Monocot leaf tissue is not much different from dicotyledonous leaves, but there are some tissue constituents that have different shapes. Included in one of the living things that one of the characteristics is to develop and grow, of course it makes plants need supporting materials for growth and development so that they can stay alive. Therefore, plants need a process called photosynthesis to obtain food and nutrients.
Each plant must have a different leaf shape, with different constituent structures. The leaves on each plant also generally have a green color (though not all). Leaves have limited growth, unlike stems, roots, or other plant parts, which can grow according to the plant's needs.
For example, the roots of some plants can continue to lengthen and go deeper into the soil if they have not found a water source. The roots will continue to grow until they find a water source in the soil. However, this is not the case with leaves. The leaves will grow according to the habit of leaf size on the plant. (Also read: Organs in Plants)
Based on the number of seeds, plants are divided into dicotyledonous plants and monocotyledonous plants. The characteristics of monocot plants are:
A plant that has a single seed.
Have only one cotyledon or leaf candidate.
Has a distributed transport network.
Usually have petals consisting of three or multiples thereof.
Have stems that are not cambium.
Have choleoriza (protective sheath on the roots)
Has a coleoptile (protective sheath on the shoot) and,
Has fibrous roots.
Examples of monocot plants are orchids, grains, areca nut, onions and bananas.
Apart from being a photosynthetic medium for plants, leaves also function as a medium for transpiration and the exchange of carbon dioxide (CO2) gas with oxygen (O2) in plants. Leaf tissue structure is divided into two, namely the outer structure which can also be called leaf morphology, and the inner structure which can be called leaf histology. (Also Read: Examples of Weak Electrolytes).
Morphologically, the outer structure of the leaf consists of the base, midrib or upih, stalk (petiole), and leaf blade (lamina). While the inner structure or leaf histology consists of epidermal tissue, and mesophyll tissue, the transport tissue. It should be understood, the structure in the leaf is found in the leaf blade. (Also read: Vapor Pressure Drop)
Well, here's an explanation of the tissue that makes up monocot leaves:
1. Epidermal Tissue
Epidermal tissue in monocot leaves is the outermost tissue of the leaf. In the epidermis, there is no intercellular space. There is an upper epidermis and a lower epidermis. The upper epidermal tissue is also known as adaxial, while the lower epidermal tissue is also called abaxial. (Also Read: Boiling Point Increase)
The cells that make up the upper epidermal tissue of a leaf are different from the lower epidermis tissue. The upper epidermal tissue consists of a cuticle composed of cutin which functions as a barrier to water evaporation and stomata flanked by guard cells or guard cells. While the lower epidermis tissue has a thinner cell wall and a less cuticle layer. (Also read: Gibberellins Hormone)
In monocot leaves, the epidermis consists of a single layer of cells thickened by cutin. Cells found in the epidermal tissue of monocot leaves are usually elongated. The epidermis layer of the leaf functions to:
Prevents dryness of the inner cell layers of leaves
Prevents evaporation of water through the leaf surface
Prevent physical damage
Protects against temperature changes
Prevents loss of nutrients
(Also Read: External Growth Factors)
Epidermal tissue also has additional parts called epidermis derivatives. These additional sections consist of:
The cuticle is composed of cutin (wax layer) which coats the upper (adaxial) epidermal tissue.
Stomata or leaf mouths, which are green holes or pores on leaves surrounded by guard cells or coverings that are different in shape from the surrounding epidermis. Guard cells in monocot leaves are usually dumbbell-shaped. Usually, more stomata are located in the lower epidermis (abaxial) tissue and are lined up between the leaf bones. Stomata function as a medium for photosynthesis and the entry and exit of air and water in the transpiration process. (Also read: Dicotyledonous Leaf Composition Network). Stomata consist of:
Stoma in the form of holes or pores on the surface of the leaf.
The guard cells around the stomata consist of 2 cells and contain chloroplasts.
