Contact Us
Contact
Need assistance? Contact us on below numbers

For Enquiry

10:00 AM to 7:00 PM IST all days.

Business Enquiry (North & South)

Business Enquiry (West & East)

Or

Want a call from us
give your mobile number below

Thanks, You will receive a call shortly.
Customer Support

You are very important to us

For any content/service related issues please contact on this number

8788563422

Mon to Sat - 10 AM to 7 PM

Your cart is empty

NEET Biology Plant Growth and Development

Plant Growth and Development PDF Notes, Important Questions and Synopsis

SYNOPSIS

  • Growth is an increase in the size of an organism or part of an organism, usually as a result of an increase in the number of cells.
  • An auxanometer is used to measure the rate of growth in terms of shoot length.
  • Phases of Growth


  • Growth rate is the number of individuals added per thousand individuals which is represented by a growth curve.
  • The population growth curve is of two types—arithmetic growth and geometrical growth [sigmoid growth curve (S-shaped)]
  • Totipotency is the ability of a single cell to divide and develop into a new organism.
  • A growth regulator or phytohormone is an organic substance produced naturally in plants controlling growth and other functions.

  • Physiological Effects of Plant Growth Regulators


    Hormone

    Effect

    Auxins

    • Promotes the elongation and the growth of stems and roots.

    • Promotes cell division in vascular cambium.

    Gibberellins 

    • Cause stem elongation and leaf expansion but have no effect on roots.

    • Break dormancy of buds and tubers.

    • Used to promote elongation of internodes in sugarcane.

    Cytokinins

    • Stimulate cell division and prevent the onset of senescence in tissues.

    • Promote the growth of lateral buds.

    • Break dormancy of seeds.

    Hormone

    Effect

    Ethylene

    • Inhibits the growth of lateral buds and causes apical dominance.

    • Breaks the dormancy of buds and seeds.


    Abscisic Acid

    • Induces and maintains dormancy in many seeds.

    • Inhibits cell division and cell elongation.

  • The response of plants to the relative lengths and alternations of light and dark periods with respect to the initiation of flowering is called photoperiodism.


  • Vernalisation is a method of inducing early flowering in plants by pre-treatment of their seeds at low temperature.