Brittany Richardson How Inducible Defenses Occur Biology 2023 Introduction to inducible defenses Over the course of evolution plants have developed ways to communicate and react with the world around them. Some of these interactions are methods to protect themselves from would-be predators. One category of defense is known as constitutive defenses, which exist in the plant before herbivory takes place. Examples of these would include thorns, toughness, and trichomes. This type of defense comes at a cost to the plant, in what is known as a trade-off. The plant in its development must dedicate precious resources away from growth to the formation of these defenses, which may or may not be necessary (Barton and Hanley 2013). The other group of defenses is called inducible defenses. These occur as or after herbivory happens, through a complex series of mechanisms that is still not fully understood (Kempel et al. 2011). The inducible mechanisms result in the plant becoming toxic or less nutritious to the herbivore, or sometimes in the release of compounds that attract predators to attack the threat to the plant. Inducible defenses also have trade-offs associated with them, although induced defenses are more regulated, and which is more beneficial to the plant is still undecided (Baldwin and Wu 2009). Research on the mechanisms of induced defenses is ongoing, and defenses differ among species of both plant and herbivore. Researchers are gradually discovering small parts of this complex structure, a process that has been made easier due to the greater understanding of genetics. By isolating a molecule that is produced during an induced defense, and finding mutations that lack this phenotype, it is possible to f... ... middle of paper ... ...luding herbivory and pathogens. MAPKs lead to pathways in the nucleus and chloroplasts (Baldwin and Wu 2009). They regulate hormone signaling, and the transcription of defense related genes (Baldwin and Wu 2009). Phosphorylation amplifies the signal systemically throughout the rest of the plant. This is made possible by the plasmosdesmata, which are necessary for the communication of these stress signals to neighboring and far away cells, as shown by a study in which plants with a mutation for a loss of function in the plasmodesmata proteins displayed a diminished defense response (Bertea et al. 2012). ROS and NO The increase in Ca2+ ions also lead to an increase in active oxygen species, ROS. These include molecules like hydrogen peroxide (H2O2), the hydronium ion, and O2-. ROS are preceded by, and thought to be produced by, NADPH oxidases (Baldwin and Wu 2009).
More hydrogen ions in a solution is a result of lower pH, while fewer hydrogen ions in a solution is a result of increased pH. Meaning that a lower pH level results in a higher enzyme activity reaction and a higher pH level results in a lower enzyme activity reaction (Christianson, 2011 ).
Charles Darwin once compared the root tips of plants to “the brain of one of the lower animals” he even reported electrical signal systems in plants, much like a nervous system. More than a century after Darwin, a scientist named Mancuso discovered the center for the electrical signals, or action potentials, is located in the root tips. Even small plants had nearly 14 million root tips, all acting in a similar way to a nervous system. Humans and most animals have centralized brains, meaning it is all grouped together in one spot, forming what we envision as a brain. Plants may not have a centralized brain like humans, but that doesn’t mean they lack a brain, in fact plants have “decentralized intelligence” distributed throughout them. Since plants cannot react quickly, they have no way of defending themselves against predators, so by scattering the “brain” plants avoid dying off when damaged (Marinelli). The root tips and sensory cells allow plants to feel and react to different stimuli. It is uncertain as to whether plants feel pain, but they do respond to anesthetics and react to being damaged. For example, when a caterpillar eats a plant’s leaf, the plant begins to secrete defensive chemicals. The censor cells react to the damage being done and cause the leaf to secrete chemicals to fend off the predator, as well as repair the
A population of Plantago lanceolata (ribwort plantain) on the path was found to have higher trampling tolerance than populations away from the path; this reflected the sharp differences in the conditions of the plant at these sites. Ribwort Plant had generally a higher tolerance to trampling than any other plants as more were found on the path, but there were less compared with other plants as distance increased from the path. These results suggest that the competition level found on the path was sufficient enough to impose a selection pressure for the evolution of tolerance in a sensitive species, but in some areas the distribution of Ribwort Plantain were the same. This provides that other conditions affect the tolerance of trampling for Ribwort Plantain.
Thomas R. Warne, Leslie G. Hickok and Rodney J. Scott. (1988). Botanical Journal of the Linnean Society. Characterization and genetic analysis of antheridiogen-insensitive mutants in the fern Ceratopteris. 96 (1), 371-379.
Plasmolysis However when the plant cell is placed in a more concentrated solution the water inside the cell passes out the cell. The cytoplasm... ... middle of paper ... ...
