Monday, June 20, 2011



  • Root is a part of plant that commonly found under soil and the elongation of plant axis..

The structure of root

  • The structure of root is composed of outer structure (morphology) and inner structure (anatomy).

Outer Structure

  • The outer structure of root is composed of root hair and root cap (calyptra).
  1. Root hairs
  2. Calyptra

Root hairs

  • Root hairs commonly is formed near the tip of root and has short age, as well as theEnlargement of surface of root epidermic cells.
  • The root hairs has function to enlarge absorption region of mineral and water from soil.
  • The root hair will absorb mineral and water from soil about 95%. The result of research of experts shows that root can make root hairs of 100 million/day.

Root cap (calyptra)

  • Root cap (calyptra) protects the tip of root that has property very soft and easily broken.
  • The outer part of root cover will produce acidic liquid, that inside is found enzyme that has function to decompose certain substance, that are not easily penetrated the tip of root.
  • By that enzyme, the tip of root can penetrate wall even very strong foundation of building.
  • Root cap has function too protect root cells from destruction as the effect that root growth penetrates soil.

Inner structure

  • The inner structure of root is composed on tissues that forms four layers consecutively from the most outer layer until the most inner layer those are epidermis, cortex, endodermis, and central core (stele).


  • Epidermis is layer that is composed of one layer of cell
  • It has thin wall has Semipermiable property.
  • The wall of root epidermis forms lumps that finally can form root hairs.


  • Cortex is layer that composed of several cell layers that have thin walls.
  • In cortex is found intercellular chambers that has function to gaseous exchange process.
  • Cortex is found in the inner part of epidermis, it has ring shape from parenchyma cells, and it has function for food reservation.
  • Endodermis is cell layer that is located between cortex and central core.
  • Endodermis has function to control the flow of water and mineral salts from cortex to central core.
  • In Endodermic cell is found a part of band shaped called casparian strip . The casparian strip has function to block the passing of liquid from soil through cell wall, so liquid flows through cytoplasm

Central core (stele)

  • Central core is the middle part of root that is located in inner part of endodermis.
  • The central core consist of pericycle and vascular bundles (xylem and phloem).
  • The pericycle consist of parenchyma type cell that lies between endodermis and vascular tissue that comes from procambium cells.
  • In pericycle is formed branches of root and inside pericycle of young root is found xylem tissue and phloem tissue.
  • In dicotyledon plant, woody vascular (xylem) is located in wood part, while filter vascular (phloem) is located in the skin part of the plant.
  • Xylem and phloem lie in one bundle called vascular bundle.
  • Between xylem and phloem is found cambium that has function to form new phloem outward and new xylem inward, so dicotyledon plant can get enlargement growth..


  • In monocotyledon plant, woody vascular (xylem) and filter vascular (phloem) are located spreadingly .
  • Commonly monocotyledon plant has no cambium so monocotyledon plant doesn’t have enlargement growth.

The Function of Root

1. Absorbing Water and mineral salt

  • Through its root hair, the root can absorb water and mineral salts solved in soil by Osmosis.
  • Osmosis is transfer of water molecule from higher concentration to the lower concentration through membrane.
  • The movement of water and mineral salts solved in the water from one cell to another cell caused by the presence of root pressure power that phuses water and mineral salts go up from woody vascular (xylem) of root to woody vascular (xylem) of stem.

2. Sticking and Supporting Body

  • Root has function to stick plant body to the soil so plant can sticks stongly in the place where a plant lives.
  • Besides, root also has function to support another part of plant body (organs).

3. As storage of food reservation

  • In certain plant, such as cassava, carrot, and dahlia flower, root has function as place to store food reservation.

4. Helping Respiration

  • Root can function to help respiration, because oxygen can enter through root by diffusion.
  • Diffusion is transfer process of molecule from one solution of higher concentration to the solution of lower concentration..


  • Stem is organ of path of photosynthesis product food that is produced by leaf. Some of that photosynthesis products are carried to the entire part of body and some more are stored in the stem as food reservation.
  • The outer part of stem is used to identify the kinds of plant because plant stem has particular characteristics, such as soft stem of green color and hard stem of chocolate color.

The Structure of Stem

  • The Structure of stem is separated into outer structure and inner structure.
  • The outer structure of stem in higher level plants is separated of outer structure of herbaceous plant (not woody) and outer structure of woody plants.
  • The inner structure of stem is equal to root, that is consist of epidermis, cortex, endodermis, and central core.

