Question

What type of placentation is seen in sweet pea?

Answer 1

Hint: Placentation is known as the arrangement of ovules within the ovary. Placenta is a cushion-like structure that helps in holding the ovule inside it. It’s like a protective covering which covers the developing embryo inside it from outer distractions. Be it in animals or plants have also the same use. The placenta is arranged in different types. Now let us discuss the types. The plant part is equivalent to an umbilical cord.

Complete answer:
As we know, what placentation means, the placentation is of different types namely- Marginal, axile, parietal, basal, central and free-central. The first type of placentation is Marginal- In marginal placentation the placenta forms a ridge along the ventral or front part of the ovary and the ovules are borne on this ridge forming two rows. Example- pea. So, the type of placentation that can be seen in sweet pea commonly known as (Pisum sativum) is Marginal placentation.
The second type is axile- In axile placentation when the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentation is said to be axile. For example- china rose, tomato, lemon, lily.
Third type is Parietal- in parietal placentation, the ovules develop on the inner wall of the ovary or on peripheral part. Ovary is one-chambered but due to the formation of the false septum it becomes two-chambered. For example- mustard and argemone, cucumber.
Fourth type is free central- In free central placentation the ovules are borne on central axis and septa are absent. For example- Dianthus and primrose.
Fifth and last placentation is central also known to be basal placentation, the placenta develops at the base of ovary and a single ovule is attached to it. For example- sunflower, marigold.

Note:
The function of the placentation is to transfer and provide nutrients, water and other essential growth factors to the developing embryo. The placentation is frequently of taxonomic value. Placentation is mostly submarginal in a simple pistil which a female sex organ. Two or more carpets in a compound pistil are used in different ways, with placental arrangements united to carpets. Placentation is usually seen in angiosperm plants.