Structure and Function of Leaves in Plants
In addition to roots and stems, plant leaves also have an important role. The following description of the structure and function of leaves in plants. Leaves including plant organs. An organ is a collection of several tissues that together perform a special function.
Acutus (pointed)
Obtutus (blunt)
Acuminatus (tapered)
Rotundus (rounded)
Emarginatus (notched)
the edges of the leaves meet and attach to one another.
Perfoliatus
Composition of leaf bones (nervation or vernation)
The bones of the leaves (nerves) according to their size can be divided into 3 types, namely:
Costa (mother leaf bone)
Lateral nerve (branch bones)
Veins (veins of leaves)
Based on the arrangement of leaf bones (nervation) (the direction of the large branch bones) can be divided into 4 groups, namely:
Penninervis (reinforced pinned)
Palminervis (boned fingers)
Cervinervis (curved bone)
Rectinervis (parallel to bone)
Leaf edge (margo)
Broadly speaking, the edge of the leaf can be divided into 2 types, namely:
Integer (even)
Diviscus (incised)
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Function of Leaves in Plants
The leaves have an important role for the survival of plants. I wonder what the function of leaves for plants? In general, the function of leaves in plants is to:
Making food through photosynthesis.
As a place for water expenditure through transpiration and mutation.
Absorb CO2 from the air.
Respiration.
Structure of Leaves Forming in Plants
In studying the structure and function of the leaves, of course, it cannot be separated from the tissues that make up the organ of the leaf. The following will be explained briefly about the structure of leaves and their functions along with the leaf constituent network image. In general, the composition of leaf tissue consists of epidermis, mesophyll (basic tissue), transport bundles, and additional tissue.
1) Epidermis
The epidermis is in the form of a single layer of cells whose walls are thickened from a wart (cuticle) or sometimes from lignin. In the epidermis there is a stomata (leaf mouth) flanked by two closing cells. Stomata are located on the upper surface only, for example in plants whose leaves are floating (on a lotus leaf), there are only on the lower surface, and some are on both leaf surfaces (top and bottom).
The Ficus plant has an epidermis composed of two layers of cells. Additional tools found among leaf epidemics include trichomes (hair) and fan cells. You can observe the shape of the epidermis and stomata in the following figure.
2) Mesophiles (basic tissue)
Mesophiles are composed of parenchymal cells that are tenuous and have a lot of space between cells. In most dicotyledonous plant leaves, mesophyll is differentiated into palisade parenchyma (pole tissue) and spongy parenchyma (spongy tissue).
Palisade cells are elongated, contain lots of chloroplasts, and are tightly arranged. Spongy parenchyma is irregular in shape, branched, contains less chloroplasts, and is tenuous.
3) Carrier File
Transport beam contained in the leaf bone that functions as a means of transport and as a leaf reinforcement.
4) Additional Networks
Additional tissue includes special cells that are commonly found in leaf mesophils, such as crystal cells and glands.
Dikotil Plant Leaves Network Composition Network
The structure and function of the leaves of dicotyledonous and monocotyledonous plants are different. The shape of the dicotyledonous leaves of the plant varies, the leaf stem, and the leaf veins pinnate or pinch. Consider the following anatomic tissue composition of dicotyledonous leaves.
Epidermis
located on the top and bottom surface layers of leaves. The function of leaf epidermal tissue is to protect the inner layer of cells from drying out and maintain the shape of the leaves to remain. Its characteristics consist of one layer of cells except the Ficus plant (rubber plant).
Cuticle
located on the upper and lower surface of the leaf. The function of the leaf cuticle is to prevent water evaporation through the leaf surface. This feature of tissue is composed of a warty substance.
Stomata
located on the surface of the upper and lower leaves. The function of the stomata is as a way in and out of air. Whereas the stomata guard cell functions as a regulator of opening and closing the stomata. Characteristics of the leaf mouth in the epidermis with two closing cells.
Hair and glands
located on the upper and lower surface of the leaf. Its function is to place an expenditure. This tissue is an additional tool in the epidermis.
Mesophyll
located between the upper and lower epidermal layers. The function of the leaf mesophyll is for the site of photosynthesis. Mesophyll leaves consist of parenchyma cells, many spaces between cells. Most differentiate into palisade tissue (pole tissue) and sponges (spongy tissue). Pole network cells are cylindrical, tightly arranged, and contain chlorophyll. Spongy tissue cells are irregular in shape, branched and contain chloroplasts, the structure is tenuous.
Veins
lies in the leaf blade. Its function is to transport substances. Characteristics in the form of pinning or fingering.
Structure of Monocotyledon Leaves
Monocotyledonous plant leaves are shaped like a ribbon and on the base there are sheets that wrap the stem, and veins are parallel. The structure and function of the leaves of monocotyledonous plants can be explained as follows.
Epidermis and cuticles
located in the upper and lower surface layers of the leaf. The function of this tissue is to protect the inner layer of cells from drying out and prevent water evaporation through the leaf surface. The characteristics of this tissue are composed of one cell with thickening of the warts.
Stomata
located in a row between the veins. The function of this stomata is as a way in and out of air. Stomata are leaf mouths with two closing cells.
Mesophyll
located in the basin between the veins. This tissue is a place for foodstuffs to make through photosynthesis The characteristics of mesophyll in monocotyledon are not differentiated, the shape is uniform except that the mesophyll of the transporting beam is larger, the chloroplasts are less, and the walls are thicker.
Veins
located on a leaf blade. Its function is as transportation of substances. Leaf veins or leaf bone monocotyledonous plants are parallel.