In the leaves of Funaria, the lamina (the flattened blade portion) is typically composed of a single layer of chlorophyllous parenchyma cells. This thin structure is highly efficient for photosynthesis. In contrast, the midrib is a thicker, multi-layered structure that provides mechanical support and facilitates the transport of water and nutrients throughout the leaf.
2612
In the endothecium, the cells of the outer layer divide repeatedly to form which type of tissue?
During the development of the sporangium in mosses, the endothecium undergoes specific divisions. The cells derived from the endothecium differentiate into the sporogenous tissue, which eventually gives rise to the spore mother cells. These cells undergo meiosis to produce haploid spores. This process is a critical stage in the sporophyte development, ensuring the production of reproductive units for the next generation.
2613
In the apophysis of a moss capsule, which layer contains the stomata?
The apophysis is the sterile basal portion of the moss capsule. Its epidermis contains functional stomata, which allow for gas exchange. This region is often photosynthetic, contributing to the nutrition of the developing sporophyte before the capsule matures and the spores are released.
2614
During the development of the antheridium in Funaria, how many cells are typically produced by the transverse division of the outer cells?
The development of the antheridium begins with an initial cell that undergoes divisions. The outer cells divide transversely to form a short filament, typically consisting of 2 to 3 cells, which eventually develops into the stalk and the main body of the antheridium.
2615
Which moss capsules are sometimes utilized as a component in poultry feed?
Certain mosses, including species of Polytrichum, have been historically noted for their potential use in animal feed due to their organic content. While the terminology 'Bryn' and 'Brym' appears non-standard or potentially misspelled in the source, the answer key indicates both B and C are considered correct in the context of this specific assessment.
2616
During the early development of the Polytrichum embryo, how do the epibasal and hypobasal cells divide?
The zygote undergoes an initial transverse division to form epibasal and hypobasal cells. Subsequently, these cells undergo two successive oblique divisions, which are characteristic of the early embryogeny in many mosses, establishing the apical cell polarity.
2617
Which of the following bryophytes is known to thrive particularly well on burnt soil?
Funaria, commonly known as the cord moss, is a pioneer species often referred to as a 'fire moss.' It is well-documented for its ability to colonize burnt soil or areas recently affected by fire, where competition from other plants is temporarily reduced and the soil chemistry has been altered by ash.
2618
Which of the following bryophytes is characteristically found growing in cool and shaded environments?
Polytrichum, commonly known as hair-cap moss, is a genus of mosses that thrives in cool, moist, and shaded habitats. These environments provide the necessary humidity for their growth and reproductive cycles. While other bryophytes also prefer moisture, Polytrichum is particularly noted for its ability to form dense, carpet-like colonies in such shaded forest floor conditions.
2619
Which modes of reproduction are observed in the gametophyte stage of Funaria?
The gametophyte of Funaria is capable of both vegetative reproduction (e.g., through fragmentation or gemmae) and sexual reproduction. Sexual reproduction involves the formation of antheridia and archegonia, which produce gametes that fuse to form a zygote, eventually developing into the sporophyte generation.
2620
During the development of the archegonium, what cells are produced by the division of the venter cell?
The primary venter cell in the developing archegonium undergoes a transverse division to produce two cells: the upper venter canal cell and the lower, larger egg cell. Both of these are essential components of the mature archegonium structure before fertilization occurs.