Botany

A typical anther in an angiosperm (flowering plant) is characterized by the following structure:

1. Bilobed Structure: The anther is generally composed of two distinct lobes connected by a region called the connective.
2. Dithecous Condition: Each lobe of the anther contains two chambers or sacs, called thecae. An anther with two lobes, each having two thecae, is described as dithecous.
3. Microsporangia: Each theca represents a microsporangium. A microsporangium is the structure where meiosis occurs to produce microspores, which eventually develop into pollen grains.

Therefore, in a typical bilobed, dithecous anther:

Number of lobes = 2

Number of microsporangia (thecae) per lobe = 2

Total number of microsporangia = (Number of lobes) (Number of microsporangia per lobe)

Total number of microsporangia =

When viewed in a transverse section, the bilobed anther often appears somewhat tetragonal (four-sided), with one microsporangium located in each of the four "corners" of the structure.

Thus, there are 4 microsporangia located at the corners of a typical bilobed anther of an angiosperm.

The terms hypogynous, perigynous, and epigynous describe the position of the floral whorls (sepals, petals, stamens) relative to the ovary on the receptacle.

• Hypogynous Flower: The sepals, petals, and stamens are inserted below the ovary. The ovary is said to be superior.
• Perigynous Flower: The sepals, petals, and stamens are inserted on the rim of a floral cup (hypanthium) that surrounds the ovary but is not fused to it. The ovary is still typically considered superior (or sometimes half-inferior), but the other parts arise around it.
• Epigynous Flower:

The epigynous flower:

• The margin of the thalamus grows upward, completely enclosing the ovary.
• The wall of the thalamus is fused with the wall of the ovary.
• The other floral parts (sepals, petals, stamens) appear to arise from the top of the ovary.
• Ovary is superior and other floral parts are inferior: This describes a hypogynous flower.
• Ovary is inferior and other floral parts are superior: This correctly describes an epigynous flower.
• All the floral parts are at the same level: This loosely describes a perigynous flower where parts arise from a rim around the ovary.
• None of the above: Incorrect, as the second option is correct.

• Jaya and Ratna are high-yielding, semi-dwarf varieties of rice developed in India.
• These varieties were bred for better yield, shorter plant height, and resistance to lodging.
• They are suitable for high-density planting and are recognized for their improved productivity.

The correct answer is (B) : Jaya and Ratna.