Q.(a) Draw the structure of ovule and label it. OR

(a) The ovule's parts include the funicle, integuments, micropyle, nucellus, embryo sac, and chalaza; (b) plant succession's significance is the progressive restoration of bare land into a stable climax community.

(a) Structure of the Ovule

The ovule is the structure within the ovary that, after fertilization, develops into the seed. A typical anatropous ovule (the common type in flowering plants) has the following parts:

• Funicle: the stalk that attaches the ovule to the placenta of the ovary.
• Hilum: the point at which the funicle joins the body of the ovule.
• Integument(s): one or two protective layers surrounding the ovule body, derived from the ovule's outer tissue; they enclose the nucellus almost completely, leaving only a small opening at the tip.
• Micropyle: the small pore left at the tip of the integuments, through which the pollen tube usually enters during fertilization.
• Nucellus: the megasporangial tissue enclosed within the integuments, in which the embryo sac develops.
• Embryo sac (female gametophyte): typically 8-nucleate and 7-celled, consisting of an egg apparatus at the micropylar end (one egg cell flanked by two synergids), three antipodal cells at the chalazal end, and a large central cell containing two polar nuclei.
• Chalaza: the basal region of the ovule, opposite the micropyle, where the integuments, nucellus, and funicle merge.

A labelled diagram would show these parts arranged from the micropylar end (funicle, hilum, micropyle, egg apparatus) through the nucellus and embryo sac to the chalazal end (antipodals, chalaza), enclosed by the integuments.

(b) Significance of Plant Succession

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