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ASEXUAL REPRODUCTION IN FUNARIA

Asexual Reproduction: The sporophyte in Funaria is commonly called sporogonium. The asexual reproductive units, the spores are produce in it. Meiosis takes place before spore formation. 
Structure of Sporogonium: A mature sporogonium is borne at the end of a female branch. It can be differentiated into a massive foot, a long seta and a pear shaped capsule. The foot is embedded in the apical tissue of female branch. It absorbs water and nutrients from the gametophyte. The seta is a long stalk that carries capsule at its apex. The capsule is pear shaped highly organized spore producing structure. The young capsule is green but as it matures it turns dark brown. The apical part of the capsule exhibits considerable tissue differentiation.
Internal Structure of Sporogonium: The foot is bulbous mass of tissue embedded in the apical tissue of the female branched. The seta consists of aa central conducting strand composed of thin walled cells surrounded by cortex and epidermis which i8s covered with cuticle.
The capsule is differentiated into three regions , the apophysis, theca and operculum.
Apophysis: It is slightly swollen base sterile region of the capsile. The wall consists of epidermis that contains stomata. Beneath it is photosynthetic spongy layer formed of parenchyma cells with intercellular spaces. The center is occupied by a strand of thin walled, vertically elongated cells that are conducting in nature.
Theca: It is central part of the capsule and is characterized by presence of sterile central column of tissue called columella. It is surrounded by barrel shaped spore sac that contains spore mother cells.  Outer to spore sac there is a wide air space traversed by transverse strands called trabeculae which connect the capsule wall to the spore sac. The wall of the theca consists of epidermis, hypodermis and two cells thick photosynthetic spongy layer.
Operculum: The operculum is conical and cap like terminal region of the capsule. It consists of 3-4 layers of thin walled cells covered with epidermis. Immediately below the operculum is peristome. It is a ring of tooth like segments. It is double consisting of 16 long, incurved teeth and 16 thin walled inner segments. The peristome is attached to a ring of thin walled cells that form rim of the capsule. The peristome teeth are hygroscopic and respond to slight changes in humidity.
The region of capsule above the theca consists of 4-5 layers of epidermal cells. The lower two layers of cells are thin walled and constitute annulus. The degeneration of annulus cells results in loosening and dropping off of operculum.
Development of Sporogonium: The zygote enlarges and divides by a transverse division into an upper epibasal and a lower hypobasal cell. Both these cells divide by two oblique divisions to produce two apical cells. The segments cut off from upper apical cell mature into capsule and upper part of the seta, and the segments cut off from lower apical cell develop into lower part of seta and foot.
The segments cut off by upper apical cell divide vertically and appear as a quadrant in transverse section. A vertical wall perpendicular to an inner cell results in formation of a triangular and a rectangular cell in each quadrant. The four rectangular cells divide by a periclinal wall to produce a 4-celled endothecium surrounded by an 8-celled amphithecium. These layers act as fundamental embryonic layers of the sporogonium. 
In the theca region of the capsule, the endothecium cells divide first by a curved vertical wall to separate a triangular and a rectangular cell and then by a periclinal wall to produce four central cells and aring of peripheral cells. The central cells divide and differentiate into central columella. The peripheral cells divide pericilinally into outer layer, the cells of which divide repeatedly to form sporogenous tissue (archigonium); and inner layer cells which give rise to inner spore sac.
The cells of amphithecium divide pericinally to separate outer and inner layers of eight cells each. The inner layer is called first ring and its cells divide and mature into outer spore sac. The cells of outer layer divide anticlinally first and then periclinally to produce an inner 16 celled second ring, the cells of which give rise to trabeculae. The cells outer to second ring divide again anticlinally first and periclinally later to produce a 32 celled inner third ring, the cells of which differentiate into spongy layer. The cells external to third ring divide periclinally to separate 32 celled each, fourth and fifth ring. The cells of these rings differentiate into hypodermis and epidermis respectively.
In the apical region of capsule the endothecium cells undergo anticlinal and periclinal divisions to produce five concentric rings of cells comprising of 8, 16 and 32 cells. The cells of first and second ring differentiate into perisome. The cells of third and fourth ring from thin-walled tissue of the operculum, while the cells of fifth ring give rise to epidermis. The epidermal cells at the base of operculum enlarge to form annulus.
In region of apophysis, the endothecium cells divide repeatedly to form conducting strand. On the other hand the cells of amphithecium divide by anticlinal and periclinal divisions to produce five rings of cells. The cells first four rings differentiate into spongy zone while the cells of the fifth ring give rise to epidermis.
Dehiscence of Capsule and dispersal of spores: During ripening of the capsule, the thin walled operculum cells below the base of annulus begin to dry and shrivel. This results in a loose connection between operculum and under laying tissue. Finally the operculum is shed exposing the peristome. Teeth of the peristome exhibit pronounced hygroscopic movements. In dry weather they bend outward and pave the way for spores to move out of the capsule. However in moist weather they bend down over the spore sac preventing the dispersal of spores. Thus peristome regulates s the dispersal of spores.
Germination of Spores and Development of Protonema: A spore starts germinating immediately after it is shed from the capsule. The spore increase in size and the outer spore ruptures. The inner spore wall grows out into one or two germ tubes. Each germ tube is separated from the spore by the formation of a cross wall near its point of emergence. The cell cut off soon develops into a branched multicellular filament, the protonema.
A protonema is differentiated into two kinds of branches; chloronema which grow along the surface of the substratum or into the air; and rhizoids which penetrate the substratum. The chloronemal stage grows extensively. After about 20 days most of the cells of chloronema degenerate except for a few apical cells which give rise to another type o f filaments, the caulonema. Buds develop on the caulonema filaments which give rise to gametophores.
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