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Plants, taxonomically grouped in the kingdom Plantae, are a diverse group of autotrophic organisms. What does this mean? That they are capable of producing substances that are essential for the maintenance of their metabolism, from water, minerals and solar energy that they obtain from the environment that surrounds them. This process is known as photosynthesis and thanks to photosynthetic autotrophic organisms, vast trophic chains are sustained.
Although plants depend mostly on solar energy, to a lesser extent they require energy obtained through respiration. For this reason, from Ecologist Verde we will focus on the plant respiration and, in particular, we will develop the theme of when do plants breathe, where they do it and we will also tell you if the roots breathe or not. We invite you to continue reading.
When do plants breathe during the day or at night?
We will start directly by clearing up the mystery about when do plants breathe. Like other living organisms, plants always breathe. Yes always. This means that breathe both day and night. Now, how is the process of plant respiration defined? It can be broadly defined as the mechanism by which plants incorporate oxygen into plant tissues and release carbon dioxide and water vapor into the atmosphere. Thus, respiration is the opposite process of photosynthesisSince in the latter, plants incorporate carbon dioxide from the atmosphere and expel oxygen, thanks to the energy provided by sunlight. Therefore, photosynthesis, being a process that requires light, only occurs during the day, while respiration always occurs.
As we have seen, both photosynthesis and plant respiration involve the same components: water, carbon dioxide and oxygen, only they do it in different ways, as a substrate or as a product. Another fundamental difference is that respiration occurs in all cells of the plant, since they all have mitochondria, these are organelles specialized in the cellular respiration. While in contrast, photosynthesis occurs only in cells that have chloroplasts, which are organelles responsible for carrying out photosynthesis. Another difference lies in the different metabolic pathways that are used for both processes.
We recommend you learn more by reading this other article about the Difference between photosynthesis and plant respiration.
Where do plants breathe?
Now that we know when plants breathe, we can delve even further into how is respiration in plants. In principle, plants breathe thanks to structures called stomata. Stomata They are small holes formed by occlusive cells of the epidermis that delimit a pore called ostiole, this leads to a substomatic chamber in which gases are stored. Thus, stomata allow gas exchange that occurs during photosynthesis and respiration of plants. They are commonly located on the underside of the leaves and green stems of all plants, and some mosses can also have stomata. The truth is that stomata are so tiny that they can measure between 0.006 and 0.035 millimeters depending on the plant species.
As we have mentioned, stomata make it possible to gas exchange that occurs both in respiration and in photosynthesis. In addition to this, stomata are the main route by which the plant loses water in the form of water vapor, through the process called plant transpiration. Eventually, the stomata can close to prevent excessive water loss, this mainly occurs in environments that are very dry or where water is scarce. Likewise, the opening or closing of the stomata can be influenced by other environmental factors, such as the concentration of carbon dioxide and the light that falls on the plant. In this way, the stomata can be closed or opened depending on the physiological needs of the plant.
A special case is the plants with CAM metabolism (acid metabolism of crassulaceae), which absorb carbon dioxide during the night. Then, in the presence of sunlight, the photosynthesis process is triggered with carbon dioxide that was fixed during the night. This mechanism is an adaptive strategy that allows plants to keep their stomata closed during the day to avoid excessive loss of water through perspiration. In contrast, plants with this type of metabolism absorb carbon dioxide at night while the other plants at night release carbon dioxide from the respiration process. If you want to know plant species with CAM metabolism, we recommend reading the article Plants that produce oxygen at night.
Also, here you can read and learn much more about where and how plants breathe and about the Parts of the stoma.
Do plant roots breathe?
While photosynthesis occurs in green leaves and stems, respiration occurs in leaves, stems, and roots too!. Among the many functions that roots carry out, such as anchoring, absorption of nutrients and water and more, one of them is respiration.
In the case of roots, respiration does not take place through the stomata, but rather through the lenticels. These are small lenticular-shaped openings, hence their name, that allow the gas exchange of lignified roots and stems, since in the latter, the lenticels are located on the crust. Also, lenticels may be present on some fruits. like apple and pear, and in tubers, like potato. In particular, lenticels are easier to see than stomata, because they are larger and raised. Some lenticels have particular shapes that are useful, for example, to identify tree species.
If you want to read more articles similar to When plants breatheWe recommend that you enter our Nature Curiosities category.
