Climate Change & Plant Health: How Abiotic Stress Will Affect Crops
Climate change is a major and divisive topic of discussion, and while it is known that the climate has always changed over time, human impact unquestionably accelerates these changes in significant ways. Observation of rapid changes in weather and discussion with farmers, ecologists, and fishermen is enough to concern anyone who depends on environmental stability for their livelihood and food production.
Whether you’re a New Englander preparing your landscape garden for a change in USDA hardiness from zone 4 to zone 5, or a major corn producer in southern Missouri watching with great concern as the “corn belt” creeps ever northward away from your generational farmland, anyone who eats food or grows plants outdoors should be aware of how changes to the environment stress and kill the plants we love and depend on.
What is Abiotic Stress?
These broadly categorized environmental factors known as “abiotic stresses” include heat, cold, flooding, drought, and salinity. While they are undoubtedly concerning to both plants and animals, fortunately there are some solutions we can look forward to that may help us continue to feed ourselves and others while we look for means to slow climate change back down to a more natural rate of progression.
How to Combat Abiotic Stress
The first and most frequently applied means of combating abiotic stressors is the choice of which crops we attempt to grow in a given environment. “Crop selection” involves identification of what environmental conditions will limit a cultivator's options, followed by a selection of crops that have either naturally evolved to suit that environment or have been artificially adjusted to be able to tolerate adverse conditions.
This may include choosing a specific cultured variety (cultivar) of corn that can tolerate higher temperatures, or an engineered cultivar of tomatoes with genes added to produce extra “cold shock” proteins allowing the fruit to survive a surprise frost. While crop selection is a great method to ensure crops can continue to be grown in impacted areas, it is not the only tool available to us. Other approaches like beneficial microbe usage, or induction of plant microbial synergies, keep us from sacrificing crops we know and love to produce in areas with increasing abiotic stress.
Plant growth promoting microbes (PGPMs) help plants tolerate abiotic stress in myriad ways. While sometimes this is more physical, ie: arbuscular mycorrhizae enhancing water uptake through plant roots, in other cases the compounds produced by PGPMs help the plants survive stress through their own enhanced capabilities. Certain signaling molecules produced by beneficial microbes can stimulate plants to induce physical and chemical changes that better help them survive, leading to improved outcomes in worsening environmental conditions. For example, bacterial exudates that cause a plant to produce more wax within a leaf cuticle can help a plant tolerate periods of drought without wilting and dying.
In other circumstances microbial compounds may stimulate a plant to produce more heat and cold shock proteins, allowing crops to tolerate colder northern and hotter southern climates than they could without that molecular stimulus. As climate change continues to rock the agricultural landscape, these techniques will become increasingly more important to sustain healthy crops.