Light and Temperature Effects - High Tunnels

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Presented by University of Minnesota professor John Erwin at the 2009 Minnesota Statewide High Tunnel Conference in Alexandria, MN on Dec. 2-3, 2009.

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Light and Temperature Effects - High Tunnels

  1. 1. Light and Temperature Effects in High Tunnels • Light Intensity and Photosynthesis • Carbon dioxide (CO2) • Light color • Shading issues • Temperature effects on: – Development, stem elongation, photosynthesis and flowering. © 2009 Regents of the University of Minnesota
  2. 2. © 2009 Regents of the University of Minnesota
  3. 3. © 2009 Regents of the University of Minnesota
  4. 4. Light and Temperature Effects in High Tunnels • Light Intensity and Photosynthesis • Carbon dioxide (CO2) • Light color • Shading issues • Temperature effects on: – Development, stem elongation, photosynthesis and flowering. © 2009 Regents of the University of Minnesota
  5. 5. How much light can a plant use for photosynthesis? + CO2 + H2O C2H + O2 © 2009 Regents of the University of Minnesota
  6. 6. SOUTHERN GROWERS NORTHERN GROWERS © 2009 Regents of the University of Minnesota
  7. 7. Response to increasing light intensity (irradiance). Units are in umol m-2 s-1 Multiply umol m-2 s-1 by 5 to get footcandles. © 2009 Regents of the University of Minnesota
  8. 8. Variation in photosynthetic responses of different species to increasing light intensity © 2009 Regents of the University of Minnesota
  9. 9. © 2009 Regents of the University of Minnesota
  10. 10. © 2009 Regents of the University of Minnesota
  11. 11. © 2009 Regents of the University of Minnesota
  12. 12. What we learned • Species differed in how much light saturates photosynthesis. • Species studied showed photosynthetic saturation between 200 and 600 umol m-2 s-1 (1,000-3,000 footcandles). • When crops are spaced close, lighting levels should be based on light intensity at lower leaf levels. • By all accounts, tomato and pepper are high light requiring plants, i.e. saturate at 600 umol m-2 s-1 (3000 footcandles). © 2009 Regents of the University of Minnesota
  13. 13. How much light is getting to your plants? © 2009 Regents of the University of Minnesota
  14. 14. 750 ft-c January Daily Light Integrals © 2009 Regents of the University of Minnesota
  15. 15. 3700 ft-c April Daily Light Integrals © 2009 Regents of the University of Minnesota
  16. 16. In general, light penetration into a greenhouse varies from about 30-85%. 60% light transmission is very common. Single glass is the highest (85-90%), followed by Exalite and single poly (65- 75%), following by double poly (45-60%). This is without condensation! © 2009 Regents of the University of Minnesota
  17. 17. © 2009 Regents of the University of Minnesota
  18. 18. 3700 ft-c x 0.45 = 1,665 ft candles (333 umol m-2 s-1) April Daily Light Integrals © 2009 Regents of the University of Minnesota
  19. 19. SOUTHERN GROWERS NORTHERN GROWERS © 2009 Regents of the University of Minnesota
  20. 20. Increasing DLI versus total flower bud number 10 moles/day © 2009 Regents of the University of Minnesota
  21. 21. Light and Temperature Effects in High Tunnels • Light Intensity and Photosynthesis • Carbon dioxide (CO2) • Light color • Shading issues • Temperature effects on: – Development, stem elongation, photosynthesis and flowering. © 2009 Regents of the University of Minnesota
  22. 22. Response to increasing carbon dioxide (CO2). Units are in umol m-2 s-1 Multiply umol m-2 s-1 by 5 to get footcandles. © 2009 Regents of the University of Minnesota
  23. 23. © 2009 Regents of the University of Minnesota
  24. 24. © 2009 Regents of the University of Minnesota
  25. 25. © 2009 Regents of the University of Minnesota
  26. 26. © 2009 Regents of the University of Minnesota
  27. 27. How much light can a plant use for photosynthesis? + CO2 + H2O C2H + O2 © 2009 Regents of the University of Minnesota
  28. 28. © 2009 Regents of the University of Minnesota
  29. 29. What we learned . . . • Species differed in how much CO2 they could utilize under our conditions (300 umol m-2 s-1). • Photosynthesis of some species is saturated at lower CO2 levels (600 ppm; Rieger Begonia, Poinsettia), while photosynthesis on other species saturated at higher CO2 levels (<1000 ppm; cyclamen, impatiens, tomato, pepper). • High tunnel crops are likely CO2 starved! High light with limited CO2 is useless! © 2009 Regents of the University of Minnesota
  30. 30. Light and Temperature Effects in High Tunnels • Light Intensity and Photosynthesis • Carbon dioxide (CO2) • Light color • Shading issues • Temperature effects on: – Development, stem elongation, photosynthesis and flowering. © 2009 Regents of the University of Minnesota
  31. 31. © 2009 Regents of the University of Minnesota
  32. 32. © 2009 Regents of the University of Minnesota
  33. 33. © 2009 Regents of the University of Minnesota
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  35. 35. © 2009 Regents of the University of Minnesota
