RS300
Quiz
09-20-99
1. Dr. Trlica defines plant stress as a external factor applied to the plant, i.e., heat, cold, nutrients, drought, defoliation, etc. (a) true (b) false
2. Dr. Trlica defines strain as the plant responses to applied stress, i.e., Ps, growth rate, death rate, seed production, etc (a) true (b) false
3. Light is often growth-limiting to grasses on semi-arid rangelands. (a) true (b) false
4. Over story shading by trees might alter species composition and productivity of under story plants. (a) true (b) false [Although a common response to this question is “true,” I’m not so sure. I think it is more a response to water and nitrogen; I’m seeing more and more evidence to back me up.]
5. Under story productivity declines with an increase in conifer cover (albeit not linearly). (a) true (b) false
6. Under story productivity declines with an increase in deciduous tree cover. (a) sometimes (b) not always
7. Tallgrass prairie or bunchgrasses with high leaf area may shade under story photosynthetic tissue. (a) true(b) false
8. C3 and C4 grasses have similar optimal temperatures for photosynthesis. (a) true (b) false
9. C4 grasses can extract more water at higher temperatures than C3 grasses. (a) true (b) false
10. When nutrients, like nitrogen, are limiting, individual plant growth rates may be depressed, but the system is more stable.(a) true (b) false (c) how can that make sense?
11. Respiration is often inversely related to photosysthesis, i.e., as Ps goes down, Rs goes up. (a) true (b) false
12. Defoliation (decrease in leaf area) often results in decreased total transpiration. Defoliation often results in decreased total photosynthesis. (a) true-true (b) true-false (c) false-true (d) false-false
13. Defoliation (decrease in leaf area) often results in decreased aboveground Rs, but increased below ground Rs. (a) true (b) false
14. Defoliation (decrease in leaf area) generally results in decreased seed production. (a) true (b) false
15. Plant must maintain a positive carbon balance over time to survive. (a) true (b) false
16. When apical dominance in a grass is removed, because the inflorescence is mature, a new rhizome begins growth.(a) true (b) false
17. When apical dominance in a grass is removed by biting, a new tiller is initiated. (a) true (b) false
18. Biting almost always removes apical dominance in a grass at the 4-leaf stage of growth. (a) true (b) false
19. Light often limits plant production on arid rangelands. (a) true (b) false
20. There is no competition between plants and microbes for nutrients. (a) true (b) false
21. C3 plants usually grow better under warm and dry conditions. (a) true (b) false
22. Blue grama grass is a C3 species. (a) true (b) false
23. Plants that exhibit a U shaped carbohydrate reserve cycle usually “do better” when grazed during the dormant period. Plants with a “V” shaped reserve cycle are often most vulnerable to defoliation during the period of rapid internode elongation. (a) true-true (b) true-false (c) false-true (d) false-false
24. Grazing can be heavier if opportunity for regrowth and environmental conditions are conducive to regrowth following grazing. (a) true (b) false
25. Litter buildup in nongrazed areas is beneficial to tillering. (a) true (b) false
26. Red light near the soil surface can stimulate tillering of grasses.(a) true (b) false
27. Trampling of plants and soils by hooves may mechanically injure plants and compact moist soil. (a) true (b) false
28. Trampling may be of little significance because wet-dry and freeze-thaw cycles mitigate negatives impact of compaction. (a) true (b) false.
29. Grasses typically have hollow, jointed stems with leaves on two sides of the stem. Leaves are narrow with nearly parallel venation and fibrous root system. (a) true (b) false
30. The interaction of an individual plant to herbivory depends on (a) phenological stage of development (b) associated species (c) morphogenesis [short shoot/long shoot ratio] (d) environment [opportunity to regrow]
31. Some grazing avoidance mechanism in grasses might be (a) lignin (b) alkaloids (c) awns (c) cyanogenic compounds
32. Grazing reduces or stops root growth and recovery may be slow (a) true (b) false
33. Little bluestem is known to have a high ratio of long shoots to short shoots and mature shoots break down (oxidize) slowly. How would that contribute to grazing resistance? (a) interferes with access to current, growing phytomass (b) Just too tough to eat (c) produces toxins that cause digestive problems.
34. Plants with persistent leaves tend to be high in secondary compounds (a) true (b) false
35. Root growth typically occurs at times other than when top growth is active. (a) true (b) false
36. Root growth often stops within hours to days of defoliation, but is species specific. (a) true(b) false
37. Root exudation may support microbial populations that facilitate availability of nutrients. (a) true (b) false
38. Management of leaf area sufficient for photosynthesis is an important tool for vegetation managers; that might be more critical in plants that produce a higher ratio of short to long shoots than vice versa, for example needleandthread grass.(a) true (b) false
39. You want to bio-engineer a plant community north of Fort Collins to another plant composition. One of the plants, buffalograss, is found in much greater abundance than desired; western wheatgrass in lower abundance. Should I first develop management strategies to deal with (1) buffalograss or(b) western wheatgrass?
40. You want to bio-engineer a plant community in northern Utah to another plant composition. One of the plants, big sagebrush, is found in greater abundance than desired; bluebunch wheatgrass and Idaho fescue are found in lower abundance. Should I first develop management strategies to deal with (a) big sagebrush or (b) bluebunch wheatgrass and Idaho fescue?
