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Ecology

Effect on soil fauna

There is no known negative effect of auxin on soil fauna. However, earthworms take up nutrients through their coelum and may be affected by heightened auxin concentrations, although this has not been established in the literature (Dr Alexandru Milcu, oral communication).

Effect on soil microorganisms

E. coli do not naturally occur in the soil (REF), which makes it hard to predict its influence on other soil microorganisms.

Effect on plant population composition

Monocots such as grasses typically grow fibrous root networks while dicots tend to grow long, deep roots, from which other roots branch outwards. Auxin influences dicots and monocots differently. While it induces lateral root growth and inhibits deep root growth in both types of plants, only diots are influenced negatively by exogenous auxin, on which it can act as a herbicide (McSteen, 2010). Supplying auxin to the soil may therefore result in selecting against dicots and causing a predominantly monocot population to grow fibrous networks of plants.

While this may be detrimental for crop usage, dense netowrks of roots lead to an exponential water erosion decrease (Gyssels & Poesen, 2003). Fibrous root networks are therefore advantageous when trying to prevent soil erosion.

Skewing the plant population may have negative impacts from an ecological perspective, affecting diversity, but this effect may be counterbalanced by the conservation of plant habitation in general.

Another aspect that needs to be taken into account is that auxin affects plant growth indiscriminately as far as human plant usage is concerned. It is therefore not feasible to use our auxin-secreting bacteria as soil “fertiliser“ for crops.