Abscisic acid is one of the phytohormones present in plants and was firstly discovered in 1963 by Frederick Addicott and his colleagues (Fursule, Kulkarni, & Agarkar, 2006). It plays an important role in regulating the physiological process especially in extreme conditions, besides plant growth and plant development. Under non-stressful conditions, abscisic acid presents in low levels in plants cells. This is because plant cells require just a low level of abscisic acid for normal growth. In stress conditions like extreme environments, abscisic acid content increases when plants exposed to extreme environments such as water shortage, salt stress, and cold. When there is water deficiency in plants, the concentration of abscisic acid in plants’ cells increases triggering the closure of stomata. Karp (2009) stated that “abscisic acid binds to a GPCR in plasma membrane of guard cells” (p.638). The receptors then activate several pathways in response to this condition. This attachment causes the opening of Ca2+ channels which transfer Ca2+ from vacuole into cytosol. At ...
Most substances fall on a scale ranging from the most acidic to the the most basic with neutral substances falling somewhere in the middle. Scientists call this the pH scale. pH levels are measured in numbers,0 to 14. The closer a substance is to zero the more acidic it would be. The closer to 14 the more basic a substance would be.Now what defines an acid and a base, one might ask? There are three ways of defining acids, each singling out a specific property. The first theory is the Arrhenius Theory with states, that an acid is a substance that produces the ion H+ when in a water solution, while a base is a substance which produces the ion OH- when in a water solution. Examples of an Arrhenius acid are HCl and HNO3. Examples of an Arrhenius base are NaOH and AlOH3.
The basis for the symbiotic relationship in these species is complex. The infection of the host cell by rhizobia occurs within the plant’s root nodules. Bacteroides, gram-negative anaerobic bacteria, are isolated from the host cell by a peribacteroid membrane; the membrane between the plasma membrane of the cell and the membrane of the bacteroid. The bacteroid contains differentiated rhizobia, which are able to fix nitrogen due to the supply of carbon from the host plant. Sucrose is delivered to the nodules of the root via the phloem, where it is cleaved by suc synthase, and enters the Krebs cycle. The product of glyco...
All living things depend on a source of energy for their survival. These sources may vary from one species to another. For example, human’s and animal’s main source of energy is food, while plants main source of energy is sunlight. Plants lack the ability to move and look for sources of energy, runaway from predators, or avoid Abiotic stress. Instead, they have Photoreceptors such as chlorophyll found in plants’ chloroplasts which absorbs light and changes it into a cascade of electron transfer that serve as the main source of energy for plants. Moreover, different kinds of proteins regulate the plants life cycle such as phytochrome, cryptochromes, and phototropins. These proteins are mostly pigments that intercept light at different wavelengths and thus each photoreceptor is activated by different light conditions. Using their Photoreceptors, plants transform different light signals to regulate the plant’s growth, development, defense mechanisms, and stress responses. Most of the processes and mechanisms taking place in plant cells usually rely on signaling pathways. These signaling pathways depend on proteins that have different function in activating, inhibiting, or relying the signal from a protein to another. The most important proteins in these signaling pathways are kinases and phosphatases. Studies have recently shown important data that proves the interaction of these photoreceptors and some kinases and phosphatases, for example the interaction of phytochromes with PP2A phosphatases (Bissondial, 2005).
Imagine all the nutrients, like nitrogen, potassium, phosphate, water, and minerals, that are in regular soil; some put there by decomposing plants or animals and others by rain, fungi, and organic wastes. A good question to ask is how does this type of soil help a plant flourish and grown to its best potential? Since plants are made up of a root system, which are responsible for anchoring the plant and water and nutrient uptake, it is good to take a look at the kinds of nutrients that the plant will be up taking. One of focus is fungi, which is engrained in the soil. The fungus attaches to the plant root to sometimes help with nutrient intake, but also at times, can hinder the plant by absorbing its resources.
Jackson, R.D. 1986, Remote sensing of biotic and abiotic plant stress. Annual Review Phytopathology, 24, pp. 265-287.
