Plant Morphology
Morphology
The study of forms and features of different parts of plants like roots, steams, flowers, fruits etc is called Morphology.
Root
» Root is the descending part of the plant which develop from radicle.
» Root generally grows in the soil away from light.
» Roots are of two types — Taproot and Adventitious root.
» Root hairs arises from epidermis.
Modification of Tap roots are :
1. Conical - like Carrot
2. Napiform - like Turnip, beet etc.
3. Fusiform - like Radish.
» Rootless plant is lemna.
Stem
» This is the part of a plant which grows towards light.
» They are usually positively phototrophic.
» It develops from plumule.
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 synthesis of food through photosynthesis.
» In cactus leaves are modified into spines.
» Cactus is referred as xerophyte.
Flower
This is the reproductive part of the plant.
In the flower Calyx, Corolla, Androedum and Gynoecium are found. Out of these androedum is male sex organ and the Gynoecium is female sex organ.
» Androedum : Unit of androecium is stamen there is one or more stamens in the androecium. Pollen grains are found in anther.
» Gynoedum : Unit of gynoecium is carpel. There are three parts of carpel - Ovary, Style and Stigma
» Pollination: After maturation of Anther, the process of transfer of pollen grains to stigma is called pollination. Pollination is of two types - Self-pollination and Crosspollination
» Fertilization : Pollen tube reaches the egg cell after entering into the ovule through a pore called micropyle. After that a male nucleus fuse with egg-cell. This is called fertilization. Fertilized egg is called zygote.
In angiosperm, the fertilization is triple fusion where as in other category of plants it is double fusion.
» 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.
» Bulbil take part in vegetative reproduction.
» The inflorescence of wheat is spike.
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 takes part. These types of fruits are called False fruits.
» Water of coconut is liquid nucellus.
» The medicinal plant used in the preparation of skin care is aloevera.
» In the seed of neem major pesticidal properties are present.
» The alkaloid naturally found in Coffee, Cocoa, and Cola nut is Caffeine.
» Hot peppers are hot due to presence of capsaicin.