Plant Reproduction and Development

1
Plant Reproduction and Development

• Chapter 28

2
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
3
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
4
Egg Formation

• Meiosis in ovule produces megaspores all but one
  disintegrate

5
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
• Coevolution- flowers and insects

6
Seeds and Fruits

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

7
Seed Dispersal

• Fruit structure is adapted to mode of dispersal
• Modes of seed dispersal include
• Wind currents
• No showy flowers
• Dry windy areas
• Includes grasses, deciduous trees
• Water currents
• Animals
• Most likely to spread the seeds of fleshy fruits

8
Seed Germination

• The most critical factor affecting seed
  germination is moisture