Which of the following structures is well-developed in a mature seed of black pepper ?

The correct option is Perisperm.

To understand why this is the correct answer, let's break down the seed structure and the role of the perisperm:

1. What is Perisperm?
In most angiosperms, the nutritive tissue inside the seed is the endosperm, which is consumed during embryo development or seed germination. However, in some families (like Piperaceae, which includes black pepper, and Chenopodiaceae), a portion of the nucellus (the central nutritive tissue of the ovule) persists and remains in the mature seed as a nutritive tissue. This persistent, residual nucellus is called the perisperm.

2. Seed of Black Pepper (Piper nigrum):
Black pepper seeds are classic examples of perispermic seeds. In a mature black pepper seed, the endosperm is very small, and the majority of the food storage tissue that is well-developed and fills the seed is the diploid perisperm (derived from the maternal nucellar tissue).

3. Evaluation of other options:
• Thalamus: The thalamus (or receptacle) is the thickened part of a stem from which the flower organs grow. It is not a structure inside a seed.
• Sepals: Sepals are outer floral leaves that protect the flower bud. They are vegetative/floral parts and do not form the internal structure of a mature seed.
• Peduncle: The peduncle is the stalk supporting an inflorescence or a flower. It is not part of the internal seed structure.

Therefore, the well-developed, persistent nutritive tissue found in a mature seed of black pepper is the perisperm.