Nutrients reach plant roots through three mechanisms: mass flow with water, diffusion along concentration gradients, and root interception as roots extend. Roots absorb nutrients both passively through membranes or actively through ion-specific carriers. To maintain electrical balance, plants absorb cations and excrete hydrogen ions or produce organic anions, while absorbing anions and excreting bicarbonate ions or compensating cations. Nutrients can also be absorbed through leaves via stomata, allowing rapid uptake to correct deficiencies, though this does not build soil fertility and can cause toxicity.

1. B Y – V I G Y A N A S H R A M , P A B A L
Nutrient absorption / uptake in
Plants.

2. Nutrients Absoption

3. Mechanisms of Nutrient Uptake
 Prior to absorption, nutrients reach the root by 3
mechanisms:
 Mass flow – movement with the water flow.
Most prominent.
 Diffusion – movement in response to a
concentration gradient. Slow.
 Root interception – root extension. Very
important to find new nutrient sources.

4. Absorption through roots
 Passive Uptake: Some ions such as nitrate, can move
passively through the outer membrane of the root surface
along with water in the transpiration stream.
 Active Uptake: Not well understood, but many nutrients (e.g.,
K+ and H2PO4
-) must somehow bond with an ion-specific
carrier (see Insight: p.270).
 Maintaining an Electrical Balance: As cations are absorbed
H+ is excreted or organic anions are produced. As anions are
absorbed HCO3
- is excreted or compensating cations are
absorbed.
For more information on this you can visit -
http://www.docstoc.com/docs/20285167/PLANT-NUTRITION-AND-
NUTRIENT-TRANSPORT-IN-SOILS.

6. Stomatal Absorption:
•Rapid absorption of soluble ions from nutrient
enriched water.
•Used mostly for the immediate correction of
critical nutrient deficiencies.
•Most efficient for the micronutrients. Does not
build soil fertility. Danger of phytotoxic effects
if over applied.
Absorption through leaves

7.  Thank you!