BRASSICA PLANT

IMPORTANCE OF BRASSICA:

  • Brassica is used as a food, e.g. leave are used as vegetables.
  • From its seeds oil is extracted, which is known as MUSTARD.

PARTS OF BRASSICA PLANT:

Brassica plant is divided on the basis of their functions onto two categories:
  • VEGETATIVE PART.
  • REPRODUCTIVE PART.

VEGETATIVE PART: 

They are those, which do not take part directly in sexual reproduction.

This part includes:
  • Root .
  • Stem .
  • Leaves.

ROOTS OF BRASSICA: 

  • Root is the underground part of the plant, which moves towards the force of gravity.
  • It is the first part of the plant, which develops from the RADICLE.
  • TAP ROOT SYSTEM is present in brassica plant.
  • The first thick root, which arises from the radical, is known as PRIMARY ROOTS.
  • It gives of branches, which are known as SECONDARY ROOTS.
  • From the secondary roots fine branches comes out, known as TERTIARY ROOTS.
  • Tertiary roots have root hairs.
  • A cap like structure called ROOT CAP protects the tips of the roots. 
                                     Labelled diagram of brassica plant

FUNCTIONS OF ROOTS: 

Root performs various functions:

FIXATION: Root fixes the plant in the soil.

ABSORPTION: The plant absorbs water and mineral salts from the soil through the root hairs only.

CONDUCTION: Root conducts water and mineral salts to the upper part f the plant i.e. stem

STEM OF BRASSICA: 

The stem of brassica is soft and green :
  • Stem is present above the ground, and always moves against the force of gravity.
  • It is the part of the plant, which develops from PLUMULE.
  • The point on the stem which gives rise to the leave is known as NODE.
  • The distance between two nodes is INTER-NODE.

FUNCTIONS OF STEM: 

SUPPORT: Stem gives support to the plant body. It gives support to the branches and leaves in such a way that leaves get maximum amount of light for photo synthesis.

CONDUCTION: Stem conducts water and salts from the roots to the upper parts of the plant body. It also transport prepared food from the leaves to the lower parts of plant body.

PRODUCTION: Stem produces branches, leaves and flowers.

LEAVES OF BRASSICA: 

The leaves of brassica is soft and green in color.
  •  Leaves arise on the stem from the NODES.
  • Its leaves are always parallel to the ground, in order to get maximum light, for the preparation of their food.
  • Leaves of brassica are BI-FACIAL(their upper surface differs from the lower surface)
  • The upper surface of leaves has less stomata, while the lower surface has less stomata.

PARTS OF LEAVES: 

Brassica leaves has two parts;

i- PETIOLE: It is the lower stalk like part, by which the leaves is attached to the stem.

ii-LAMINA:It is surface of the leaf, which is also known as LEAF BLADE.
  • Brassica leaves has WAVY MARGIN.
  • In the center of the leaf, a swollen vein known as MID- RIB is present.
  • From the mid-rib are made up of VASCULAR TISSUES.
  • On the surface of the leaf, waxy layer is present known as CUTICLE.
  • The function of cuticle is to prevent extra evaporation of water.

FUNCTION OF LEAF: 

Leaf perform various functions:

SYNTHESIS: Leaves have chlorophyll so they can synthesize their food (glucose) by the process of photosynthesis.

RESPIRATION: Plants take in oxygen and give out carbondioxide through stomata.

EXCRETION: Extra water, carbondioxide and oxygen are taken out through stomata.

REPRODUCTIVE PARTS OF BRASSICA:

FLOWER:

  • Flower is the reproductive part of the plant, which is beautiful and attractive. 
  • They are yellow in color.
  • They are arranged in a special way on the young branches, arrangement is called as INFLORESCENCE.
  • Brassica flower is BISEXUAL.
  • Flower is attached to the branches with the help of stalk like structure known as PEDICEL/PEDUNCLE.
  • The upper portion of the pedicel is flattened and broad, which is known as THALAMUS.

PARTS OF FLOWER:

 There are FOUR parts of flower.

Labelled diagram of brassica flower 
CALYX:  
  •  It is the outer most part or whorl of the flower.
  • It protects the inner part from rain and sun, when the flower is in the BUD.
  • It consists of FOUR sepals.
  • The sepals are light greenish in young flowers, but as the flower matures they become yellowish, like PETALS.

COROLLA:                                                                                   

  • It is the second whorl of the flower.
  • It consists of four petals, which are yellow in color.
  • The function of corolla is to attract insects, butterflies and bees for cross pollination.

ANDREOCIUM:

  • It is the third whorl of the flower.
  • This the MALE REPRODUCTIVE part of the plant.
  •  It consists of SIX STAMENS, which are arranged in two circles.
  • Each stamen consists of two parts.
  • The LOWER PART is called as FILAMENT, while the upper swollen part is called as ANTHER.
  • In anther the MALE SEX CELLS known as POLLEN GRAINS are produced.
  • At the basal portion of the stamens small NECTARIES are present, which produce sweet liquid called NECTAR for insects (food for insects).

GYNOECIUM:

  • This is the FOURTH whorl of the flower.
  •  It is the FEMALE REPRODUCTIVE part of the flower.
  • It consists of TWO CARPELS. Each carpel has three parts
STIGMA(upper swollen part).
 
STYLE (middle stalk like part).  

OVARY (lower swollen part which contains).
  • OVULES: EGGS are present in the ovule.