DEV BIO LT 2

• General diagram of a monocot seed (corn)

  A) Seed Coat fused with ovary wall

  B) endosperm cells

  C) cotyledon

  D) coleoptile

  E) epicotyl

  F) hypocotyl

  G) radicle

  H) embryo

  
• Closeup of a corn embryo.

  A) Scutellum

  B) Pericarp

  C) Coleoptile

  D) Plumule

  E) Radicle

  F) Coleorhiza

  
• After fertilization, the zygote divides to form an upper terminal cell and a lower basal cell. (a) In the first stage of development, the terminal cell divides, forming a globular pro-embryo. The basal cell also divides, giving rise to the suspensor. (b) In the second stage, the developing embryo has a heart shape due to the presence of cotyledons. (c) In the third stage, the growing embryo runs out of room and starts to bend. (d) Eventually, it completely fills the seed. 
• First stage of embryogenesis. Here, the terminal cell divides, forming a globular pro-embryo.

  A) proembryo

  B) suspensor

  C) basal cell

  
• Second stage of embryogenesis. Here, the developing embryo has a heart shape due to the presence of cotyledons. 

  A) Cotyledons

  B) embryo

  C) suspensor

  D) basal cell

  
• Third stage of embryogenesis. Here, the growing embryo runs out of room and starts to bend.

  A) Endosperm

  B) Cotyledons

  C) Embryonic Axis

  
• Fourth and last stage of embryogenesis. Here, the embryo completely fills the seed.

  A) Short Meristem

  B) Seed Coat

  C) Cotyledons

  D) root meristem

  
• Cross Section of a mature ovary.

  A) ovary

  B) Megaspore (mother cell)

  C) megasporangium

  D) integument

  E) micropyle

  
• Lily ovary

  A) Ovary

  B) Locule

  C) Ovule integuments

  D) Megasporocyte

  E) Funiculus

  F) megasporangium

  G) Septum

  
• Lilium ovule after the first meiotic division of the megasporocyte to produce two nuclei. (there could be 4 megaspores here, depending on the cross section)

  A) Funiculus

  B) integument

  
• Three of the four nuclei migrate to one end and fuse together while the lone one migrates to the opposite end (micropyle end)

  
• The triploid nucleus (formed from the fusion of the three nuclei) and the haploid nucleus (at the micropylar end) undergo mitosis

  A) micropyle

  
• After this first mitotic division the embryo sac contains 2 triploid and 2 haploid nuclei. During double fertilization in Lilium, the pollen tube ruptures into the embryo sac releasing two sperm. One sperm fuses with the egg nucleus to form the diploid zygote. The second sperm fuses with both the triploid and the haploid nucleus in the center of the embryo sac to form a pentaploid endosperm nucleus.

  A) diploid zygote

  B) pentaploid endosperm nucelus

  
• Mature embryo sac with 7 cells and 8 nuclei.

  A) egg

  B) synergid cells

  C) polar nuclei

  D) polar nuclei

  E) antipodal cells

  
• Corn seed (monocot) layers

  A) pericarp

  B) endosperm

  C) aleurone

  
• Mature corn seed

  A) coleoptile

  B) pericarp

  C) endosperm

  D) Scutellum

  E) radicle

  F) coleorhiza

  G) shoot meristem

  
• In Shepherd's purse, basal cell derivatives in the globular embryo form the hypophysis that goes on to develop into the radicle.

  A) basal cell

  B) suspensor

  C) globular embryo

  D) integuments

  
• In the heart and torpedo stages, the embryo has organized to form an apical meristem, radicle, cotyledons and hypocotyl.

  A) integuments

  B) heart shaped embryo

  C) apical meristem

  
• Embryo of Solanum viarum seed

  A) cotyledon

  B) root tip

  C) hypocotyl axis

  D) endosperm

  E) seed coat