Question

Placentation of pea flower is
A) Parietal
B) Marginal
C) Axile
D) Superficial

Answer 1

Placentation is the arrangement of ovules within ovary or placentas in the ovary and it is usually sub marginal in pistil (female sex organ).

Superficial placentation occurs in water-lily.
Parietal placentation occurs in cucurbits.
Axile placentation takes place in the flowers of Rutaceae, Malvaceae Family.

Complete answer:
Marginal placentation occurs in a monocarpellary, unilocular ovary. Plants belonging to Fabaceae family like Gram, Pea, Arhar, Sunhemp, Moog, Lupin bear Marginal placentation.
Placentation is of following types:
Parietal- carpels united by their adjacent margins, ovules disposed along inner ovary walls. For example: mustard and argemone.
Axile- carpels folded inward, ovules along the central axis of the ovary wall that create chambers which separate the placenta and ovaries from each other. For example: tomato, banana.
Superficial- ovules are borne on placentae and they develop all round the inner surface of the partition wall. For example: water lily and Family is Nymphaeaceae.
Marginal- for example: pea, gram.
Basal- one or more than one ovules that develop at the base of the ovary which can be simple or compound. This type of placentation is found in Asteraceae Family.

So, the correct answer is option B i.e, marginal.

Note: Pea flower that has marginal placentation develops on the future of the ovary wall. It has a single chambered ovary and ovules, arranged in a row. The main function of placentation is to transform various nutrients and water to the embryo from the maternal tissue.