Question

Write procedure to prepare transverse section of Cycas stem and describe the structure by a labelled diagram.​

Answer 1

External Features of Cycas:

1. Sporophytic plant body attains a height of 8 to 15 feet or more and appears like a small palm.

2. The plant body is differentiated into roots, stem and leaves (Fig. 1).

Cycas Circinalis

3. Roots are of two types: normal roots and coralloid roots.

4. Normal roots grow deep into the soil and are well- branched and positively geotropic.

5. Coralloid roots (Fig. 2) are coral-like, dichotomously branched, fleshy, negatively geotropic and arise from the lateral branches of normal roots.

Cycas. A Bunch of Coralloid Roots

6. Coralloid roots are green in colour because of the presence of an algal zone. In this zone are present members of Myxophyceae, such as Nostoc and Anabaena and some bacteria.