Tag: pictorial feature of plant kingdom

When a moss spore germinates, it first produces a filamentous, branched, green, and algal-like juvenile stage called the protonema, from which the leafy gametophores later develop.

The sporophyte of Anthoceros is unique because it possesses a basal intercalary meristematic zone situated between the foot and the capsule, which allows for continuous, indeterminate growth of the sporophyte.

Anthoceros (a hornwort) has mucilage cavities on the ventral surface of its thallus which are colonized by the nitrogen-fixing cyanobacterium Nostoc, forming a symbiotic relationship.

In all bryophytes, including Riccia, the sporophyte is physically attached to and nutritionally dependent (either partially or completely) on the dominant, independent gametophyte. Thus, the sporophyte is parasitic on the gametophyte.

In Anthoceros, the ventral surface of the thallus contains slime pores (mucilage clefts) through which mucilage is secreted, and these pores also serve as entry points for symbiotic Nostoc colonies.

Stomata in mosses are restricted to the sporophyte generation, specifically on the apophysis region of the capsule. The gametophytic structures like the stem and leaves lack stomata entirely. This localization helps in gas exchange and transpiration during the development of the capsule.

Riccia is a liverwort that possesses unicellular rhizoids of two distinct types: smooth-walled and tuberculate. Smooth-walled rhizoids have smooth inner walls, while tuberculate rhizoids have peg-like internal projections extending into the lumen. Multicellular rhizoids are characteristic of mosses, not liverworts like Riccia.

The stem (axis) of the Funaria gametophyte is covered by a single-layered epidermis. This epidermis lacks both a protective cuticle and stomata, which allows for direct absorption of water and gases. Stomata in Funaria are only found on the apophysis of the sporophytic capsule.

The archegonium of Riccia is a flask-shaped structure consisting of a neck and a swollen venter. The neck contains a row of 4 neck canal cells, while the venter contains a single venter canal cell and a single large egg cell (oosphere). This cellular composition is characteristic of many primitive bryophytes.

The protonema is a filamentous, branched, and multicellular green structure that develops from a germinating moss spore. Because of its photosynthetic nature and filamentous growth, it closely resembles a multicellular green alga. This structural similarity is often cited as evolutionary evidence linking bryophytes to green algae.