Question

How many theca are present in each lobe of a typical bilobed angiosperm anther?

• A. 12
• B. 2
• C. 6
• D. 8

Hint:

• Key Terminology Distinction: itemize

• Number of theca per lobe = \(2\) (dithecous)

• Number of theca per entire typical anther = \(4\) (tetrathecous / tetrasporangiate)
A distinct longitudinal groove runs along the outer surface of each anther lobe, marking the internal division between the two corresponding theca. itemize

Answer 1

The Correct Option is B

Concept:

• Structure of the Anther: The anther is the fertile, pollen-bearing part of the stamen in angiosperms.

• Bilobed Arrangement: A typical angiosperm anther is a bilobed structure, meaning it consists of two distinct lobes joined together by a band of sterile parenchymatous tissue called the connective.

• Dithecous Lobes: Internally, each individual lobe of the anther is divided into two separate chambers or pollen sacs, which are anatomically referred to as

theca.

• Since each lobe possesses two theca, the lobes are described as

dithecous.

• Consequently, a complete, mature bilobed anther is tetrasporangiate, containing a total of four microsporangia (pollen sacs) distributed across its two lobes.

Step 1: Analyze the spatial structure of the anther
To determine the correct count, we must distinguish between the structure of a single lobe and the structure of the entire anther.

• A typical anther has two lobes in total.

• Each of these lobes is structurally partitioned into two longitudinal cavities (theca).

Step 2: Evaluate the count of theca per individual lobe
The question asks specifically for the number of theca present in

each lobe. Since each individual lobe is dithecous (possessing two chambers), there are exactly \(2\) theca per lobe. This corresponds to option (B).