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1 Chapter 6 – LIGHT CC 3.0 CC 3.0. Back to the Land Rural poverty and food shortage are forcing nations and scientists to engineer a new Green Revolution.

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Presentation on theme: "1 Chapter 6 – LIGHT CC 3.0 CC 3.0. Back to the Land Rural poverty and food shortage are forcing nations and scientists to engineer a new Green Revolution."— Presentation transcript:

1 1 Chapter 6 – LIGHT CC 3.0 CC 3.0

2 Back to the Land Rural poverty and food shortage are forcing nations and scientists to engineer a new Green Revolution. But theres a lot of lost ground to make up (Time, Oct. 26, 2009) 2

3 3

4 INTRODUCTION Plants respond to light quality, quantity, & photoperiod Light is electromagnetic radiation (fig. 7-2) Wave Particles: photons 4

5 5 Fig. 7.2 Electromagnetic spectrum nm Fig. 7.2 Electromagnetic spectrum

6 6 Fig. 7.1 Light is a transverse electromagnetic wave

7 7 5-12, 7.10 (excitation energy) PS1, PS2 ATP, NADPH 2 Calvin cycle CO 2

8 8 (Nobel, P. S Physical and Environmental Plant Physiology.)

9 9 Fig Basic concept of energy transfer during photosynthesis

10 Photosynthesis 12H 2 O + light + 6CO 2 C 6 H 12 O 6 + 6O 2 + 6H 2 O Chloroplasts (fig. 7-15) Process of photosynthesis Light rx Carbon dioxide fixation 3 carbon pathway 4 carbon pathway Crassulacean acid metabolism (CAM) table 5-1) 10

11 11 Fig Transmission electron micrograph of a chloroplast from pea (Pisum sativum)

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14 14 Ornamental cabbage Corn Jade plant

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17 Spacing & orienting plants for light interception Optimal spacing Frequently planted at the ideal spacing for mature plants Interplanting : plants w/ upright habits & spreading plants w/n or between rows is efficient Programmed dense planting : dense initially, thinned later Weed control Containerized plants Hydroponical growing system: automatically adjusting spacing 17

18 Spacing & orienting plants for light interception Double, triple or wide rows utilize space more efficiently for backyard gardeners (fig. 7-19) Landscape plants must be properly spaced Other methods for fruit trees Pruning Dwarf rootstocks Plant growth retardants Manipulating difference between night & day temp (DIF) 18

19 Orientation Often-debated subject Greenhouse orientation East-west above 40°N North-south below 40°N Gutter-connected greenhouse North-south Open garden The tallest plants to the north, and the shortest to the south 19

20 Pruning plants for light interception Fruit trees Thinning-out pruning (fig. 5-8, 5-9, 5-10) Open-center training : peach (fig. 5-9, 5-10) Objective Constant yield Good-quality fruits Ornamentals Hedge : wider on the bottom than the top (fig. 5-12, 5-13) Espalier (fig. 5-14) Topiary (fig. 5-14) Bonsai (fig. 5-15) 20

21 21 Thinning-out cuts(5-8)

22 22

23 23 Maximize light interception(5-10)

24 24

25 25 Hedge(5-12)

26 26 An improperly pruned hedge The resulting holes impair the desired visual effect.(5-13)

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28 28

29 Etiolation Plants often become etiolated in response to a blanching treatment Symptoms (fig. 5-16) White to yellowish stems & leaves Spindly growth of stems Extreme elongation of internodes Formation of seedling hooks Role of hook (fig. 5-19) Use Cauliflower (fig. 5-20), table onion (fig. 5-21) Vegetative propagation: cutting, layering (fig. 5-22) 29

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32 32 hook

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37 Effect of pigments-- carotenoids Carotenoids Accessory pigments for photosynthesis Photoprotection Impart color to flower, fruits, seeds 37

38 Cryptochromes & Phototropins Blue-light photoreceptors Cryptochromes Control stem elongation , cotyledon & leaf expansion, daily rhythms, & flowering Phototropins : phototropism auxin 38

39 Phototropism in wild type (A) and mutant (B) Arabidopsis seedlings

40 40

41 Phytochromes General characters H. A. Bothwick & S. B. Hendricks of USDA Red (R) or far-red (FR) effect on lettuce seed germination 17.2 (table 5-2) Phytochrome interconversions (fig. 5-23) The highest amounts exists in meristematic tissues & their newly formed daughter cells. Seed Dormancy Photoblastic Stimulated: carrot, gloxinia (, weeds Inhibited: tomato Unaffected: peas & sweet corn 41

