf blade and leaf apex ?
Biologists or Botanists have categorised or named various parts of the Leaf for its easy recognition and understanding the various functions performed by them. Likewise a Leaf has various parts with different names. The Leaf blade is the total flat structure of the Leaf that is connected to the stem or branch by a thin projection called petiole. While Leaf Apex is only the external tip part of any Leaf. The shape of the Apex is different for leaves of different Plants.
4. How does the stomata of leaves function ?
Stomata are the small openings present on both the surface of any Leaf. The basic function of the stomata is to carry out the respiration and intake of carbon dioxide in air. Water vapour also exits through these openings and this process is known as transpiration. The guard cells present around the opening open and close according to the availability of water. In the daytime, when there is sunlight, only then the leaves carry out photosynthesis. The guard cell gets filled with water and gets turgid and bent apart. At night the guard cells shrink and get closed.
5. Is it sufficient for students of Class 11 Science stream to learn only about the exterior parts of a Leaf ?
In Class 11, science stream of both CBSE and ICSE boards, the subject of Biology covers all the external parts of a Leaf and the internal parts as well such as Chlorophyll, Chloroplast, Stomata etc. The basic functions of each and every part is also taught in this Class and has been mentioned in the textbooks. So students are advised to complete the topic for external parts before learning about the chemical functions performed by the internal organs of a Leaf. All the parts are equally important from the examination point of view.
6. Where can I find the study materials to learn about the internal structures of the Leaf and their functions ?
Leaves are the very crucial organs for the survival of any tree or Plant. It helps trees to get food for their growth and nutrition. All these processes are carried out by very well defined organs and paths. Learning and remembering the various functions needs a clear understanding of these processes. The notes and study material prepared by expert Biology teachers at Vedantu can help students in this direction. Students can get all the study materials on the Vedantu website after they register themselves on the portal.
7. What is the cost of all the study materials provided by Vedantu ?
Vedantu website is a platform for online studies helping out students for their exam preparation across India. Any student can get enrolled in Vedantu after registration with some basic details and without any payment. Products such as videos of theory Classes are available on the Vedantu. Other than that some products such as the detailed description of every topic is also available on Vedantu website that is provided to the users free of cost.