Angiosperms

Phylem anthophyta (2 classes)

• Monocotyledonae (monocot)

• Eucotyledonae (Eudicots)

Angiosperms (some characteristics)

• Most free-living

• Some parasitic (mictletoes, Rafflesia, etc)

• Absorptive organs (haustoria) penetrate hosts.

Mycoheterotrophic (Ghost pipe)

• Lack chlorophyll, non-photosynthetic, obigate with mycorrhizal fungi.

Monocots (basic characteristics)

• Flower parts in threes

• Pollen are monoaperturate

• Cotyledons are one

• Leaf venation is parallel

• Primary vascular bundles in the stem are often scattered

• True secondary growth is rare

Eudicots (Basic Characteristics)

• Flower parts in fours or fives

• Pollen is triaperurate

• Cotyledons are in twos

• Leaf venation is usually network

• Primary vascular bundles are in a ring

• True secondary growth is commonly present.

Consists of carpels

They are megasporophylls that folded lengthwise.

• Carpel encloses one or more ovules

• Separate/partly/fused together

• Locules (chambers) generally related to # of carpel

Types or ovary

• Superior Ovary (hypogynous)

• Inferior Ovar (Epigynous)

• Perigynous Ovary

Superior Ovary (Hypogynous)

Perianth and staments bellow ovary

Inferior Ovary (Epigynous)

Perianth and stamens above ovary.

Microsporogenesis (male phase)

Single-celled precursor of a pollen grain

Microspore (Male phase)

Product of meiosis of sporogenous tissues (microsporocyte)

This takes plave in microsporangia (pollen sacs of anthers)

Microganetogenesis

Mitotic division of microspore

• Product: vegatative (tube) cell and generative cell

• Generative cell: 2 sperm (male gametes)

• Microgametophyte: 3 cells

Pollen Morphology

• Exine (Outer wall, sporopollenin)

• Intine (Inner wall, cellulose and pectin)

Megagametogenesis (Female phase)

Involves meiosis, formation of megaspores in nuclellus of ovule (megasporangium)

3-4 megasporoes disintegrate

Megagametogenesis (Female phase)

Development of megaspore into embryo sac (megagametophyte)

• 3 metoitc divisions = 2 polar nuclei (central), 3 antipodals, 2 synergies flanking 1 egg cell.

Megagametophyte (Female Phase)

8 nucleate, 7 celled (polygonum type).

Germination of pollen grain = Pollen tube

• Grows between cells of stigma and transmitting tissue of stype

• In ovadry, the micropyte enters the ovule.

Double Fertilization

• The pollen tube enters one synergids

• Aggregation of actin (actin caronas) = migration pathways for sperm cells

• One sperm with an egg (zygote)

• One sperm with polar nuclei (triploid endosperm).

Fruit much have

matured ovary (pericarp)

3 types of fruit

1) Simple: 1 ovary (1+ united carpels)

2) Aggregate: Many individual carpels (apocarpous)

3) Multiple: Derived from inflorescence

Accessory Fruit - any fruit containign non-ovary tissue

Fruits and seed dispersal agents

• Wind Dispersal

• Water Dispersal

• Animal Dispersal