Tag: plant kingdom

The diploid sporophyte or sporogonium reproduces by spores and represents the asexual generation. The mature sporophyte of Funaria is differentiated into foot, seta and capsule. 

Antheridia are borne in groups at the expanded convex apex of the antherdiophore. The archegonial branches arise laterally at the base of the male branch. Achegonia are borne in groups at the apex of these branches.

The peristome lies immediately below the operculum. It consists of two overlapping rings of periostomial teeth, which is long, conical teeth, one within the other. There are sixteen teeth in each set. The teeth of both the sets are on the same radii and thus opposite to each other.

The life cycle of Funaria is haplo-diplontic type. In the life cycle free living haploid gametophyte alternates with a semiparastitic diploid sporogonium (Sporophyte). In this type alternation of generations is called as heteromorphic or heterologous. In Funaria the main plant body is free-living gametophyte (n) which exist in 2 forms i.e. protonema (juvenile gametophyte) and leafy gametophore (adult gametophyte). The leafy gametophyte is the dominant phase of Funaria as the vegetative body of itself is represented by these leafy gametophores. It has two distinct growth stages, a prostrate filamentous alga-like protonema and an upright gametophore.

Apophysis is the solid, somewhat swollen basal, green photosynthetic portion of the capsule. It is sterile in nature. It also helps in conduction of water and food materials. It gradually narrows down into seta; hence it is also called as the neck of the capsule. Internally the apophysis is covered by epidermis. In capsule of Funaria stomata present only in apophysis.

A mature archegonium has a long columnar stalk, a swollen venter and an elongated neck. The wall of the venter is two layered, but that of neck is single layered consisting of cells arranged in six rows. The neck encloses an axial row of six or more neck canal cells. Neck consists of 6 or more neck canal cells (6-11).

In moss, when the mature capsule begins to dry up, the thin walled cells of the annulus break and the operculum is thrown away. Dropping off the operculum is assisted by the outward hygroscopic movement of the underlying peristomial teeth. Due to this movement, slits between the inner thin walled peristomial teeth become wider and spores escape gradually through these slits. In a wet atmosphere, the wet peristomial teeth bend inwards and thus closing the slits and prevent the escape of spores. The seta of the mature sporophyte also exhibits hygroscopic movements. In dry weather, by loosing water, it twists and bents, thus helping in dispersal of spores. The sporogonium of Funaria is photosynthetic, hence semi-parasitic on gametophore. It differentiates into foot, seta and capsule. The foot embedded in the female receptacle and absorbs inorganic nutrients.

Vegetative propagation in Funaria takes place by various methods like- fragmentation of the primary protonema, secondary protonema, gemmae, bulbils, apospory.

In Funaria, stomata are absent in leaf and is present in capsule (apophysis). Internally the apophysis is covered by epidermis. The epidermis is interrupted by stomata, which leads into air space below, called as the sub stomatal cavity. Within the epidermis is a broad spongy zone of sterile cells, rich in chloroplasts. There are distinct intercellular spaces between these cells. Stomata in present only in the apophysis, which is present at the basal part of the capsule.

The spores of Funaria are 12 - 20 microns in diameter, and represent the first cell of the gametophytic generation. The spore wall consists of two layers, the outer smooth and brown coloured exosporium, and the inner colourless endosporium. The cytoplasm of spore is rich in oil globules and chloroplasts. The spore germinates under favourble conditions. The exospore is ruptured and the endospore produces a papilla. It soon forms a long filamentous protonema. The protonema shows apical growth and forms two types of branches, the chloronemal branches and the rhizoidal branches.