The leaves are part of plants that have an important function and role to carry out the survival of the plants themselves. Characteristics of the leaves, generally green form of the leaf is largely widened, has a chlorophyll substance that is useful to assist the process of photosynthesis.
Leaves also have parts that play an important role to help the process of growth in plants, after being studied and understood in depth, then humans will realize how important leaves are in plants. So that humans can also indirectly know the importance and use of plants in life. In the informal environment, humans generally know the shape of the leaves, but in this environment humans do not know and know the leaves specifically (Fahn, 1991).
The leaves are generally green organs located above the ground. Leaves contain large amounts of chlorophyll, the pigment that causes leaves to absorb light energy and use it to produce sugar through photosynthesis. Leaf morphology is very varied, the result of adaptation that often occurs with environmental factors pembata plant. The leaves are attached to the stem by a narrow section called the petiole. The width of the leaf is called a leaf blade. Leaf blade is usually thin and flat, and has a reinforcement system that causes the leaves to be flexible and strong (Hidayat, 1995).
One of the powers of Allah regarding plants is to grow a variety of beautiful plants. The purpose of beautiful plants is a plant that has a complete organ, including roots, stems, leaves, and flowers. With all these organs, plants can be said to be perfect plants.
General Functions of Leaves
The general functions of the leaf include:
The place of photosynthesis, in dicotyledonous plants, photosynthesis occurs in the palisade parenchyma network, whereas in monocotyledonous plants, photosynthesis occurs in spongy tissue. As a respiratory organ.
On the leaves there are stomata that function as respiration organs.
Place of transpiration.
Place of mutation.
Vegetative propagation tools, for example in the duckling "leaf bud" cocor plant.
LEAF MORPHOLOGICAL STRUCTURE
In general, the leaves have the following morphological structure (Tjitrosoepomo, 2009):
Leaf blade (lamina).
Petiolus, there is a part that attaches to the stem called the base of the petiole. There are certain plants whose leaves are not stemmed, such as grass.
Leaf midrib (folius), on the base of the monocot plant flat and flat leaf and wrap the stem. For example: banana leaf midrib and taro leaf midrib.
Leaves that have all three parts are called perfect leaves, such as banana leaves and taro leaves. Leaves that do not have one or more leaf parts are called imperfect leaves, such as mango leaves and guava leaves.
On the surface sheet of leaves there are bones or veins of leaves. There are four types of leaf bone types, namely:
Pinnate, for example on mango leaves,
Dancing, for example on papaya leaves,
Curved, for example on yam leaves,
Parallel, for example to corn leaves,
Dicotyledonous plants generally have leaves with an arrangement of pinnate and menjari leaf bones. While monocotyledonous plants have leaves with an arrangement of parallel or curved leaf bones.
STRUCTURE OF ANATOMY LEAVES
There are 3 leaf tissue structure, including epidermal tissue, mesophyll tissue, and transport tissue.
EPIDERMIC NETWORK
The epidermis is in the form of a single layer of cells whose walls are thickened from the substance of the cuticle (cuticle) or sometimes from lignin. In the epidermis there is a stomata (leaf mouth) flanked by two closing cells. Some stomata are located on the upper surface, 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 (Mulyani, 2006)
The leaf epidermis of different plants varies in number of layers, shape, structure, stomata structure, appearance, and trichome structure, and the presence of special cells. The internal structure is usually flat. Leaves have two types of epidermal tissue namely the upper surface of the leaf is called the adaxial surface and the lower surface is called the abaxial surface. At this layer there is no space between cells.
Among the epidermis cells are guard cells that form stomata. This stomata structure that can open and close functions as a place for gas and water exchange. The most important trait in this leaf tissue is its compact cell arrangement and the presence of cuticles and stomata (Campbell, 2005).
MESOFIL NETWORK
Mesophyll is the basic tissue layer located between the upper epidermis and the lower epidermis and between the transport beams. Mesophiles can be composed of relatively homogeneous parenchyma or differentiate into palisade parenchyma and spongy parenchyma. In accordance with its function, the mesophyll parenchyma is a major photosynthetic region because it contains chloroplasts (Sutrian, 2004).
Palisade parenchyma is cylindrical cells, arranged in a row lined up like a fence. Palisade parenchyma is generally found in the upper layers of the leaves, occupying up to ½ to 2/3 mesofi, but can also be found on both sides of the leaf surface. The number of layers of palisade cells can be one layer or more (Hidayat, 1995).
Mesophyll consists of parenchymal tissue found inside the epidermis. Mesophiles undergo differentiation to form photosynthetic tissue containing chloroplasts. In most plants there are two types of parenchyma in mesophyll, namely palisade parenchyma and spongy parenchyma.
Palisade parenchyma
Palisade parenchyma cells are elongated and the cross section looks like a rod arranged in a row. In certain plants, palisade cells take different forms. In Lilium there are large lobes in palisade cells and appear to be branched (Fahn, 1991).
Palisade cells are located under the unilateral (layer) or multilateral (multi-layered) epidermis. There is often hypodermis between the epidermis and palisade tissue. Palisade parenchyma cells are composed of one or more layers. When composed of more than one layer, the length of cells in each layer or the same, or even getting to the middle is getting shorter. Palisade tissue is usually found on the abaxial surface of the leaf.
Although the palisade tissue looks more dense, the long sides of the cell are separated so that the air in the intercellular space still reaches the long side; chloroplast in the cytoplasm attached to the edge of the cell wall. This resulted in the process of photosynthesis can take place efficiently (Kertasapoetro, 1991).
Perenkin Sponge
Sponge tissue consists of branched cells which are irregular in shape. The shape of spongy parenchyma cells can take many forms. Its specialty is the presence of lobes (cavities) that exist between one cell and another. Differentiating between palisade parenchyma cells and spongy parenchyma is not always easy, especially if the palisade parenchyma consists of several layers.
The reason is that if the palisade consists of several layers, usually the innermost layer is very similar to the sponge parenchyma that is nearby (Mulyani, 2006).