  36. 36. What we know . . . • Any leaf filtering increases leaf size, increases stem elongation, and decreases flower number. • It is desirable to have short plants, that are well spaced to maximize leaf area per plant and limit shading. • Spacing plants too close reduces yield, increases labor/management costs. © 2009 Regents of the University of Minnesota
  37. 37. Light and Temperature Effects in High Tunnels • Light Intensity and Photosynthesis • Carbon dioxide (CO2) • Light color • Shading issues • Temperature effects on: – Development, stem elongation, photosynthesis and flowering. © 2009 Regents of the University of Minnesota
  38. 38. Shade Cloth Issues © 2009 Regents of the University of Minnesota
  39. 39. SOUTHERN GROWERS NORTHERN GROWERS © 2009 Regents of the University of Minnesota
  40. 40. © 2009 Regents of the University of Minnesota
  41. 41. Why do we use shade cloth? • Limit heating in the greenhouse! • In general, we have been finding that any shading that reduces light levels below 3000 footcandles (600 umol m-2 s-1) is detrimental to yield! • Shading selection should be based on light level at plant level! • Shading selection/management will change if covering materials age and light transmission is reduced over time. © 2009 Regents of the University of Minnesota
  42. 42. © 2009 Regents of the University of Minnesota
  43. 43. We routinely over-shade in greenhouses and high tunnels! The best shading materials are materials that we can change the % shading over time such as: 1) spray on shading 2) having different levels of light screening. © 2009 Regents of the University of Minnesota
  44. 44. © 2009 Regents of the University of Minnesota
  45. 45. Open roof greenhouses allow for maximum lighting for photosynthesis, little depletion of CO2, and maximum cooling. © 2009 Regents of the University of Minnesota
  46. 46. © 2009 Regents of the University of Minnesota
  47. 47. © 2009 Regents of the University of Minnesota
  48. 48. Over-shading is often worst than no shading! © 2009 Regents of the University of Minnesota
  49. 49. Take Home Messages • Get a light meter! • Don’t over-crowd! • Find out how much CO2 is in your high tunnels! High light with little CO2 is useless! • Consider shading screens with high light transmission if needed that are pulled only on certain days and at certain times of the day! Also consider spray shading compounds. • Realize that poly transmission decreases over time and that your shading management should change as well! © 2009 Regents of the University of Minnesota
  50. 50. Take Home Messages • Consider retractable roof high tunnels to maximize light/CO2/temperature for optimal plant growth. © 2009 Regents of the University of Minnesota
  51. 51. Light and Temperature Effects in High Tunnels • Light Intensity and Photosynthesis • Carbon dioxide (CO2) • Light color • Shading issues • Temperature effects on: – Development, stem elongation, photosynthesis and flowering. © 2009 Regents of the University of Minnesota
  52. 52. Response to increasing temperature. Units are in degrees Celsius Multiply times 1.8 plus 32 to get units in Fahrenheit. © 2009 Regents of the University of Minnesota
  53. 53. © 2009 Regents of the University of Minnesota
  54. 54. © 2009 Regents of the University of Minnesota
  55. 55. © 2009 Regents of the University of Minnesota
  56. 56. © 2009 Regents of the University of Minnesota
  57. 57. © 2009 Regents of the University of Minnesota
  58. 58. What did we learn? • Species differed in how temperature affected photosynthesis. • The optimal temperature for photosynthesis varied from low temperature optima crops (59oF; Rieger begonia) to medium temperature optima (68oF; New Guinea impatiens) to high temperature optima (76oF; gerbera, tomato, pepper) under our experimental conditions. © 2009 Regents of the University of Minnesota
  59. 59. Rate of Plant Development © 2009 Regents of the University of Minnesota
  60. 60. © 2009 Regents of the University of Minnesota
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  63. 63. © 2009 Regents of the University of Minnesota
  64. 64. Optimum leaf unfolding rate of many plants occurs around 76- 84oF. When temperatures exceed 84oF, leaf unfolding slows and yield will be reduced! © 2009 Regents of the University of Minnesota
  65. 65. How does temperature effect stem elongation? © 2009 Regents of the University of Minnesota
  66. 66. © 2009 Regents of the University of Minnesota
  67. 67. © 2009 Regents of the University of Minnesota
  68. 68. © 2009 Regents of the University of Minnesota
  69. 69. © 2009 Regents of the University of Minnesota
  70. 70. Sensitivity of stem elongation to temperature varies within a day/night cycle. © 2009 Regents of the University of Minnesota
  71. 71. © 2009 Regents of the University of Minnesota
  72. 72. Variation in Daily Temp Sensitivity of Stem Elongation During the Day © 2009 Regents of the University of Minnesota
  73. 73. Does temperature effect flowering? © 2009 Regents of the University of Minnesota
