Plant Stress Physiology

Plant Stress Physiology is the sub-discipline of botany that investigates how plants respond to adverse environmental conditions, or stressors, that negatively impact their growth, development, and survival. This field examines the full spectrum of plant reactions to both abiotic (non-living) factors like drought, extreme temperatures, and salinity, and biotic (living) factors such as pathogens and herbivores. It delves into the physiological, biochemical, and molecular mechanisms that enable plants to perceive, signal, and ultimately tolerate or defend against these challenges, providing critical knowledge for developing more resilient crops to ensure global food security.

1. Introduction to Plant Stress Physiology
   1. Defining Plant Stress
      1. The Concept of Homeostasis in Plants
         1. Maintenance of Internal Environment
         2. Homeostatic Set Points
         3. Feedback Mechanisms
      2. Stress vs. Strain
         1. Definitions and Distinctions
         2. Examples in Plant Systems
         3. Quantifying Stress and Strain
      3. Eustress and Distress
         1. Beneficial vs. Harmful Stress
         2. Thresholds and Tolerance Limits
         3. Hormesis in Plants
   2. Classification of Stressors
      1. Abiotic Stressors
         1. Physical Factors
            1. Temperature Extremes
            2. Light Intensity
            3. Mechanical Forces
            4. Radiation
         2. Chemical Factors
            1. Salinity
            2. Heavy Metals
            3. Nutrient Imbalances
            4. Pollutants
      2. Biotic Stressors
         1. Pathogens
            1. Fungi
            2. Bacteria
            3. Viruses
            4. Oomycetes
            5. Nematodes
         2. Herbivores
            1. Insects
            2. Mammals
            3. Other Invertebrates
         3. Parasitic Plants
         4. Competition
   3. Plant Responses to Stress
      1. Acclimation vs. Adaptation
         1. Short-Term vs. Long-Term Responses
         2. Phenotypic Plasticity
         3. Genetic vs. Physiological Adjustments
      2. Resistance, Avoidance, and Tolerance Strategies
         1. Resistance Mechanisms
         2. Avoidance Mechanisms
         3. Tolerance Mechanisms
         4. Escape Strategies
      3. General Adaptation Syndrome in Plants
         1. Alarm Phase
         2. Resistance Phase
         3. Exhaustion Phase
         4. Recovery Phase