PLSC 210-Horticulture Science Examination II October 23, is a plant hormone responsible for apical dominance.

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1 PLSC 210-Horticulture Science Examination II October 23, 2002 Name 1. is a plant hormone responsible for apical dominance. a. Cytokinin b. Auxin c. Abscisic acid d. Ethylene 2. Which of the following plant growth regulators would convert flower sex expression from maleness to femaleness on cucurbit plants? a. Ethylene b. Gibberellin (GA) c. Auxin d. Cytokinin 3. Phytochromes (P r and P fr ) trigger plants to respond to photoperiod for flower induction. Phytochromes are also responsible for phototropism. a. Both statements are true. b. The first statement is true, but the second statement is wrong. c. The first statement is wrong, but the second statement is true. d. Both statements are wrong.. 4. Which of the following plant growth regulators can be used to induce shoot proliferation during in vitro culture? a. Indoleacetic acid b. Cytokinin c. Indolebutyric acid d. Gibberellin 5. Which of the following is not true for ethylene as a plant growth regulator? a. It induces flowering in pineapple and other bromeliads. b. It hastens flower senescence. c. It promotes multiple shoot formation during in vitro culture. d. It converts flower sex expression from male to female. 1

2 6. Seed is used to break the seed coat dormancy, while is used to break the physiological embryo dormancy. a. stratification b. scarification 7. Apple trees planted in Florida grow well but will not produce fruit, because: a. flower buds are not formed during the summer. b. a winter cold period needed to break flower bud dormancy is absent. c. who will prefer apples to oranges there anyway. d. of high incidents of the June-drop phenomenon. 8. Higher the C/N ratio, the greater the reproductive growth. a. True b. False 9. Which of the following is a short-day plant? a. Azalea b. Daylily c. Petunia d. Poinsettia 10. If grown on the equator, which of the following plants would not bloom? a. Long-day plants b. Short-day plants c. Day-neutral plants d. Both the short-day and day-neutral plants. 11. Parthenocarpy is a phenomenon of fruit development without pollination and fertilization. Parthenocarpic fruits always contain seeds. a. Both statements are true. b. The first statement is true, but the second statement is wrong. c. The first statement is wrong, but the second statement is true. d. Both statements are wrong. 12. The stimulating influence of pollination on ovary expansion is referred as: a. phase change. b. June-drop. c. metaxinia. d. senescence. 2

3 13. Segregation of certain genetic traits can be found in the progenies obtained from: a. sexual reproduction. b. asexual reproduction. c. vegetative propagation. d. clonal reproduction. 14. In which of the following cell divisions would the number of chromosomes be reduced to one half? a. Mitosis b. Somatic cell division c. Meiosis d. Both mitosis and meiosis 15. Which of the following identifies a trisomic (aneuploid) condition in spinach (X=12)? a. 2N = 3X = 36 chromosomes b. 2N = 4X = 48 chromosomes c. 2N-1 =2X-1 = 23 chromosomes d. 2N+1 = 2X+1 = 25 chromosomes 16. The genomic (X) number of chromosomes for watermelon is 11. How many chromosomes would a seedless watermelon (triploid) have in each cell? a. 2N = 1X = 11 b. 2N = 2X = 22 c. 2N = 3X = 33 d. 2N = 4X = A life cycle is defined as the alternation of the generation and generation in plants. 18. Which of the following chemicals is commonly used to develop polyploid plants by doubling chromosome numbers? a. Auxin b. Kinetin c. Colchicine d. Ethephon 19. In the process of double fertilization, one (N) of the two sperm nuclei unites with to form an embryo (2N) and the other sperm nucleus (N) unites with to form endosperm (3N). 3

4 20. Given that the genomic (X) number of chromosomes for potato is 12 and the cultivated potato is a tetraploid (2N = 4X), indicate the number of chromosomes contained by cells of the following tissues of commercial potato: a. Somatic cells b. Microgametophyte (pollen) c. Egg cells d. Zygote e. Polar nuclei f. Endosperm 21. List three functional phases of a growing medium: a. b. c. 22. The gas phase of growing media is needed for: a. photosynthesis. b. root respiration. c. transpiration of water. d. conduction of water through xylem tissues. 23. At container capacity, the moisture condition in the growing medium is maintained by: a. capillary water, hygroscopic water, and gravitational water. b. hygroscopic water and capillary water. c. gravitational water only. d. hygroscopic water only. 24. Which of the following is not true for the optimum ph range required by plants? a. It enhances the availability of water to plants. b. It controls the amount of oxygen available in the growing medium. c. It maximized the absorption of essential nutrients by roots. d. It limits the growth of soil microorganisms. 25. Soils having a high level of cation exchange capacity (CEC) would: a. have the individual soil particles positively charged. b. absorb and store negatively charged ions. c. repel negatively charged ions (anions). d. repel positively charged ions. 26. can be used to raise the ph of a growing medium. a. Aluminum sulfate b. Iron sulfate c. Phosphoric acid d. Dolomite 4

