Question

In Pinus, the third tier of embryonal cells from below is known as

• A. rosette tier
• B. suspensor tierl
• C. embryonal tier
• D. free - nuclear tierl

Answer 1

Answer: (A)

rosette tier

Answer 2

The cells of lower tier divide twice to form three tier of four cells each. At this stage the proembryo consists of $16$ cells arranged in four tiers. Each tier has a specific function.
(i) The lowermost tier is known as the embryonal tier, its cells divide to form embryo
(ii)The cells of the next tier called suspensor tier elongate to form suspensor.
(iii) The cells of $3^{rd}$ tier, known as the rosette tier conduct nourishment to the embryo.
(iv) The uppermost tier consisting of incomplete cells is known as nutritive tier and it provides nutrition.