Root exudates are chemicals secreted by plant roots into the soil. They perform several important functions, such as regulating soil microbes, encouraging symbiotic relationships, and changing soil chemical and physical properties. Root exudates are categorized as either low or high molecular weight compounds. Low molecular weight exudates like amino acids and organic acids make up most root exudates. Certain exudates play a role in root-microbe communication during processes like nitrogen fixation. The amount and type of root exudates are influenced by numerous plant and environmental factors.

2. ROOT EXUDATES
Rashid Iqbal, Rabia tariq
Roll No: 24, 84
Soil & Environmental Science
University Of Poonch, Rawalakot

3. Root Exudate
The various compounds that leak from
growing and expanding sections of roots as
well as from broken cells at exit points.
OR
The chemicals secreted into the soil by roots
are broadly referred to as root exudates.

5. Image of root exudates

6. Functions of root exudates
Through the exudation of a wide variety of compounds
1. Roots may regulate the soil microbial community
2. Encourage beneficial symbioses.
3. Change the chemical and physical properties of the soil .
4. Inhibit the growth of competing plant species .
5. 5% to 21% of all photosynthetically fixed carbon being
transferred to the rhizosphere through root exudates

7. Groups of root exudates
Root exudates have traditionally been
grouped into:
1. Low-M r compounds
2. High-M r compounds

8.  Low-M r compounds such as amino acids,
organic acids, sugars, phenolics, and
various other secondary metabolites are
believed to comprise the majority of root
exudates.
 whereas high-M r exudates primarily
include mucilage and proteins.

9. Root-Microbe Communication
1. Some compounds identified in root exudates that
have been shown to play an important role in
root-microbe interactions include flavonoids present in the root
exudates of legumes that
activate Rhizobium meliloti genes responsible for
the nodulation process
2. Root exudates often include phenylpropanoids and flavonoids
3. Root exudation stimulates the food-web of organisms around roots.

10. Effect root exudates on nutrients
availability in rhizospher.
Factors of major importance for:
2. Rhizosphere pH
3. Amount and composition of root exudates
These changes are in many instances root responses
to the nutritional status of plants.
. Examples are given for zinc, iron, and
phosphorus nutritional status in plants.

11. Factors affecting root
exudates
1. Plant species
2. Plant age
3. Temperature
4. Light
5. Plant nutrition
6. Microorganism
7. Soil moisture
8. Root damage
9. Medium supporting to root