Lecture Notes on Plants

Introduction to Plants

• Similarities between plants and humans
• Different parts of plants serve various functions

Important Parts of a Plant

1. Buds
   • Protect baby flowers/leaves from harmful elements.
2. Flowers
   • Colorful part of the plant that attracts pollinators like bees.
3. Leaves
   • Contain chlorophyll, absorbs sunlight, and makes food.
4. Fruits
   • Contains excess food and seeds; can be sweet or inedible.
5. Stems
   • Supports plant structure and transports nutrients and water.
6. Roots
   • Absorb water and minerals, anchor plant in soil.

Fun Plant Facts

• 90% of humans' food comes from 30 species of plants.
• Over 18,000 species of edible plants on Earth.

Carnivorous Plants

• Insectivorous plants: Capture and digest prey for nutrients.
• Types include:
  • Pitfall traps (Pitcher plants): Insects drown in fluid.
  • Fly paper traps: Sticky leaves trap insects.
  • Snap traps (Venus flytrap): Mouth-like leaves snap shut on prey.
  • Bladder traps: Create vacuum to suck prey.
  • Lobster Pot traps: Misdirect insects to their doom.

Photosynthesis

• Definition: Using light to create food from sunlight, water, and carbon dioxide.
• Process breaks down:
  • Stomata: Tiny openings in leaves that take in carbon dioxide and release oxygen.
  • Chloroplasts: Contain chlorophyll, convert sunlight into sugar and oxygen.
• Importance of photosynthesis: Plants provide oxygen for humans.

Plant Excretion

• Plants remove waste through stomata and vacuoles.
• Abscission: Aging leaves drop to remove waste.
• Plants also produce useful substances (e.g., latex).

Plant Adaptation

• Adaptation: Process by which plants become better suited to their environment.
• Examples:
  • Desert plants: Cacti have spines and thick waxy coverings to store water.
  • Tropical rainforest plants: Drip tips and waxy leaves to shed excess water.
  • Temperate forest plants: Thick bark for winter protection; deciduous trees drop leaves.
  • Aquatic plants: Different leaf coloration and structure for survival underwater.

Pollination

• Definition: Transfer of pollen from anther to stigma for reproduction.
• Types:
  • Self-pollination: Pollen from the same flower.
  • Cross-pollination: Pollen from different plants, aided by animals or wind.
• Importance: Over 70% of flowering plants depend on animal pollinators.

Fertilization and Seed Formation

• Fertilization: Male and female gametes merge to form a zygote.
• Process includes:
  • Pollination leads to pollen tube formation.
  • Double fertilization occurs, forming zygote and endosperm.
• Seeds develop in the ovary after fertilization.

Germination

• Definition: Process by which a seed grows into a plant.
• Steps:
  1. Seed absorbs water and swells.
  2. Seed coat ruptures, and root emerges.
  3. Plant grows and pushes through soil.
• Importance: Proper conditions (moisture, temperature, sunlight) are crucial.

Conclusion

• Importance of plant adaptation and knowledge for successful planting.
• Fun Fact: Seeds can remain viable for thousands of years under the right conditions.