Question

Why is it necessary to reduce the moisture in freshly harvested grains before storing them for a long period?

Answer 1

Hint: Moisture i.e. water is essential for all living organisms. Every cell is made up of 70% percent water. Water provides the medium in which metabolic reactions take place. Thus if moisture is not removed from freshly harvested grains, then it will be suitable for all kinds of living organisms to grow.

Complete answer:
Freshly harvested grains need to be dried properly in order to avoid rotting or germination of the seeds. Rotting occurs if bacteria or fungi grow on a substance. And moisture and food in the form of seeds are ideal conditions for the growth of such organisms. Also if there is enough moisture the seeds might end up germinating because the ideal conditions for seed germination include water, high temperature, and sunlight. Such rotten and germinated grains cannot be used for food anymore.

Additional Information: Let us study more about the germination of seeds.
-Seeds use water to break their dormancy. This is done by absorbing large amounts of water which will break the seed coat. This process is known as imbibition.
-Seeds are kept in dormancy by the hormone abscisic acid and this dormancy is broken by the hormone gibberellin which starts metabolism and respiration in them.
-This finally leads to the rupture of the seed coat as radicle and plumule emerge out.

Note: -Adsorption is a phenomenon in which the adsorbate (the substance getting adsorbed) is taken up by the outer surface of the adsorbent (the substance on which it is adsorbed).
-An example of this is when we use chalk (adsorbate) to write on board (adsorbent). As chalk is adsorbed only by the surface of the board and not on the entire volume.
-In contrast, an example of absorption is when we dip chalk in ink, the ink gets absorbed uniformly throughout the volume of the chalk.