BRASSICACEAE

BRASSICACEAE

CRUCIFERAE (OR) MUSTARD FAMILY

Systematic Position

                                                                               Class : Dicotyledonae,

                                                                                 Sub class : Polypetalae,

                                                                                Series : Thalamiflorae,

                                                                        Order : Parietales

                                                                                Family : Brassicaceae.

DISTRIBUTION

Brassicaceae is represented by about 375 genera and 3,200 species. They are Cosmopolitan in distribution, but widely occurs in the Mediterranean region. About 200 species distributed in 25 genera are reported from India.

EXAMPLES

Brassica nigra (mustard)

Brassica rapa (turnip)

Brassica napus (rape seed)

Brassica oleracea Var. capitate (Cabbage)

Brassica oleracea Var. botrytis (Cauliflower)

Brassica oleracea Var. gongylodes (Knol—khol)

Capsella bursa pastoris (Shepherd's purse)

Cheiranthes

Iberis amara (Candy tuft)

Raphanus  sativus (radish)

Subularia aquatica (hydrophyte)

HABITAT

The plants are mostly mesophytes. Subularia aquatica is a hydrophyte.

HABIT

The plants are mostly herbs. They may be annuals (Brassica), biennials (Raphanus) or perennials (Cheiranthus, Cardamine) Many plants are cultivated as they produce vegetables.

VEGETATIVE CHARACTERS

ROOT SYSTEM

The plants possess tap root system. In some biennials the tap root stores food materials and becomes tuberous. It is fusiform in radish and napiform in turnip.

STEM

Stem is aerial, erect and herbaceous. It is extremely condensed in radish and turnip. In Knol—khol, the stem is tuberous due to storage of food materials. In cabbage the terminal bud is the largest vegetative bud.

LEAVES

Leaves are simple, alternate, exstipulate and lyrate. They are cauline (Brassica) or radical (Raphanus). Leaves show reticulate venation. In cabbage, young leaves store food materials.

ANATOMICAL FEATURES

The vegetative parts of the plants contain secretory cells which secrete myrosin. The stomata are surrounded by three unequal subsidiary cells (cruciferous).

FLORAL CHARACTERS

INFLORESCENCE

Inflorescence is mostly terminal and racemose type. It may be simple raceme or corymbose raceme. In Cauliflower the inflorescence is a compound corymb It is fleshy and edible.

FLOWER

Flowers are ebracteate, ebracteolate pedicellate, complete, bisexual, actinomorphic, hypogynous and tetramerous or dimerous. In Cheiranthes the flowers are zygomorphic.

CALYX

It consists of 4 sepals. They are free and arranged in two whorls of two each. The sepals in outer whorl are anteroposterior and that of inner whorl are lateral. Aestivation is valvate or imbricate.

COROLLA

It consists of 4 petals. They are free and present in one whorl. The petals are clawed and arranged diagonally in the form of a cross. (Cruciform corolla). In Lepidium and Capsella bursa the petals are narrow or even absent. Aestivation is valvate

ANDROECIUM

It consists of 6 free stamens arranged in two whorls. The outer whorl consists of two short stamens and the inner whorl is with four long stamens. Thus the stamens are described as tetradynamous. Anthers are dithecous, introrse, basifixed and the dehiscence is longitudinal. Nectaries are present at the base of the stamens.

GYNOECIUM

It consists of 2 carpels. They are fused (syncarpous) and placed transversely in the flower. Ovary is superior and unilocular. It becomes bilocular due to the development of a false septum (replum) from the placenta. Style is terminal and short. Stigma is commissural.

POLLINATION

Pollination is carried out by insects (entomophily). Self pollination is present in Subularia and Cardamine as they posses cleistogamous flowers.

FRUIT

Siliqua (Brassica), silicula (Capsella) or Lomentum (Raphanus).

SEED

Seed is non endospermic with a large embryo having two cotyledons. The cotyledons are oily and completely fills the seed. Testa is mucilagenous.

ECONOMIC IMPORTANCE

1. Seeds of Brassica juncea, B. nigra, B. napus yield mustard oil which is used in cooking.

2. Tuberous storage roots of radish and turnip, vegetative bud of cabbage, inflorescence of cauliflower and tuberous stem of knol khol are used as vegetables.

3. Iberis amara (candy tuft), Cheiranthus are ornamental plants.

4. Mustard seeds are used as condiment.

5, Plants like Nasturtium and Lepidium are medicinally important.