Plant Health and Resistance to Stress
Plants are resilient organisms. They cannot grow or thrive when circumstances are unfavourable, thus they rely on countless transformations to withstand less than optimum conditions. Whether it's drought, heat, frost, or any other climatic stress, they have genetically integrated responses that make them capable of enduring without suffering catastrophic losses.
Yet just like us, healthy individuals are more competent and equipped to come out undamaged from environmental stress. Unhealthy plants tend to be more sensitive to environmental conditions and can suffer severe consequences from environmental stress. This means rapidly declining plant health, expedited by feedback loops of slow growth, disease, and other life-threatening conditions.
This is just one of the reasons why ensuring plant health is so important to any farmer or gardener. It not only means the difference between a so-so and amazing growth result, but it can also make the difference between survival or ruin.
How Healthy Plants Resist Environmental Stress
When climatic conditions are less than optimal, plants undergo genetic and physiological responses that make them more equipped to overcome environmental stresses. They may regulate the expression of certain genes or have other climatically triggered responses built directly into their tissues and cells.
For example, during drought conditions plants have 2 options to overcome the lack of water. These are either reducing their rate of water loss or increasing their ability to uptake water.
Reducing water loss is most often done by closing small holes on the leaf surface called stomata. Healthy plants have greater control of their stomata and will be able to more quickly respond in this situation. They also may have greater energy reserves that will help make up for reduced rates of photosynthesis. Healthy plants may also better resist oxidative damage that occurs from the closing of stomata.
Increasing water uptake can happen through a variety of mechanisms. For example, healthy plants with energy reserves can stimulate the growth of mycorrhizal fungi that live in their roots. This can help give them more access to any water that is in the soil.
Frost is another environmental stress that can cause serious damage to plants. Late frosts in the spring can be fatal or interfere with important parts of the life cycle such as flowering. Yet, there are ways that healthy plants have increased resistance to frost.
One of these is because of the high levels of trace minerals found within well-nourished plants. When minerals such as potassium, sodium, and magnesium are found in higher quantities, the freezing temperature of plant tissues is reduced. This phenomenon can be compared to how mineral-rich salt water has a lower freezing temperature than freshwater.The leading cause of declined health from all biotic and abiotic stresses in plants is often caused by oxidative stress. This is a complex phenomenon that occurs due to the build-up and accumulation of free electrons in the form of reactive oxygen species. Healthy plants can resist oxidative stress by removing reactive oxygen species and producing antioxidant defence compounds.