Plant Reproduction and Development

1
Plant Reproduction and Development

• Chapter 19

2
Imperiled Sexual Partners

• Many flowering plants rely on animal pollinators
  to transfer pollen

3
Flower Structure
STAMEN (male reproductive part)
CARPEL (female reproductive part)
filament
anther
stigma
style
ovary

• Nonfertile parts
• Sepals
• Receptacle
• Fertile parts
• Male stamens
• Female carpel (ovary)

OVULE (forms within ovary)
petal (all petals combined are the flowers
corolla)
sepal (all sepals combined are the flowers calyx)
receptacle
4
Pollen Formation
pollen sac
anther
filament
microspore mother cell

• Each anther has four pollen sacs
• Inside pollen sacs, cells undergo meiosis and
  cytoplasmic division to form microspores

Diploid Stage Haploid Stage
Meiosis
microspores
pollen grain

• Microspores undergo mitosis to form pollen grains

pollen tube
stigma
sperm nuclei
mature male gametophyte
style of carpel
5
Egg Formation

• Meiosis in ovule produces megaspores all but one
  disintegrate

6
Pollination

• Transfer of pollen grains to areceptive stigma
• Pollen can be transferred by a varietyof agents
• When a pollen grain lands on the stigma it
  germinates

7
Seeds and Fruits

• The seed is the mature ovule
• The fruit is the mature ovary

8
Seed Dispersal

• Fruit structure is adapted to mode of dispersal
• Modes of seed dispersal include
• Wind currents
• Water currents
• Animals

9
Seed Germination

• Process by which the plant embryo resumes growth
  after seed dispersal
• Depends upon environmental factors
• Temperature
• Soil moisture
• Oxygen levels