Article review and summary Essay Example | Topics and Well Written Essays - 1250 words

Article review and summary - Essay Example Their population is also closely regulated by the presence of predators that are feeding on these bacteria like protozoa and nematodes. But also the opposite is true where the presence and activity of the rhizosphere bacteria determines the root growth patterns and concentrations of plant roots (Bowen 1999) (Gryndler 2000). This is because the plants and the rhizosphere flora are interconnected and they are dependent on the bacteria in the rhizosphere. There are bacteria from different species (Bradyrhizobium, Sinorhizobium, Rhizobium and others) for example that posses the nitrogenase enzyme and are able to reduce the atmospheric nitrogen into soluble ammonia that can be used by root plants. These bacteria also secrete root factors that promote the growth of root nodules that are N2 fixating symbiotic organs of the plants. Other way of interaction between thee roots and the rhizosphere bacteria is the antagonistic effect that some bacteria have on other bacteria that are pathogenic and harmful for the plant (Pythium, Rhizoctonia, Phytophthora etc.). The ability of the bacteria to antagonize the growth of organisms that are pathogenic to plants is researched on many prokaryotic and eukaryotic organisms (Bacillus species, Pseudomonas species, Agrobacterium species etc) (Whipps 1997). Pseudomonas fluores cence one of the most effective bacteria that colonizes the roots and has important function in antagonizing the flourishing of pathogenic bacteria that can have significantly negative effect on the rot health and agricultural impact. This is why there is a substantial interest about the effect of different fertilizers and additives that are used in the agriculture today and the impact of these materials on the rhizosphere (Kennedy 1998). The normal population of Pseudomonas spp. has important role in the normal functioning of the plant roots and this is why it is a subject of a number of studies that are trying to explain the mechanisms of growth for this