The sex organs in bryophytes are multicellular. These two generations follow each other in regular sequence. The second phase is sporophytic phase 2n , which starts with' zygote and ends with reduction division of spore mother cell. The spongy layer is also 1 or 2 cells thick. Each archegonium is flask shaped and is distinguished into a large venter and long neck region. The paraphyses cells contain chloroplasts and the apical cell of each paraphyses is globose and meet over an antheridium to protect it.
It is covered by outer spore sac wall which is 3-4 layers in thickness. It is chiefly concerned with the formation and dispersal of the spores. These cells are covered with epidermis. Antheridium is red or dark orange in color. Both epibasal and hypobasal cells divide by two oblique divisions. Capsule can be divided into three parts they are; Apophysis It connects seta and capsule.
Peristome is a ring of tooth-like segments. The development of the rhizoids takes place from the base of the stem l The erect gametophores of the moss plants develop by the activity of the apical cell. The inner 2-3 layers of parenchymatous cells are chlorophyllous, which constitute the photosynthetic tissue of the capsule. Now sugar containing mucilaginous substances ooze out through the opening of the archegonial neck. Each germ tube is separated from the spore by the formation of a cross wall near its point of emergence. Funaria hygrometrica is most common and world wide species.
The foot is small, conical and is embedded in the gametophyte. The terminal cell of the filament differentiates into apical cell. The epidermis is covered with cuticle. The plants grow in dense mats over moist shady places, especially during rains. Soon after the formation of the buds near a cross wall towards the base of the choloronemal branches or even on the rhizoidal branches the growth of protonema stops.
The vegetative reproduction takes place in favourable conditions for the vegetative growth. Epidermis: A layer of epidermis present outer to the cortex. The lower two layers of cells are thin-walled. The formation of the zygote begins the second phase of the moss life cycle where the zygote develops into a spore-plant. Buds develop on the caulonema filaments. The diaphragm demarcates the upper limit of the theca proper.
The sporophyte begins to grow by cell division out of the top of the archegonium on the female gametophyte plant. Scales are found on the margins, while rhizoids are present in the mid-rib region of thallus. Paraphyses meet over an antheridium to protect it. The sporophyte is differentiated into a foot, seta and capsule. The adult leaves have distinct midrib.
It can be differentiated into a massive foot, a long seta and a pear shaped capsule. Each antheridium develops from a superficial cell of apex. Each sperm mother cell metamorphosed into a biflagellate male sperm. Paraphyses are multicellular filamentous cells with high sterile structure. The neck is closed with cover cells. Vegetative reproduction It takes place by different ways: a By decay: The prostrate branches die. During development, some of the potentially spore-bearing is used as nutrient by the sporocytes as they complete the meiotic divisions that result in colourless kidney-shaped spores.
These cells are surrounded by a layer of jacket cells. Reproduction in Gametophyte Funaria gametophyte reproduces by vegetative and sexual reproductions. The formation of these two type of filaments depends on the environmental conditions in response to which the protonema is extremely plastic. The wounded part produces a protonema. The hydroids conduct water and the leptoids conduct food. The inner cell gives rise to lower embedded part of the stalk. Germination of the spores: During favorable conditions, spores germinate to form a multicellular, filamentous, branched structure called protonema.
The spore wall is differentiated into an outer thick, brown coloured exine exosporium and an inner thin, colourless intine endosporium Fig. Collumela is surrounded by barrel shaped spore sac that contain spore mother cells Outer to these sac, there is a wide air space called as trabeculae that connects capsule wall to the wall of spore sac The wall of theca consist of 1. The genus comprises of 117 species. The site of origin of the sporangia is the receptacle; the latter, with its groups of sporangia, is called a. It is double consisting of 16 long, incurved teeth and 16 thin walled inner segments.