Test: Pteridium - Class 11 MCQ

The fern leaf, differs from the true leaf (euphyll) of the flowering plants in its vernation, or manner of expanding from the bud. In most ferns, vernation is circinate; that is, the leaf unrolls from the tip, with the appearance of a fiddlehead, rather than expanding from a folded condition. Vernation refers to the growing of a new leaf; circinate refers to the arrangement of the leaf, which is  circular.

In the late Roman Empire and early Byzantine Empire, an exarch was a governor of a particular territory diarch.  adj. (Botany) botany (of a vascular bundle) having two strands of xylem.

In amphicribal vascular bundles, which protoxylem first develops in the centre of the strand and continues to develop both centrifugally and centripetally; a condition termed as 'mesarch' xylem. 

In functional analysis and related areas of mathematics, a continuous linear operator or continuous linear mapping is a continuous linear transformation between topological vector spaces. An operator between two normed spaces is a bounded linear operator if and only if it is a continuous linear operator.

Sorus, plural sori, in botany, brownish or yellowish cluster of spore-producing structures (sporangia) usually located on the lower surface of fern leaves. A sorus may be protected during development by a scale or flap of tissue called an indusium.

The shape of sporangium in fern is biconvex. Each sporangium has a multicellular stalk and a biconvex capsule. A sporangium is an enclosure in which spores are formed. It can be a single cell or multicellular. Sporangia can produce asexual spores by mitosis, but in nearly all land plants and many fungi, sporangia are the site of meiosis, and produce genetically unique haploid spores. In ferns, each sporangium is a capsule, that contains spores. They are usually aggregated into clusters called as sori. The position and arrangement of the sporangia are very important for the identification of ferns. Fronds that have sporangia on their underside are fertile, and those that don't are sterile.

Sex organs are multicellular, stalked and jacketed. Male sex organ is antheridium and female is Archegonium. Zygote is formed in the archegonial venter. It develops into undifferentiated embryo and later into sporophyte

Diploid sporophyte cells undergo meiosis to produce haploid spores. Each spore goes through mitotic divisions to yield a multicellular, haploid gametophyte. Mitotic divisions within the gametophyte are required to produce the gametes. The diploid sporophyte results from the fusion of two gametes.

A state in hermaphroditic systems that is characterized by the development of male organs or maturation of their products before the appearance of the corresponding female product thus inhibiting self-fertilization and that is encountered commonly in mints, legumes, and composites and among diverse groups.

The gametophytes bear male and female sex organs called antheridia and archegonia, respectively. Water is required for transfer of antherozoids the male gametes released from the antheridia, to the mouth of archegonium. Fusion of male gamete with the egg present in the archegonium result in the formation of zygote.. If a flower is stalkless, i. e. sits directly in the axil or other support, it is said to be sessile.

The leaves of Pteridium display a simple structure

Significant differences such as presence or absence of indusial the outgrowth covering sorus in ferns or vascular plants may represent either an ancestral absence (plesiomorphy) or a derived loss (apomorphy). hence the presence and absence of indusial is a morphological feature viewed as an ancestral trait or a derived loss. thus the accumulation in changes in the morphological features of the indusial especially is a means of differentiating it on the basis of its origin.

The plant body of Pteridium is sporophytic and it is differentiated in root, stem and leaves. Root and stem are underground and leaves are aerial.Horizontal in Soil biologists measure how plants and microbes absorb nutrients, and incorporate them into organic matter, which is the basis for the carbon cycle. There are two main processes. Immobilization is when soil organisms take up mineral nutrients from the soil and transform them into microbial and plant tissues.

In Pteridium, the annulus and the stomium help in the dehiscence of the sporangium and dispersal of spores. At maturity, the sporangium dehisces by drying action, which exerts pressure on mouth assisted by shrinkage of the annulus. Lastly mouth of sporangium open and spores are liberated.

The roots of vascular plants are normally considered to have exarch development. Endarch is used when there is more than one strand of primary xylem in a stem or root, and the xylem develops from the inside outwards towards the periphery, i.e. centrifugally. The leaves and stems of many ferns have mesarch development.

The archegonia have a shorter neck than those of the ferns, and the neck is straight. The reproductive organs borne by the thallus or plant Short and curved  are called antheridia and archegonia , and serve for sexual reproduction.

The parenchymatous region left behind in the main stele  after the diparture of the leaf trace is called 'leaf gap'.

The ferns compose a group of several thousand species growing in many diverse habitats, the most common being shady places with abundant moisture. The most conspicuous part of the fern sporophyte is the leaf. The typical fern leaf, often termed a frond, is an elaborate structure composed of numerous leaflets.

Sorus bearing leaf of Pteridium is called Sporophyll.
In these type of leaves when the leaves get matured they bear a cluster or a group of sori formations beneath the surface of fertile pinnae. These fronds are then termed as sporophylls.

Ferns have 3 major parts – the rhizome, the fronds and the reproductive structures called sporangia. The characteristics of each of these 3 parts of the fern plant are used for classification and identification. The rhizome is the stem of the fern plant.

Some roots, called adventitious roots, arise from an organ other than the root—usually a stem, sometimes a leaf. They are especially numerous on underground stems, such as rhizomes, corms, and tubers, and make it possible to vegetatively propagate many plants from stem or leaf cuttings. Certain adventitious roots.

A sporophyte is a multicellular diploid generation found in plants and algae that undergo alternation of generations. It produces haploid spores that develop into a gametophyte. The gametophyte then makes gametes that fuse and grow into a sporophyte. In many plants, the sporophyte generation is the dominant generation.

Young prothallus is a dark-green, heart-shaped structure consisting of single-layered sheet of cells. Middle region of the prothallus is several cells thick. Several antheridia and archegonia are present.

Ramenta is thin brownish chaffy scales upon the leaves or young shoots of some plants, especially upon the petioles and leaves of ferns. 

Pteridium is homosporous i.e. It produces only one type of spores. These spores are produced inside sporangia, which in turn are grouped together to form sorus (pi. sori). Many sporangia are present in each sorus.

The fern plant with which we are familiar usually grows on land; it represents the asexual generation – the sporophyte – and bears spores on mature fronds. These spores are borne in cases, the sporangia, which are usually collected in groups or sori, on the under surface of the leaf.

The prothallus is haploid, since it grew from a spore which had been formed by meiosis. It does not have any vascular tissue and uses small rhizoids to anchor it to the ground. On the underside of the prothallus the sex organs form. The female structure, called an archegonium, contains a single egg.An antheridium is a haploid structure or organ producing and containing male gametes. The plural form is antheridia, and a structure containing one or more antheridia is called an androecium. 

It develops near the notch of the prothallus from an archegonial initial. It divides by a transverse division to form an upper primary cover cell and a lower cell.

Dictyostele : A stele in which the vascular cylinder is broken up into a longitudinal series or network of vascular strands around a central pith (as in many ferns).