Sexual reproduction in Marchantia

It is highly advanced oogamous type and takes place by male and female reproductive organs called Antheridium and Archegonium. Both organs are present on gametophytic thallus and are borne on special talked erect structures raised above vegetative thallus.

Marchantia is heterothallic i.e. antheridia and archegonia are borne on separated thalli.
Male Reproductive organs Or Male Receptacle:- The are antheridia borne on discs raised above the thallus on slender stalk, called antherudiophores. Each antheridispore bears eight lobed disc. A number of marginal growing points are formed at the tips of labes, from each of which an aeropetal series of antheridia extend towards the centre. Antheridia are located in flask shaped cavities antheridial chamber on the surface of receptacle.

Mature antheridium is cup shaped structure with short stalk and globular body. Jacket of body consists of single layer of thin walled cells inside with a large number of andryocytes which get metamorphosed into antherozoids which are biciliate and rod like.

Development of antheridial receptacle or Male reproductive organs:- Any cell from the dorsal surface of thallus near mid rib functions as antheridiophors initial. It increases in size and divides by several division to from multicultural elongated stalk of antheridiophore. The apical portion of stalk swollens and eight lobed disc is formed called antheridial disc. Now cell in each antheridial disc’s lobe functions as antheridial initial cell and develops into mature antheridium.

Female reproductive organs or female receptacle:- The are archegonia borne on discs raised above thallus on slender stalks called archegoniphores which consist of a stalk and archegonial disc which becomes lobes structure. Apex of archegoniaphore becomes swollen and dichotomy is repeated in succession as a result of which young anchegoniophore becomes a rosette like eight lobed disk. Apical cells of each lobe of disc cuts of segments on the dorsal and ventral faces. The archegonia being to form in acropetal succession from the segments cut off on dorsal face. Soon eight groups of archegonia develop on the upper surface of disc from eight growing points of disc. 

After fertilization the stalk of archegoniophore begins to elongate and there is over growth in the sterile central part of disc. The growing apices are turned downwards and is curved and be close to stalk of the archegoniophore. Each group of archegonia is enclosed by two lipped pendent, fringed, involved sheatk known as perichastium on involucre. The bulbous venter is separated by slender stalk. Neck consists of six vertical rows of jacket cells surrounding 4 to 6 neck canal cells.


Fertilization: Water medium is necessary for fertilization. Neck canal cells and ventral canal cells of archegonium disorganise forming a mass of chemical substance which help in attraction of antherozoids. Free swimming antherozoids enter archegonium neck. One of the antherozoid fuses with the egg and forms zygote.

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