Designed by Pyeongsug Kim ©2008 SI session Angiosperms Early deveopment Topic 20 Spring 2010 Dr. Hughey’s Bio 3

Review: Fertilization after pollination How are the sperms convey to the embryo sac? By pollen tube What is “double fertilization?” -the union of one sperm(n) with egg(n) :__________  Becomes ___________ -the other sperm with _____________ : ___________  Becomes ____________________________ Designed by Pyeongsug Kim, ©2009 Zygote(2n) fertilization Two polar nucleiTriple fusion Primary endosprem nucleus(3n)

__________ =Nutritive tissue Designed by Pyeongsug Kim, ©2009 Review: After double fertilization The zygote(2n) develops into __________. an embryo The primary endosperm nucleus(3n) develops into __________.endosperm *Endosperm formation begins before the zygote begins to divide. Endosperm

Designed by Pyeongsug Kim, ©2009 ____________- formation of an embryo. Embryogenesis Zygote(2n) after fertilization  Embryo(2n) Heart stage (Emerging cotyledon) Torpedo stage (Elongated Cotyledon) Proembryo Embryo proper tissue that differentiates to form 3 primary meristems. 3 primary meristems. - Protoderm Ground meristem Procambium

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Protoderm Endosperm Suspensor with basal cell Embryo proper(globular) Root tip Emerging cotyledons Endosperms Procambium _____stage! Endosperms Heart

Designed by Pyeongsug Kim, ©2009 _______ stageTorpedo ( Eudicot / Monocot ) Two cotyledons are present. AB C D E F G A: B: C: D: E: F: G: Endosperm Two cotylendons Protoderm Procambium Meristem Root tip Basal cell of suspensor

Designed by Pyeongsug Kim, ©2009 A A: B: C: D: E: B CE Mature embryo Hypocotyl Shoot apical meristem Procambium Radicle Two cotyledons D ( Eudicot / Monocot )

Designed by Pyeongsug Kim, ©2009 External (Environmental) factors Internal (Biological) -Hormones- ____________. gibberellins Seed germination - Water - Oxygen - Temperature - Light

What structure emerges first from the germinating bean seed? Why? Root -anchors the plant -enable it to absorb water and nutrients Designed by Pyeongsug Kim, ©2009

Seed Terms Hypocotyl- stemlike axis below the cotyledons. Hypocotyl-root axis- an undistinguished radicle. Epicotyl- stemlike axis above the cotyledons. Plumule- the first bud of an embryonic shoot. Pericarp- the fruit wall, which develops from the wall of the ovary. -From Dr. Hughey’s class slide

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__________- cotyledons remain underground. Seed Germination ___________- cotyledons are carried above ground level. Epigeous Hypogeous Ground

EpicotylHypocotyl Designed by Pyeongsug Kim, ©2009 Epigeous/Hypogeous (Epicotyl /Hypocotyl) Epigeous/Hypogeous

Designed by Pyeongsug Kim, ©2009 A B Epigeous/Hypogeous Monocot/Eudicot A: B: Epicotyl Cotyledons A: B: Epicotyl Cotyledon A B Epigeous/Hypogeous Monocot/Eudicot

Designed by Pyeongsug Kim, ©2009 A B C D E A: B: C: D: E: Hypocotyl Endosperm Cotyledons Hypocotyl Epicotyl Epigeous/Hypogeous Monocot/Eudicot

Designed by Pyeongsug Kim, ©2009

Non-endospermic Seed Endospermic Seed

Designed by Pyeongsug Kim, ©2009 Non-endospermic In Non-endospermic seed, the stored food occurs in the _________. cotyledons endospermic The endospermic seed, the stored food occurs in the ___________. endosperm

Designed by Pyeongsug Kim, ©2009 Endosperm : Food(starch) storage Seed staining with I2-KI (2% iodine and 3% potassium iodide)