• Apical meristems.
• Lateral meristems.

The changes in organisms which start from the zygote stage to an adult.

• The zone of cell division takes place at the apical meristems.
• The increase of the number of cells causes the elongation of the plant stem.
• When the new cells are forming, the cells formed previously are pushed to the zone of cell elongation.

• The zone of cell elongation consists of cells that are increasing in size.
• Happens through water diffusion by osmosis and the absorption of nutirents into the cells and stored in the vacoule.
• Small vacoules fuse to form a large vacoule through vacuolation.
• The diffused water exerts pressure against the cell wall which pushes, elongates and widens the cells.

• The zone of cell differentiation consists of differentiating cells that differentiate once they have reached their maximum size.
• Cells differentiate to form permanent tissues such as epidermis,cortex,xylem and phloem.
• The cells change their shapes and structures to become specialised cells with specific functions.

• Primary growth is the growth that occurs after germination and it takes place in all plants to elongate their stems and roots.
• Takes place in the apical meristems at the shoot tips and root tips.
• At the shoot tips, leaf primordia and shoot primodia will grow to form new leaves and shoots.
• Enables plants to increase in height.
• At the root rips, the root cap will become exhausted when they penetrate the soil.
• Root cap to be replaced by the meristem cells.

• Secondary growth occurs mainly in eudicots and a small number of monocots (shrub) to increase the circumference or diameter of plant stem and root
• Lateral meristems consists of vascular cambium (located between phloem and xylem tissues in vascular bundles) and cork cambium (located under the epidermal layer).
• Secondary growth at the stem:
  • Secondary growth starts when the vascular cambium divides actively through mitosis.
  • The cells in the cambium ring divide inwards to form new xylem and outwards to form new phloem. The new xylem tissues become secondary xylem and the new phloem tissues become secondary phloem.
  • When undergoing secondary growth, primary xylem is pushed towards the pith whereas primary phloem is pushed towards the epidermis.
  • As a result, the primary xylem tissues are compressed to form a stronger wood layer.
  • When the secondary xylem layer is compressed,there is an addition to the circumference of the stem which causes the epidermis of the stem to strecth and crack. 
  • Cork cambium actively divides to form cork cells on the outer side and cortex on the inner side.
• Secondary growth at the root:
  • Vascular cambium cells divide actively and combine to form a complete ring.
  • The cells in the cambium ring divide inwards to form secondary xylem and outward to form secondary phloem.
  • Due to vascular cambium activity, the root becomes thicker.
  • The cork cambium located under the epidermis divides actively to form cork cells. The cork cells provide protection to the root tissues.
• Secondary Growth of Monocots:
  • Even though most monocots do not undergo secondary growth, some do, such as Draceana sp., Aloe sp. and Agave sp.

• Provides stability to plants by increasing the stem and root diameters to suit the height of plants.
• Provides mechanical support to plants.
• Produces more xylem and phloem tissues.
• Produces xylem and phloem tissues continuosly to replace old and damaged xylem and phloem tissues.
• Produces stronger and thicker bark to provide protection to the plants.
• Able to live longer by increasing the chances of seed production and reproduction.

• Both growths can increase the size of plants permanently.
• Both growths occur in woody plants.
• Both growths involve cell division by mitosis.

• Plants that undergo secondary growth have high economic values because they can produce timber such as Shorea sp. (meranti) and Balanocarpus sp. (cengal).
• Plants that undergo secondary growth have strong and hard woods which are suitable to be used as structures for houseboats, furniture, fences, doors and others.
• The presence of annual rings makes furniture look attractive and they can be made as decorative items.
• The woods and barks of some plants such as Hopea sp. (merawan) and meranti can produce resin and oil. The substances can be commercialised as varnish, adhesive substance, perfume and medicine.
  • Flowering plants can be made as decorative plants.
  • Commercialised fruits such as mangoes and mangosteen, are products of plants that have undergone secondary growth and they are able to generate income as well as boost economic growth.

