Question

Which one of the following pairs is wrongly matched?
A.Salvinia – Prothallus
B.Viroids- RNA
C.Mustard- Synergids
D.Ginkgo- Archegonia

Answer 1

Hint:A prothallus is used to describe the gametophyte stage in the lifecycle of a Fern or any Pteridophyte. Prothallus is developed from a germinating spore. It is homosporous in nature and contains both male and female sex organs known as antheridia and archegonia respectively.

Complete step by step answer:Salvinia is a Fern producing two different kinds of spores, that is, it is heterosporous. The fruiting bodies are produced in structures called sporocarps. These structures bear any one of the spore-producing structures, that is, microsporangia or megasporangia. They are monosporangiate. Thus in this plant the spores are borne on sporocarps and not on the prothallus which is a homosporous structure.
Considering the other given options:
Viroids are the smallest infection-causing pathogens. The genetic material present in these cells is only a short, circular single-stranded RNA. These cells are devoid of a protein coat. They survive mainly as parasites in higher plants, causing a variety of diseases such as the potato spindle tuber disease.
Synergids are a pair of specialized cells lying on either side of the ovum inside the female gametophyte in angiosperms. It is haploid in nature, and the main function of these cells is in the guidance of the pollen tube into the female gametophyte. Since it is a distinguishing feature of angiosperm plants. These cells are present in the megagametophyte of mustard plants.
Ginkgo also known as Ginkgo biloba, belongs to the division ginkgophyta. Belongs to gymnosperms. Archegonia is the female reproductive organs present mainly in ferns and mosses, but can also be found in some gymnosperms. It produces ovum or the female gametes. And these structures can be found in Ginkgo.
Thus from the above-given options, the wrongly matched pair is option A. That Salvinia species do not contain prothallus but contain Salviniospores.

Note:Prothallus is usually a heart-shaped structure. It is green and has a photosynthetic function. And formed by the process of meiosis.