Question: 122: The residual persistent part which forms the perisperm in the seeds of beet is :
(1) Calyx
(2) Endosperm
(3) Nucellus
(4) Integument
Answer: Option (3)
Explanation:
Perisperm is a nutritive tissue present in some seeds which is derived from the residual,
persistent nucellus.
Normally, after fertilization, the nucellus is consumed by the developing embryo and endosperm.
However, in certain plants like beet, black pepper and water lily, a part of the nucellus remains intact
and persists in the mature seed.
This persistent nucellus stores food and is known as perisperm.
Calyx does not participate in seed formation.
Endosperm is formed after fertilization from the primary endosperm nucleus and is different from perisperm.
Integuments develop into the seed coat and do not form perisperm.
Hence, the perisperm in beet seeds is formed from the nucellus.