Briefly describe the male and female strobili of Gnetum with suitable labelled diagrams. Why should you consider this plant a gymnosperm?
Gnetum, a dioecious genus, presents unique reproductive strobili.
Male Strobilus of Gnetum
The male strobilus is compound, appearing as a spike. It features a central axis with nodes bearing cup-shaped collars formed by fused bracts. Above these collars, several whorls of male flowers are present. Each reduced male flower typically has a perianth and two stamens (microsporangiophores) with two anthers. Interestingly, a whorl of abortive (sterile) ovules is often found at the top of each collar.
Female Strobilus of Gnetum
The female strobilus is also compound and cone-like. It similarly has a central axis with nodes bearing cup-shaped collars. Within the axil of each collar, one to several fertile ovules are present. Each orthotropous ovule is encased by multiple envelopes: an inner integument, a middle envelope, and an outer fleshy envelope. Usually, only the uppermost ovules are fertile.
Why Gnetum is considered a Gymnosperm:
Despite exhibiting angiosperm-like traits such as compound strobili, simple leaves with reticulate venation, and the presence of vessels in its xylem, Gnetum is classified as a gymnosperm due to fundamental reproductive characteristics:
These core reproductive traits firmly place Gnetum within the gymnosperm lineage.
Answered By:
How many types of gametophytes are found in Lycopodium? Why is it difficult to collect such prothalli in nature?
How does heterocyst differ from vegetative cell ? Mention the factors controlling its formation and add a note on functions of heterocysts.
Explain how the numerical expression of data is utilized in plant systematics.
"Mycoplasma causes serious diseases in humans, animals and plants." Substantiate the statement with suitable examples.
How does the infection of a pathogen affect the host plant physiology?
Enumerate the types of fruiting bodies of Ascomycota and Basidiomycota. Write the various steps of ascus formation in Ascomycetous members with suitable illustrations.
What are the various modes of infection and dissemination of plant diseases caused by viruses ? Describe.
Discuss how progressive sterilization of sporogenous tissue occurs in bryophytes, with suitable diagrams and examples.
Describe the ranges of thallus organization in the members of Chlorophyceae.
Explain holotype, isotype, paratype, lectotype and neotype. Mention the advantages of binomial system of plant nomenclature.
How will you manage a case of misplaced copper-T (Cu-T)?
Describe the embryogenesis, clinical features and principles of management of cleft palate.
Write short notes in 150 words:
Metagenesis
Write short notes in 150 words:
Book lungs
Write short notes in 150 words:
Paedomorphosis