Phenes are the fundamental units of the phenotype that are both unique and elementary to a given level of biological organization. A phene state is the outcome of complex synergistic developmental systems, influenced by genes and gene products, as well as the environment. Root architectural and anatomical phenes determine the temporal and spatial distribution of root foraging in specific soil domains, and therefore affect resource capture. Mobile resources, such as nitrate and water are generally found in deeper soil domains over time due to crop uptake, evaporation, and leaching throughout the growth season. Whereas, immobile soil nutrients, including phosphorus and potassium, are more available in the topsoil. In a heterogenous matrix of soil, plants that are able to acquire edaphic resources at reduced metabolic cost will be favored, as these plants can allocate more resources towards growth, continued soil resource and reproduction.