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46 Phytochromes (Cont. 1) Branching & stem elongation R: short internodes, vigorous axillary bud growth (fig. 5-24) Ecological significance (fig. 9.4, 5-25, 5-26) Anthocyanin production A typical high irradiance reaction mediated by phytochrome Effect of light on coloring of eggplant (fig. 5-29) apple, peach 46

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48 Fig. 9.4 Optical properties of a bean leaf

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52 Photoperiodism W. W. Garner & H. A. Allard (1920) A response to day length Darkness is critical Phytochrome is the photoreceptor Each species has its own requirement for a minimum number of inductive photoperiods Flowering Formation of storage organs Stem elongation Temperate trees & woody shrubs 52

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57 Flowering Juvenile adult 3 distinct classes Day neutral plants (DNP) Initiate flowers under a wide range of day length Example Cucumber, everbearing strawberry, sweet corn Quantitative long-day plants Petunia, carnation Quantitative short-day plants Tomato, Rieger begonia 57

58 Flowering (Cont. 1) Long-day plants (LDP) Summer-flowering plants Evening primrose, spinach (fig. 5-31) Short-day plants (SDP) Late summer- or fall-flowering plants Cocklebur (Xanthium pennsylvanicum), chrysanthemum, kalanchoe, poinsettia

59 59

60 60 dandelion( )

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63 Flowering (Cont. 2) Photoperiodic control of flowering Revolutionize the floriculture industry Chrysanthemum can be programmed to flower at any desired time at any location Critical day length vary among crops & cultivars Manipulate critical day length either by controlling lighting or by providing darkness Lighting Incandescent lamps are commonly used (fig. 5-34, 5-35) Night interruption by lighting for 2-4 hr in the middle of night 63

64 64 Cuttings for vegetative propagation ( )

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67 Flowering (Cont. 3) Darkening Black cloth or plastic is pulled over the crop in the late afternoon & again in the early morning (fig. 5-36) Alternating day lengths SD followed by LD Bell flower, creeping white clover LD followed by SD Kalanchoe & some lilies 67

68 68 (fig. 5-36)

69 Formation of storage organs Stimulated by SD Tubers of potato, Jerusalem artichoke, scarlet runner bean, Begonia Stimulated by LD Bulbs of onion, early garlic Tuberous root formation of Dahlia occur under any day length, but greater root under SD (fig. 5-38) 69

70 70 Potato tubers from in response to short days.

71 71 Formation of tuberous roots on dahlia is accelerated by short days.(fig. 5-38)

72 Stem elongation Runner formation Stimulated by LD: strawberry Stimulated by SD: spider plant (fig. 5-19) 72

73 73 spider plant (fig. 5-19)

74 74

75 Temperate trees & woody shrubs Stimulated by SD Fall coloration of leaves Leaf fall (abscission) Onset of cold hardness Onset of dormancy Phytochrome is involved 75

76 Light quantity & quality Light quantity & photosynthesis Light compensation point Light saturation point 9-7 Vary w/ plant spp. & growing condition ( 9-8 Shade tolerance Sun & shade leaves Leaf area index Acclimatization of foliage plants 76

77 77

78 Shade tolerance Category (table 5-3) Nearly all vegetables & fruit crops grow best in full sun Must select the genotype to fit the location (fig. 5-41) Many understory plants are quite shade-tolerant & intolerant of full sunlight Foliage plants are produced under shading materials (fig. 5-42, 5-43) 78

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80 80 Impatiens azaleas Plants that grow well and flower in shaded locations

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87 Sun & shade leaves Comparison (table 5-4) Shade leaves under bright sunlight Leaf scorch (fig. 5-44) Photoinhibition, photodecomposition 87

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89 89 Leaf scorch (fig. 5-44)

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91 Leaf area index Leaf area index (LAI) Ratio of the area occupied by all the leaves to the surface of ground that the plant covers LAI as related to the plant productivity ( ) Leaf orientation (vertical) as related to yield 91

92 Fig. 9.4 Optical properties of a bean leaf

93 93 Fig. Crop growth rate (CGR) of soybean communities as a function of the leaf area index (LAI) (Loomis, R.S., D. J. Connor Crop Ecology, p.42)

