Bryophytes

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                  Bryophytes

The fossil record indicates that bryophytes evolved on earth about 395_430 million years ago(during silurian period of paleozoic era) . The study of bryophytes is called bryology. Hedwig is the father of bryology.

Small non vascular plants , such as mosses, liverworts, hornworts. They play vital role in regulating ecosystems because they provide an important buffer system for other plants. 

Bryophytes are called amphibians plants because they are terrestrial plants, but they require water to complete their life cycle at the time of sexual reproduction.



General characteristics of bryophytes

* plants occur in damp and shady areas.

* the main plant body is thallus

* it is attached to the substratub by rhizoids which are unicellular or multicellular

They lack true vegetative structure

They occupy the position between algae and pteridophytes

Life cycle of bryophytes

* gametophyte= ( haploid, main plant body, independent)

* sporophyte= ( diploid , attached to the gametophyte, depended to the gametophyte)

1  alternation og generation

The phases gametophyte and sporophyte alternate each other.

2  Heterophic alternation of generation

Means both gametophyte and sporophyte are morphologically different in appearance.

3 true roots absent and rizoids are present on the ventral surface of the thalloid or base in the leafy forms

Rizoids _ unicellular in hepaticopsida and                        anthocerotopsida

                    Multicellular in bryopsida

4 marchantials= scales arr obtained to protect thallus 

*Vegetative reproduction by  tuber , gemmae etc 

Sexual reproduction by oogamous 

( male sex organ _ anthridia, female sex organ- archegonia)

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