Question

Alternation of generations between bryophyta and thallophyta

Answer 1

Answer:

Thallophyta (Algae):

1. They are mostly aquatic.

2 The thallus consists of a single cell to well developed uniseriate or branched filaments.

3. There is no or ill defined tissue differenti­ation

4. In each cell one or few chloropasts are present. In other cases instead of chloroplasts, the chromatophores are present.

5. The stomata or pores are not present

6. Generally rhizoids are not present and if present they are of simple type

7. Every cell is capable of growth and development.

8. Asexual reproduction takes place by means of zoospores or aplanospores. In many cases vegetative reproduction is commonly found.

9. Sexual reproduction may be isogamous, anisogamous or oogamous.

10. The sex organs are unicellular, and when multicellular every cell forms a gamete. There is no jacket of sterile cells.

11. The female sex organ is single-celled oogonium. It is not covered by any sterile jacket layer.

12. The zygote is liberated from the plant and passes into the resting stage.

13. No embryo is formed after fertilization.

14. They show ill defined homologous type of alternation of generations.

15. The gametophyte and sporophyte are independent.

Bryophyta:

1. Mostly terrestrial and prefer damp and shady places.

2. The thalles is not filamentous except in protonema stage. It is made up of parenchymatous cells.

3. There is well defined tissue differenti­ation.

4. In each chlorophyllous cell many well developed chloroplasts are present.

5. The pores or stomata are present.

6. The rhizoids are present. They may be smooth walled, tuberculate or obliquely septate. The scales are also present.

7. Only the special cells are capable of growth and development.

8. Asexual reproduction is absent. Vegetative reproduction is