Soybean and Bees
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Embryo, endosperm <strong>and</strong> seed coat development<br />
After fertilization, the soybean plant becomes far more susceptible to insect pests, especially<br />
those feeding on pods <strong>and</strong> seeds. Once fertilized, the vacuole in the zygote becomes smaller<br />
<strong>and</strong> finally disappears entirely about the time of the first cell division, which occurs about 30<br />
hours after pollination (Pamplin, 1963; Rustamova, 1964).<br />
Soueges (1949) described soybean embryogeny from the first division of the zygote through<br />
the early cotyledon stages. The first division of the zygote is transverse. The apical cell, facing<br />
the central cell, will become the embryo. The basal cell, facing the micropyle, forms the<br />
suspensor, an ephemeral structure that may aid early embryo growth. Continued divisions<br />
of the derivatives of the apical cell produce the spherical proembryo, at about 3 days. The<br />
proembryo is approximately the same size as the somewhat conical suspensor (LINSKENS et<br />
al., 1977). A well-defined protoderm is present in the proembryo ca. 5 days after fertilization<br />
(Figure 21).<br />
Illustration: Decio Luiz Gazzoni<br />
Shoot apical meristem<br />
Protoderm<br />
Endosderm<br />
Hypocotyl<br />
Procambium<br />
Ground meristem<br />
Seed coat<br />
Cotyledons<br />
Root apical meristem<br />
Basal cell of suspensor<br />
Figure 21. Development of the embryo, seed <strong>and</strong> endosperm.<br />
About 6 to 7 days after fertilization, localized divisions at opposite sides of the proembryo,<br />
just below the protoderm, initiate the cotyledons. Pamplin (1963) observed that the cotyle-<br />
SoybeAn <strong>and</strong> bees<br />
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