Hostname: page-component-78c5997874-g7gxr Total loading time: 0 Render date: 2024-11-18T15:01:44.519Z Has data issue: false hasContentIssue false
  • English
  • Français

Applications of Physiological Ecology to Weed Science

Published online by Cambridge University Press:  12 June 2017

Jodie S. Holt
Jodie S. Holt*
Affiliation:
Dep. Bot. and Plant Sci., Univ. California, Riverside, CA 92521
Get access Rights & Permissions [Opens in a new window]

Abstract

Weed scientists are trained broadly in agronomy, botany, chemistry, soils, and other agricultural disciplines. The study of weeds, rather than the techniques used or the questions asked, unifies weed scientists around a common focus. It is often difficult for weed scientists to identify closely with any one scientific discipline, since the techniques and questions of many disciplines are needed to address problems posed by weeds. One discipline with relevance and potential for addressing weed science problems is physiological ecology. The study of the functioning or adaptation of plants in relation to environmental influences has its roots in both classical ecology and experimental physiology. Application of this discipline to weed science may take an environmental approach (e.g., studying limiting factors in the environment), a physiological approach (e.g., studying the responses of critical plant processes to environmental stress), or a more autecological approach (e.g., studying the physiological basis for the adaptation of a particular weed to a particular habitat). Many methodologies and technologies are available for both field and laboratory investigations. For example, photosynthesis, a major determinant of plant growth, can be investigated in the field at the leaf, plant, or canopy level using plant growth analysis or a portable infrared gas analyzer (IRGA) and appropriate assimilation chambers. Investigations of photosynthesis in the laboratory can focus on the plant, leaf, chloroplast, or thylakoid level using an IRGA or the techniques of polarography (measurement of evolved oxygen) or fluorometry. Application of such approaches to weed science should improve our understanding of the basis for particular weed problems and thus broaden our options for management.

Keywords

Ecophysiologyenvironmentphotosynthesisgas exchangetechniques
Type
Special Topics
Information
Weed Science , Volume 39 , Issue 3 , September 1991 , pp. 521 - 528
Copyright
Copyright © 1991 by the Weed Science Society of America 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Literature Cited

1. Allen, J. F. and Holmes, N. G. 1986. Electron transport and redox titration. Pages 103–141 in Hipkins, M. F. and Baker, N. R., eds. Photosynthesis: Energy Transduction: A Practical Approach. IRL Press, Ltd., Oxford, GB.Google Scholar
2. Alm, D. M., McGiffen, M. E. Jr., and Hesketh, J. D. 1991. Weed phenology. Pages 191–218 in Hodges, T., ed. Predicting Crop Phenology. CRC Press, Boca Raton, FL.Google Scholar
3. Alm, D. M., Pike, D. R., Hesketh, J. D., and Stoller, E. W. 1988. Leaf area development in some crop and weed species. Biotronics 17:29–39.Google Scholar
4. Barbour, M. G., Burk, J. H., and Pitts, W. D. 1980. Terrestrial Plant Ecology. Benjamin Cummings Publ. Co., Inc., Menlo Park, CA. Pages 2–12.Google Scholar
5. Baskin, J. M. and Baskin, C. C. 1978. A discussion of the growth and competitive ability of C3 and C4 plants. Castanea 43:71–76.Google Scholar
6. Beadle, C. L. 1985. Plant growth analysis. Pages 20–25 in Coombs, J., Hall, D. O., Long, S. P., and Scurlock, J.M.O., eds. Techniques in Bioproductivity and Photosynthesis. 2nd ed. Pergamon Press, Oxford, GB.CrossRefGoogle Scholar
7. Beerling, D. J. and Fry, J. C. 1990. A comparison of the accuracy, variability and speed of five different methods for estimating leaf area. Ann. Bot. 65:483–488.Google Scholar
