Introduction to Plant Physiology
Plant Physiology is the branch of biology that deals with the functions and vital processes of plants. While plant anatomy explains structure, plant physiology explains how plants live, grow, reproduce, and respond to their environment.
It focuses on fundamental processes such as:
- Photosynthesis
- Respiration
- Transpiration
- Mineral nutrition
- Transport of water and food
- Plant growth and hormones
Understanding plant physiology is essential because plants form the base of all food chains and maintain atmospheric balance by regulating oxygen and carbon dioxide.
For competitive exams like NDA CDS 1 2026, conceptual clarity in plant physiology is extremely important as questions are generally application-based MCQs, not purely theoretical.
Core Topics in Plant Physiology (Important for MCQs)
1️⃣ Photosynthesis
Photosynthesis is the process by which green plants prepare their own food using sunlight, carbon dioxide, and water.
Equation:6CO2+6H2Olight,chlorophyllC6H12O6+6O2
Key Points for MCQs:
- Occurs in chloroplast
- Light reaction occurs in grana
- Dark reaction (Calvin cycle) occurs in stroma
- Chlorophyll absorbs red and blue light
Frequently asked:
- Site of photosynthesis
- C3, C4 and CAM plants
- Role of ATP and NADPH
2️⃣ Respiration in Plants
Respiration is the breakdown of glucose to release energy (ATP).
Types:
- Aerobic respiration (with oxygen)
- Anaerobic respiration (without oxygen)
Important concepts:
- Glycolysis occurs in cytoplasm
- Krebs cycle occurs in mitochondria
- Electron Transport Chain produces maximum ATP
Common MCQ focus:
- ATP yield
- End products
- Difference between photosynthesis and respiration
3️⃣ Transpiration
Transpiration is the loss of water in the form of water vapour through stomata.
Functions:
- Cooling effect
- Ascent of sap
- Maintains turgidity
Types:
- Stomatal transpiration
- Cuticular transpiration
- Lenticular transpiration
Questions often asked:
- Factors affecting transpiration
- Role of stomata
- Transpiration pull theory
4️⃣ Plant Hormones (Growth Regulators)
Plant growth regulators control development and responses.
Major Hormones:
- Auxins – Cell elongation
- Gibberellins – Stem elongation
- Cytokinins – Cell division
- Ethylene – Fruit ripening
- Abscisic Acid (ABA) – Dormancy and stress response
MCQ Tips:
- Match hormone with function
- Identify deficiency symptoms
- Application in agriculture
5️⃣ Transport in Plants
Two important tissues:
- Xylem – Transport of water and minerals
- Phloem – Transport of food
Important theories:
- Cohesion-tension theory
- Pressure flow hypothesis
Often asked:
- Direction of flow
- Structure of xylem and phloem
- Mechanism of translocation
6️⃣ Mineral Nutrition
Plants require essential macro and micronutrients.
Macronutrients:
- Nitrogen
- Phosphorus
- Potassium
- Calcium
- Magnesium
Micronutrients:
- Iron
- Zinc
- Copper
Common MCQ Areas:
- Deficiency symptoms
- Nitrogen cycle
- Role of minerals in chlorophyll formation
Special Focus for NDA CDS 1 2026 Exam
The NDA (National Defence Academy) & CDS (Combined Defence Services) examination conducted by the Union Public Service Commission tests:
- Basic biological concepts
- Application-based reasoning
- Scientific understanding at 10+2 level (NDA)
- Graduation level basics (CDS)
Exam Pattern (Biology Section)
- Questions are objective type (MCQs)
- Negative marking is applicable
- Biology is part of General Ability Test (NDA)
- Plant Physiology questions are usually 3–5 per paper
Preparation Strategy
- Focus on NCERT (Class 11 Biology – Plant Physiology chapters)
- Practice previous year questions
- Revise diagrams and processes
- Understand concepts rather than rote learning
Why Plant Physiology is Important for Defence Aspirants
- Helps in understanding environmental science
- Important for survival knowledge
- Strengthens scientific aptitude
- Improves analytical thinking for MCQs
In competitive exams like NDA/CDS, conceptual questions may include:
- Identify the incorrect statement
- Match the following
- Assertion-Reason
- Process-based application questions
Conclusion
Plant Physiology is a fundamental and scoring topic in Biology for NDA CDS 1 2026 aspirants. It provides insight into how plants sustain life on Earth through processes like photosynthesis, respiration, and mineral nutrition.
A strong grasp of:
- Biological processes
- Functional mechanisms
- Hormonal control
- Transport systems
will significantly enhance performance in MCQ-based examinations.
With systematic preparation, regular revision, and practice of previous year questions, Plant Physiology can become one of the most scoring and conceptually strong areas in the Biology section.
