Flashcards
Plant Final
Cards in this deck (16)
- 1the organism that caused the Irish Potato FaminePhytophthora infestans (water mold)
- 2what weather conditions contributed to the Irish Potato Famine?Cool, wet, rainy weather
- 3What types of organisms cause diseases in plants?Fungi, Bacteria, Viruses, Nematodes
- 4What are the signs of a pathogen?Appearance or evidence of the pathogen itself
- 5What are the symptoms of a disease?visible disorder or abnormality of the host due to the disease
- 6What is host range?The types of plants that can be infected by a pathogen
- 7How can we control diseases?1. Eradication of the pathogen
2. Exclusion of the pathogen
3. Protection of the plant (e.g., fungicide sprays to protect plant from fungal pathogen)
4. Use of genetically resistant plants that are immune or highly resistant to infection by the pathogen - 8Invent your own plant disease. What organism causes the disease? What are the symptoms of the disease? What signs, if any, are associated with the disease? What is the host range of the disease?Bacteria causes the disease, symptoms: wet rot on fruits, signs: ooze on the fruit, Host range: effects all citrus fruits
- 9Take a look at the hypothetical results of growth of microbes from a diseased plant, shown on the slide. Obviously several different things are growing on the plate. How do you know which one (if any) caused the disease?1. Grow each one separately in culture
2. Infect healthy plants with each microbe separately, using plants of the same species and type wherein you saw the disease originally, see if you get disease occurring in the inoculated plants with one or more of the microbes
3. Re-isolate the candidate pathogenic microbe from the plants in Step 2 that got diseased. - 10In an attempt to reduce the use of chemical herbicides, and possible environmental contamination, plant scientists are turning to use of biological control agents (biocontrols) to control invasive plants. What are some potential advantages of using biocontrols rather than chemical herbicides? What are some potential disadvantages of using biocontrols?Potential advantages of biocontrols: environmentally friendly, less chemical application in the environment, self-maintaining, and inexpensivePotential disadvantages of biocontrols: might kill non-target organisms, might kill target too slowly to be useful, might not disperse in the environment, might not survive in the absence of the host, might no reproduce in the environment, and might not work under a wide range of environmental conditions.
- 11Once an Agrobacterium tumefaciens-created crown gall has formed on a plant, even if you treat the gall with an antibiotic and successfully kill all the A. tumefaciens cells inside, the gall can continue to grow. Why?The bacteria transferred their T-DNA into the plant cells in the gall and the T-DNA became incorporated into the plant cell’s DNA.Each time the plant cells in the gall divide, they duplicate their own DNA, which contains the T-DNA.The T-DNA directs the plant cells to divide and expand out of control.Therefore, the gall keeps growing, even if all the bacterial cells have been eliminated, since the plant cells in the gall have the T-DNA as part of their chromosomes and duplicate the T-DNA as part of their own DNA as they divide.
- 12Draw a diagram showing the movement of Agrobacterium tumefaciens’ T-DNA from the Ti plasmid to the plant cell chromosome.
- 13How could microbes help to mitigate the effects of climate change on agriculture?By priming the plants to activate their resistance to drought, cold, heat, salt, and other environmental stresses. Some microbes, including viruses, appear to provide stress tolerance benefits to plants. Not all microbes infecting plants are harmful, many may be beneficial!
- 14How do the lines “water, water everywhere/ and not a drop to drink” apply to the situation that plants find themselves in with respect to nitrogen, a key macronutrient?The lines refer to being stuck out in the ocean surrounded by seawater and having nothing to drink, since the water is salt water and not useful for drinking. Similarly, plants find themselves in a sea of nitrogen gas, since the atmosphere is 78% N2; however, the N2 molecule is extremely difficult to break apart, and so the nitrogen, while plentiful, is in a form that the plant cannot use.
- 15Why are Rhizobium root nodules different from Agrobacterium galls?Rhizobium nodule (RN) formation is fundamentally under the control of the plant, while Agrobacterium galls (AG) are triggered by the bacteria and the plant cannot control their formation or growth Related Note: If there is plenty of nitrogen available in the soil, the plant won’t make nodules or engage in the symbiosis, since the plant does not want to waste energy on the symbiosis if there is enough nitrogen available.
RNs are the site of nitrogen fixation, which benefits the plant by providing it with the essential mineral nitrogen. AGs drain resources and energy from the plant while providing nothing in return. - 16Why are researchers excited about the germination of a 2,000-year-old date palm seed in 2008, from the standpoint of date palm genetics and breeding? (Reading: Sallon et al., 2008)By examining contemporary accounts, researchers and historians have concluded that the date palm culture of the Dead Sea region 2,000 years ago was more diverse and of higher quality than it is today. Much of the date crop diversity has been lost over the centuries, with production now dominated by a few relatively low-quality cultivars. The 2,000-year-old date palm seed that was germinated represents a way to retrieve some of the genetic diversity that has been lost over time. The resulting tree is quite different genetically from modern cultivars, with up to a 35% difference in DNA content compared to modern cultivars. This plant could be used in date palm breeding to boost the diversity of the modern date palm population.
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- Flashcards on Plant Final, created by Danielle LeDonne on 12/12/2018.
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- Danielle LeDonne
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