Body Plan of a Dicotyledonous Plants (With Diagram)

The below mentioned article provides a practical exercise to observe the Body Plan of a Dicotyledonous Plant.

Exercise 1:

To study the body plan of a dicotyledon­ous plant.

Requirements:

A complete, small-sized herbaceous plant (e.g., Brassica campestris or Solanum nigrum, etc.) and a chart showing basic anatomical details of the plant.

Observations and Comments:

1. The plant body is divisible into roots, stem, leaves, flowers and fruits (Fig. 149A).

2. Roots are well-developed and branched. They are covered with root hair. Their function is to absorb water from the soil.

3. Stem is solid, branched and erect. It is divisible into nodes and internodes.

4. Leaves are simple, broad, petiolate or sessile. Their margin is serrate and their apex is acute.

5. Several flowers bearing seeds are also present.

6. Anatomically, root has root hair, epiblema, cortex, endodermis, phloem and xylem (Fig. 150). They are exarch (i.e., their protoxylem faces towards outer side). They have a root cap. Main function of roots is to absorb water.

7. Stem or shoot contains pith, xylem, cambium, ph­loem, cortex and epidermis. Stem shows endarch condition (i.e., their protoxylem faces towards in­ner side). Upward movement of water (i.e., ascent of sap) and translocation of food takes place through various parts of stem. Stem divides into many branches, on which develop leaves.

8. Leaves are responsible for photosynthesis and tran­spiration, the two main functions of plant. They have palisade and spongy parenchyma, filled with chloroplasts. Stomata are found on the leaf epidermis.

9. Flowers are the reproductive parts of plant. After fertilization, the ovary wall develops into fruit wall while the ovule develops into seed.