Outer Structure

  • The outer structure of stem of herbaceous plants
  • The Stem of herbaceous plant commonly has characteristics : Soft, has green color, its woody tissue is a little amount or not existing at all, the size of stem is small, and has short age
  • The outer part of stem is thin epidermis. In epidermis is found stomata so can happen gaseous exchange of oxygen with carbon dioxide .
The outer structure of stem of woody plants
  • The stem of woody plant commonly has characteristic: It has hard stem , thick, has chocolate color, and has long age.
  • The old stem, its surface is rather rough, and in certain region is found lenticels.
  • Lenticel is opened lumps in stem and relates with intercellular chamber in inner part that has function as gaseous exchange place in plant.
The young stem is equal to herbaceous stem.
  • Both have chlorophyll so can do photosynthesis process.
  • But, ability to do photosynthesis will disappear when cork layer is formed.

Inner Structure

1. Epidermis

  • Epidermis is the outer layer so intercellular chambers are not found. Its cell wall is rather thick and its outer layer is covered by cuticule.
  • Epidermis has function as protector layer to protect layers inside of it.

2. Cortex

  • Cortex is layer that is found in the inner of epidermis. Its cell is round, has thin cell wall, and has big vacuole. Cortex has function to store food in stem. Cortex consist of several cell layers with air cavities between its cells so have function for gaseous exchange.
  • In certain plant, cortex cell wall has thickening that has function to support or strengthening plant body.

3. Endodermis

  • Endodermis is layer that is located between cortex and central core. Commonly endodermic cells contain flour substance grains. In stem, this layer is not too clear and almost unites with cortex.

4. Central core

  • Central core is the most inner layer. Inside of it is found xylem, phloem, and medulla. Xylem and Phloem form transport vascular bundle that is found along stem, branch, trunk, and leaf bone.
  • Xylem consist of tubes of thick walls with not smooth walls, but spiraled to form ring or spiral. Xylem has function to transport water and minera salt that solve in root to the leaves.

Function of Stem

  • Stem has main function to distribute water and mineral salt from root to leaves and distributing food substance of photosynthesis products from leaves to entire part of plant.
  • Besides, stem also has function as the place of sticking of leaves, flower , and seed so easily to struct by sunlight and it is easily happens pollination as well s spreading of fruit and seed.


  • Leaf is one main organ in plant.
  • Leaf has shape widening flat and commonly has green color because contains chloroplast in its cells.
  • Leaf is found in the top part of plant and sticks in the stem.

The structure of Leaf

  • In leaf is found leaf bone that is the elongation of woody vascular (xylem) and filter vascular (phloem) that is found in the stem.

Outer Structure

  • Based on composition of leaf, leaf is separated to be simple leaf and compound leaf
  • Simple leaf is leaf that has one leaf in its stalk, while compound leaf is leaf that has some (more than one) leaves in one of its stalk.
Based on the shape of composition of veins, leaf is separated as follows.

  1. Pinnafitied leaf, like in mango leaves
  2. Palmate leaf, like in papaya leaves
  3. Bending boned leaf, like in wheat leaves
  4. Lancolate leaf, like in corn leaves
  • Pinnafitid leaf and palmate leaf are commonly found in dicotyledon plants, while bending and parallel boned leaves are commonly found in monocotyledon plants.
  • Based on the shape of leaf edge, leaf is separated to be entire edged leaf, for example in jackfruit leaves, and nonflat edged leaf, for example in rose leaves.

Inner Structure

1. Epidermis

  • Epidermis consists of top epidermis and bottom epidermis.
  • Stomata that is only pound in the bottom epidermis commonly is found in dicotyledon plant,while in monocotyledon plants,stomata is commonly found in top epidermis and bottom epidermis.

2. Pallisade tissue (pole tissue) (xylem)

  • Pallisade tissue is found under top epidermis.
3. Spongy tissue (coral flower tissue)
  • Spongy tissue is located under palisade tissue.In this tissue is found transport vascular of vein transport tissue consists of woody vascular (xylem) and filter vascular (phloem)
The Function of Leaf
  1. The place of Photosynthesis
  2. The Place of Gaseous Exchange
  • Transportation of solved water and mineral in plant is done by xylem tissue that iis found in root, stem, and leaf.
There are three fctors tht cause solved water and mineral can move up from root to leaf, those are.
  1. Root Pressure Root pressure is pressure that comes from outside of root so causes water with solved substances move upward. Root hairs take water from soil by osmosis because its cell wall has semipermiable property and its cell liquid is denser than soil water. When root hairs absorb water, cell liquid of root hairs becomes thinner from liquid of cells that are located inside root. Because inner part of cell is denser thee inner part of cell will absorb water from root hairs and by this way then water will move from cell to cell until woody vascular (xylem) of the stem. Water movement by osmosis from cell to cell produces a pressure called root pressure.
  2. Capillarity Power Woody vascular (xylem) that is found in root , stem, and leaf connected each other forming capillary vascular, so y the presence of that capillary property, water and mineral salts found in it can move. The workingmethod of this capillary power is equal to stove fuse that is immersed in kerosene. Although only the bottom part of fuse that is immersed by kerosene, but the top part of fuse becomes wet because oil penetrates from the bottom part to the top part. The rise of the water and mineral salts is the cause of adhesion power between xylem with water molecules. The adhesion power in xylem causes water is inclined to stick and spread upward, so the narrower vascular bundle the higher the water moves upward. Root pressure and capillarity power don’t satisfy yet to drive upward water and mineral salt to the leaf. Leaf makes transpiration (vaporization) process to pull water so the water arrive to the leaf.
  3. Absorptive Capacity of Leaf
  • Transpiration in the leaf causes decrease of water in the leaf. This condition causes the arising of absorptive capacity of leaf. Absorptive capacity of leaf causes water in vascular bundle is sucked up into the leaf. Water that is sucked functions to replace the loose water as the cause of transpiration process.
  • The water absorb from xylem is replaced by water from stem xylem. Water in stem xylem is replaced by water from root xylem so all of this process produces water flow continuously from root to leaf. This transpiration process produces power. The power produced by transpiration process is called absorptive capacity of leaf.

