A Look at Plant Stress and Their Coping Strategies
As growers, you see the field-level impact that drought, hot or cool temperatures, hail, and excessive moisture have on your plants: you see symptoms such as burnt leaf tips, wilting, delayed development or even death.
What you can’t easily see is how the effects of stress are preventing normal plant function at the cellular level.
Plant physiology specialist Mike Dolinski hosted an interesting webinar entitled A Look at Plant Stress and Their Coping Strategies, on behalf of Earth Dirt Soil.
While Mike covers some complex concepts, we’ve tried to distill it down to some simple takeaways that all growers should be aware of.
Abiotic Stress is Perhaps the Biggest Factor Limiting Yield
According to Dolinski, abiotic stress is the limiting factor that stands in the way of our ability to increase global food production required to meet the demands of a growing population.
He shares the following insights on plant stress:
- Plants can’t run or hide from abiotic stress. The plant must change its chemistry to adapt.
- A number of key nutrients are critical to this chemical process.
- It is imperative that these nutrients are available to the plants. A strong, healthy root system is required to acquire them.
- Nutrient levels can vary dramatically in the same field. Tissue testing, soil testing and precision agriculture are valuable tools for addressing the imbalances across the field to produce a more uniform crop.
- Fighting the effects of stress requires the plant to expend energy, which must be diverted from other plant functions.
Plant Nutrition is Crucial to Managing Stress
Dolinski reveals that the most effective way to ward off abiotic stress is by managing plant nutrition. As mentioned above, plants rely on chemistry to counter the effects of abiotic stress. For the chemistry to work, it requires the presence of several key nutrients (which are, in fact, chemical elements).
Key Nutrients Involved in Stress Management
Plants need good, balanced nutrition, but the key nutrients related to stress management are Potassium, Sulphur, Iron, Manganese, Zinc and Copper. In stress situations, plants can draw down even more of these nutrients. These nutrients are used to deal with stress and create proteins and enzymes that regulate plant physiology.
How Stress Creates Toxins Inside the Plant
One of the plant’s primary responses to stress is to close the stomata – the openings in leaves that allow the leaf to take in CO2 while releasing oxygen.
If the stomata remain closed for long, oxygen radicals can build up and damage plant cells. This can be seen through leaf damage, frequently starting with the tips. Under extended stress, the plant can die. (Mike’s video covers this topic in amazing detail).
How Plants Can Defend Against Stress
Changing the root system: plants can make physiological changes in an effort to increase nutrient uptake. This includes altering the angle of the roots, promoting the growth of root hairs or lateral roots, or forming microbial relationships with mycorrhizae. Again, this is all regulated by nutrients. Foliar nutrients are shown to build and improve the root systems.
Breaking down excess oxygen compounds: In times of stress, “super oxides” (complex oxygen compounds) can build up in the plant. These are harmful. To counter this, plants can produce antioxidants. Manganese, Iron, Copper, Zinc and Sulphur are some of the key nutrients required to create these antioxidant enzymes, which help relieve stress in the plant.
Utilizing Potassium: Out of all mineral nutrients, K plays a particularly critical role in plant growth and metabolism and contributes greatly to the survival of plants that are under various biotic and abiotic stresses. Potassium is involved in enzyme activations, protein synthesis, photosynthesis, osmoregulation, stomatal movement, energy transfer, phloem transport, cation-anion balance and stress resistance. This is why it is vital to guard against potassium deficiency, especially in stress conditions.
How Growers Can Equip Plants to Fight Stress
Mike Dolinski says there are several ways growers can aid their crops to better deal with the impacts of stress.
- Take a look at real big issues in the field (such as pH, salinity and compaction).
- Conduct regular soil and tissue testing to make data-based decisions regarding nutrients.
- Look after soil health (including beneficial microbes such as mycorrhizae).
- Ensure timely access to nutrients. This includes using foliar products that encourage root growth.
- Employ a sound rotation, being mindful of soil health.
- Consider intercropping where it makes sense.
- Follow smart seeding practices (top-quality seed, seed coatings and disease prevention).
- Be aware of the role, function and importance of S, K, Cu, Zn, Mn, Fe and Ca in combating stress.