8. Benech Arnold, R. L., Ghersa, C. M., Sanchez, R. A., and Insausti, P. 1990. A mathematical model to predict Sorghum halepense (L.) Pers. seedling emergence in relation to soil temperature. Weed Res. 30:91–99.CrossRefGoogle Scholar
9. Biggs, W. 1986. Radiation measurement. Pages 3–20 in Gensler, W. G., ed. Advanced Agricultural Instrumentation. Design and Use. Martinus Nijhoff Publ., Dordrecht, The Netherlands.CrossRefGoogle Scholar
10. Billings, W. D. 1985. The historical development of physiological plant ecology. Pages 1–15 in Chabot, B. F. and Mooney, H. A., eds. Physiological Ecology of North American Plant Communities. Chapman and Hall, New York, NY.Google Scholar
11. Black, C. C. 1985. Effects of herbicides on photosynthesis. Pages 2–36 in Duke, S. O., ed. Weed Physiology. Vol. II. Herbicide Physiology. CRC Press, Inc., Boca Raton, FL.Google Scholar
12. Black, C. C., Chen, T. M., and Brown, R. H. 1969. Biochemical basis for plant competition. Weed Sci. 17:338–344.CrossRefGoogle Scholar
13. Bloom, A. J. 1989. Principles of instrumentation for physiological ecology. Pages 1–13 in Pearcy, R. W., Ehleringer, J. R., Mooney, H. A., and Rundel, P. W., eds. Plant Physiological Ecology. Field Methods and Instrumentation. Chapman and Hall, London, GB.Google Scholar
14. Brewer, P. E., Arntzen, C. J., and Slife, F. W. 1979. Effects of atrazine, cyanazine, and procyazine on the photochemical reactions of isolated chloroplasts. Weed Sci. 27:300–308.Google Scholar
15. Caemmerer, S. von and Farquhar, G. D. 1981. Some relationships between the biochemistry of photosynthesis and the gas exchange of leaves. Planta 153:376–387.Google Scholar
16. Chapin, F. S. III., Bloom, A. J., Field, C. B., and Waring, R. H. 1987. Plant responses to multiple environmental factors. Bioscience 37:49–57.CrossRefGoogle Scholar
17. Chiariello, N. R., Mooney, H. A., and Williams, K. 1989. Growth, carbon allocation and cost of plant tissues. Pages 327–365 in Pearcy, R. W., Ehleringer, J. R., Mooney, H. A., and Rundel, P. W., eds. Plant Physiological Ecology. Field Methods and Instrumentation. Chapman and Hall, London, GB.Google Scholar
18. Cudney, D. W., Jordan, L. S., and Hall, A. E. 1991. Effect of wild oat (Avena fatua) infestations on light interception and growth rate of wheat (Triticum aestivum). Weed Sci. 39:175–179.Google Scholar
19. Ehleringer, J. R. 1989. Temperature and energy budgets. Pages 117–135 in Pearcy, R. W., Ehleringer, J. R., Mooney, H. A., and Rundel, P. W., eds. Plant Physiological Ecology. Field Methods and Instrumentation. Chapman and Hall, London, GB.CrossRefGoogle Scholar
20. Ehleringer, J. R. 1978. Implications of quantum yield differences on the distribution of C3 and C4 grasses. Oecologia 31:255–267.CrossRefGoogle Scholar
21. Elmore, C. D. 1980. The paradox of no correlation between leaf photosynthetic rates and crop yields. Pages 155–167 in Hesketh, J. D. and Jones, J. W., eds. Predicting Photosynthesis for Ecosystem Models. Vol. II. CRC Press, Inc., Boca Raton, FL.Google Scholar
22. Etherington, J. R. 1982. Environment and Plant Ecology. 2nd ed. John Wiley & Sons, New York. Pages 1–4.Google Scholar
23. Evans, G. C. 1972. The Quantitative Analysis of Plant Growth. Univ. of California Press, Berkeley, CA. Pages 189–417.Google Scholar
24. Field, C. B., Ball, J. T., and Berry, J. A. 1989. Photosynthesis: principles and field techniques. Pages 209–253 in Pearcy, R. W., Ehleringer, J. R., Mooney, H. A., and Rundel, P. W., eds. Plant Physiological Ecology. Field Methods and Instrumentation. Chapman and Hall, London, GB.Google Scholar
25. Fitter, A. H. and Hay, R.K.M. 1987. Environmental Physiology of Plants. 2nd ed. Academic Press, London, GB. 421 pages.Google Scholar
26. Fritschen, L. J. and Gay, L. W. 1979. Environmental Instrumentation. Springer-Verlag, New York. 216 pages.Google Scholar
