NUTRITION IN PLANTS
The mode of nutrition in which
two plants of a same part of plant
help each other in preparing their
food is called saprophytic
Saprophytic nutrition is that
nutrition in which an organism
obtains its food frm decaying
organic matter. For ex- dead
plants, dead animals, rotten
'Sapros' refers to rotten and
'trophic' refers to food.
Saprotrophic nutrition is the
process by which the organisms
feed on dead and decaying matter.
The food is digested outside the
cells or even the body of the
organism - extracellular digestion.
The organism secretes digestive
juices that contain enzymes
directly on to the food. The
digestion makes the food soluble
and it is then absorbed by the
As matter decomposes within a medium in which a
saprotroph is residing, the saprotroph breaks such matter
down into its composites.
Proteins are broken down into their amino
acid composites through the breaking of peptide
bonds by proteases.
Lipids are broken down into fatty
acids and glycerol by lipases.
Starch is broken down into simple disaccharides
These products are re-absorbed into the hypha
through the cell wall via endocytosis and passed on
throughout the mycelium complex. This facilitates
the passage of such materials throughout the
organism and allows for growth and, if necessary,
In order for a saprotrophic organism to facilitate optimal
growth and repair, favourable conditions and nutrients
must be present.Optimal conditions refers to several
conditions which optimise the growth of saprotrophic
organisms, such as;
Presence of water: 80–90% of the fungus is composed
of water by mass, and requires excess water for
absorption due to the evaporation of internally retent
Presence of oxygen: Very few saprotrophic organisms
can endure anaerobic conditions as evidenced by their
growth above media such as water or soil.
Neutral-acidic pH: The condition of neutral or
mildly acidic conditions under pH 7 are required.
Low-medium temperature: The majority of
saprotrophic organisms require temperatures
between 1 °C and 35 °C, with optimum growth
occurring at 25 °C.
Plants that use the saprotrophic mode of nutrition are
Plants get nitrogen from the soil by a mechanism of
A bacterium called rhozobium plays an important role
in symbiotic nitrogen fixation.
This type of nitrogen fixation is observed in plants like
peas, moong beans and other legumes.
By this process, both bacteria and plants get benefited