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herbicides piercing mouthparts hail damage enzymes
The plant would become incapable of producing roots. The plant would be less able to repel insect predators. The plant’s leaves would turn yellow and fall off. The plant would no longer be able to photosynthesize.
it is produced only after an appropriate stimulus. it is present at all times regardless of the stimulus. it is present only during daylight. it is produced only under laboratory conditions.
The alkaloid would also attract beneficial pollinators. The plant would have to produce only one defense compound for all predators and pathogens. It would be difficult for a pathogen to evolve resistance to such a toxin. The single target alkaloids also would inhibit the plant’s own enzyme systems.
A scientist grows two populations of Arabidopsis plants (Populations A and B). Each population showed a range of physical defense (trichomes) and chemical defense (glucosinolates) levels against insects, varying from low (few trichomes, low glucosinolates) to high (abundant trichomes, high glucosinolates). Population A was exposed to the insect predators, while Population B was not. When seeds are harvested from each of the populations, which of the following would be the likely result? [Hint]
Population A would yield no seeds because the insect predators would eat all the plants. Population A would have the greatest yield of seeds from plants with the lowest level of defense, Population B would have the greatest yield of seeds from plants with the highest level of defense. Population A would have the greatest yield of seeds from plants with the highest level of defense, Population B would have the greatest yield of seeds from plants with the lowest level of defense. All plants in both populations would have roughly equal yields.
hypotrophic response. immune response. hypersensitive response. hypertrophic response.
The gene-for-gene hypothesis relies on [Hint]
secondary metabolite production. localized cell death. correspondence between R (red-flower) alleles and r (white-flower) alleles. correspondence between R alleles in host plants with avr alleles found in pathogens.
Clusters of similar R loci, called gene families, are thought to have originated when [Hint]
plant breeders cross-pollinate nonresistant plants. errors in recombination occur because chromosomes misalign during crossing over. the number of R genes is reduced by mutation. R genes correspond with avr genes during infection.
Which of the following pieces of evidence does NOT support the involvement of NO and ROI in plant resistance to pathogens? [Hint]
Production of ROI alone resulted in localized cell death, but at a low level. Both ROI and NO appear to be triggered by the R-avr interaction. Plants with abnormally low NO production cannot stop bacterial infection. Our immune system frequently uses a combination of NO and ROI to kill bacteria and diseased host cells.
phytochromes. phytohormones. phytoalexins. phytotoxins.
Strong increases of phytoalexin production in plants exposed to the pathogen. Phytoalexins are low molecular weight compounds. Correlation between the increased phytoalexin production and lower incidence of pathogen infection. Phytoalexins limit the growth of the pathogen.
What is the relationship between systemic acquired resistance (SAR) and hypersensitive response (HR)? [Hint]
HR is a precursor to SAR. The force is exerted by a cell on the surrounding fluid. SAR and HR are entirely independent and do not interact. The rapid SAR is the precursor to the slower HR.
Plant pathogenic fungi are not affected by endochitinase. The enzyme would eventually degrade the plant cell walls, killing the plant. The presence of endochitinase may kill any beneficial fungi associated with the plant. Endochitinase would interfere with photosynthesis.
SA is a plant secondary metabolite that poisons fungi exclusively. SA is one of the R genes. SA has no role in plant defense. SA is a molecule involved in triggering systemic acquired resistance.
Tasting a large amount of proteinase inhibitor causes herbivores to eat ravenously. The taste of proteinase inhibitors attracts potential herbivores. The taste of proteinase inhibitors stimulates increased production of digestive enzymes in the herbivore’s stomach. Herbivores recognize the taste of the proteinase inhibitors and avoid eating plant tissues that contain them.
The healthy plant would accumulate high levels of proteinase inhibitors. The healthy plant would become attractive to hornworms. The healthy plant would begin to produce salicylic acid. The healthy plant would lose its leaves.
A systemic reaction protects healthy, undamaged tissues. Salicylate hydroxylase catalyzes an important reaction. Each has an initial localized reaction. There is a signal molecule involved.
parasitic only on wasp larvae. parasitic only on major crop plants. parasitic throughout its life cycle. parasitic as a larva but free-living as an adult.
Plants kill the herbivores and the dead tissue attracts the parasitoids. Parasitoids produce volatile compounds that help herbivores locate injured plants. Flowers produce volatile compounds that attract parasitoids. Plants injured by herbivores produce volatile compounds that attract parasitoids.
acts as a hormone in the systemic production of proteinase inhibitors. mimics parasitized caterpillars. is a defensive volatile compound produced by plants in response to insect damage. is found in insect saliva that induces production of defensive volatile compounds in plants.