2 or more neighboring cells. (Also Read: Disorders of the Respiratory System)
Based on the structure, number and location of neighboring cells, stomata types are divided into anomocytic, anisocytic, diacytic, actinocytic, and bidiasitic types. Here is the explanation:
Anomistic type is stomata that have 3 or more number of neighboring cells that are difficult to distinguish. Neighboring cells and epidermal cells look the same so they are often said to have no neighboring cells.
Anisocytic type is stomata that has 3 or more neighboring cells, and one cell will look smaller than the other cells.
Diacytic type is stomata which has 2 neighboring cells and crosses the stomata gap.
Parasitic type is stomata that has 2 neighboring cells and is in line with the stomata gap.
Actinocytic type is stomata which is a variation of the anomocytic type but with neighboring cells that are flat and have a circular arrangement.
Bidiasitic type is stomata that cross the stomata if two neighboring cells line one guard cell. (Also read: Dicot stem structure)
Epidermal tissue on the next monocot leaf is:
Epidermal hairs or trichomes are located on the upper and lower epidermis tissue. Epidermal hairs function as leaf reinforcement and glandular producers. There are several types of trichomes, including:
Non-glandular trichomes, ie thymicomas that do not secrete or secrete glands.
Glandular trichomes, namely trichomes that secrete or produce glands. The glands of glandular trichomes contain certain chemicals and sometimes cause itching.
Fan cells or bulliform cells, part of the epidermal tissue that is only owned by monocot leaves. Fan cells have a larger size than ordinary epidermal cells, thin walls and large vacuoles. These cells contain a lot of water and do not contain chloroplasts. The inner wall is composed of cellulose and pectin, while the outer cell is composed of cutin and is covered by cuticle. The fan cell is used to store water. (Also Read: Internal Growth Factors)
2. Mesophyll tissue
Between the adaxial and abaxial epidermal tissue, there is mesophyll tissue. This tissue contains chloroplasts which contain chlorophyll. Chloroplasts are part of the mesophyll tissue that functions to capture sunlight as energy for photosynthesis. Therefore, the process of photosynthesis can certainly occur in the mesophyll tissue. (Also read: Boiling Point Increase)
In dicotyledonous plants, the mesophyll tissue consists of palisade tissue or pole tissue and spongy tissue or spongy tissue. However, monocotyledonous plants only have spongy tissue and do not have palisade or pole tissues. So that the process of photosynthesis in monocot plants occurs in the cells that make up the spongy tissue. All cells in monocot leaf mesophyll are spherical. Mesophyll tissue functions to produce food substances in the process of photosynthesis. (Also read: Characteristics of Moss Plants)
Sponge Tissue or Sponge Tissue, has the following structure:
Shaped like labyrinths that can be a pathway for CO2 and O2 circulation from the epidermis through the stomata.
This tissue has a loose intercellular network or has many spaces that are in direct contact with the stomata.
These spaces function to supply and accommodate CO2 . gas
Contains fewer chloroplasts, often called chlorenchyma.
Contains transport vessels.
Because they do not have palisade tissue, in monocots there is no significant difference between palisade and spongy tissue. (Also read: Human Reproductive Diseases)
3. Leaf bone or carrier tissue
Leaf veins or veins are also known as transport tissues. The leaf bones spread in all directions and are located on the leaf blade in the spongy tissue region, while the mother leaf bone or costa is located along the spongy tissue. Leaf bones function as a medium for transporting substances from the photosynthesis process and substances needed for the photosynthesis process.
As previously explained, monocot leaves have parallel veins. In monocot leaves, the veins can be the same or different thicknesses. Leaf veins that have different thicknesses are arranged alternately and the leaf bone which is located in the middle is the thickest leaf bone. (Also read: Characteristics of Ions)
Leaf bones or connective tissue are composed of:
Sclerenchyma membrane that functions to cover part (or all) of the vascular bundle and as a leaf reinforcement. The sclerenchyma membrane is usually only found on the mother leaf bone. The sclerenchyma membrane found in the veins or veins usually consists of parenchyma cells.
Vascular files or transport files, namely:
Phloem, which functions to transport the photosynthetic products of leaves throughout the plant body.
Xliem, which functions to transport water and minerals from the roots to the leaves to the top layer of the leaf tissue.