Powered by Blogger.

Funaria grow on ground, walls and rocks in close tufts.
Gametophyte: Adult plan body of moss represents gametophytic phase of life cycle. Gametophyte has two growth stages:

(a) Creeping filaments (b) gametophore.
Protonema: The spore, which is unit of gametophyte on its germination produces a protoneus. It is prostrate, filamentous alga like ephemeral structure. Protonema filaments are separate and have many small chloroplasts, protonema is branched. Some branches penetrate the soil and form rhizoids. Some branches of protonema give rise to an erect leafy stem the gametophore which grows by tetrahederal apical cell. After formation of leafy shoot protonema disintegrates but in some cases it may contribute to the mass of rhizoids which arise from lower end of stem.

It is small 1 to 3 cms high and bears slender, erect, radial stem covered with small, simple leaves. The stem is branched. At the base of gametophyte there are many branched slender multi-cellular rhizoids, each rhizoid arises from a superficial cell on the lower part of the stem and consists of branching row of cells with oblique septa. Leaves are spirally arranged on the stem. The lower leaves are smaller and scattered while upper leaves are larger and crowded at apex of stem. Leaves are sessile, ovate with a pointed apex and entire margin. The adult leaves have distinct midrib.

Reproduction: It takes place by vegetative and sexual methods.
(1) Vegetative reproduction: It takes place as under:

(a) By death and decay of rhizoids: Few rhizoids run prostate and erect branches are given out from them. Sometimes rhizoids die out erect branches and form single independent plant.

(b) By Gammae formation: Barkley in 1941 found that in Funaria hygrometric gammae were formed from terminal cells of the protenemal branches by transverse longitudinal and oblique divisions. The gammae had thin walls, contained many chloroplasts and radially generated protonema.

(c) By protonema formation: Protonema may be either germinated from spore (primary) or from rhizoids or branches (secondary) multiplies vegetatively either by braking of branche or small terminal group of cells.
Sexual reproduction: Sexual reproduction in Funaria is oogamous type. Male and female sex organs known as Antheridia and archegonia are borne in clusters at the tips of main axis and branches. These are protected by covering of leaves called involucre. Plant may be monoecious (but male and female sex organs are borne on different branches) or dioecious. Large number of multicellular hairs the paraphysis is found growing along with sex organs. Function of this paraphysis is protection of sex organs and conservation of water.

Male Reproductive organs of Funaria:
They are antheriduim which develop from single superficial cell lying at the apex of male branch; this cell is termed as antheridial initial cell. This cell increases in size and divides into upper apical cell and lower stalked cell. Lower stalk cell divides further and forms the stalk of antheriduim. Upper apical cell divides to form an apical cell with two cutting faces. Apical cell undergoes several divisions and forms a mass of primary androgonial cells surrounded by a single celled layer of jacket cell. Primary androgonial cells finally form biciliated coiled antherezoids. Each antheriduim is club shaped structure borne on a short stalk. It opens through the operculum. Antherezoids are liberated out embedded in a multi-nucilagenous mass. Antheridia are surrounded by paraphysis.

Female Reproductive organs:
They are archegonia which develop from an apical cell at archegonial branch which functions as archegonial initial cell which cuts off 3 peripheral cells and an axil cell. The peripheral cells are a result of vertical divisions from six jacket initials. The axil cell divides transversely into a primary cover cell and a central cell. The jacket initials from the median and lower part of the neck. The primary cover cell besides forming the cover cells also contribute to the formation of upper portion of the neck. The central cells forms primary canal cell and veuter cell. The primary canal cell forms six or more neck canal cells while the neutral cell forms a neutral canal cell and an egg. The mature archegonium is a flask shaped structure covered by leaves of archegonial branch.

Fertilization: Water medium is essential. Antherizoids are liberated in water which come on the apex of archegonium and reach egg cell by neck. Male and female nuclei fuse together result in formation of zygote or oospore which diploid or sporophytic in nature.

Related Posts Plugin for WordPress, Blogger...