Plant life cycle and alternation of Generation

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Plant life cycle and alternation of Generation –

- Alternate stages of haploid (n) and Diploid (2n) phase in life cycle of plants.

- Three Patterns -

Haplontic

 Diplontic

Haplodiplontic

Dominating phase haploid (n).

-only zygote diploid (2n).

-Haploid spores form the main plant body

 

 

eg. Algae viz. Ulothrix, Spirogyra etc.

 

 -Dominating phase diploid (2n).

-Haploid phase only in single cell or few celled gametophyte.

-Zygote forms embryo which forms Sporophyte (main plant body).

eg. Gymnosperms& Angiosperms

-Intermediate i.e.haploid& diploid stages equal.

-Gametophyte & Sporophyte stages both may be free living.

 

 

eg. Bryophytes&Pteridophyte.


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