CSS Paper Botany 2013 MCQs

Vegetative reproduction is highly prevalent in the gametophyte stage of bryophytes. Methods include fragmentation, gemmae formation, or the development of tubers. This allows the plants to propagate rapidly in favorable environmental conditions without the need for sexual reproduction, which is often dependent on specific moisture levels.

The upper surface of Polytrichum leaves features numerous longitudinal, vertical plates of photosynthetic cells known as lamellae. These structures significantly increase the surface area for photosynthesis, allowing the plant to thrive in various light conditions.

In the development of antheridia in various bryophyte species, the terminal cells undergo repeated divisions. These divisions result in the formation of segments arranged in two rows. Observations of these developmental stages indicate that the number of segments produced by these terminal cells typically ranges between 5 and 15 before the final maturation of the antheridial structure.

Bryophyte gametophytes exhibit diverse sexual arrangements. They can be monoecious, where both male and female sex organs are present on the same thallus, or dioecious, where male and female organs are borne on separate thalli. Therefore, both conditions are commonly observed across different species.

The division Bryophyta traditionally includes three main classes: Hepaticopsida (liverworts), Anthocerotopsida (hornworts), and Bryopsida (mosses). While the question lists liverworts as the correct answer, it is important to note that mosses are also members of the Bryophyta division. The provided answer key identifies liverworts as the intended selection for this specific context.

In the development of the antheridium in Funaria, a superficial cell on the receptacle acts as an antheridial initial. This cell undergoes a transverse division to form a basal cell and an outer cell, which then becomes papillate in appearance as it develops into the antheridial structure.

In many thalloid bryophytes, the thallus is differentiated into a dorsal photosynthetic region containing chlorophyll and a ventral storage region. The ventral parenchyma cells are typically devoid of chloroplasts, making them appear colourless, and they function primarily in food storage.

In the life cycle of mosses, the protonema is the initial filamentous stage. From this structure, buds develop that grow into erect, leafy shoots known as gametophores. The gametophore is the mature, dominant phase of the moss gametophyte that eventually bears the sex organs.

Funaria is widely recognized for forming dense, carpet-like, velvety green patches on moist soil, walls, or shaded damp areas. This growth habit is characteristic of many mosses, which thrive in high-humidity environments. While other bryophytes like Riccia also grow in damp places, the specific description of velvety green patches is most frequently associated with the dense colonies formed by Funaria.

Research into the secondary metabolites of liverworts like Conocephalum conicum and Dumortiera has revealed significant antifungal properties. Specifically, extracts from these plants have been shown to inhibit the growth of Candida albicans, a pathogenic yeast, highlighting the potential for discovering new antifungal agents in bryophytes.