Class 12th Biology 2017 Set2 Delhi Board Paper Solution
Describe the development of a dicot embryo in a viable seed.
Development of a dicot embryo (i) Embryo formation starts after a certain amount of endosperm is formed. (ii) Zygote divides by mitosis to form a proembryo. (iii) Formation of globular and heart-shaped embryo occurs, which finally becomes horse shoe-shaped forms a mature embryo. (iv) In dicot plants, embryo consists of two cotyledons and an embryonal axis between them.(v) The portion of embryonal axis above the level of attachment of cotyledons is epicotyl and it terminates in the plumule. (vi) The portion of embryonal axis below the level of attachment of cotyledon is the hypocotyl, it becomes radicle (root tip). The embryonic stages during the development of a mature embryo sac are:
(a) Fertilised embryo sac showing zygote and Primary Endosperm Nucleus (PEN).
(b) Stages in embryo development in a dicot.
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