Our cultivated crops generally live in a relatively nutrient-rich environment. But, according to a recent paper published in the journal Nature Communications, plants have been shown to “forage” for nitrogen (N) in low-N conditions, growing longer primary and lateral roots in order to find nutrients in the surrounding area.
However, this foraging action has been the least understood N-dependent root response — until now.
The paper reveals findings from a study being done at the Leibniz Institute of Plant Genetics and Plant Research (IPK) in Gatersleben, Germany, led by professor N. von Wirén, that has identified the hormone pathway that regulates root foraging in low-nitrogen environments.
According to the summary of the study, “Plants sense changes in their nutritional status and respond to these by tailoring the growth and development of their roots. These responses express in an altered degree of branching, extension, placement, and growth direction of individual parts of the root system.
“Nitrogen is an essential mineral element and nutrient for plants. When nitrogen availability is low, plant roots preferentially grow into nitrogen-enriched soil patches by locally expanding their lateral roots. As soon as plants run into nitrogen deficiency, they immediately induce a foraging response, in which roots elongate to explore a larger soil volume.”
The researchers, studying the plant Arabidopsis thaliana, a brassica commonly known as thale cress, found a brassinosteroid called BSK3, in conjunction with the brassinosteroid co-receptor BAK1, work together to modulate root growth under low N. This suggests that naturally occurring variations in the BSK3 hormone can be selected for to favor variants that promote a stronger foraging response.
This development could lead to the development of new crop varieties with root systems that better exploit the soil for nutrients, thereby requiring lower N inputs.
Nutrient placement for crops is a frequent topic of discussion among no-tillers, with some debate as to whether plants seek out nutrition or live in the presence of nutrition.
Coupled with the conscientious farmers and researchers who are already improving their nutrient management systems, this research points to a promising path on the road to reducing inputs. You can read more about the study here.