Page 1 - Lesson Notes-Morphologyof flowering plant

The angiosperms or flowering plants show a large diversity in external structure
called as morphology (Gk. Morphe—form; logos—study). However, they all are
characterised by the presence of roots, stems, leaves, flowers and fruits.

1. Flowering Plants

The plant body consists of a main axis, which may be branched or unbranched
bearing lateral appendages.
The main axis is divided into two parts
(i) Root system The underground root system develops from the radicle embryo and
helps in fixation of the plant as well as absorption of water and minerals.

(ii) Shoot system The aerial shoot system develops from the plumule embryo.
It contains root, stem, leaves as vegetative parts and flowers, fruits and seeds as
reproductive parts. The Vegetative parts are involved in various vegetative functions
like structural organisation, fixation, absorption, nourishment, growth and
maintenance of various components and ” reproducting parts are for sexual
reproduction and germination of new plants.
The Root
In plants, root is the non-green (due to absence of chlorophyll), cylindrical and
descending part that normally grows downwards into the soil. It does not bear
leaves, buds and not distinguished into nodes and inter nodes.
Regions of the Root
A typical root contains following five regions. However, there is no clear line of
distinction between these regions.
i. Root Cap (Calyptra)
The root is covered at the apex by a thimble or cap-like structure called the root cap.
It protects the root meristem from friction of the soil particles and also protect
tender apex which allow the passage of root through cells, e.g., Lemna, Eichhornia.
ii. Growing Point (Meristematic) Zone
It is a small (about 1 mm in length) thin-walled region having dense protoplasm. It