27. Garbutt, K., Williams, W. E., and Bazzaz, F. A. 1990. Analysis of the differential response of five annuals to elevated CO2 during growth. Ecology 71:1185–1194.Google Scholar
28. Gealy, D. R. 1987. Gas exchange properties of jointed goatgrass (Aegilops cylindrica). Weed Sci. 35:482–489.Google Scholar
29. Ghersa, C. M., Satorre, E. H., Van Esso, M. L., Pataro, A., and Elizagaray, R. 1990. The use of thermal calendar models to improve the efficiency of herbicide applications in Sorghum halepense (L.) Pers. Weed Res. 30:153–160.CrossRefGoogle Scholar
30. Goodell, P. B., Plant, R. E., Kerby, T. A., Strand, J. F., Wilson, L. T., Zelinski, L., Young, J. A., Corbett, A., Horrocks, R. D., and Vargas, R. N. 1990. CALEX/Cotton: an integrated expert system for cotton production and management. Calif. Agric. 44:18–21.Google Scholar
31. Graham, P. L., Steiner, J. L., and Wiese, A. F. 1988. Light absorption and competition in mixed sorghum-pigweed communities. Agron. J. 80:415–418.Google Scholar
32. Hart, J. J. and Stemler, A. 1990. High light-induced reduction and low light-enhanced recovery of photon yield in triazine-resistant Brassica napus L. Plant Physiol. 94:1301–1307.Google Scholar
33. Hart, J. J. and Stemler, A. 1990. Similar photosynthetic performance in low light-grown isonuclear triazine-resistant and -susceptible Brassica napus L. Plant Physiol. 94:1295–1300.Google Scholar
34. Havaux, M. 1989. Comparison of atrazine-resistant and -susceptible biotypes of Senecio vulgaris L.: Effects of high and low temperatures on the in vivo photosynthetic electron transfer in intact leaves. J. Exp. Bot. 40:849–854.CrossRefGoogle Scholar
35. Hodges, T., ed. 1991. Predicting Crop Phenology. CRC Press, Boca Raton, FL. 233 pages.Google Scholar
36. Holt, J. S. and Orcutt, D. R. 1991. Functional relationships of growth and competitiveness in perennial weeds and cotton (Gossypium hirsutum). Weed Sci. 39:(In press).Google Scholar
37. Hunt, R. 1978. Plant Growth Analysis. Studies in Biology No. 96. Edward Arnold Publ., Ltd., London, GB. Pages 1–25.Google Scholar
38. Hunt, R. 1982. Plant Growth Curves. The Functional Approach to Plant Growth Analysis. University Park Press, Baltimore, MD. Pages 1–248.Google Scholar
39. Izawa, S. 1980. Acceptors and donors for chloroplast electron transport. Methods Enzymol. 69:413–434.Google Scholar
40. Jarvis, P. G. and Sanford, A. P. 1985. The measurement of carbon dioxide in air. Pages 29–57 in Marshall, B. and Woodward, F. I., eds. Instrumentation for Environmental Physiology. Cambridge Univ. Press, Cambridge, GB.Google Scholar
41. Jones, H. G. 1983. Plants and Microclimate. A Quantitative Approach to Environmental Plant Physiology. Cambridge Univ. Press, Cambridge, GB. 323 pages.Google Scholar
42. Jones, M. B. 1985. Plant Microclimate. Pages 26–40 in Coombs, J., Hall, D. O., Long, S. P., and Scurlock, J.M.O., eds. Techniques in Bioproductivity and Photosynthesis. 2nd ed. Pergamon Press, Oxford, GB.Google Scholar
43. Jursinic, P. A. and Pearcy, R. W. 1988. Determination of the rate limiting step for photosynthesis in a nearly isonuclear rapeseed (Brassica napus L.) biotype resistant to atrazine. Plant Physiol. 88:1195–1200.Google Scholar
44. Krause, G. H. and Weis, E. 1984. Chlorophyll fluorescence as a tool in plant physiology. II. Interpretation of fluorescence signals. Photosynth. Res. 5:139–157.CrossRefGoogle ScholarPubMed
45. Lange, O. L., Nobel, P. S., Osmond, C. B., and Ziegler, H. 1981. Introduction: perspectives in ecological plant physiology. Pages 1–9 in Lange, O. L., Nobel, P. S., Osmond, C. B., and Ziegler, H., eds. Physiological Plant Ecology I. Responses to the Physical Environment. Springer-Verlag, Berlin, FRG.Google Scholar
46. Larcher, W. 1980. Physiological Plant Ecology. 2nd ed. Springer-Verlag, New York. 303 pages.CrossRefGoogle Scholar
