For plants, life below the soil is every bit as complex as life above it. Their roots are not just passively searching for nutrients and water, but they are part of a complex soil ecosystem thriving with microscopic life. While some microorganisms may pose threats to plant health, a large number form intimate beneficial relationships with plants.
Plants Reward Soil Microorganisms with Root Exudates
While plants provide nectar and sweet fruits to the beneficial biology that exists above ground, below-ground plants also reward their favorite microorganisms. They do this with organic compounds called Root Exudates.
Root Exudates are sugars, proteins, flavonoids, and other organic compounds that either signal or feed populations of beneficial organisms in the soil. In this way, plants actively regulate the diversity of microorganisms in the soil ecosystem, “pulling the strings” of what organisms they want present.
How Do Root Exudates Work?
Root Exudates are a diverse arsenal of organic compounds, each with different effects on the biology of the soil. Depending on what the plants require, they secrete different exudates to employ the help of specific soil organisms. They are so important that plants use up to 20-40% of their carbon in the production of root exudates.
Root Exudates and Mycorrhizal Fungi
One example of how plants use root exudates is in their relationship with mycorrhizal fungi. Mycorrhizal fungi are fungi that help augment the efficiency of a plant's root system via their fungal mycelium. To attract mycorrhizal fungi to their roots, plants utilize specialized exudates which signal to the fungi that the plant is present and open to making symbiosis. While it is not completely clear, it is believed mycorrhizal fungi follow the concentration gradient of these compounds to find their way to the roots.
Root Exudates and Nitrogen-Fixing Bacteria
Nitrogen-fixing plants also utilize root exudates to attract free-living nitrogen-fixing bacteria to their root hairs. In this case, they use specialized flavonoids that attract specific strains of nitrogen-fixing bacteria to the surface of the root hairs. Once present on the root hair, a series of biochemical reactions causes the root hair to curl and envelop the nitrogen-fixing bacteria and eventually form "nodules" on the roots where nitrogen fixation takes place.
Rhizosphere Priming
Plants also utilize root exudates for a process known as "rhizosphere priming". The rhizosphere refers to the unique ecological microsite that occurs directly on the surface of the roots. Through this process, plants nurture the decomposers in the soil via root exudates to promote the breakdown of organic matter in the soil. This speeds up the nutrient cycling in the soil and then releases otherwise locked-up nutrients that were held within the organic matter.
The Rhizophagy Cycle
One of the most fascinating ways in which plants utilize root exudates is in a process known as the " rhizophagy cycle". While this process is extremely complex, here we will give you a quick intro to the concept. In the Rhizophagy Cycle plants use exudates to attract bacteria to their root tips. Here the roots consume the bacteria, internalize them, and harvest nutrients from within the bacterial cytoplasm. At the end of this process, bacteria are released alive from the roots into the soil where they once again form part of the soil food web.
CropBioLife and Root Exudates
Over a decade of trials and testing we’ve witnessed unique effect on a plant’s root exudates when it has been sprayed with CropBioLife. CropBioLife improves the overall health of a plant, and thus how efficient a plant’s energy production and metabolism is. This boost in energy production means there’s greater amount of carbohydrates that can be exuded into the ground, strengthening the symbiotic relationship between plant and soil.