. Embryogenesis in plants. Embryology. 296 EMBRYOGENESIS IN PLANTS cylinder of the hypocotyl is already delimited; and the pattern of the root meristem is apparent in embryos showing cotyledon primordia. The number of cells in the nucellus is still on the increase up to the spherical embryo stage, but thereafter the perisperm starch begins to accumulate, thus affording evidence of active translocation, probably of sugars, into the ovule by way of the funiculus. The funiculus of the young ovule has only an incipient vascular strand, yet it is able to translocate all the metabolites which are us
. Embryogenesis in plants. Embryology. 296 EMBRYOGENESIS IN PLANTS cylinder of the hypocotyl is already delimited; and the pattern of the root meristem is apparent in embryos showing cotyledon primordia. The number of cells in the nucellus is still on the increase up to the spherical embryo stage, but thereafter the perisperm starch begins to accumulate, thus affording evidence of active translocation, probably of sugars, into the ovule by way of the funiculus. The funiculus of the young ovule has only an incipient vascular strand, yet it is able to translocate all the metabolites which are used in. B Fig. 82. Dicmthiis chinensis Starch in ovule and seed. A, Longitudinal section of ovule (diagrammatic) with a seven-nucleate embryo sac and enveloping starch-containing tissue. B, Ovule with young embryo. C, Ovule with maturing embryo. (A, x 102; B, x 29; C, x 21; after Buell.) the growth of the ovule. Indeed, some starch may actually be stored in the young ovule. By the time the ovum is mature, the funiculus strand has become fully differentiated into xylem and phloem. The synergids, the basal cell of the proembryo, and the endosperm, may all function as absorbing systems and all eventually contribute to the embryonic development. The partial digestion of the nucellus follows a regular pattern, the micropylar region disappearing most rapidly. Indeed, a kind of biochemical pattern is followed during the whole post-fertilisa- tion phase, the central and controlling component being the developing embryo. The large basal suspensor cell has probably an absorptive function. Perotti (1913) found protein granules in it in Stellaria media. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Wardlaw, C. W. (Claude Wilson), 1901-. London, Methuen; New York, Wiley
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