  74. 74. Arabidopsis after 8 d Temperature Exposures 20 C 24 C 28 C 32 C 36 C 40 C Warner, R. Studies on high temperature effects on flower development. PhD Thesis, Department of Horticultural Science, University of Minnesota, St. Paul, MN USA. © 2009 Regents of the University of Minnesota
  75. 75. -These data suggest that the window for inhibition of flowering may be smaller than we thought. -These data also suggest that there is a cumulative effect and how temperatures were provided was irrelevant. Rather, it was an accumulation of degree-hours that was important (>32C). Warner, R., and J.E. Erwin. 2005. Naturally-occurring variation in high temperature induced floral bud abortion across Arabidopsis thaliana accessions. Plant, Cell and Environ, 28:1255-1266. © 2009 Regents of the University of Minnesota
  76. 76. Heat stress © 2009 Regents of the University of Minnesota
  77. 77. 68 ºF 86 ºF © 2009 Regents of the University of Minnesota
  78. 78. © 2009 Regents of the University of Minnesota
  79. 79. In general, your leaf temperature is 5-7oF warmer than the air temperature on sunny days. © 2009 Regents of the University of Minnesota
  80. 80. New Guinea Impatiens ‘Celebration Orange’ © 2009 Regents of the University of Minnesota
  81. 81. Does the length of the high temperature exposure make a difference in how long or much photosynthesis is depressed? © 2009 Regents of the University of Minnesota
  82. 82. N.G. Impatiens ‘Divine White’ 2 Days After a 1 or 2 hour 95oF Exposure © 2009 Regents of the University of Minnesota
  83. 83. © 2009 Regents of the University of Minnesota
  84. 84. Cooling leaves in the middle of the day on sunny days can increase photosynthesis! Why? By cooling leaves. . . . . © 2009 Regents of the University of Minnesota
  85. 85. Overhead irrigation increases photosynthe sis in the middle of the day. This occurs presumably through leaf cooling. © 2009 Regents of the University of Minnesota
  86. 86. Fog Evaporative Cooling © 2009 Regents of the University of Minnesota www.truefog.com
  87. 87. Take Home Messages • Buy an infrared thermometer ($75). • When you let your night temperatures drop and allow day temperatures to get hot, you INCREASE stem elongation. • Consider dropping temperatures during the first 2-3 hours to no lower than 55oF for tomatoes/peppers and 45-50oF for spinach and other leafy crops. • Manage high tunnel environments to achieve as close to 76-80oF LEAF temperatures on bright days as possible! © 2009 Regents of the University of Minnesota
  88. 88. Other Research Areas © 2009 Regents of the University of Minnesota
  89. 89. © 2009 Regents of the University of Minnesota
  90. 90. © 2009 Regents of the University of Minnesota
  91. 91. © 2009 Regents of the University of Minnesota
  92. 92. Potted Plants? Garden Plants? © 2009 Regents of the University of Minnesota
  93. 93. © 2009 Regents of the University of Minnesota
  94. 94. 0 ppm 600 ppm Marigold Fast-drying (86 F/ 45% RH) Afternoon Slow-drying (59 F/ 85% RH) Morning © 2009 Regents of the University of Minnesota
  95. 95. Airborne interplant signalling for plant defence © 2009 Regents of the University of Minnesota
  96. 96. Other Airborne Signals? volatile profile from undamaged Alnus volatile profile from beetle-infested Alnus From Tscharntke et al. 2001. Biochem. Syst. Ecol. 1025–1047. © 2009 Regents of the University of Minnesota
  97. 97. Jasmonates ►Methyl Watercress jasmonate elicits defense responses, just like jasmonic acid. © 2009 Regents of the University of Minnesota
  98. 98. © 2009 Regents of the University of Minnesota
  99. 99. K. glaucescens K. manginii K. uniflora 9 10 11 12 13 14 15 hrs Photoperiod (hrs) © 2009 Regents of the University of Minnesota
  100. 100. Green Roofs © 2009 Regents of the University of Minnesota
  101. 101. © 2009 Regents of the University of Minnesota
  102. 102. © 2009 Regents of the University of Minnesota
  103. 103. © 2009 Regents of the University of Minnesota
  104. 104. © 2009 Regents of the University of Minnesota
  105. 105. © 2009 Regents of the University of Minnesota
  106. 106. Liquid culture Seed germination Meristemoid induction in liquid culture In vitro multiplication © 2009 Regents of the University of Minnesota
  107. 107. Bailey Endowed Chair for Nursery Crops Research Todd and Barbara Bachman Chair for Marketing of Horticulture Crops © 2009 Regents of the University of Minnesota
  108. 108. Additional Special Thanks • Participants in the FRA and the Young Plant Center • USDA-ARS, SAF, Lin Schmale, and you for your support through the National Floriculture and Nursery Research Initiative © 2009 Regents of the University of Minnesota
  109. 109. Industry Acknowledgements ► MNLA Foundation ► American Floral Endowment ► Gloeckner Foundation ► Altman Plants, Inc. ► Oro Farms/Florida Specialty Plants ► Nurseryman’s Exchange ► Wagner’s Greenhouse ► Pleasant View Gardens ► Smith Greenhouses ► Sakata, Syngenta, Goldsmith, Ball Horticultural © 2009 Regents of the University of Minnesota
  110. 110. © 2009 Regents of the University of Minnesota

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