As we know, plants are characterized by being autotrophic organisms, that is, they are capable of making their own food by obtaining energy and certain elements such as water and minerals. For this reason, both the richness of the soil, the presence of water, and a correct exposure to sunlight, are essential for the development of all plant organisms.
In addition, plant respiratory processes play a fundamental role in plant production and plant survival. But what exactly are those respiratory processes used by plants? What specifically do they use each process for? Let’s find out in detail in this article and learn where plants breathe and how they do it.
What are stomata of plants
The stomata of the plants are cellular structures involved in any gas exchange. They are of vital importance for the survival of any plant organism since they are responsible for the correct functioning of plant respiration, as well as the control of other processes such as, for example, their action as a defense mechanism against situations seriously harmful to plants. (water stress, saline, and/or desiccation).
Stomata are made up of two epidermal cells with a rounded or kidney-shaped shape, with an orifice called the ostiole, which is capable of closing automatically in situations of excess carbon dioxide or due to lack of water. Mainly, they are located in the lower part of the leaf (underside), thus avoiding direct exposure to sunlight. Sometimes they also appear on the herbaceous stems of some plants.
Next, we will see in more detail how stomata intervene in the plant respiration process.
Where do plants breathe
During the plant respiration process, gas exchange takes place in plants through stomata and/or lenticels.
While stomata, as we have seen in the previous section, are made up of epithelial cells (and therefore are found in the epidermal tissue of plant leaves and stems), lenticels, on the other hand, are located in inert areas of the bark of stems and roots. These lenticels have a lenticular shape (similar to a biconvex lens) and their function is to allow gas exchange between the internal tissues of the plant and the atmosphere.
In this way, thanks to their own epidermal tissue, stomata, and lenticels, plants are able to carry out a correct diffusion of oxygen towards the inside and carbon dioxide towards the outside.
How plants breathe – plant respiration process
As we have seen previously, plants are able to breathe both in the dark and in the presence of sunlight. In addition, numerous scientific studies have come to verify how plants carry out the complex process of respiration in each and every one of their organs: roots, stems, leaves, flowers, and fruits.
This incredible phenomenon of nature, plant respiration, is based on several stages of chemical reactions in which gases are exchanged, chemical energy is obtained in small quantities and organic compounds (such as glucose or sucrose) are converted into inorganic acids. All this is possible thanks to the intervention of surprising enzymatic machinery, which directs the set of reactions that are carried out throughout the process of metabolic routes of plant respiration.
Thus, in general, the substrates of respiration reactions in plants are oxygen and glucose (or sucrose); while the products resulting from these reactions are carbon dioxide together with water and energy. All this is essential for the development of new plant cells and the correct growth of the plant.
Difference between photosynthesis and plant respiration
Both photosynthesis and plant respiration are physical-chemical processes that intervene in the complex mechanism of plant nutrition.
On the one hand, thanks to photosynthesis, plants are capable of producing the plant organic matter necessary to feed themselves, since they are autotrophic living beings, using inorganic matter (water and carbon dioxide) and minerals. This process is carried out in chloroplasts, requires a certain amount of light, and will result in the production of organic matter and the release of oxygen.
On the other hand, in parallel, the plant respiration process is carried out, through which the plants take oxygen from the air and subsequently expel carbon dioxide. It takes place in the mitochondria of the plant organism. It is important to highlight how two fundamental components intervene during the plant respiration process:
- Mitochondrial respiration: a process totally independent of sunlight, through which it is possible to release the energy that plant cells have been storing in the carbohydrates generated during photosynthesis.
- Photorespiration: light-dependent process, used for the healthy growth and maintenance of plants, also acting as a protective mechanism in charge of releasing excess photochemical energy and thus protecting the leaves of the plant against possible photo-oxidation (damage due to excess light).
