ROOT EXUDATES Rashid Iqbal, Rabia tariq Roll No: 24, 84 Soil & Environmental Science University Of Poonch, Rawalakot
Root ExudateThe various compounds that leak fromgrowing and expanding sections of roots aswell as from broken cells at exit points. OR The chemicals secreted into the soil by roots are broadly referred to as root exudates.
Functions of root exudatesThrough the exudation of a wide variety of compounds1. Roots may regulate the soil microbial community2. 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 beingtransferred to the rhizosphere through root exudates
Groups of root exudatesRoot exudates have traditionally been grouped into:1. Low-M r compounds2. High-M r compounds
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.
Root-Microbe Communication1. 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 process2. Root exudates often include phenylpropanoids and flavonoids3. Root exudation stimulates the food-web of organisms around roots.
Effect root exudates on nutrientsavailability in rhizospher. Factors of major importance for:2. Rhizosphere pH3. Amount and composition of root exudatesThese 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.