Short Questions (Pteridophytes + Gymnosperms) Part-I

Q.NO.1. Define Morphology?

Ans: The scientific study of the structure and specific structural features of either animals or plants is called Morphology.

 

Q.NO.2. what do you mean by diversity of plants?

Ans: Biodiversity is the total variability within and among species of all living organisms and their habitats. Plant diversity is the variety of plant species on the basis of their diagnostic characteristics and their habitats. It is estimated that there are between 300,000 and 500,000 species of higher plants (i.e. flowering and cone bearing plants).of which approximately 250,000 have been identified or described.

 

Q.NO.3. Define Pteridophytes?

Ans: The term Pteridophyte is derived from two words ‘Pteron’ meaning feather and ‘phyton’ meaning plant. Thus, Pteridophytes are the plants with Feather-like leaves. Pteridophytes occupy the intermediate position between Bryophytes and Phanerogams (seed plants)., there are approximately 11,000 different species with the most been found in trophics. An example of Pteridophyte is the fern. They reproduce by releasing spores in to the air.

 

Q.NO.4.Why Pteridophytes are known as Cryptogams?

Ans: Pteridophytes are cryptogams. Because they produce neither seeds not flowers. They reproduced by spores.

 

Q.NO.5.Pteridophytes cannot become complete land pants. Why?

Ans: Pteridophytes cannot become complete land pants

  • Because they cannot produce flowers and seeds.
  • They grow or live mostly in moist soil or in aquatic environment.

 

Q.NO.6.Name the spore producing organs in different groups of Pteridophytes?

Ans: Synangia (three fused sporangia) develop in Psilotum. The leaves which bear synangia in Tmesipteris may be murconate rather than lanceolate. Lycopodium and Equisetum bear cones containing similar spores (homosporous). Selaginella, Marsilea, Salvinia, Azolla, Regnellidium, Pilularia, Stylites, lsoetes and Platyzoma are heterosporous (produce two types of spores-microspores and megaspores. The spores are contained in sporangia which are borne on sporophylls or sporangiophores .These becomes aggregated into cones or strobili.

 

Q.NO.7. Differentiate between microphylls and megaphylls?

 Ans: Microphylls: The sporophytes with small and scale like leaves, for example those found in Ephedra.

Megaphylls: These are large and well developed leaves, for example those found in Cycas and Pinus. These are foliage leaves and are protected by thin layer of cuticle ore waxy layer.

 

Q.NO.8.What are sporophylls mention their types with example?

 Ans: The special type of reproductive leaves which produce sporangium (spore producing structure) is called sporophylls.

There are two types of sporophylls.

  • Microsporophyll (Produce Micro-sporangia)
  • Megasporophyll (Produce mega-sporangia)

Q.NO.9. Differentiate between homosporous and heterosporous plants. Give example in each case?

Ans: Homosporous Ferns: produce only one type of spore that contains both male and female parts. The resulting gametophyte is monoecious that is both antheridia and archegonia are present on the same plant .E.g.Lycopodium, Equisetum.

Heterosporous Ferns: Produce two types of spores or distinct male and female spores or microspore and megaspores. The resulting gametophyte is dioecious. Microspore germinates to form male gametophyte that bears antheridia. Megaspore germinates to form female gametophyte that bears archegonia. E.g. Selaginella, Marselia.

 

Q.NO.10. Define Sporocarp?

Ans: Sporocarp is a Bean shaped structure attached to the petiole through a small stalk called Peduncle in which spores are produced. The young Sporocarp is relatively soft and green but they become hard brown and nut-like at maturity.

 

Q.NO.11.What is false indusium compare it with true indusium?

Ans: True indusium: A delicate membranous structure arises from the lower side and covers the sorus of sporangia. Seen in Dryopteris.

False indusium: It is formed by the curving of margins of the pinnae or leaflet that protects the marginal sorus. It originates from the upper side of the pinnae. Seen in Pteris, Adiantum etc.

