Please read the Rhizosphere-N interaction dynamics article, available free online at the following URL.

https://doi.org/10.1093/jxb/erv307 (Links to an external site.)Links to an external site.

After reading this article, reflect on the corn plant’s sensing mechanism for focusing root development in zones of high fertility. Comment on how the plant responds in such a rapid and site-specific fashion. In addition, reflect on why the authors chose to use nitrate-nitrogen as the dominant N source rather than ammonium (they did apply very small amounts of the latter but much less so than nitrate). The rhizosphere has bacterial concentrations that are several fold greater than the bulk soil. Which form of N will be preferred by microorganisms? Do you think roots in close proximity to microbes are more competitive than microbes in meeting their respective N requirements in soil? Or do you think roots get the scraps that fall of the table so to speak with regard to what is leftover after microbes immobilize soil N?

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