The elaborated SAP Is an aqueous substance that flows through the interior of plants and whose composition is derived from the modified raw sap through the process of photosynthesis.
It should not be confused with other substances produced by plants, such as resins or latex, as their function is completely different.
The sap is the substance that moves through the interior of the small cavities and ducts located inside the plants, including the trees. When the sap has not gone through the process of photosynthesis, it is called Raw sap . It flows through capillary vessels known as xylems.
Once the plant does photosynthesis , The composition of the raw sap is altered, and it is then when it becomes known as"elaborated sap", and its displacement happens to occur by different types of tubular conduits, called floemas (Britannica, 2017).
The elaborated sap, therefore, is known to be the substance that runs through the floemas, and whose main objective is to distribute the sugar, nutrients and water present in it throughout the body of the plant (including Leaves and roots).
The elaborated sap is composed mainly of high amounts of sugars, minerals, amino acids, organic acids, vitamins, phytoregulators, and inorganic ions.
On the other hand, it is responsible for hydrating the leaves of the plants once the water present in them evaporates. The way the sap manages to be transported into plants has been the subject of debate historically.
At present, it is believed that this process of vertical and ascending movement of the sap is possible thanks to the variation of the pressure inside the cells and ducts through which it is displaced.
Composition of the elaborated sap
The elaborated sap is rich in nutrients, contains high amounts of sugars, minerals, amino acids, organic acids, vitamins, phytoregulators and inorganic ions.
Thanks to its richness in nutrients and its purity (it does not contain toxins), it is commonly consumed by insects whose diet and nutrition depends clearly on it (Escuelapedia, 2017).
Sometimes the composition of the sap can be altered due to the interaction that the insects that consume it with, since these insects can carry easily transmissible pathogens at the moment they pierce the structure of the plant (Scientists, 2016 ).
On the other hand, the elaborated sap is considered a complete mixture of organic to inorganic substances. Some studies have shown that sugars and amino acids are the predominant substances present in the processed sap.
Sucrose is the main sugar found in processed sap; however, other sugars such as glucose, fructose, mannitol and sorbitol may also be present in its composition.
Amino acids are the main form of reduced nitrogens found in the processed sap. Their total concentration varies depending on the plant species.
Organic acids such as malic, succinic, ascorbic and citric acids can also be found in several plant species (Hijaz & Killiny, 2014).
Transformation
The production process of the elaborated sap begins when the plant absorbs nutrients from the soil through its root. In this way, it takes salts, water and minerals present in the earth.
This is how the Raw sap , Which is transported by the stem with the help of the xylem or woody vessels until reaching the leaves.
Once in the small cavities located in the leaves, the raw sap is converted into sap elaborated thanks to the process of photosynthesis.
Photosynthesis is the process by which all living things with chlorophyll (plants, algae and some bacteria) are able to take energy from sunlight to convert it into chemical energy.
The elaborated sap occurs when the raw sap is mixed with the substances resulting from the process of photosynthesis. Once transformed, the sap moves through the plant through the Liberian phloem or vessels, aiming to distribute nutrients, sugars, amino acids and water throughout the body of the plant. It also has the ability to store substances such as starches (Luengo, s.f.).
Transport
The elaborated sap is transported to the interior of the plants by means of the Liberian phloem or vessels. In this way, it reaches all parts of the body of the plant, more specifically the tissues where it will be consumed (such as meristems) or stored in seeds, fruits or roots.
There are a number of theories about the way the elaborated sap moves upward in the plant, against the force of gravity. However, the accepted theory is known as the cohesion hypothesis (Shah, 2016).
Cohesion Hypothesis
The hypothesis of cohesion, in botany, is the generally accepted explanation of how sap in plants ascends through their bodies with the help of intermolecular attractions.
Various calculations and experiments indicate that the cohesive forces between the water molecules and the adhesion forces between the molecules and the walls of the cell vessels are sufficient to give sufficient tensile strength to the water to move it into the plant.
The tensile force that the water present in the sap obtains inside the plant is enough to carry it up to the top of the tree continuously, that is to say, without ruptures in the sap flow into the conduits of plant.
These constant currents of sap are known as columns, and are responsible for the vertical and upward movement of water in plants.
The mechanism of ascent of the sap is of perspiration, since it involves the evaporation of the water of the leaves, reason why it becomes necessary that the elaborated sap moves of vertical form to re-hydrate them.
The theory of cohesion is a hypothesis that several researchers have proposed to explain the movement of the sap elaborated inside the plants (Britannica, Encyclopædia Britannica, 2017).
References
- Britannica, T.E. (2017). Encyclopædia Britannica . Retrieved from 'Sap': britannica.com.
- Britannica, T.E. (2017). Encyclopædia Britannica . Retrieved from"Cohesion hypothesis: britannica.com".
- (2017). View Forum Posts . Obtained from Savia elaborada: escuelapedia.com.
- Hijaz, F., & Killiny, N. (July 11, 2014). US National Library of Medicine . Retrieved from the Collection and Chemical Composition of Phloem Sap from Citrus sinensis L. Osbeck (Sweet Orange): ncbi.nlm.nih.gov.
- Luengo, L. (s.f.). The plant nutrition . Obtained from 3.5 Transport of the elaborated sap: recursostic.educacion.es.
- Scientists, A.S. (2016). Plants in Action . Retrieved from Techniques to collect phloem sap: plantsinaction.science.uq.edu.au.
- Shah, R. (2016). Biology Discussion . Obtained from Phloem Sap in Plants: Composition and Movement | Plants: biologydiscussion.com.