Biostimulant Glossary

As biostimulants become part of the crop production portfolio, they bring with them new terminology and definitions. A short glossary of biostimulant key words includes:

Abiotic stress – Naturally occurring stresses, often intangible factors such as sunlight, temperature, water, salinity, elevation, etc.

Bacteria – Microscopic, single-cell plants, which have cell walls, lack defined organs and nucleus, but have DNA and reproduce by cell division. Large in numbers and range from beneficial to parasitic.

Biostimulant – A substance or microorganism that stimulates a natural process when applied to seeds, plants, or the rhizosphere (soil), in order to enhance or benefit nutrient uptake, nutrient efficiency, tolerance to abiotic stress, crop quality or yield. (The legal definition from the December 2018 U.S. Farm Bill.)

Biotic stress – Stress caused by other living organisms such as insects, disease, weeds, fungi, bacteria, molds, etc.

Colony-forming unit (CFU) –
A unit used in microbiology to estimate the number of viable bacteria in a container. Viability is defined as the ability to multiply via binary fission (split into two equal bodies) under controlled conditions.

Ethylene – A plant growth regulator that is produced in all parts of the plant when triggered by abiotic or biotic stress. A hormone that promotes early maturity, leaf senescence, yield loss, and declining forage quality.

Metabolism – Includes all biochemical processes in the plant that are necessary for life.

Microbiology – The study of the structure, function, and classification of simple life forms such as algae, bacteria, fungi, yeast, molds, etc.

Sub-clinical stress – Early stage, mild or temporary abiotic or biotic stresses that aren’t detectable or producing effects that are not detectable in the plant by usual diagnostic analysis.