Class 9 Biology Chapter 9 – Plant Physiology (2026 New Syllabus)

Plant Physiology is a fascinating branch of biology that explores the vital life processes in plants. From how plants obtain and use nutrients to how they transport water, food, and gases, this chapter gives students a deep understanding of the mechanisms that keep plants alive and thriving.

In this chapter, we will study:

• Nutrition in Plants – How plants make their own food through photosynthesis and absorb essential nutrients.

• Transport in Plants – The movement of water, minerals, and organic substances throughout the plant body.

• Transpiration – How water is lost from plants and its role in cooling and nutrient movement.

• Transport of Water in Plants – Mechanisms like xylem transport, root pressure, and cohesion-tension theory.

• Translocation of Food in Plants – How sugars and other organic compounds move through phloem to different parts of the plant.

• Gaseous Exchange in Plants – How plants exchange oxygen and carbon dioxide for respiration and photosynthesis.

• Mechanisms for Excretion in Plants – How plants remove metabolic wastes efficiently.

• Osmotic Adjustment in Plants – How plants maintain water balance and survive under stress conditions like drought or salinity.

This chapter builds a foundation for understanding how plants live, grow, and respond to their environment, making it essential for Class 9 students to master.

Clas 9 Biology Chapter 9 Plant Physiology MCQs

Which of the following plant nutrients is required in large amount?

(a) Iron
(b) Zinc
(c) Potassium ✅
(d) Boron

Which ion plays a role in the opening of stomata?

(a) Sodium (Na⁺)
(b) Potassium (K⁺) ✅
(c) Calcium (Ca²⁺)
(d) Magnesium (Mg²⁺)

Which process allows plants to make their own food?

(a) Respiration
(b) Osmosis
(c) Photosynthesis ✅
(d) Fermentation

Which factor decreases the rate of transpiration?
(a) Wind
(b) High temperature
(c) High humidity
✅
(d) Large surface area of leaves

Which cells provide energy for active transport of food into phloem?

(a) Mesophyll cells
(b) Guard cells
(c) Companion cells ✅
(d) Epidermal cells

📥 Download Chapter 9 Notes – Plant Physiology

Get Class 9 Biology Chapter 9 complete notes for the 2026 syllabus, including:

• Nutrition in Plants

• Transport in Plants

• Transpiration & Water Transport

• Translocation of Food

• Gaseous Exchange

• Excretion Mechanisms

• Osmotic Adjustment

• Important MCQs, Short & Long Questions

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📥 Click to Download Chapter 9 Notes – Plant Physiology