5 26. Which of the following crops tolerates high ph soils? a. Alfalfa b. Blueberry c. Azalea d. Hydrangea 27. Which of the following statements is true for soil nitrification? a. The ammonifying bacteria (Actinomycetes) convert ammonium (NH 4+ ) to nitrite (NO 2 ) during nitrification. b. The final product of soil nitrification is nitrate (NO 3- ). c. Nitrosomonas, as nitrifying bacteria, converts nitrite (NO 2 ) into nitrate (NO 3- ) during soil nitrification. d. The first step of soil nitrification involves the conversion of nitrite (NO 2 ) into ammonium (NH 4+ ). 28. Which of the following soil amendments would have the lowest ph? a. Perlite b. Vermiculite c. Peat d. Sand 29. Which of the following is not true for the Cornell peat-lite mix? a. The major ingredients are peat, perlite and vermiculite. b. It contains sand. c. It is used for pot plant culture. d. It contains no soil. 30. Which of the following lights has the shortest wave length? a. Red light b. Blue light c. UV light d. Green light 31. When light intensity is measured for brightness, ( radiometric, photometric) units are used. (Check one) 32. Which of the following photometric units shows the highest light intensity? a. 1 foot candle b. 1 lux c. 1 mol m -2 s -1 5

6 33. Which of the following statements is not true for the atmospheric window? a. It allows the visible light to reach the earth s surface. b. It allows the photosynthetically active radiation (PAR) to reach the earth s surface. c. The ozone layer, CO 2 and water vapor filter out cosmic ray, -ray, x-ray, and UV light as well as infra-red lights in the atmosphere. d. It allows more UV light on earth s surface. 34. One lux is approximately foot candle. 35. Which of the following processes would consume the largest amount of energy from solar radiation received by a crop field? a. Heating of soil. b. Water transpiration by plants c. Photosynthesis d. Reflection of light by plants 36. The so called greenhouse effect is brought up by retention of in the atmosphere or inside a greenhouse. a. UV light b. visible light c. PAR (photosynthetically active radiation) d. infra-red light 37. The spectral range of the photosynthetically active radiation (PAR) is: a. 100 nm nm. b. 400 nm nm. c. 700 nm -1,000 nm. d. 1,000 nm - 2,000 nm. 38. For photosynthesis enhancement, fluorescent lamps are ( more, less) efficient than the incandescent lamps. (Check one) 39. Incandescent lamps are commonly used to light plants for photoperiod control, because: a. the cost of incandescent light bulbs is cheaper than that of fluorescent lamps. b. incandescent lamps are more energy efficient in emitting the red and far-red light compared to fluorescent lamps. c. incandescent lamps last longer than the fluorescent lamps. d. it is easier to screw in an incandescent light bulb than to install fluorescent lamps. 6

7 40. The night break method of lighting is used to: a. prevent flower initiation on short-day plants. b. prevent flower initiation on long-day plants. c. induce flower initiation on short day plants. d. none of the above. 41. At a dew point, the relative humidity reaches: a. 50%. b. 75%. c. 95% d. 100%. 42. Water boils at o C, and freezes at o C. a. 0 b. 32 c. 100 d Provided that 1 kg = 2.2 lb = 1,000 g and o F = 9/5 o C + 32, which of the following would contain the great amount of heat energy? a. 1 kcal b. 500 cal c. 1 BTU 44. The heat of vaporization is: a. released to the surrounding when water evaporates. b. absorbed from the surrounding when steam condenses to form water. c. absorbed from the surrounding when water evaporates to form vapor. d. released when water freezes. 45. Plant damage at high temperature is usually caused by tissue desiccation. a. True b. False 46. When water freezes to form ice, it will: a. absorb heat from the surrounding. b. release heat to the surrounding. 7

8 47. The wet-bulb temperature of an ambient air: a. increases as the relative humidity decreases. b. decreases as the relative humidity decreases. c. stays the same over a range of relative humidity when dry-bulb temperature is the same. d. is always higher than the dry-bulb temperature. 48. Transfer of heat energy from a point of higher temperature to that of lower temperature through metal or other solid material is called: a. conduction. b. convection. c. radiation. d. condensation. 49. The phenomenon of super-cooling occurs in evergreen trees when: a. cell saps freeze at temperature lower than 32 o F. b. cell saps do not freeze to form ice crystals at temperature below 32 o F. c. air temperature stays above the freezing point. d. they become physiologically dormant during the winter time. 50. Fruit orchards can best be located on a thermal belt since it is warmer than the low-lying valley during the flowering season. A south-facing thermal belt is better than the northfacing thermal belt as a site for orchard establishment. a. Both statements are true. b. The first statement is true, but the second statement is wrong. c. The first statement is wrong, but the second statement is true. d. Both statements are wrong. 51. Bonus Question (4 points). Make a question of your own from subjects you have studied but was not covered in this exam and answer it correctly. Honor Pledge: Upon my honor I have neither given nor received aid in writing this examination. Signed 8