TYPES OF GERMINATION

Biology

TYPES OF GERMINATION

What are the types of germination?

  • The nature of germination varies in different seeds.
  • During germination the cotyledons may be brought above the soil surface.
  • This type of germination is called epigeal germination.
  • If during germination the cotyledons remain underground the type of germination is known as hypogeal.

 

Epigeal Germination

  • During the germination of a bean seed, the radicle grows out through the micropyle.
  • It grows downwards into the soil as a primary root from which other roots arise.
  • The part of the embryo between the cotyledon and the radicle is called the hypocotyl.
  • This part curves and pushes upwards through the soil protecting the delicate shoot tip.
  • The hypocotyls then straightens and elongates carrying with it the two cotyledons which turn green and leafy.
  • They start manufacturing food for the growing seedling.
  • The plumule which is lying between two cotyledons, begins to grow into first foliage leaves which start manufacturing food.
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Hyopgeal Germination

  • In maize, the endosperm provides food to the embryo which begins to grow.
  • The radicle along with a protective covering(c(?/eorfci2a) grows out of the seed.
  • The epicotyl is the part of the embryo between the cotyledon and the plumule.
  • The epicotyl elongates and the plumule grows out of the coleoptile and forms the first foliage leaves.
  • The seedling now begins to produce its own food and the endosperm soon shrivels.
  • This type of germination in which the cotyledon remains below the ground is known as hypogeal germination.
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Practical Activity

To investigate epigeal and hypogeal germination Requirements

  • Tin or box, soil, water, maize grains and bean seeds. Procedure
  • Place equal amounts of soil into two containers labelled A and B.
  • In A, plant a few maize grains.In B, plant a few bean seeds.
  • Water the seeds and continue watering daily until they germinate.
  • Place your set-ups on the laboratory bench.
  • Observe daily for germination.
  • On the first day the seedlings emerge from the soil, observe them carefully with regard to the soil level. Carefully uproot one or two seedlings from each set.
  • Observe and draw the seedlings from each set Label the parts and indicate the soil level on your diagram.
  • On the fifth day since emergence, again uproot another seedling.
  • Observe and draw.
  • Indicate the soil level on your diagram..
  • Tabulate the differences between the two types of germination studied.
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See also:

CONDITIONS NECESSARY FOR GERMINATION

STRUCTURE OF A SEED

TO MEASURE THE GROWTH OF A PLANT

GROWTH AND DEVELOPMENT

FERTILIZATION IN ANIMALS

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