47. Leuning, R. and Sands, P. 1989. Theory and practice of a portable photosynthesis instrument. Plant Cell Environ. 12:669–678.Google Scholar
48. Long, S. P. 1986. Instrumentation for the measurement of CO2 assimilation by crop leaves. Pages 39–91 in Gensler, W. G., ed. Advanced Agricultural Instrumentation. Design and Use. Martinus Nijhoff Publ., Dordrecht, The Netherlands.CrossRefGoogle Scholar
49. Long, S. P. and Hallgren, J.-E. 1985. Measurement of CO2 assimilation by plants in the field and me laboratory. Pages 62–94 in Coombs, J., Hall, D. O., Long, S. P., and Scurlock, J.M.O., eds. Techniques in Bioproductivity and Photosynthesis. 2nd ed. Pergamon Press, Oxford, GB.CrossRefGoogle Scholar
50. Marshall, B. and Woodward, F. I. 1985. Instrumentation for Environmental Physiology. Cambridge Univ. Press, Cambridge, GB. 241 pages.Google Scholar
51. McGraw, J. B. and Wulff, R. D. 1983. The study of plant growth: A link between the physiological ecology and population biology of plants. J. Theor. Biol. 103:21–28.CrossRefGoogle Scholar
52. Milthorpe, F. L. and Moorby, J. 1979. An Introduction to Crop Physiology. 2nd ed. Cambridge Univ. Press, Cambridge, GB. 244 pages.Google Scholar
53. Mooney, H. A., Pearcy, R. W., and Ehleringer, J. 1987. Plant physiological ecology today. Bioscience 37:18–20.Google Scholar
54. Nobel, P. S. and Long, S. P. 1985. Canopy structure and light interception. Pages 41–49 in Coombs, J., Hall, D. O., Long, S. P., and Scurlock, J.M.O., eds. Techniques in Bioproductivity and Photosynthesis. 2nd ed. Pergamon Press, Oxford, GB.CrossRefGoogle Scholar
55. Norman, J. M. and Campbell, G. S. 1989. Canopy structure. Pages 301–325 in Pearcy, R. W., Ehleringer, J. R., Mooney, H. A., and Rundel, P. W., eds. Plant Physiological Ecology. Field Methods and Instrumentation. Chapman and Hall, London, GB.CrossRefGoogle Scholar
56. Patterson, D. T. 1986. Responses of soybean (Glycine max) and three C4 grass weeds to CO2 enrichment during drought. Weed Sci. 34:203–210.Google Scholar
57. Patterson, D. T. 1985. Comparative ecophysiology of weeds and crops. Pages 101–129 in Duke, S. O., ed. Weed Physiology. I. Reproduction and Ecophysiology. CRC Press, Inc., Boca Raton, FL.Google Scholar
58. Patterson, D. T. 1982. Effects of light and temperature on weed/crop growth and competition. Pages 407–420 in Hatfield, J. L. and Thomason, I. J., eds. Biometeorology in Integrated Pest Management. Academic Press, Inc., London, GB.CrossRefGoogle Scholar
59. Patterson, D. T. 1982. Effects of shading and temperature on showy crotalaria (Crotalaria spectabilis). Weed Sci. 30:692–697.Google Scholar
60. Patterson, D. T., Highsmith, M. T., and Flint, E. P. 1988. Effects of temperature and CO2 concentration on the growth of cotton (Gossypium hirsutum) spurred anoda (Anoda cristata), and velvetleaf (Abutilon theophrasti). Weed Sci. 36:751–757.CrossRefGoogle Scholar
61. Patterson, D. T., Meyer, C. R., Flint, E. P., and Quimby, P. C. Jr. 1979. Temperature responses and potential distribution of itchgrass (Rottboellia exaltata) in the United States. Weed Sci. 27:77–82.Google Scholar
62. Patterson, D. T., Meyer, C. R., and Quimby, P. C. Jr. 1978. Effects of irradiance on relative growth rates, net assimilation rates, and leaf area partitioning in cotton and three associated weeds. Plant Physiol. 62:14–17.Google Scholar
63. Pearcy, R. W. 1989. Field data acquisition. Pages 15–27 in Pearcy, R. W., Ehleringer, J. R., Mooney, H. A., and Rundel, P. W., eds. Plant Physiological Ecology. Field Methods and Instrumentation. Chapman and Hall, London, GB.CrossRefGoogle Scholar
64. Pearcy, R. W. 1989. Radiation and light measurements. Pages 97–116 in Pearcy, R. W., Ehleringer, J. R., Mooney, H. A., and Rundel, P. W., eds. Plant Physiological Ecology. Field Methods and Instrumentation. Chapman and Hall, London, GB.CrossRefGoogle Scholar
