Rhizosphere

Rhizosphere

Rhizosphere

Rhizosphere is the region outside the root   where microbial activity is usually high.

The rhizosphere is the actual root surface. Microbial numbers are always higher in the rhizosphere and rhizoplane than in region of soil devoid of roots. Here moisture is less variable, nutrient concentration is high and microbial communities are the most diverse and abundant. These roots excrete significant amount of sugars, amino acids and hormones, vitamins.

Bacteria and fungi often form microcolonies on the root surface.

Rhizosphere Effect

Within the rhizosphere plant roots have a direct influence on the composition and density of the soil microbial communities.

Rhizosphere Microflora

The interactions of plant roots and rhizosphere microorganisms are based largely on interactive modifications of soil environment methods.

There is a higher proportion of Gram negative rod shaped bacteria and a lower proportion of Gram positive rods, cocci and pleomorphic forms in the rhizosphere than in root free soil.

There is also motile, rapidly growing bacteria,  Pseudomonus.

‌The microaerophilic Azospirillum and the aerobic Azotobacter paspali are nitrogen fixing soil bacteria associated with the tropical grasses of Digitaria, Panicum and paspalum genera.

‌These bacteria use root exudates as the energy source to support nitrogen fixation.

‌The rhizosphere of eel grass and turtle grass in the site of high nitrogen fixation activity by Desulfovibrio, Clostridium and other anaerobes.

Rhizosphere

Written By

Sadia Akhtar
Student of Department of Microbiology
Jagannath University.
Email- sadiabd810@yahoo.com