Transpiration is influenced by several factors,those are as follows.

  1. Temperature
  2. Relative humidity
  3. Atmospheric pressure
  4. Light
  5. The reservation of soil water


a. Photosynthesis Process

  • Photosynthesis happens in chlorophyllose plant. Chlorophyllose plant’s leaves are contained green pigments or colourant matter called chlorophyll.
  • Reaction of Photosynthesis / Reaksi Fotosintesis

b. Factors That Infuance Photosynthesis Process

Factors that influence photosynthesis are light, chlorophyll, temperature, carbondioxide, and water.
  1. Light / Light is required in photosynthesis process as energy source.
  2. Chlorophyll / Chlorophyll is required to absorb light.
  3. Temperature / Temperature influences enzyme the works in that photosynthesis.
  4. Carbondioxide / Carbondioxide is raw material to form glucose.
  5. Water / Water is raw material in photosynthesis process.


The Structure of Flower

  1. Sepal ( Calyx ) Sepal is the outer part of flower that consist of connection of leaf modifications, that is composed in one or several circles. Sepal has function to protect inner parts of flower.
  2. Petals ( Corolla ) Petal is located inside Sepal. The size of petal is usually larger than its sepal and has various colour.
  3. Stamen Stamen is male reproduction organ that located in the middle of petal, its location is adjacent with pistil and commonly surrounds pistil.
  4. Pistillum Pistil is female reproduction organ that is found in centre part of flower.
The Function of Flower
  • The main function of flower is as generative reproduction organ.


  • Fruit is not main organ in plant. Not all plants have the fruits. Commonly fruit develops from female reproduction organ (pistil) in seed plant.
The kinds of fruit
  • Fruit develops from pistil, that is the part of its ovary if happens fertilization. Fertilization is fision process of ovum with sperm inside pistil.
Based on its formation, fruit is divide into two kind, those are true fruit and false fruit.

1. True Fruit

  • True Fruit that is formed by all tissue in ovary. The fruit is found in fruits of papaya, durian, mango, tomato, and so on.

2. False Fruit

  • False fruit I fruit that is formed not only from its ovary, but also comes from another parts of the flower.
  • The Example of false fruits is Mede guava its fruit comes from enlarging flower stalk.
The structure of fruit / Struktur buah
  • Fruit is composed of seed, fruit meat, and fruit skin. Fruit skin in unripe fruit is different with ripe fruit. In unripe fruits, its skin tissue unites, while in ripe fruit,
Fruit skin is separated into three layers, those are.
  1. Outer layer (Epicarp) that is hard
  2. Middle layer (Mesocarp) of thick and has meat of fibrous
  3. Inner layer (Endocarp), of thin layer or hard cell layer

The Function of Fruit / Fungsi buah

  • Fruit that inside is found seed has function as plant embryo

  • Seed is formed from fertilization product that happen inside ovary. Ovary is separated into two, those are ovule packed by fruit leaves, such as seeds of mango, rambutan, salak. And ovule that is not packed by fruit leaves, such us seed of pakis haji (Cycas rumphii).
  • Seed is divided into 3 main parts, those are seed ski, endosperm, and embryo (fortcoming of new plant).

  1. Autonomic (Endogenous) Movement
  • Autonomic (Endogenous) Movement is movement that is not known yet it cause certainly but predicted this motion is caused by stimulus that comes from the body of plant itself. In other words Autonomic movement is movement that is not caused by external stimulus. For example The flowing movement of cytoplasm in cell.
Exogenous Movement
  • Exogenous Movement is plant movement that is caused by external stimulus, for example light, Earth Gravitational force, water, touch, and chemical substance. For example the opening and closing of mimosa pudica leaves.
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