65. Pearcy, R. W., Ehleringer, J. R., Mooney, H. A., and Rundel, P. W., eds. 1989. Plant Physiological Ecology. Field Methods and Instrumentation. Chapman and Hall, London, GB. 457 pages.Google Scholar
66. Pearcy, R. B., Tumosa, N., and Williams, K. 1981. Relationships between growth, photosynthesis and competitive interactions for a C3 and a C4 plant. Oecologia 48:371–376.Google Scholar
67. Pinches, C. 1985. The effective use of microprocessors in a scientific environment. Pages 157–170 in Marshall, B. and Woodward, F. I., eds. Instrumentation for Environmental Physiology. Cambridge Univ. Press, Cambridge, GB.Google Scholar
68. Platt, R. B. and Griffiths, J. F. 1964. Environmental Measurement and Interpretation. Reinhold Publ. Corp., New York, 235 pages.Google Scholar
69. Poorter, H., Remkes, C., and Lambers, H. 1990. Carbon and nitrogen economy of 24 wild species differing in relative growth rate. Plant Physiol. 94:621–627.CrossRefGoogle ScholarPubMed
70. Radosevich, S. R. and Holt, J. S. 1984. Weed Ecology. Implications for Vegetation Management. John Wiley & Sons, New York. Pages 139–193.Google Scholar
71. Regnier, E. E., Salvucci, M. E., and Stoller, E. W. 1988. Photosynthesis and growth responses to irradiance in soybean (Glycine max) and three broadleaf weeds. Weed Sci. 36:487–496.Google Scholar
72. Robinson, H. 1986. Non-invasive measurements of photosystem II reactions in the field using flash fluorescence. Pages 92–106 in Gensler, W. G., ed. Advanced Agricultural Instrumentation. Design and Use. Martinus Nijhoff Publ., Dordrecht, The Netherlands.Google Scholar
73. Rosenberg, N. J., Blad, B. L., and Verma, S. B. 1983. Microclimate. The Biological Environment. 2nd ed. John Wiley & Sons, New York. 495 pages.Google Scholar
74. Roush, M. L. and Radosevich, S. R. 1985. Relationships between growth and competitiveness of four annual weeds. J. Appl. Ecol. 22:895–905.Google Scholar
75. Russell, G., Jarvis, P. G., and Monteith, J. L. 1989. Absorption of radiation by canopies and stand growth. Pages 21–39 in Russell, G., Marshall, B., Jarvis, P. G., eds. Plant Canopies: Their Growth, Form and Function. Cambridge Univ. Press, Cambridge, GB.Google Scholar
76. Ryel, R. J., Barnes, P. W., Beyschlag, W., Caldwell, M. M., and Flint, S. D. 1990. Plant competition for light analyzed with a multispecies canopy model. I. Model development and influence of enhanced UV-B conditions on photosynthesis in mixed wheat and wild oat canopies. Oecologia 82:304–310.CrossRefGoogle ScholarPubMed
77. Sage, R. F., Sharkey, T. D., and Seemann, J. R. 1989. Acclimation of photosynthesis to elevated CO2 in five C3 species. Plant Physiol. 89:590–596.Google Scholar
78. Satorre, E. H., Ghersa, C. M., and Pataro, A. M. 1985. Prediction of Sorghum halepense (L.) Pers. rhizome sprout emergence in relation to air temperature. Weed Res. 25:103–109.Google Scholar
79. Schreiber, U. and Bilger, W. 1987. Rapid assessment of stress effects on plant leaves by chlorophyll fluorescence measurements. Pages 27–53 in Tenhunen, J. D., Caturino, F. M., Lange, O. L., and Oechel, W. C. Plant Response to Stress. Functional Analysis in Mediterranean Ecosystems. NATO ASI Series. Springer-Verlag, Berlin, FRG.Google Scholar
80. Schreiber, U., Groberman, L., and Vidaver, W. 1975. Portable, solid-state fluorometer for the measurement of chlorophyll fluorescence induction in plants. Rev. Sci. Instrum. 46:538–542.CrossRefGoogle Scholar
81. Schreiber, U., Schliwa, U., and Bilger, W. 1986. Continuous recording of photochemical and non-photochemical chlorophyll fluorescence quenching with a new type of modulation fluorometer. Photosynth. Res. 10:51–62.Google Scholar
82. Sestak, Z. and Catsky, J. 1990. Bibliography of reviews and methods of photosynthesis-70. Photosynthetica 24:326–376.Google Scholar
