NCERT Solutions for Class 11 Biology Chapter 15

NCERT Solutions for Class 11 Biology Chapter 15 Plant Growth and Development to Study online or download in PDF form free. Download NCERT Solutions are applicable for all boards like UP, MP, CBSE, etc. who are following NCERT Books as course book.

NCERT Solutions for Class 11 Biology Chapter 15

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Plant Growth and Development: Solutions

11 Biology Chapter 15 Question Answers

NCERT Solutions for Class 11 Biology Chapter 15 Plant Growth and Development
NCERT Solutions for Class 11 Biology Chapter 15 in PDF

NCERT Solutions for Class 11 Biology Chapter 15 in English Medium
11 Biology chapter 15 answers

11 bio ch. 15

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Important Notes on Plant Growth and Development

  • IAA: Indole acetic acid
  • NAA: Napththalene acetic acid
  • ABA: Abscisic acid
  • IBA: Indole-3 butyric acid
  • 2.4D: 2.4 dichlorophenoxy acetic acid
  • PGR: Plant growth regulator

  • A period of suspended activity and growth usually associated with low metabolic rate. Some, seeds undergo a period of dormancy and can germinate only after dormancy period gets over.
  • Phytochrome: A pigment, found in plants which control the light dependent developmental process.
  • Phytohormone: Chemicals secreted by plants in minute quantities which influence the physiological activities.
  • Sensecene: The last phase of growth when metabolic activities decrease.
  • Vernalisation: A method of promoting flowering by exposing the young plant to low temperature.
    Growth: An irreversible permanent increase in size, volume and weight of an organ or its parts or even of an individual.
  • According to duration of exposure of plants to light, plants are divided in 3 categories:
    1. Long Day Plants (LDP) – Plants which need exposure to light for period exceeding critical duration e.g., wheat, rice, cucumber.
    2. Short Day Plants (SDP) – Plants that need exposure to light for period less than the critical length e.g., Cabbage.
    3. Day Neutral Plants (DNP) – There is no correlation between exposure to light duration & induction of flowering e.g., Tomato.

Seed Germination

The seed germinates only when favourable conditions for growth exists in the environment. In absence of favourable conditions it goes into a period of suspended growth or rest, called dormancy.
Abscission: Shedding of plant organs like leaves, flowers and fruits etc. from the mature plant.
Apical dominance: Suppression of the growth of lateral buds in presence of apical bud.
Quiescence: Non germination of a viable seed due to non-availability of proper environmental conditions.


It is the germination of seed while it is still attached to the parent plant and is nourished by it. e.g., Rhizophora and Sonneratia. As the germinating seed forms a seedling. It all down into the mud due to increase in weights. In the mud, lateral roots develops for anchorage.
Heterophylly: Occurrence of more than one type of leaves in plants e.g., larkspur, Coriander leaves of Juvenile plant are different in shape from mature plant.