Identify the pair of heterosporous pteridophytes among the following:
Selaginella and Salvinia
Psilotum and Salvinia
Equisetum and Salvinia
Lycopodium and Selaginella
The question requires identifying the pair of heterosporous pteridophytes. Let's first define what heterosporous pteridophytes are. Heterosporous plants produce two distinct types of spores: microspores (male) and megaspores (female). This differentiation helps in the sexual reproduction process.
Now, let's analyze the options:
Selaginella and Salvinia
Both of these plants are well-known heterosporous pteridophytes. Selaginella belongs to the group known for having ligules and producing two types of spores, while Salvinia, an aquatic fern, also produces distinct spores. Therefore, this option is correct.
Psilotum and Salvinia
Psilotum is a homosporous plant, meaning it does not produce two distinct types of spores, which makes this pair incorrect.
Equisetum and Salvinia
Equisetum, commonly known as horsetail, is a homosporous species. Hence, it cannot pair with Salvinia for this category.
Lycopodium and Selaginella
Lycopodium is another example of a homosporous genus, therefore making this pair incorrect.
Conclusively, the correct answer is: Selaginella and Salvinia.
Heterospory involves the creation of spores in two distinct sizes and developmental trajectories: smaller ones known as microspores with a male role, and larger ones referred to as megaspores with a female role. This phenomenon, which is pivotal in the evolution of vascular plants, has ultimately paved the way for the emergence of seeds. Examples of plants showcasing heterospory include Selaginella, Salvinia, Azolla, and others.
Therefore, The correct option is (A): Selaginella and Salvinia
S.No. | List - I | List - II | List - III |
---|---|---|---|
I | Algae | Phaeophyceae | Sargassum |
II | Bryophyta | Hepaticopsida | Marchantia |
III | Pteridophyta | Pteropsida | Equisetum |
IV | Gymnosperms | Gnetopsida | Pinus |
A sphere of radius R is cut from a larger solid sphere of radius 2R as shown in the figure. The ratio of the moment of inertia of the smaller sphere to that of the rest part of the sphere about the Y-axis is :
Predict the major product $ P $ in the following sequence of reactions:
(i) HBr, benzoyl peroxide
(ii) KCN
(iii) Na(Hg), $C_{2}H_{5}OH$
AB is a part of an electrical circuit (see figure). The potential difference \(V_A - V_B\), at the instant when current \(i = 2\) A and is increasing at a rate of 1 amp/second is:
Pteridophytes are the first terrestrial vascular plants. Carolus Linnaeus classified them under the group cryptogamae. Pteridophytes occupy a transitional position between bryophytes and spermatophytes.
For Example, Silver fern, Equisetum, Selaginella