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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Cryptogams and it's classification

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Cryptogams- Introduction

     The term cryptogams came from Greek word kryptos( hidden) and gamos ( marriage) . It was coined by the 19th century botanist for the plants in which sexual reproduction is hidden or not seen. The seed plants have been accordingly termed phanerogams, from the Greek words phaneros( visible). Such names as thallophytes, lower plants and spore plants are also assigned to the cryptogams. These make up around 84% of the world's botanical diversity. Algae, lichen, Mosses, and ferns are well known cryptogams. The group also includes non photosynthetic organisms traditionally classified as plants, such as Fungi and bacteria. 

Ancient system of classification of cryptogams. 

   Carolus Linnaeus (1701-1778) recognized cryptogams as a bro with in plant kingdom. Hre divided plants into 25 classes and cryptogamia is one of them. It was further divided into 4 orders ie

1.algae( algae, lichens, and thallose bryophytes) 
2.musci( mosses and leafs liverworts) 
3.fungi( a group of nonphotosynthetic thallophytes) 
4.filices( ferns and allies) 

     Linnaeus system Was wholly artificial. For this purpose hr considered structure of flowers more fundamental than vegetative characters. He grouped plants on the basis of number of stamen and carpels, there union and presence or absence of flowers. 

   In later system, called natural system, plants were grouped according to their natural affinities. The first such system was given by A. L. de Jussieu(1789) . He divided plants into three major groups ie   
1.Acotyledones
2. Monocotyledones
3.Dicotyledones
     
Acotyledones are equivalent to that of Linnaeus's cryptogamia. However, most of the classification proposed during the first half of nineteen century were qualities less systems so far as the classification of cryptogams concerned. It was due to the insufficient regarding the life history of cryptogams.
        The scene, however, changed after the publication of  Wilhelm Hofmeister's work in 1851.he studied the life cycles of a number of different groups of cryptogams and mosses. He failed to understand the processes of gametic Union and meiosis., but he knew that sperm stimulates the egg to develop into new sporophyte . Thus the concept of alternation of gametophytic generation and sporophytic generation was given by him.       
           At the same time, phycologists and mycologists brought out the distinctive features of algae and fungi by studing their life cycles. The approach to taxonomy changed significantly with the publication of Darwin's theory of evolution in 1859.the systems of this period are based on phylogeny in which plants are arranged in ascending series from most primitive to the most advance. 

A. W. Eicher ( 1886) system of classification
    
   Based on the baaics of evolution he divided the plant kingdom into cryptogamae ( flowerless plants) and phanerogamae( flowering plants) 

     Thallophyte   have a plant like body that is thallus ( not differentiate into roots, stem, and leaves), lack  vascular tissue, sex organs are one celled, or when multicellular ( as in certain brown algae ) they don't have the gametes surrounded by a layered of sterile cells. Their zygotes never develop into multicellular embryo while still with in the female sex organ. 

    Thallophytes includes algae and fungi. Algae are autotrophic contain chlorophyll  and other pigments. Most of them are aquatic, they are either marine or fresh water. The fungi are heteroteophic the groups include molds, mushroom and other similar organisms. The thallus consist of microscopic tubular fillaments called hyphae and the mass of fillaments constituting the thallus called mycelium. They may be saprophyte or parasites. A few fungi form mutual beneficial partnership with certain algae( lichen) or with roots of certain trees ( mycorrhiza) . 

    Bryophytes are simpler and smaller embryophytes. Lack well developed vascular tissue, life cycle have morphologically distinct sporophytic and gametophytic phases. Gametophytic generation is dominate than sporophytic generation. The gametophyte is prostrate, errect and differentiate into axis ( stem) and lateral appendages( leaves) . They lack roots but possess roots like rhizoids which perform the function of roots. The reproductive structures are multicellular and much more complicated than those of thallophytes. 

   The pteridophytes are also called vascular cryptogams, they have a well developed specialized conducting system. The sporophytic generation is large and dominant than gametophytic generation. It's differentiate into roots, stem and leaves. The vascular tissue consist of xylem and phloem with out vessels and sieve tubes. 

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