 

Q.NO.12. Define Circinate Vernation?

Ans: A form of vernation in which the leaf primordia are rolled in on themselves from the apex to the base, so that the apex is in the middle of the coil. It is seen in most ferns (except the Ophioglossales) and in certain of the cycads and extinct seed ferns. The young leaves are coiled inward in the embryonic state. It is called circinate vernation.

 

Q.NO.13. Define Fronds?

Ans: Brightly colored complex green leaves of Ferns are called Fronds.

 

Q.NO.14. what are “synangia” Name the plant in which these structures are formed?

Ans:  Synangium is a trilocular or three chambered, spore bearing structure in Psilotum.  It is considered as a fusion product of three sporangia. Synangia are characteristic of the ancient group Psilotophyta, some ferns and fern like gymnosperms (seed ferns).Special type of synangia called microsynangia are found in ancient group of gymnosperms.

 

Q.NO.15. what is meant by Dichotomous branching system?

Ans: The type of branching in plants those results when the growing point (apical bud) divides into two equal growing points, which in turn divide in a similar manner after a period of growth, and so on. Dichotomous branching is common in ferns and mosses.

 

Q.NO.16. Give one main difference between rhizoids and roots?

Ans: A rhizoid (such as is found on the gametophytes of bryophytes or ferns) is basically just a filament or a root-like structure that anchors the plant to the ground. Rhizoids absorb water and nutrients from the soil through the process of capillary action

A root, on the other hand, is a sophisticated structure containing many different layers including vascular tissue, playing a key role in water and nutrient uptake.

 

Q.NO.17.Why the members of lycopsida are known as club mosses?

Ans: They are called club mosses because of their small size and moss like leaves and aggregation of sporophylls into terminal groups.

 

Q.NO.18.What are Ligules, give its function with example?

Ans: Ligule is a membranous outgrowth present at the base of leaves and considered as water secreting structure that protect the young leaves and sporangia from desication.It is present in the members of lycopsida, example Selaginella and Isoetes. Those plants in which Ligule is present are known as Ligulates.

 

Q.NO.19.What is Medan hair ferns/why adiantum is known as Medan hair ferns?

Ans: The genus name of the maidenhair fern, Adiantum, is derived from the Greek word ‘Adiantos’ – meaning ‘unwetted’ – as the leaves of the fern repel water, while the species name is taken from the Latin words ‘capillus’ and ‘veneris’, meaning ‘hair of Venus’, giving this plant its alternative common name, the Venus maidenhair fern. The Petiole of the leaves are shining black and brittle. Due to these characteristics the Adiantum is also known as maiden hair fern.

 

Q.NO.20.What is tapetum give its role in the development of sporangium?

Ans: Tapetums is the innermost layer of the microsporangium. It provides nourishment to the developing pollen grains. During microsporogenesis, the cells of tapetum produce various enzymes, hormones, amino acids, and other nutritious material required for the development of pollen grains.

 

Q.NO.21. What is Rhizophore, give its formation?

Ans: Rhizophore is a colorless or leafless structure arises from the rhizome and bear adventitious roots at their like in Selaginella.

 

Q.NO.22.What is carbon dating? How is it used for the study of fossils?

Ans: Carbon-14, The Radiocarbon dating involves determining the age of an ancient fossil or specimen by measuring its carbon-14 content. Carbon-14, or radiocarbon, is a naturally occurring radioactive isotope that forms when cosmic rays in the upper atmosphere strike nitrogen molecules, which then oxidize to become carbon dioxide. It can only be used to date fossils younger than about 75,000 years.

References:

Mycorrhizae Book By Smith 1997

Mycorrhizael Anatomy and molecular biology Book by Patel

Related Posts:

Short Questions (Pteridophytes + Gymnosperms) Part-II

Mycorrhizae Genral

Arbascular Mycorhizae Part-I

Arbascular Mycorhizae Part-II

Ectomycorhizae Part-II

 

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