Hi, today we are going to discuss general characteristics of bryophytes which were present in our very primitive earth and their body structure is very simple so we study their characteristics and other aspects before studying other higher plants groups.
Bryophytes are non vascular non flowering plants and their names bryophyta suggest the word moss and they generally grow in damp conditions and they are generally very small shaped. As flowers not produced in bryophytes they perform reproduction through the formation of spores and they are all embryophyta and their study is known as bryology.
General Characteristics of Bryophytes:
- Bryophytes generally grow in the place where water is present in soil so they generally grow in damp areas because a water layer is required on the soil for their reproduction.
- They are known as thallus because they generally grow parallel to ground and sometimes they grow vertically but their body is not differentiated into root, stem and leaves like other advanced plants.
- Their plant bodies show some structure which exactly resemble the actual plant leaves but they are not actual leaves and their other structures which resemble the stems and roots of higher plants but they are not actual stem and root they only resemble like leaves, stem and root externally.
- In some bryophytes the plant body is attached to the soil by help of some fibrous structure which may confuse us as root but in actual they are not ideal root, they are known as rhizoids which helps the thallus plant body to anchor with the soil and they may be unicellular or multicellular.
- Their stem like structure which know as axis do not have any vascular tissue, xylem and phloem so they are not vascular plants and they can easily meet their water requirements because they live in watery soils so they do not need to struggle much to collect water and vascular tissue also not necessary.
- Their life cycle shows two types of plant body one is known as gametophyte while another stage is known as sporophyte and in the life cycle of bryophytes gametophyte is the most prominent stage and gametophyte bears reproductive organs.
- Gametophyte is capable to perform photosynthesis so they are independent for food and the haploid gametophyte have multicellular male reproductive organs antheridium and female reproductive organ archegonium and their thallus plant body show root like unicellular or multicellular rhizoids, axis and false leaves.
- In gametophyte the male reproductive organ antheridium produce large numbers of flagellate male gametes which are able to move by their flagella to reach upto the female gametes but water layer is required for swimming of male gametes for this reason they need water.
- In gametophyte the archegonium produce eggs and when the male gametes reach to the eggs then fertilization occurs so without water layer it is impossible to reach the male gamete upto the female gamete or eggs.
- The flagellated male gametes or antherozoid fuse with the eggs in flask shaped archegonium and produce diploid zygote which further divide and form multicellular diploid sporophyte which is attached with the gametophyte.
- The sporophyte generally has three parts: foot, seta and capsules and in bryophytes the sporophyte plant body is dependent on gametophyte for nutrition so they are semi parasitic.
- In bryophytes diploid sporophytic plant body undergo reduction cell division to produce haploid spore which on germination give rise to a thread like structure, protonema and the protonema grow further and give rise to haploid gametophytic plant body which contains reproductive organs.
Why are Bryophytes Known as Amphibia of Plant Kingdom?
As we discussed earlier that during reproduction the male gametes or antherozoid have to reach upto the female gametes for getting and male gametes can swim with the help of their movable flagella but without water it is not possible to swim and reach upto female gamete so for reproduction they must need water.
It means that in their life cycle one stage must require water which is similar as in the case of amphibia in animal kingdom and their vascular system is not present so they need water availability in their surroundings for those reasons bryophytes are known as amphibians of plant kingdom.
Read More: Gymnosperms Definition and Examples
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