Question

Write the features of rhizosphere.

Answer 1

The rhizosphere is the narrow region of soil that is directly influenced by root secretions and associated soil microorganisms. The rhizosphere contains many bacteria and other microorganisms that feed on sloughed-off plant cells, termed rhizodeposition, and the proteins and sugars released by roots. This symbiosis leads to more complex interactions, influencing plant growth and competition for resources. Much of the nutrient cycling and disease suppression needed by plants occurs immediately adjacent to roots due to root exudants and communities of microorganisms. The rhizosphere also provides space to produce allelochemicals to control neighbors and relatives.The plant-soil feedback loop and other physical factors are important selective pressures for the communities and growth in the rhizosphere. Rhizodeposition allows for the growth of communities of microorganisms directly surrounding and inside plant roots. This leads to complex interactions between species including mutualism, predation/parasitism, and competition.

Answer 2

Hello,

Rhizosphere bacteria play vital roles in plant nutrition, growth promotion, and disease interactions. Several studies have indicated that bacteria are the most numerous inhabitants of the rhizosphere, although they account for only a small portion of the total biomass due to their small size. Typically, a 1-g sample of rhizosphere soil contains approximately 108–1012 bacterial cells; Gram-negative bacteria predominate in the rhizosphere; of these, the most efficient bacterial root colonizers belong to the genus Pseudomonas. Actinomycetes are filamentous chemoorganotrophic bacteria that form asexual spores. Populations of these bacteria are usually higher in rhizosphere than in nonrhizosphere soil. There are indications that actinomycetes may comprise higher percentages of the total bacterial numbers than fluorescent pseudomonads in the root zone of some plants. Although some actinomycetes may cause plant diseases, many species have the potential to produce antibiotics that could impact plant–microbe interactions, such as nodulation in legumes or biocontrol efforts against plant pathogens.