RS300
Quiz
09-24-99
1. You are a range conservationist with a Federal agency. You find yourself in a staff meeting defending the concept of range readiness. You would feel comfortable describing the impact of a grazing regime (time and season of grazing) on a target species, based on our description of organismal response to defoliation. (a) strongly agree (b) agree (c) disagree
2. You would feel comfortable describing the tillering response of a growing cool-season grass following removal of the apical meristem (growing point). For example, you could defend an argument regarding survivability of that tiller or the survivability of the plant. (a) strongly agree (b) agree (c) disagree
3. You have been invited to give a presentation to the Fort Collins Garden Club. You are well into your presentation, when someone asks if the wildrye (a cool-season bunchgrass) in their pasture will set seed if their horse eats some of the green leaves in late April. You assure the person the grass will set seed. (a) strongly agree (b) agree (c) disagree
4. Response of an individual plant to herbivory under natural conditions depends on frequency, intensity and timing of defoliation in relation to phenological development, associated plants, individual species’ characteristics (morphogenesis) and opportunity to compensate for herbivory (environment). Dr Woodmansee wants you to elaborate on these ideas in his basic ecology class. You volunteer to help him lead the discussion. (a) You are confident you understand the facts. (b) You are confident you understand the application. (c) no response
5. In temperate zones like Colorado, 25 days opportunity to regrow following defoliation in late spring is probably adequate, even if more than 50% of the leaf was removed. (a) almost certainly (b) probably not
6. An understanding of the mechanisms that allow a plant, monocot or dicot, to withstand the effects of defoliation is fundamental to the professional rangeland manager. (a) yes (b) no
7. You can think of scenarios where removal of a high proportion of the phytomass (e.g., 60% of leaves) of perennial grasses would not change the stability of the system. (a) For example, if plants were allowed opportunity to compensate for that herbivory. (b) For example, plants had continuous and adequate supply of nutrients and water. (c) For example, as long as tissue was removed by elk, not domestic sheep.
8. The ideas presented in the section apply only to defoliation of plants by domestic herbivores. (a) yes (b) no
9. Shrubs may be more sensitive to herbivory than the herbaceous layer and require greater periods of compensation. This is especially true of cold desert shrubs; maybe less true of montane or sub-humid shrubs. Many shrubs invest heavily in secondary compounds as a mechanism to resist herbivory. (a) true (b) false
10. Tall wheatgrass is known to have a high ratio of long shoots to short shoots and mature shoots break down (oxidize) slowly. That means animals never remove growing points during herbivory. (a) true (b) false
11. Short shoots (graminoids) are represented by phytomers with elongated internodes. (a) true (b) false
12. Plants that exhibit a “U-shaped” carbohydrate depletion/replenishment cycle are vulnerable to herbivory during the active growing period, i.e., they recover more slowly than if defoliated during a dormant period. (a) true (b) false
13. Plants with a “V” shaped CHO depletion/replenishment cycle are often most vulnerable to defoliation at the 4-leaf stage of development. (a) true (b) false
Depends on how frequently tillers are bitten. Young tissue is photosynthetically very active and efficient. Once apical meristem is removed, plants need an environment that allows adequate time to compensate for tissue removal, i.e., need to regain 25 to 30 % of tissue that would have been grown had the tiller not been grazed.
14. Root growth typically occurs much earlier in the growing season than top growth. (a) true (b) false
15. The stem is the basic unit of the grass tiller. (a) true (b) false
16. Sedges/Carex spp typically have hollow, jointed stems with leaves on two sides of the stem. Leaves are narrow with nearly parallel venation and fibrous root system. (a) true (b) false
17. A grazed tiller always dies during that growing season. (a) true(b) false
No, parts of leaf could have been removed, but not apical meristam. In that case tiller could live more than one year – seldom more than 2
18. Grazed grass plants die each season and are replaced with plants that generate (colonize) from new seedlings each year. (a) true (b) false
A common misconception is that plants die each year and regenerate from seed. Simply not so.
19. When a short shoot of a dicot is removed vis-a-vis herbivory, that shoot dies back to the nearest meristimatic tissue. (a) true (b) false
20. C4 compared to C3 grasses generally have more fiber, the fiber is more lignified, lower nitrogen content (especially at maturity), carbohydrates in form of starch vs sugars, have greater tolerance for high temperatures (optimal photosynthesis occurs at higher temperatures), etc. (a) true (b) true
RS300
Quiz
10-01-99
1. Start with an unfenced parcel of land. Your planning team decides the best way to meet a goal related to some value is to graze each area (equal size in this instance) for 13 days and rest each area 42 days. How many pastures would fit that scenario, on average?
P = (R + DG)/DG P = (42 +13)/13
Answer is 4 to 5 pastures
2. Given another scenario. The area is already fenced into 16 similar sized pasture which are contiguous. If animals are in each pasture 10 days, what is the rest period? If animals are in each pasture 4 days, what is the rest period?
R = DG(P – 1) R = 10 (10 – 1) = 90
R = 4 ( 10 – 1) = 36
3. Given another scenario. An area is already fenced into 10 similar sized pastures which are contiguous. I want to set a rest period of 40 days on the first rotation, 60 days on the second rotation and infinity on the 3rd rotation, how long would animals stay in each pasture on each rotation?
DG = R/(P – 1) DG = 40/(10 – 1) = 4 to 5 days
DG= 60/(10 – 1) = 6 to 7 days