Basic Flower Structure stigma style ovary locule ovule carpel gynoecium pollen anther filamentstamen androecium petal corolla perianth sepal calyx receptacle pedicel Perianth is complete Flower is perfect Flower is monoecious superior Flower is hypogynous Pistil is simple This longitudinal section view does not allow us to consider symmetry
pollen dehiscence pollination pollen tube growth chemotropism syngamy x vectors: animals, wind Flower Functions Leading to Sex 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 CellGenerative Cell cytoplasm nucleus nucleolus cytoplasm nucleus nucleolus Pollen Wall 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. Waterproofing prevents desiccation during pollen transfer. Recognition proteins cause allergic reactions.
Pollen Grain Pollen Wall Generative Cell Tube Cell Cytoplasm Nucleus Nucleolus Cytoplasm Nucleus 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 cell divides to make two sperm cells. tube nucleus generative nucleus pollen tube Golgi and vesicles Synergids burst end of pollen tube. Sperm released into embryo sac. Syngamy events follow. Generative cell follows pathway of pollen tube.
Rhododendron maximum ovule ls Embryo Sac disintegrate + sperm = endosperm + sperm = zygote burst pollen tube release sperm disintegrate Micropyle of Integument 2 Synergid Cells Egg Cell Central Cell 3 Antipodal Cells Integument
Embryo Sac in Ovule Ovule Embryo Sac Antipodals Central Cell Egg Synergids Integument Funiculus Micropyle