MORPHOLOGY
Gr. Morphos = Form, logos = Study
Morphology is the branch of science which deals with the study of form and structure. In botany, it generally means the study of external features, forms and relative positions of different organs on plants.
Angiosperms or flowering plants show a great variety of shape, size and form. The size ranges from the minute Wolffia and Lemna (0.1cm) to the tall Eucalyptus (up to 100 metre) and large sized Banyan (Ficus benghalensis).
PARTS OF A FLOWERING PLANT
The Root
The root is usually an underground part of the plant which helps in fixation and absorption of water. The root with its branches is known as the root system.
(i) Characteristics of the root
(ii) Types of root system:
The root system is generally of two types:
THE STEM
(i) The stem develops from the plumule of the germinating seed.
(ii) The stem shows the differentiation of nodes and internodes.
(iii) The place where the leaf develops on the stem is called the node.
(iv) The portion of the stem between two successive nodes is called the internode.
(v) Characteristics of stem:
- Stem is an ascending axis of the plant and develops from the plumule and epicotyl of the embryo.
- It is generally erect and grows away from the soil towards light. Therefore, it is negatively geotropic and positively phototropic.
- The growing apex of stem bears a terminal bud for growth in length.
- In flowering plants, stem is differentiated into nodes and internodes.
- The lateral organs of stem (i.e., leaves and branches) are exogenous in origin (from cortical region).
- The young stem is green and photosynthetic.
- Hair, if present, are generally multicellular.
- In mature plants, stem and its branches bear flowers and fruits.
(vi) Diverse forms of stem
THE LEAF
The leaf is a green, flat, thin, expanded lateral appendages of stem which is borne at a node and bears a bud in its axil. It is exogenous in origin and develops from the leaf primordium of shoot apex. The green colour of leaf is due to presence of the photosynthetic pigment – chlorophyll which helps plants to synthesize organic food. The green photosynthetic leaves of a plant are collectively called foliage. They are borne on stem in acropetal succession.
(i) Characteristics of leaf
(ii) Types of leaf
FLOWER
It can be defined as modified dwarf shoot which is meant for sexual reproduction.
Floral Parts of a typical flower
(i) Calyx: It is the outermost whorl composed of sepals.
The calyx may show number of modifications. They are:
(ii) Corolla: It is composed of petals and is the second whorl. The corolla may undergo modification or possess some special appendages.
(iii) Androecium: It is the third whorl composed of stamens. The mode of attachment of a filament to anther by connective is called fixation.
It is of following types:
(iv) Gynoecium: It is the innermost whorl and is also called pistil. It shows carpels.
Accordingly the gynoecium may be described as follows:
AESTIVATION
The arrangement of sepals and petals in bud condition of the flower is called “aestivation”. It is may be of following types:
FLORAL FORMULA
It is an expression summarizing the information given in a floral diagram. It represents the information given in a floral diagram in the form of an equation. Following symbols are used in constructing a floral formula.
1. What is the importance of studying the morphology of flowering plants for the NEET exam? |
2. How can the study of the morphology of flowering plants help in taxonomy? |
3. What are the different types of root systems found in flowering plants? |
4. How does the structure of leaves contribute to plant survival? |
5. What is the role of flowers in the reproductive process of flowering plants? |
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