Biology Ab Abs Root Word: Ab or Abs, Meaning & Examples (ab, abs: away, from)

Many root words have the prefixes ab-, abs-, a-, and apo-. These prefixes have the Latin meaning of "away, from," which is where these root words come from. The phrases abscission, adaxial, ablation, and aphasia are a few examples of words that begin with ab, ad, or abs. Abscission, which means to cut off, is a term used to describe how sections of plants naturally separate from the main plant. Adaxial refers to a plant part's location close to the axis. Ablation is the process of removing a structure's biological functioning. And finally, aphasia is a language disability that impairs both reading and writing skills as well as speech production or comprehension. This article has gone to great lengths to define each of these concepts.

What Is Abscission

The word "abscission" comes from the Latin words "ab," which means "away," and "scindere," which means "to cut." It is a cutting off action or procedure. It is the organic separation of plant components, such as fruit ripening and dropping. It is a biologically defined program of controlled cell separation that takes place at the abscission zones (AZs) at certain locations on the plant body. Abscission is regulated by a number of phytohormones and environmental elements.

Abscission zone has the following traits:

• Their cytoplasm is thick.

• They may differ in the cell's composition and have smaller intercellular gaps.

• walls.

• They react differently to plant hormones like auxins and ethylene.

Mechanism Of Abscission

The turgor theory postulated that starch breakdown raised the solute content at the separation zone cells. They rounded up and tore the wall along the side of the middle lamella as a result of the increased turgor pressure.

The synthesis of hydrolytic enzymes during abscission causes the middle lamella's pectin to break down, causing the actual cell separation.

The cells that make up the abscission zone experience cell separation as well as other alterations. Many of these have to do with preventing opportunistic infections from invading the fracture surface. These processes include the creation of fresh cell walls and proteins that resist pathogenesis.

Abscission Of Leaves

Abscission of leaves is the scientific name for the process by which older (more senescent) leaves fall off or detach from plants. Abscission, when all the leaves of a plant fall at about the same time and leave the plant looking bare, is highly characteristic in deciduous trees and shrubs of temperate areas. New leaves will grow next spring.

At the base of the petiole, where leaf abscission occurs, there is a distinctive zone of a few layers of thin-walled cells organised transversely across the petiolar base. The abscission zone or abscission layer is this region. Under the impact of enhanced pectinase and cellulase enzyme activity, the intermediate lamella as well as the primary cellulose walls dissolve, causing the cells of the abscission layer to separate from one another.

At this point, the petiole is solely connected to the stem by vascular components and will soon get separated from it owing to its own weight and wind pressure. In a short time, tyloses or gums are used to seal the damaged vascular components.

Fruit Abscission

While global transcriptome studies have been utilised to explore immature fruit abscission in fleshy fruit, no global gene expression alterations unique to MFA have been identified. Mature-fruit abscission (MFA) is a genetically regulated process. Research and analysis of gene expression from these AZs point to the probable involvement of membrane microdomains including signalling proteins, sterols/sphingolipids, and remorins (a class of plant-specific proteins) in MFA.

Abscission Signalling

Numerous environmental stressors, including UV exposure, cold temperatures, salt exposure, and pathogen infection, result in the production of reactive oxygen species (ROS). Some plants also experience similar stressors in conjunction with leaf abscission, however, it is unclear how these two processes are related. Stresses including UV, cold, bright light, salt, and pathogen assault create a range of ROS, including H2O2, superoxide, singlet oxygen, and the hydroxyl radical.

In order to indicate leaf abscission, hydrogen peroxide (H2O2) is continuously produced. The expression of the cell wall-degrading enzyme cellulase, which works downstream of ethylene in abscission signalling, must be continuously produced H2O2. Additionally, increased H2O2 synthesis occurs throughout the execution stage of abscission, indicating that H2O2 also participates in the cell wall deterioration process. These findings imply that H2O2 plays a number of roles in the signalling of leaf abscission.

Phytohormonal Control Of Abscission

Fruitlets' development and abscission are influenced by the interaction between ABA, IAA, and GAs (Smith, 1969). So, by increasing the effect of moderate amounts of ABA, proper alterations in auxin levels might either exacerbate or mitigate abscission (Addicott, 1970). Auxin, a hormone found in plants, and ethylene have been identified as important controllers of abscission signalling. The two substances complement one another's actions. The flow of auxin to the abscission zone decreases as auxin levels rise. The abscission zone becomes ethylene sensitive when auxin is exhausted. The rate at which de-bladed petioles abscise rises when GA is applied to the stem apex. Increased endogenous auxin levels in the stem accompany the effect on abscission.

Last Few Words On Abscission

As a result, abscission happens naturally in plants. The ability of the plant to shed leaves and fruits is another adaptive benefit. Fruits and leaves that are dead, damaged, or sick fall to the ground as opposed to shading healthy leaves or dispersing disease. In the winter, when the water in the plant is frequently frozen, or in the summer, when water is in short supply, the plant can reduce water loss.

What Does Adaxial Mean

Adaxial refers to a location that is closest to an organ or organism's axis. The adaxial side of a lateral organ, such as a leaf or petal, is its top surface.

Adaxial leaf surface characteristics

The following describe an adaxial leaf surface:

• Cell walls are gently waved on the adaxial surface.

• In all growing circumstances, the ratio of stomata on the adaxial and abaxial (side opposite to adaxial) leaf surfaces is comparable.

• The abaxial surface always transpires and photosynthesizes at a higher pace than the adaxial surface.

• Adaxial surface photosynthesis's CO2-response curve, which also monitors transpiration, is especially influenced by growing CO2 abundance. On the other hand, photosynthesis on the abaxial surface is mostly independent of CO2 levels and somewhat independent of stomatal activity.

What Is Ablation

Ablation in biology is the elimination of a biological structure or functionality, such as an organ or a cellular component. Ablation of genes and organs are two examples. Genetic slicing is also known as gene ablation.