Having performed several further experiments, the Darwins’ stated when seedlings are exposed to a lateral source of light; an (unknown) inducer is transmitted from the upper part to the lower part of the plant, causing a curvature-like appearance (Source 9). Continuing onto Darwins’ discovery, Peter Boysen-Jensen and Arpad Paal determined the substance that caused the bending was due to a chemical present in the plant (Source 7). One year later, scientist F.W. Went concluded the initial discovery, calling the substance responsible for the bending in the plant, Auxin (IAA) (Source 9). Biologists have since recognized the extent of Auxin’s role in plant growth, as well as its location within the plant
On the other hand, senescence process including senescence rate and molecular nature is influenced by various environmental and internal factors (Lim et al., 2007). The internal factors influencing leaf senescence includes phytohormones such as cytokinins, ethylene, auxin, JA, ABA, and SA, while the external factors includes UV rays , nutrient limitation, temperature, drought, shading, and pathogen attach or wounding. It can be said that to form a complex network of regulatory pathways for senescence, there should be an existence of various pathways responding to several external and internal factors all the pathways should be interconnected (He et al., 2001). Having said that, leaf senescence should be an excellently regulated process, taking into account its potential role in plants health and the various factors involved in senescence control (Lim et al.,
ACE Inhibitor medications such as Lotensin are angiotensin converting enzyme inhibitors. This can be used in conjunction with loop diuretics. This classification of drugs works by inhibiting the production of angiotensin II. This inhibition results in vasodilating therefore reducing arterial pressure, venous pressure, preload, and afterload on the heart. Ace inhibitors also decrease aldosterone formation which reduces sodium absorption and water retention. Reduced aldosterone puts Johnas at risk for hyperkalemia, a side effect of ACE inhibitors This can be used to treat his high blood pressure and tachycardia by reducing the need for compensation. This will allow his heart to also reach the oxygen demands and by reducing the preload this will
Plant defences are those mechanisms employed by plants in response to herbivory and parasitism. According to Hanley et al. (2007), “the tissues of virtually all terrestrial, freshwater, and marine plants have qualities that to some degree reduce herbivory, including low nitrogen concentration, low moisture content, toxins or digestibility-reducing compounds”. The type of chemical defence may be species specific (Scott 2008). The defences that plants possess may be in the form of chemical production or in the form of physical defences such as thorns or spikes and even through reinforced, rigid leaves. “The compounds that are produced in response to herbivory can either have a direct effect on the attacker itself (e.g. toxins or digestibility reducers), or serve as indirect defenses by attracting the natural enemies of the herbivores” (Bezemer & van Dam 2005). This essay will focus on chemical plant defences and in particular the effects of terpenes, phenolics, nitrogen-based defences as well as allelopathy in plants.
shows how different abiotic stresses result in unique responses from a plant cell wall [4].
Background Information: Over time the study of plants has revolutionized technology, allowing scientists to engineer solar panels, create cures and medicines, and even bring high definition television to the homes of millions. The examination of plants is interesting and useful, indeed, and this usefulness is definitely a factor in why the Photosynthesis Lab experiment was preformed.
If a plant cell is places in a hypotonic solution the cell has a lower water concentration to that of the solution. Water will move into the cell by osmosis from a high water concentration outside the cell to a lower water concentration inside the cell through a selectively permeable membrane. The cell becomes turbid
Tropical roots and tubers exhibit very low lipid content. The lipids are mainly structural lipids of the cell membrane which enhance cellular integrity and help to reduce enzymatic browning (FAO, 1987). Most of the lipids present in tropical roots and tubers consist of equal amounts of unsaturated fatty acids, linoleic and linolenic acids and the saturated fatty acids, stearic acid and palmitic acid etc.
Acids are substances that, when added to water produce hydrogen ions. Hydrogen Ions are the combination of hydrogen and water molecules. There are many types of acids, which consist of citric, hydrochloric, carbonic, sulfuric, acetic, nitric, phosphoric, and lactic acids. Acids react with zinc, magnesium, and aluminum forming hydrogen. They turn blue litmus paper red. Litmus is used to check for acidity. Acids are sour, react with metals to produce hydrogen gas, and react with carbonates to produce carbon dioxide gas. Strong acids dissociate in water forming hydrogen ions and an anion. Weak acids partially dissociate in water, to form hydrogen ions and an anion, an anion is a negatively charged particle.
Water passes into cells through a special type of diffusion called osmosis. Water molecules diffuse through the membrane from a weak solution into a strong solution until the concentration is the same on both sides. A membrane that allows only certain molecules to pass through is called a semi-permeable membrane. In a plant, water passes from a weak cell sap solution to an adjoining cell with a stronger solution, as water passes in, the volume of the sap vacuole increases. When a full sap vacuole presses against the cell wall, it is said to be turgid. If water that is lost is not replaced the sap vacuole shrinks and pulls on the cell wall, the cell becomes flaccid; this is known as plasmolysis.