Several potato plants carry resistance genes against PVX. Up to date two resistance genes have been identified. One gene product mediates salicylic acid systemic defense responses, whereas the other encodes the Rx protein. This protein has a nucleotide binding-site (NBS) and a leucine-rich repeat (LRR). The native fold of Rx confers an inactive conformation. Upon interactions with the viral CP, Rx partially unfolds, thereby its NBS-LRR domain [27]. This activates the signaling cascade mediating virus resistance.
Levitt, Jacob. Responses of plants to environmental stresses. 2d ed. New York: Academic Press, 1980. Print.
Schumann, Gail L., and Cleora J. D'Arcy. Hungry Planet: Stories of Plant Diseases. St. Paul: American Phytopathological Society, 2012. Print.
Plant hormones are certain chemicals present in plants that control plant growth and development by affecting the division, differentiation, and elongation of cells. (Campbell, 2008) Each hormone has multiple effects depending on its site of action, its concentrations, and the developing stage of the plant. (Campbell, 2008) Auxin is a plant hormone that is synthesized within the apical meristems and young leaves of a growing plant. Auxin stimulates stem elongation when it is present is low concentrations. It promotes the formations of lateral and adventitious roots, regulates development of fruit, enhances apical dominance, functions in gravitropism and phototropism, promotes vascular differentiation, and retards leaf abscission. Gibberellic acid is one of several plant hormones that govern a plant’s growth. Gibberellins allow for stem elongation in plants. Plants without enough of this hormone tend to grow short or stunted. This chemical is high in the element potassium, which is one the main components of plant fertilizer and very important for plant growth on its own. The...
Throughout The Botany of Desire by Michael Pollan, the author argues that the coevolution of plants and humans is seen within the relationship of humans manipulating plants to fulfill their desires. Pollan touches on four main examples where coevolution can be easily seen throughout history and the present. The apple satisfies sweetness, the tulip beauty, marijuana intoxication, and the potato control. As we are benefitting from evolving the plants for our own interest, the plants themselves are benefitting as well. The environmental message of the book surpasses that of coevolution and dives into the technology of genetic engineering
Another advantage of GM crops is the increased insect resistance from the use of pesticides. The first and best known example is the various sub-species of the bacterium ‘Bacillus thurnigenesis’. As mentioned earlier, these produce crystalline proteins, otherwise known as ‘-endotoxins’ or ‘cry proteins’ (Ellis et al, 2002). These endotoxins attack the digestive tract of the insect.
this, and the. [ IMAGE] The graph shows that the concentration of hydrogen peroxide is increased, the more oxygen is given off. This is because there is more
One of the most important changes would be an alteration in the concentration of hydrogen ions in the blood, this could be caused by a rise in blood carbon dioxide or an increase in tissue respiration in the muscles during the exercise. The respiratory centre is in its self. sensitive to raised hCo2 and responds by increasing the rate and depth. of the breath of the mind. In the aortic arch and carotid bodies there are chemoreceptors.
Insect pollination as we all know, is the process that enables reproduction and fertilization by the transfer of pollen performed by insects. Insects are some of the oldest pollinators of plants. Pollinating insects date back to 140 million years ago. Since then, due to how effective insect pollinators are, these flowering plants have become the major group of terrestrial vascular plants. Flowering plants, also known as angiosperms, have imperative roles within our ecosystems, both natural and agricultural. For instance, insects provide food, fiber and shelter for wildlife and humankind alike (2007). It is commonly know that in humans, high levels of fruit and vegetable consumption are associated with decreased risk of chronic disease (Calderone 2012). Aside from these important roles, plants have also been considered as a viable option for fuel sources (Calderone 2012). There are around 300,00 species of flowering plants in the world and without pollination, the reproductive process would be very difficult since pollination causes the production of seeds (Calderone 2012). Of the 300,000 plant species worldwide, a little over 3,000 of these plants have been used as a source of food. Close to 300 of these species are grown around the world today and only 12 of these plants make up about 90 percent of the food sources in our world. These 12 include the grains...
Genetic engineering enhances plant resistance to drought, salinity, disease, pests and herbicides. The aim is to try and enhance the growth, productivity, nutrient value, and chemical composition of the plants. Chemicals are constantly being developed or improved to enhance the competitiveness and adaptability of crops, and to kill the parasites and weeds which plague the agricultural sector. . This however is not always good as the plant and the pests then become resistant to these new chemicals defeating the purpose of it being used. The new chemicals which are produced to kill these strong pests and weeds may be more harmful to other plants and remove nutrients within the soil in turn reducing the yield of agricultural crops. The benefits of these characteristics are seen in Argentina according to Pelletier (2010) as they use glyphosphate resistant soybean which allowed the comeback of this crop, as the so...