Question

Which of the given statements are true?
(i) During the development of a dicot embryo, a heart-shaped embryo is followed by a globular embryo.
(ii) The part of the embryonic axis above the level of cotyledons is epicotyl, while the part below the level of cotyledons is hypocotyl.
(iii) Monocot seeds possess a single cotyledon represented by scutellum.
A. (i) and (ii)
B. (ii) and (iii)
C. (i) and (iii)
D. (i), (ii) and (iii)

Answer 1

Hint: Embryogeny is the stage of embryo development. The process of embryo development in dicot starts once the fertilized egg (zygote) passes through 2- celled, 8-celled, globular, heart shaped, torpedo and finally mature embryo formation takes place.

Complete Answer:
We can solve this question by understanding the different developmental stages of dicot embryo development.
- The development of the dicot embryo starts with a globular and undifferentiated stage. The early embryo has a radial symmetry and is known as a pro-embryo. This changes into an embryo with different parts i.e. radicle, plumule and cotyledons.
- The two cotyledons start differentiating from the sides with presence of a faint plumule in the centre. This embryo now becomes heart-shaped.
- The part of the embryonal axis in between plumule and cotyledon is called as epicotyl, whereas the part in between the radicle and cotyledon is called as hypocotyl (the level of cotyledons).
- A monocotyledonous seed with a single cotyledon (e.g., maize grain) is known as scutellum. It is known to occupy a major portion of the embryo regions of grain.

So, the correct answer is option (B) '(ii) and (iii)'.

Note: The process of advancement starts simply after the development of an endosperm as it needs nourishment. There are mainly two embryonic stages. They are as following:
a) Heart molded organism.
b) Development of organism with radicle, plumule, and cotyledons.
The development of endosperm is before the improvement of incipient organism: the incipient organism is in need of nourishment for it to build up.