Tag: biology

Sex organs in Funaria develop at the tip of gametophore since the plant itself constitutes the gametophytic phase. After fertilization develops the capsule from which protonema develops from the spores that dehisces from the capsule. The capsule constitutes the sporophytic phase. The plant shows an alternation of generation, between the sporophytic and gametophytic phase.

The mature sporophyte of Funaria is much more complex than that of the liverworts. It is differentiated into foot, seta and capsule. The foot forms the basal portion of sporophyte. The seta is a long cylinder reddish brown, stalk-like structure. It carries the capsule at its top and raises it more than an inch above the apex of the leafy gametophore.

In Funaria, fertilization occurs, as in other Bryophytes, when the plants are wet with rain or dew. The apical cell of the antheridium, which forms operculum absorbs water and bursts. The spirally coiled bi-flagellate antherozoids escape from antheridium, while still enclosed within a vesicle. The vesicle eventually dissolves in water and the antherozoids are set free. They reach the archegonial cluster.

Funaria is monoecious and autoecious i.e., male and female reproductive structures develop on different branches of the same plant. Monoecious means both male and female sex organs are borne on the same plant body.

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).