Unit 657: Plant Biology and Physiology

1. Plant Cells and Tissues

1.1 Structure of Plant Cells

• Cell wall, plasma membrane
• Organelles: chloroplasts, vacuoles, mitochondria, nucleus

1.2 Types of Plant Cells

• Parenchyma: structure, function, examples
• Collenchyma: structure, function, examples
• Sclerenchyma: structure, function, examples

1.3 Plant Tissue Systems

• Dermal tissue: epidermis, cuticle, trichomes
• Ground tissue: parenchyma, collenchyma, sclerenchyma
• Vascular tissue: xylem (tracheids, vessel elements), phloem (sieve tubes, companion cells)

2. Photosynthesis

2.1 Overview of Photosynthesis

• Importance for plants and ecosystems
• General equation

2.2 Light-Dependent Reactions

• Location: thylakoid membranes
• Role of chlorophyll and accessory pigments
• Photolysis of water, ATP and NADPH production

2.3 Light-Independent Reactions (Calvin Cycle)

• Location: stroma
• Carbon fixation, reduction phase, regeneration of RuBP

2.4 Factors Affecting Photosynthesis

• Light intensity
• Temperature
• Carbon dioxide concentration

3. Transpiration and Water Transport

3.1 Water Absorption in Roots

• Root hairs and epidermis
• Apoplastic and symplastic pathways

3.2 Water Transport Through Xylem

• Structure of xylem vessels
• Cohesion-tension theory
• Role of adhesion and cohesion forces

3.3 Transpiration Process

• Stomatal structure and function
• Mechanism and significance of transpiration

3.4 Water Potential and Movement

• Definition and components of water potential
• Osmosis and pressure potential

3.5 Factors Influencing Transpiration Rate

• Environmental factors: humidity, temperature, wind
• Plant factors: stomatal density, cuticle thickness

4. Mineral Nutrition in Plants

4.1 Essential Minerals

• Macronutrients: Nitrogen (N), Phosphorus (P), Potassium (K)
• Micronutrients: Iron (Fe), Zinc (Zn), others

4.2 Roles of Minerals

• Functions in enzyme activation, chlorophyll synthesis, osmoregulation

4.3 Mineral Deficiency Symptoms

• Visual symptoms and physiological effects

5. Plant Hormones

5.1 Overview of Plant Hormones

• Definition and general roles

5.2 Types and Functions

• Auxins: cell elongation, apical dominance
• Gibberellins: stem elongation, seed germination
• Cytokinins: cell division, delay of senescence
• Abscisic acid (ABA): stress responses, stomatal closure
• Ethylene: fruit ripening, leaf abscission

5.3 Hormonal Interactions and Plant Development

6. Photoperiodism and Plant Responses to Light

6.1 Photoperiodism

• Definition and significance
• Long-day, short-day, and day-neutral plants
• Mechanism: phytochrome system

6.2 Phototropism

• Positive and negative phototropism
• Role of auxins in directional growth

6.3 Other Light-Induced Responses

• Flowering regulation
• Stomatal opening and closing

7. Plant Reproduction

7.1 Sexual Reproduction

• Structure of flowers
• Pollination types and agents
• Fertilization process

7.2 Asexual Reproduction

• Vegetative propagation methods: runners, tubers, bulbs

7.3 Role of Hormones and Environmental Cues

• Hormonal control of flowering
• Vernalization and photoperiodic influence

8. Stress Physiology in Plants

8.1 Types of Stress

• Abiotic: drought, salinity, temperature extremes
• Biotic: pathogens

8.2 Plant Responses to Stress

• Osmotic adjustment and accumulation of solutes
• Antioxidant defense systems
• Stress signaling pathways and gene expression

8.3 Adaptations and Tolerance Mechanisms

• Structural and physiological adaptations
• Role of abscisic acid and other hormones