Q. Which of the given statements are true?
(i) During the development of a dicot embryo, heart- shaped embryo is followed by globular embryo.
(ii) The part of embryonal 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.

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Solution:

During the development of dicot embryo, initially the dicot embryo is globular and undifferentiated. Early embryo with radial symmetry is called proembryo. It is transformed into embryo with the development of radicle, plumule and cotyledons. Two cotyledons differentiate from the sides with a faint plumule in the centre. At this time the embryo becomes heart-shaped. Part of embryo axis between the plumule and cotyledonary node is epicotyl (above the level of cotyledons) while the part between radicle and cotyledonary node is called hypocotyi (below the level of cotyledons). The single cotyledon of monocotyledonous seed {e.g. maize grain) is called scutellum. It occupies the major portion of the embryo regions of grain.