In angiosperms, in which order does the zygote develop into the mature embryo?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Proembryo → globular embryo → heart-shaped embryo → mature embryo
Proembryo — first. The zygote lies at the micropylar end of the embryo sac. Its first divisions give the proembryo, the earliest stage of the embryo.
Globular embryo — second. Further divisions of the proembryo give a rounded mass of cells.
Heart-shaped embryo — third. The globular embryo grows unevenly and takes the shape of a heart.
Mature embryo — last. In a dicot it now has an embryonal axis and two cotyledons. These early stages are alike in monocots and dicots.
NCERT Extract:
Embryo – “Embryo develops at the micropylar end of the embryo sac where the zygote is situated. … Though the seeds differ greatly, the early stages of embryo development (embryogeny) are similar in both monocotyledons and dicotyledons. Figure 1.13 depicts the stages of embryogeny in a dicotyledonous embryo. The zygote gives rise to the proembryo and subsequently to the globular, heart-shaped and mature embryo.”
Figure 1.13 (a) Fertilised embryo sac showing zygote and Primary Endosperm Nucleus (PEN); (b) Stages in embryo development in a dicot [shown in reduced size as compared to (a)]