Anther- contains pollen, the male reproductive cell

Filament- holds the anther

Stamen- Anther and filament

Sepal- small leaves under the flower

Pistil- Stigma, style, and ovary

Style-  a tube on top of the ovary

Stigma- receives pollen during fertilization

Ovule- reproductive cell which will become the seed when fertilized

 

 

Long Day (Short Night)

• Day length exceeding the period of darkness at night
• March 20: day length= night length
• March 20- June 20
• Day length triggers flowering response
• SPRING

Short Day (Long Night)

• Day length falling short of the period of darkness at night
• Flowers when day length decreases
• FALL

 

-Specific responses of plants to changes in day length

The Role of Phytocrome

• The effect of light on the short day and long day plants
• Phytochrome- the pigment absorbs light (just like in the retina of the human eye)
• P(r) inactive
• P(fr) active- triggers flowering response

Cross-Pollination

When pollen is transferred from the anther of one flower to the stigma of another (b/w 2 flowers)

Self-Pollination

When pollination is transferred from the anther to the stigma of the same flower (within 1 flower)

The movement of pollen from the anther to the stigma through the facilitation of animals, wind, water and other agents

• Some flowers don't possess male and female organs on the same flower (Dioecious)
  • This would require cross-pollination
• Self-Incompatibility
  • Self made pollen is rejected by the stigma
• Stamens and carpals are different lengths
  • They may mature at different times

The Avoidance of Self-Pollination

Adaptations to Ensure Pollination

• Sugar maple seeds (samara- "propeller" seeds)
• Dandelions- a globe of "fluff" that separates into numerous parachutes which are carried by the wing
• Bright colored blossoms
  • Attract bees, flies, butterflies, and moths inside to get the nectar and pollen
• Hooker seeds- barbs, hooks, and spurs help them stick to whatever walks by

Fertilization- the process when haploid gametes (sperm and egg) fuse to create a diploid zygote which will eventually become an embryo

Double Fertilization

 Fertilization

Importance

• To ensure the greatest possible chance is given to the seeds to produce seeds of their own
• The seeds must leave the seed pod because if they didn't, the space under the petals would be too crowded

 

Examples

• Gravity
  • ​Coconuts: The shell breaks when it hits the ground
• Force
  • ​Balsam Jewelwed: The seed pods explode when touched; they're commonly known as "Touch-me-not"s
• Water
  • ​Lotus: conical shaped fruit that is filled with seeds. Once the seeds mature, they loosen and when the pod tips down, the seeds are let down into the water
• Animals and Humans
  • Beggar-Ticks: Seed-like fruits that attach to animal fur or the clothing of humans; this expands their species geographically and promotes their survival
• WInd
  • African Tulip: boat-shaped green pods that have thin, light seeds with transparent "wings" that help them drift away from the parent plant

 

Pea Seed

Metabolic Processes for Starchy Seed Germination

• Water is absorbed and activates the metabolism of cotyledon cells
• Water absorption triggers synthesis of gibberellin (plant growth hormone) which triggers the production of the enzyme amylase
• Amylase converts food reserves (starch) from cotyledons into maltose, which is then made into glucose for energy
• Some of the cellulose is made into the cell walls