Plants are magical! Through photosynthesis, leaves and stems convert solar energy into sugar in the form of glucose, which is then used for a variety of metabolic processes throughout the plant. But did you know plants don't just make sugar - they can also consume it? Root cells use respiration to burn transported glucose from leaves and turn it into cellular energy that drives water and nutrient uptake across their systems. Truly remarkable stuff!
Respiration is impossible without oxygen - it's the final key in the aerobic respiration process that breathes life into glucose and transforms it into ATP.
Do Plants Need Oxygen?
To answer your question, yes. All plant cells continually use oxygen, making it essential for plant life. Under some conditions, plant cells must absorb oxygen from the air faster than they can produce. Why then do plants need oxygen if they produce it during photosynthesis?
That's because plants, like mammals, need to breathe air in and out. The term "respiration" may refer to more than simply the act of breathing. It's a way that all organisms on Earth get the energy their cells need to function. Respiration is the opposite of photosynthesis in plants; instead of producing sugars and releasing oxygen to capture energy, plant cells break down carbohydrates and use up oxygen to release energy for themselves. All animals get the carbs they need for respiration from the food they consume, and their cells are continually releasing the energy contained in food via respiration.
However, plants create their own carbohydrates via the process of photosynthesis, and their cells subsequently utilize those carbohydrates for energy through the process of respiration. Therefore, plants need oxygen because it aids respiration (called aerobic respiration).
The respiration process in plant cells occurs continuously. Plants produce their own oxygen when their leaves are exposed to light. Most plants have a net respiratory carbon dioxide gain during dark periods because they respire more than they photosynthesize. Plants' non-photosynthesizing portions, such as their roots and seeds, must also take in oxygen. This is why plants may "drown" in too much water.
When it Comes to Crop Yield, Oxygen is the Limiting Factor
Having enough oxygen for root cells to function properly is important for a plant's development and harvest. Due to a lack of oxygen, root cells can only use a certain percentage of their sugar supply and absorb a less percentage of water and nutrients.
If a plant can't get enough water and nutrients, it won't develop as fast and won't produce as many or as high-quality fruits. In addition, weak plants are more likely to be infected by pests and to perish in the face of natural disasters like the high temperatures seen during the summer.
Root zone aeration is frequently used in greenhouses to increase oxygen levels at the plant's base. Since greater temperatures lead water to store less dissolved oxygen (DO), this is especially important in warmer climes.
Also, farmers that recycle their irrigation water should treat it to improve its quality after each usage.
Oxygen Deficiency
Reducing and inhibiting illness caused by Pythium species or Phytophthora infections also requires adequate oxygen levels. Extremely high amounts of dissolved oxygen encourage the development of helpful bacteria like mycorrhizae while discouraging the spread of oxygen-hating diseases like Pythium.
Insufficient dissolved oxygen in the root zone may alter root and plant shape, metabolism, and physiology.
These alterations stunt plant development and leave plants vulnerable to pathogens like Pythium.
Plants are sensitive to hypoxia, which results from low oxygen levels and respond by slowing their growth or speeding up their metabolism. Excessive precipitation and saturated soil may cause hypoxia in plants, stunting their development.
Technologies for Oxygenation
Agricultural operations, until recently, were limited to a handful of standard water aeration technologies, all of which performed poorly at oxygenating water.
The oxygen transmission efficiency of diffusers is 1-2%. For this reason, many farmers supplement their standard aeration setups with water chilling devices since water loses its ability to contain dissolved oxygen as its temperature rises. However, with rising energy prices, chilling systems are becoming less sustainable and cost-effective due to the huge rise in running expenses they impose.
Water Oxygenation
Not only can greenhouse farmers profit from oxygenating their irrigation water, but specialized crop farmers may also profit.
There is often not enough oxygen in well water or reservoirs filled with well water for plants to thrive. However, the reservoir's biochemical oxygen demand (BOD) will be high if it contains organic chemicals from wind-blown seeds and leaves, bird feces, disease pathogens, and algae.
Thus, microorganisms will need much more dissolved oxygen to decompose the organic matter present. Therefore, oxygenation techniques must achieve enough dissolved oxygen to lower BOD and encourage healthy plant roots successfully.
Recent research from 2022 also reveals that increased oxygen in the soil (thanks to the treatment of water with super-oxygen) increases the activity of beneficial soil bacteria, leading to increased agricultural output, water usage efficiency, and soil fertility.
Quality irrigation water that is rich in oxygen is crucial for root growth and plant performance, whether the water is drawn from a reservoir or a natural source.
Optimal Root Development Depends on the Availability of Sufficient Oxygen in the Root Zone
Both edible and decorative plants are susceptible to damage from low oxygen levels in the growing soil. According to Ontario researchers, plant development may be stunted if the soil oxygen content is less than five parts per million.
If oxygen levels drop below five parts per million, plant growth will slow, and root death will occur. The ideal amount of oxygen in soil is between 6 and 8 parts per million. The ideal oxygen concentration is at ten ppm, although anything beyond that is welcome.
The oxygen content of water may be affected by its temperature. Warmer irrigation water has less oxygen. There is more oxygen in cold water. Normal oxygen levels in water at 20-25 degrees C are between 6 and 8 ppm. The oxygen content may decrease to 5 ppm or lower when the water heats to between 28 and 30 degrees C due to the roots of the plants absorbing part of the oxygen. In the summer, when temperatures are higher, the oxygen content in municipal tap water decreases.
Conclusion
Dissolved oxygen does more than just make for a healthier plant - it can also have significant economic impacts! With the proper use of dissolved oxygen, crop owners will be able to skip expensive chemicals such as fungicides. Plus, there's evidence that higher dissolved oxygen levels translate into increased growth rates and bumper harvests with quicker cropping times.
Who knew better Oxygen levels could mean bigger profits?