94 94

95 Acclimatization of foliage plants Foliage plants frequently are raised outdoors in the full sun & must be properly acclimatized to prevent leaf-loss before being used for interior- scaping Manipulate light, temperature, watering, & nutrition Light is the most important Lower light levels to 40%-80% for 5 to more than 10 wk Grown under 40% shade Placed indoors for decoration light is the limiting factor (fig. 5-46) 95

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97 Light sources & their use Light source Sunlight Electric lamps High-Intensity Discharge (HID) Lamps Fluorescence Lamps Incandescent Lamps 97

98 High-intensity discharge (HID) lamps Types of lamps Mercury (Hg) Metal halide (MH) Sodium w/ high- or low- pressure Property Spectral quality (fig. 5-34) Big ballasts & reflectors (fig. 5-47) More expensive but longer life expectancy 98

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100 Fluorescence lamps Types of lamps Cool white: more common Warm white Spectral property (fig. 5-34) Used for seed germination & tissue culture Lower quantity of light & overcome by extending day length 100

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102 Incandescent lamps Used primarily for photoperiodic control Emit too much heat Low in blue end of the spectrum (fig. 5-34) Exhibit tall, succulent growth characters High in red end of the spectrum Use bulbs w/ internal reflectors (fig. 5-35) 102

103 Systems for measuring light Terminology Flux: flow of a substance or transfer of energy across a surface; radiant or quantum flux Photon : an individual particle of light Quantum : energy carried by a photon Photometric System Radiometric System Photon (Quantum) Flux 103

104 Photometric system Light intensity: luminous flux emitted by a point source per unit solid angle (fig. 5-49) Units Foot-candle, lumen/ft2 Lumens Candela Lux Not very useful when describing for plants Deal specifically w/ spectral sensitivity of the standard human eye Should not used when describing light for plant growth 104

105 105

106 Radiometric system Irradiance Light (radiant flux) intercepted per unit of area Unit Joules/ sec. m 2 = watt/ m 2 Peak solar radiation level at sea level is about 1000 W. m 2 The wavelength region must be specified From 400 to 700 nm: photosynthetically active radiation (PAR) Instruments Radiometers Spectroradiometers 106

107 Photon (quantum) flux The primary photochemical act in photosynthesis depends on the number of photons that are trapped. Photon flux Unit μmole/ m 2. sec Photosynthetic photon flux (PPF) Referred to 400 to 700 nm 107

108 108 / 2 Rural poverty and food shortage ……lost ground to make up TIME Magazine, October 26, Vol. 174, No.16 (http://www.time.com/time/magazine/asia/0,9263, ,00.html) 2013/05/ P126. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A Plant Physiology (1999) 2 / Park S. Nobel (Physicochemical & environmental plant physiology) Physicochemical & environmental plant physiology 2013/05/ P131. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A

109 109 / 11 P134. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A P100. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, C3 C4 CAM (http://jpkc.yzu.edu.cn/course/zhwshl/stjj/dyzc/dyzc04.htm) 2013/05/ Flickr / TommyHAGA ornamental cabbage (http://www.flickr.com/photos/tommyhaga/ /) 2012/12/26 14 Flickr / Michael Davie Corn (http://www.flickr.com/photos/michaeldavie/ /) 2012/12/26

110 110 / 14 Flickr / Traveling Mermaid Jade plant (http://www.flickr.com/photos/travelingmermaid/ /) 2012/12/26 15 P103. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, P104. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, Wikimedia commons / SB_Johnny (http://commons.wikimedia.org/wiki/File:Magnolia_after_corrective_pruning.JPG) 2012/9/27 22 P108. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey,

111 111 / 23 Flickr / Vironevaeh Peach orchard in bloom 2012/12/26 24 P108. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, Wikimedia commons / Brian Shaw (http://commons.wikimedia.org/wiki/File:Conifer_Hedges_-_geograph.org.uk_- _ jpg) 2012/12/26 _ jpg 26 Flickr / Moochy Hedge at Montacute House, Sommerset (http://www.flickr.com/photos/moochy/ /) 2012/12/26 27 Flickr / Sam Howzit Winnie the Pooh Topiary (http://www.flickr.com/photos/aloha75/ /) 2012/12/26

