Experiment I: Maize Germination Experiment
The first experiment will take a close examination of the formative first instances of a plant’s life. Germination is an eventful time, when the plant is drawing upon maternal reserves to emerge from the ground. All kinds of microorganisms are vying to become associated with this great source of energy – some will team with the plant while others will destroy it. It is clear that the plant is able to exercise some control over who enters and who does not, but it also appears to be somewhat of a free-for-all.
I see these main microbial players during the first hours of the plant life are those borne form the seed and those borne form the soil. It has been shown that the endophytes consist of microbes from both sources.
In this experiment I want to figure out how seedborne and soilborne microorganisms interact to become a part of the developing plant. I have a hunch that seedborne microorganisms will generally slow/limit the flow of soilborne microbes into the plant, by the principle of “priority effect”, in other words, just by merit of being there first, and occupying a niche, they have first priority. So, among my treatments, I will “sterilize” the seed of its microbial inhabitants, or plant the seed into sterile soil.
Arguably the most pivotal time in the plant’s life is its germination stage, particularly when considering the assembly of plant associated microbes. Maize seedlings typically emerge from the ground within 10 days of planting, depending on soil temperature. During these first days of germination and seedling growth, the plant is exuding high quantities of organic matter and secondary metabolites, stimulating microbial populations. Seedborne microorganisms are interacting with soilborne microorganisms, with little or no contact with airborne microbes. Thus, some combination of the former two sources is likely to constitute the plant’s primary endophytic community, possibly affecting complex traits, such as the seedlings’ pathogen resistance. I will plant seeds in maternal soil (i.e. soil of the maternal plant) and foreign soil to deduce the influence of the particular soil environment in affecting the dynamics of seedborne endophytes.