Economical importance of bryophytes

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ECOLOGICAL IMPORTANCE OF BRYOPHYTES Mosses and Bryophytes are the first organiasms to colonise rocks. They colonise rock by acidic secretion. This acidic secretion is due to the death of mosses. When the rock is decomposed it helps in soil formation. Therefore New soils are formed. The soil act as binders.  It prevent soil erosion. The water retention capacity of the soil is high ie, water holding capacity of the soil is high.  This reduces surface water run-off which prevent soil erosion. Bryophyte helps in the recycling of nutrients. ECONOMICAL IMPORTANCE OF BRYOPHYTES. 1) SPHAGNUM Sphagnum has high absorptive power with antiseptic property. This can be used to replace cotton in bandages. 2) MERCHANTIA   Mercahntia cures pulmonary tuberculosisand affliction (pain) in liver. Antibiotic substances are also extracted from bryophytes. it also acts as antiseptic, and as preservative POLYTRICHUM Polytrichum dissolove stone in kidney and in gall bladder. 3) IN RESEARCH It is used in the fie
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Chlamydomonas , systematic position,occurance,thallus structure, ultrastructure and nutrition , notes

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Systematic position

    Division- chlorophyta
    Class- Chlorophyceae
    Order- volvocales
    Family- chlymadomonadaceae
    Genus- chlamydomonas


Occurance

   According to Champman there are 325 species are available but according to Prescott there are 400 species world wide distributed.they are  found in everywhere but mostly freshwater,ie ponds,lakes, tanks, rich in nitrogenous matter, provides green turbidity to the water. They are also found in terrestrial habitats and some in usual habitats ie snow regions ( C.nivalis , cause red snow phenomenon due to the pigment haematochrome) .C.halophila and C .ehrenbergii occurred in saline water.some are epizoic and endozoic.found in brekish water also.

Thallus structure

     It's a  unicellular motile alga very minute ( 20-30 micro meter) .plant body is biflaggeted( mainly)  Whiplash , equal type and at the anterior end,the anterior end is pointed and posterior end is relatively broader but in C.caudata posterior end is pointed. Each cell is surrounded by a smooth, thin, transparent cellulose ( first layer)  wall .in some species the cell wall is surrounded by a distinct gelatinous sheath.in some species pectose layer is formed outside the cell wall.most of the species have a massive cup- shaped chloroplast, however it may be H,discoid , reticulated in shape.chloroplast has single pyrenoids lying on posterior and along the median line , however in some species the pyrenoids may be more than two in each chloroplast.In C .reticulata pyrenoids are absent.pyrenoids functions is to starch synthesis. A single nucleus lies at the centre of the cytoplasm and at the anterior cup shape chloroplast. When the chloroplast is other than cup shape it lies at axial or exocenteic position.Two contractile vacuole are present at the anterior end and are concerned with osmoregulation. The cell has eyespot or stigma lies at the anterior end helps the body to swim towards the light and optimum temperature.

     The two anterior flagella are associated with the neuromotor apparatus and is represent the nervous system  of the cell and this apparatus consists of three main part ie 
I. Blepharoplast granules - a small granular structure present at the base of each flagella.
ii. Paradesmus- a thread like filament connecting the two blepharoplasts.and 
iii. Rhizoplast- a thin descending thread connecting one of the blepharoplasts with the centrosome of the nucleus.
       The centrosome remain connected with the nucleus by many fine fibrills.

Ultrastructure of Chlamydomonas cell

     Under electron microscope the cell wall is appeared multiple layers of cellulose fibrills, the plasma membrane lies inner to cell wall and is differentiate into outer and inner proteinaceous and middle lipid layer.  There are many ribosome, mitochondria and e.reticulum in the cytoplasm, present between the plasma membrane and chloroplast.  The cup shape chloroplast has a nucleus,volution granules, and gulgi apparatus , besides other organelles.the nucleus is bilayed having pores , a nucleolus and chromosomes are not visible in the nucleus.the chloroplast has thylakoids oriented in the long axis of the cell.in pyrenoids starch plates are synthesized on its periphery.the eyespot are also seen close to the anterior end.

 Nutrition
   Most species are phototrophs, however C. dysosmos is a facultative heterotrophs and can grow in the dark in presences of acetate as carbon source.

You can see for, long press at the link.

https://biobuds.blogspot.com/2021/04/fritsch-system-of-classification-of.html

https://biobuds.blogspot.com/2021/04/basics-of-biological-classification-1.html

https://biobuds.blogspot.com/2021/03/algae_23.html

https://biobuds.blogspot.com/2021/04/basics-of-biological-classification-1.html

All the best...😃😃😃😃😃

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