112 112 / 27 Flickr / jpmatth Espalier (http://www.flickr.com/photos/jpmatth/ /) 2012/12/26 27 Flickr / edenpictures (http://www.flickr.com/photos/edenpictures/ /) 2012/12/26 28 Flickr / Carol Browne Espalier (http://www.flickr.com/photos/carolbrowne/ /) 2012/12/26 28 Flickr / Carol Browne Bonsai! (http://www.flickr.com/photos/carolbrowne/ /) 2012/12/26 30 P110. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey,

113 113 / 31 P418. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A P111. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, Flickr / Fluffymuppet Cauliflower leaves (http://www.flickr.com/photos/fluffymuppet/ /) 2012/12/26 33 Flickr / Linda N. Cauliflower 2012/12/26 34

114 114 / P113. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, P447. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A P449. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A P419. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A

115 115 / 43 P115. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, P115. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, P420. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A P117. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, P201. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A

116 116 / 49 P117. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, P118. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, P119. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, P651. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A P651. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A

117 117 / 55 P651. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A P655. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A P650. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A Flickr / Nemo's great uncle #5591 dandelions ( ) (http://www.flickr.com/photos/maynard/ /) 2012/12/26 61 Flickr / Vietnam Plants & America plants Leaves and flowers of Celosia Argentea (http://www.flickr.com/photos/phuonglovejesus / /) 2012/12/26

118 118 / 62 Flickr / seven twenty five poinsettia (http://www.flickr.com/photos/725/ /) 2012/12/26 64 Flickr / sassycrafter Cuttings (http://www.flickr.com/photos/sassycrafter/ /) 2012/12/26 64 Flickr / peganum Rooted cuttings (http://www.flickr.com/photos/peganum/ /) 2012/12/26 65 P124. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, Flickr / geefour907 Geo-thermal-powered greenhouses in FAI (http://www.flickr.com/photos/alaskatravelgram/ /) 2012/12/26

119 119 / 68 Flickr / scott.zona Aroid shade house 2 (http://www.flickr.com/photos/scottzona/ /) 2012/12/26 70 Flickr / Beau B White Potatoes (http://www.flickr.com/photos/beaub/ /) 2012/12/26 71 Flickr / Satrina0 Mascot Maya tuber trimming (http://www.flickr.com/photos/satrina0/ /in/photostream/) 2012/12/26 73 Flickr / Peter Baer Spider Plant (http://www.flickr.com/photos/peterjbaer/ /) 2012/12/26 73 Wikipedia / Wildfeuer (http://zh.wikipedia.org/wiki/File: Chlorophytum02.jpg) 2012/9/27

120 120 / 74 Flickr / yellowcloud Windowsill clone warrior leaf (http://www.flickr.com/photos/yellowcloud/ /) 2012/12/26 77 / (http://www.medie.com.tw/book/c/c04.htm) 2013/05/ P129. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, Flickr / Steve Guttman NYC Impatiens under the lilac (http://www.flickr.com/photos/steveguttman/ /) 2012/12/26 80 Flickr / ukgardenphotos Leonardslee Gardens, West Sussex (http://www.flickr.com/photos/ukgardenphotos/ /) 2012/12/26

121 121 / P130. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey,

122 122 / 86 P130. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, P131. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, Wikimedia commons / Hardyplants (http://en.wikipedia.org/wiki/File:Hosta33.jpg) 2012/09/27 89 Flickr / jonathanjonl (http://www.flickr.com/photos/jonathanjo/ /) 2012/12/26 90 Flickr / ukgardenphotos Container gardening at Great Dixter Gardens, Sussex (http://www.flickr.com/photos/ukgardenphotos/ /) 2012/12/26

123 123 / 92 P201. Taiz L. and Zeiger E Plant Physiology, Fourth Edition. Sinauer Associates,Inc. U.S.A Loomis, R.S. and Connor, D.J. Crop ecology: productivity and management in agricultural systems. Chinese Translation. China Agricultural Press, Beijing, 487p. (2002) Adelana, B. O. & Milbourn, G. M Relationship between leaf area and crop growth rate in maize. Ghana Jnl agric. Sci. 9, (http://gains.org.gh/articles/gjas_v9_p175_178.pdf) 2013/05/ P133. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, P134. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey,

124 124 / P137. Preece, J. E., P. E. Read The Biology of Horticulture: An Introductory Textbook, 2nd Edition. John Wiley&Sons, Inc., New Jersey, Microsoft Office 2010 PowerPoint Microsoft Microsoft


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