Question

describe life cycle of nostoc

Answer 1

The life cycle of Nostoc cordubensis is described and illustrated. This colonial species reproduces in two different ways: 1 formation of small buds that develop into mature colonies; 2 rupture of the parent colony leading to dispersion of trichomes together with a portion of mucilage that will form another colony de novo. Observations are included about the autecology of the species, together with details of experiments carried out to explain the mechanisms involved in the two different ways of colony reproduction

Answer 2

Answer:

The life cycle of Nostoc is given as follows:

1. Initially, fresh thalli present having thin colourless envelopes.

2. After 8 weeks, macroscopic spherical and subspherical forms of the thalli are observed. When observed under the microscope, trichomes with heterocytes were found.

3. Next, the thalli released hormogonia along with heterocytes.

4. Hormogonia developed envelope and thereby formed colonies- increased and formed large thalli.

5. These growing thalli formed buds. Aseriate phase starts-->coiling of trichome--> compact mass of cells.

6. Detachment of trichomes at a mature stage and formation of akinetes( enclosed in a sheath).