This longitudinal section view does not allow us to consider symmetry Basic Flower Structure stigma carpel Pistil is simple gynoecium locule Flower is perfect Flower is monoecious style pollen ovule ovary anther superior filament stamen Flower is hypogynous androecium petal corolla sepal perianth receptacle calyx Perianth is complete pedicel This longitudinal section view does not allow us to consider symmetry

Flower Functions Leading to Sex pollination vectors: animals, wind pollen tube growth pollen dehiscence chemotropism syngamy x What are the rest of the flower parts doing?

Anther Cross Section - How many anther sacs are present? epidermis vein mesophyll pollen grains

Pollen grain Tube Cell Generative Cell Pollen Wall cytoplasm cytoplasm nucleus nucleus nucleolus nucleolus Digests path through stigma, style, and ovary. Locates micropyle of ovule. Penetrates into embryo sac. Divides by mitosis to make two sperm. Both join in syngamy events. Pollen Wall Waterproofing prevents desiccation during pollen transfer. Recognition proteins cause allergic reactions.

Pollen Grain Pollen Wall Fate: Digests Path to Egg Locates Micropyle Tube Cell Generative Cell Cytoplasm Cytoplasm Nucleus Nucleus Nucleolus Nucleolus Fate: Digests Path to Egg Locates Micropyle Enters Embryo Sac Is Burst to Release Sperm Fate: Follows Path of Tube Divides by Mitosis Makes Two Sperm Both Have Syngamy

Pollen grain deposited by vector on stigma Tube cell germinates through pollen wall Pollen tube digests pathway to egg Attracted to source of hormones, Calcium, Boron Chemotropism toward micropyle of ovule Penetrates into embryo sac generative nucleus pollen tube Generative cell follows pathway of pollen tube. Generative cell divides to make two sperm cells. tube nucleus tube nucleus Golgi and vesicles Synergids burst end of pollen tube. Sperm released into embryo sac. Syngamy events follow.

Rhododendron maximum ovule ls Integument 3 Antipodal Cells Embryo Sac disintegrate Central Cell + sperm = endosperm Egg Cell + sperm = zygote 2 Synergid Cells burst pollen tube release sperm disintegrate Micropyle of Integument

Embryo Sac in Ovule Embryo Sac Ovule Integument Antipodals Funiculus Central Cell Micropyle Egg Synergids

Plant Pornography? Disintegrating Antipodals Central Cell Polar Nuclei Sperm Nucleus Syngamy Product = Endosperm 3N Egg Cell Sperm Nucleus Egg Nucleus Disintegrating Synergids Syngamy Product = Zygote 2N

After Syngamy, the Names are Changed… Egg becomes Zygote Central cell becomes Endosperm Ovule becomes Seed Integument becomes Seed coat Ovary wall becomes Fruit

Integument became seed coat Capsella shepherd’s purse seed Integument became seed coat Egg became zygote Zygote became embryo Central Cell became endosperm Ovary became fruit