Lecture Notes: Plant Physiology and Regulation

Introduction to Plant Physiology

• Focuses on the chemistry and physics of plant functions.
• Key processes:
  • Photosynthesis: Capturing light energy to produce sugars.
  • Aerobic Cellular Respiration: Breaking down sugars to release energy.
• Response to environmental conditions through growth, life events, and movement.
• Reliance on soils for nutrients and water, replenished by biogeochemical cycles.
• Transport of water and minerals through xylem driven by transpiration.
• Sugar translocation through phloem.
• Regulation via plant hormones.

Chapter 4.1: Photosynthesis and Respiration

• Photosynthesis involves capturing carbon dioxide and synthesizing sugars using light energy.
• Oxygen is released as a byproduct.
• Two steps:
  • Light-dependent reactions
  • Light-independent reactions
• Importance of aerobic cellular respiration in breaking down sugars to release energy.

Chapter 4.2: Environmental Responses

• Plants, unlike animals, cannot move and must respond in place to environmental factors.
• Detection and response systems to:
  • Light
  • Gravity
  • Temperature
  • Physical touch
• Utilization of receptors and chemical messengers to relay information.

Chapter 4.3: Nutrition and Soils

• Essential elements required for plant growth are acquired from the soil.
• Soils consist of organic/inorganic matter, air, and water.
• Nutrient cycles influence availability of these elements.

Chapter 4.4: Hormones

• Hormones act as long-distance chemical signals.
• Coordinate growth, reproduction, dormancy, and stress responses.
• Five major hormone categories:
  • Auxins
  • Cytokinins
  • Gibberellins
  • Abscisic Acid
  • Ethylene

Chapter 4.5: Transport

• Structure of roots, stems, and leaves aids transport of water, nutrients, and photosynthates.
• Phloem and xylem are main transport tissues.
• Key processes:
  • Water potential
  • Evapotranspiration
  • Stomatal regulation
• Understanding the energetics of water potential is crucial.

Chapter 4.6: Development

• Development involves changes over the plant's life.
• Growth occurs at apical, primary, and lateral meristems.
• Embryogenesis is the development of the embryo within the seed.
• Mature seed structure differs between eudicots and monocots.
• Flowering follows the ABCDE model.

Important Figures

• Figure 4.1: Stomatal opening and closure for water balance and carbon dioxide intake.

Image Attribution

• Images by Melissa Ha under CC-BY-SA license.

These notes capture the essential concepts presented in the lecture on plant physiology and regulation, providing a framework for understanding the complex processes that govern plant life.