Plant Morphology

Plant Morphology

Morphology:

The study of forms and features of different parts of plants like roots, stems, leaves, flowers, fruits etc is called Morphology.

Root

Root is the descending part of the plant which develops from redicle. Root hairs arises from epidermis. Root generally grows in the soil away from light.

Root are of two types –

1. Tap root and 2. Adventitious root.

Modification of Tap roots are –

1. Conical – like Carrot

2. Napiform – like Turnip, beet etc.

3. Fusiform – like Radish

• Rootless plant is lemma

Stem

This is the part of a plant which grows towards light.

• So, they are usually positively phototrophic.
• It develops from plumule.

The modifications of stems are as under –

• Stem of plant help in distributing food to all parts of the plant. Beside this it also help in storing of food. Shaping the plant, respiration and photosynthesis.

Underground stem

1. Tuber – like Potato.

2. Corm – like Colocasia, Saffron etc.

3. Bulb – like Onion, Garlic etc.

4. Rhizome – like Turmeric, Ginger etc.

Leaf

• It is green. Its main function is syntheses of food through photosynthesis.
• In cactus leaves are modified into spines.
• Cactus is referred as xerophytes.

Flower

Clove is obtained from flower bud. Flower is the reproductive part of plant.

In flower Calyx, Corolla, Androecium and Gynoecium are found. Out of these androecium is male sex organ and the gynoecium is female sex organ.

Androecium:

Unit of androecium is stamen. There are one or more stamens in the androecium. Pollen grains are found in anther.

Gynoecium:

 Unit of gynoecium is carpel or pistil.

There are three parts of carpel –

1. Ovary, 2. Style and 3. Stigma.

• Flower having both stamen and carpel is called bisexual flower.

Pollination:

• After maturation of Another, the process of transfer of pollen grains to stigma is called pollination.
  Pollination is of two types –

1. Self-pollination 2. Cross-pollination

Fertilization:

Fusion of male and female gamets forming zygote is called fertilization in living organism.
In case of flowering plant an unique event double fertilization takes place. In this process after germination of pollen grain, pollen tube reach into the embryosac releasing two male gemetes. One male gemetes fuse with the egg cell (i.e. female gamete) to form zygote where as other gemete fuse with polar nuclei to form endosperm (triple fusion). This complete process is called double fertilization.

Syngamy:

Fusion of gametes resulting in the formation of diploid zygote is called syngamy.

Parthenocarpy:

In some plants fruits are developed from ovary without fertilization. This type of fruit is called parthenocarpy. Normally these types of fruits are seedless. Example – Banana, Papaya, Orange, grapes, Pine-apple etc.

• In the majority of flowering plants, out of four magaspores, the ratio of functional and degenerate megaspores is 1 : 3.
• Parthnogenesis, Apogamy and sporophytic budding are an irregular mode of reproduction resulting in the development of embryo without fertilization.
• Bulbil take part in vegetativel reproduction.
• The inflorescence of wheat is spike.
• Photoperiodism affects the flowering of plant.
• Pollination in maize takes place by air.
• Male part of flower is stamen where as female part of flower is pistil.
• Node is the part of stem where leaf arises.
• Pollination by wind is known as anemophily.
• Currently there is increased demand of fresh and good quality flower for human consumption worldwide due to –

1. Flowers are endowed with natural antioxidants and scavenging of reactive oxygen radicals.
2. Flowers are rich source of Anthocyanins.
3. Flowers are important source of vitamins and minerals.

Formation of fruits

• Fruit is a matured or ripened ovary developed after fertilization.
• Formation of fruit takes place from ovary.

Fruits are divided into three types –

1. Simple fruits – like Banana, Guava etc.

2. Aggregate fruit – Strawberry, Custard apple etc.

3. Composite fruit – Jackfruit, Mulbery etc.

In the development of some fruits, Calyx, Corolla and thalmus take part. These types of fruits are called False fruits. Example – Apple, Jackfruit, pear etc.

Some fruits and their edible parts

• Water of coconut is liquid nucellus.
• The medicinal plant used in the preparation of skin care is aboevera.
• In the seed of neem major pesticidal properties are present.
• The alkaloid naturally found in Coffee, Coca and Cola nut is Caffeine.
• Hoe peppers are hot due to presence of capsaicin.
• A clone is a group of genetically identical individuals obtained through micro propagation.
• Origin place of maize is America.
• Seedless fruit are of no use in coconut and pomegranate.
• Papaya is the source of papain.
• Vivipary germination is found in mangrove plant.