NCERT Solutions for Class 11 Biology Chapter 15 – Plant Growth and Development
If you are looking for accurate and well-explained NCERT Solutions for Class 11 Biology Chapter 15 Plant Growth and Development, Myclass24 is the best platform to find them. This chapter covers an important area of plant biology that deals with how plants grow from a seed to a mature organism, the hormones that regulate this growth, and the environmental factors that influence development. Must check the CBSE resources and NCERT Solutions.
Myclass24 NCERT solutions are structured in a way that addresses every textbook question with clarity and precision. The solutions are particularly useful for students preparing for their board exams and NEET, where questions from plant growth regulators and photoperiodism are frequently asked. Students from across India, whether from states like Rajasthan, Gujarat, Andhra Pradesh, or West Bengal, can benefit from these carefully prepared solutions. The language used is simple and the concepts are explained with examples from real plant biology, making it easier for students to retain the information and perform confidently in exams.
NCERT Solutions for Class 11 Biology Chapter 15 PDF – Plant Growth and Development
Download the free PDF of NCERT Solutions for Class 11 Biology Chapter 15 Plant Growth and Development from Myclass24. The PDF includes answers to all questions, charts on plant growth regulators, and notes on photoperiodism and vernalisation. Perfect for mobile study and last-minute revision.
Plant Growth and Development – Chapter Overview, Key Facts & Concepts
Plant growth is a permanent and irreversible increase in the size of an organ or a whole organism. It is accompanied by metabolic processes and requires energy. Growth in plants is open-ended and occurs at specific regions called meristems. This chapter distinguishes between growth, differentiation, dedifferentiation, redifferentiation, and development. Check out NCERT Solutions for Class 11 Biology and NCERT Solutions for Class 11 for the rest of the chapters.
There are three phases of growth: the meristematic phase (active cell division), the elongation phase (cells increase in size), and the maturation phase (cells reach their maximum size and develop specialised functions). Growth rate can be expressed as arithmetic growth (linear) or geometric growth (exponential). The sigmoid or S-curve is commonly used to represent the overall growth pattern of a plant or organ over time.
Plant Growth Regulators (PGRs) or phytohormones are chemical substances that influence growth and development at very low concentrations. There are five major classes of PGRs: Auxins (promote cell elongation, apical dominance), Gibberellins (promote internode elongation, seed germination, breaking dormancy), Cytokinins (promote cell division, delay senescence), Abscisic Acid or ABA (stress hormone, promotes dormancy and stomatal closure), and Ethylene (ripening of fruits, promotes senescence and abscission).
Plant Growth Regulators – Quick Reference
| Hormone | Main Effect | Key Application |
| Auxin (IAA) | Cell elongation, apical dominance | Rooting hormone in cuttings |
| Gibberellin | Stem elongation, seed germination | Breaks seed/bud dormancy |
| Cytokinin | Cell division, delays ageing | Tissue culture, delaying leaf senescence |
| ABA | Inhibits growth, closes stomata | Drought stress response |
| Ethylene | Fruit ripening, abscission | Uniform ripening in mangoes |
Photoperiodism – Plant Classification Based on Flowering
| Plant Type | Requirement | Example |
| Short Day Plant (SDP) | Dark period longer than critical length | Chrysanthemum, tobacco |
| Long Day Plant (LDP) | Light period longer than critical length | Wheat, oat, sugar beet |
| Day Neutral Plant (DNP) | Flowering not affected by photoperiod | Tomato, sunflower, cucumber |
Vernalisation is the process by which flowering is accelerated by exposure to low temperatures. It prevents precocious reproductive development and enables plants to flower in spring. Winter varieties of wheat require vernalisation to flower normally. Importantly, the perception of cold in vernalisation occurs in the shoot apex, and it is the apical meristem that responds to temperature signals.
Seed dormancy is another key concept. Seeds remain dormant due to hard seed coats, presence of inhibitors, or immature embryos. Dormancy can be broken by cold stratification, scarification, or application of gibberellins. This chapter also discusses the concept of differentiation and plasticity in plants, where a single cell can give rise to the entire plant under appropriate conditions, which is the basis of modern tissue culture techniques.
FAQs for NCERT Solutions for Class 11 Biology Chapter 15 Plant Growth and Development
NCERT Solutions for Chapter 15 explain the processes involved in plant growth, differentiation, development, and maturation. Students learn about growth phases, growth rates, plant hormones, seed germination, photoperiodism, and vernalization. These solutions simplify complex concepts through structured explanations and detailed answers to textbook questions. Understanding plant growth and development helps students connect physiological processes with environmental factors. The chapter is important for CBSE examinations and competitive entrance tests because it explains how plants regulate growth through internal and external influences. Regular practice strengthens conceptual understanding and improves examination performance.
Plant hormones regulate growth, flowering, fruit development, dormancy, and responses to environmental conditions. NCERT solutions explain the functions of auxins, gibberellins, cytokinins, ethylene, and abscisic acid in a simple manner. Students learn how these hormones influence cell division, elongation, and differentiation. Understanding hormone functions is essential because related questions frequently appear in examinations. The solutions provide clear explanations and examples that improve retention and conceptual clarity. Consistent revision helps students answer application-based and theoretical questions confidently while strengthening their understanding of plant physiology.
Photoperiodism and vernalization are important environmental factors affecting plant development. NCERT solutions explain how day length influences flowering and how exposure to low temperatures promotes flowering in certain plants. Students understand the significance of these processes in agriculture and plant adaptation. The chapter provides examples and detailed descriptions that simplify learning. Understanding these concepts helps students answer exam questions effectively and appreciate how environmental conditions influence plant growth and reproduction.
Important topics include growth phases, growth regulators, differentiation, development, plant hormones, photoperiodism, vernalization, and seed germination. NCERT solutions provide comprehensive explanations and textbook answers for all major concepts. Students can improve conceptual understanding and answer-writing skills through regular practice. These topics are frequently asked in CBSE and competitive examinations. Thorough preparation helps learners develop a strong foundation in plant physiology and achieve better academic results.