83. Sestak, Z., Catsky, J., and Jarvis, P. G. 1971. Plant Photosynthetic Production: Manual of Methods. Junk, The Hague. 800 pp.Google Scholar
84. Shaw, D. R., Peeper, T. F., and Nofziger, D. L. 1986. Evaluation of chlorophyll fluorescence parameters for an intact-plant herbicide bioassay. Crop Sci. 26:756–760.CrossRefGoogle Scholar
85. Shaw, D. R., Peeper, T. F., and Nofziger, D. L. 1985. Comparison of chlorophyll fluorescence and fresh weight as herbicide bioassay techniques. Weed Sci. 33:29–33.CrossRefGoogle Scholar
86. Sheehy, J. E. 1985. Radiation. Pages 5–28 in Marshall, B. and Woodward, F. I., eds. Instrumentation for Environmental Physiology. Cambridge Univ. Press, Cambridge, GB.Google Scholar
87. Sivak, M. N. and Walker, D. A. 1986. Summing-up: measuring photosynthesis in vivo. Pages 1–31 in Marcelle, R., Clijsters, H., and Van Poucke, M., eds. Biological Control of Photosynthesis. Martinus Nijhoff Publ., Dordrecht, The Netherlands.Google Scholar
88. Slatyer, R. O. and McIlroy, I. C. 1961. Practical Microclimatology. C.S.I.R.O. Plant Industry Division, Canberra, Australia.Google Scholar
89. Stoller, E. W. and Myers, R. A. 1989. Response of soybeans (Glycine max) and four broadleaf weeds to reduced irradiance. Weed Sci. 37:570–574.Google Scholar
90. Stowe, A. E. and Holt, J. S. 1988. Comparison of triazine-resistant and -susceptible biotypes of Senecio vulgaris and their F1 hybrids. Plant Physiol. 87:183–189.Google Scholar
91. Vasil'ev, I. R., Matorin, D. N., Lyadsky, V. V., and Venediktov, P. S. 1988. Multiple action sites for photosystem II herbicides as revealed by delayed fluorescence. Photosynth. Res. 15:33–39.CrossRefGoogle ScholarPubMed
92. Venus, J. C. and Causton, D. R. 1979. Plant growth analysis: A reexamination of the methods of calculation of relative growth and net assimilation rates without using fitted functions. Ann. Bot. 43:633–638.Google Scholar
93. Voss, M., Renger, G., Kotter, C., and Graber, P. 1984. Fluorometric detection of photosystem II herbicide penetration and detoxification in whole leaves. Weed Sci. 32:675–680.Google Scholar
94. Vredenberg, W. J. 1986. Fluorescence and absorbance measurements in leaves: sensors of photosynthetic performance. Pages 107–132 in Gensler, W. G., ed. Advanced Agricultural Instrumentation. Design and Use. Martinus Nijhoff Publ., Dordrecht, The Netherlands.Google Scholar
95. Walker, D. A. 1985. Measurement of oxygen and chlorophyll fluorescence. Pages 95–106 in Coombs, J., Hall, D. O., Long, S. P., and Scurlock, J.M.O., eds. Techniques in Bioproductivity and Photosynthesis. 2nd ed. Pergamon Press, Oxford, GB.Google Scholar
96. Walker, D. 1988. The Use of the Oxygen Electrode and Fluorescence Probes in Simple Measurements of Photosynthesis. 2nd ed. Oxygraphics, Ltd., Sheffield, UK. Pages 1–151.Google Scholar
97. Walker, G. K., Blackshaw, R. E., and Dekker, J. 1988. Leaf area and competition for light between plant species using direct sunlight transmission. Weed Technol. 2:159–165.Google Scholar
98. Welles, J. M. 1990. Some indirect methods of estimating canopy structure. Pages 31–43 in Goel, N. S. and Norman, J. M., eds. Instrumentation for Studying Vegetation Canopy for Remote Sensing in Optical and Thermal Regions. Remote Sens. Rev. 5:31–43.CrossRefGoogle Scholar
99. Welles, J. 1986. A portable photosynthesis system. Pages 21–38 in Gensler, W. G., ed. Advanced Agricultural Instrumentation. Design and Use. Martinus Nijhoff Publ., Dordrecht, The Netherlands.Google Scholar
100. Woodward, F. I. 1985. Remote site recording. Pages 139–156 in Marshall, B. and Woodward, F. I. eds. Instrumentation for Environmental Physiology. Cambridge Univ. Press, Cambridge, GB.Google Scholar
101. Zelitch, I. 1982. The close relationship between net photosynthesis and crop yield. Bioscience 32:796–802.Google Scholar