• Apical meristems.
• Lateral meristems.

The changes in organisms which start from the zygote stage to an adult.

• The zone of cell division takes place at the apical meristems.
• The increase of the number of cells causes the elongation of the plant stem.
• When the new cells are forming, the cells formed previously are pushed to the zone of cell elongation.

• The zone of cell elongation consists of cells that are increasing in size.
• Happens through water diffusion by osmosis and the absorption of nutirents into the cells and stored in the vacoule.
• Small vacoules fuse to form a large vacoule through vacuolation.
• The diffused water exerts pressure against the cell wall which pushes, elongates and widens the cells.

• The zone of cell differentiation consists of differentiating cells that differentiate once they have reached their maximum size.
• Cells differentiate to form permanent tissues such as epidermis,cortex,xylem and phloem.
• The cells change their shapes and structures to become specialised cells with specific functions.

• Primary growth is the growth that occurs after germination and it takes place in all plants to elongate their stems and roots.
• Takes place in the apical meristems at the shoot tips and root tips.
• At the shoot tips, leaf primordia and shoot primodia will grow to form new leaves and shoots.
• Enables plants to increase in height.
• At the root rips, the root cap will become exhausted when they penetrate the soil.
• Root cap to be replaced by the meristem cells.

• Secondary growth occurs mainly in eudicots and a small number of monocots (shrub) to increase the circumference or diameter of plant stem and root
• Lateral meristems consists of vascular cambium (located between phloem and xylem tissues in vascular bundles) and cork cambium (located under the epidermal layer).
• Secondary growth at the stem:
  • Secondary growth starts when the vascular cambium divides actively through mitosis.
  • The cells in the cambium ring divide inwards to form new xylem and outwards to form new phloem. The new xylem tissues become secondary xylem and the new phloem tissues become secondary phloem.
  • When undergoing secondary growth, primary xylem is pushed towards the pith whereas primary phloem is pushed towards the epidermis.
  • As a result, the primary xylem tissues are compressed to form a stronger wood layer.
  • When the secondary xylem layer is compressed,there is an addition to the circumference of the stem which causes the epidermis of the stem to strecth and crack. 
  • Cork cambium actively divides to form cork cells on the outer side and cortex on the inner side.
• Secondary growth at the root:
  • Vascular cambium cells divide actively and combine to form a complete ring.
  • The cells in the cambium ring divide inwards to form secondary xylem and outward to form secondary phloem.
  • Due to vascular cambium activity, the root becomes thicker.
  • The cork cambium located under the epidermis divides actively to form cork cells. The cork cells provide protection to the root tissues.
• Secondary Growth of Monocots:
  • Even though most monocots do not undergo secondary growth, some do, such as Draceana sp., Aloe sp. and Agave sp.

• Provides stability to plants by increasing the stem and root diameters to suit the height of plants.
• Provides mechanical support to plants.
• Produces more xylem and phloem tissues.
• Produces xylem and phloem tissues continuosly to replace old and damaged xylem and phloem tissues.
• Produces stronger and thicker bark to provide protection to the plants.
• Able to live longer by increasing the chances of seed production and reproduction.

• Both growths can increase the size of plants permanently.
• Both growths occur in woody plants.
• Both growths involve cell division by mitosis.

• Plants that undergo secondary growth have high economic values because they can produce timber such as Shorea sp. (meranti) and Balanocarpus sp. (cengal).
• Plants that undergo secondary growth have strong and hard woods which are suitable to be used as structures for houseboats, furniture, fences, doors and others.
• The presence of annual rings makes furniture look attractive and they can be made as decorative items.
• The woods and barks of some plants such as Hopea sp. (merawan) and meranti can produce resin and oil. The substances can be commercialised as varnish, adhesive substance, perfume and medicine.
  • Flowering plants can be made as decorative plants.
  • Commercialised fruits such as mangoes and mangosteen, are products of plants that have undergone secondary growth and they are able to generate income as well as boost economic growth.