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 Title: Effects of Simulated Acid Rain on Physiological Parameters of Field-Grown Corn and Soybeans Author(s): Smith, Craig Raymond Department / Program: Agronomy Discipline: Agronomy Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Agriculture, Agronomy Abstract: Simulated acid rain has been reported to cause physiological changes in various plant species. Studies were conducted in 1983, 1984, and 1985 to determine the effect of acid rain on some physiological parameters in soybeans (Glycine max L.) and corn (Zea mays L.). Simulated acid rain of pH 3.0, 4.2 and 5.6 was applied throughout the growing season onto field-grown plots of two corn hybrids and two soybean cultivars. Both crops were evaluated for changes in net photosynthesis, leaf water potentials, and leaf chlorophyll content. Nitrogen fixation, flowering and podding patterns, and dry matter and N partitioning were also measured in soybeans while pollen germination was also measured in corn.When applied to soybeans, acid rain did not affect net photosynthesis, leaf water potentials, leaf chlorophyll content, or N$\sb{2}$ fixation. Statistically significant linear or quadratic trends due to pH were not detected for these parameters. The leaf water potentials of Amsoy 71 were more negative (more moisture stressed) in 1984 and 1985 than those of Williams 82. This may explain why Amsoy 71 has been reported to be sensitive to acid rain. Amsoy 71 also had lower leaf chlorophyll content than Williams 82 in 1984. In 1983 Amsoy 71 produced fewer flowers and pods when exposed to rain of pH 4.2 compared with pH 3.0 or 5.6. However, this cultivar produced more flowers and pods than Williams 82. In 1983 Amsoy 71 abscised more leaves and petioles when exposed to rain of more acid pH, although this linear effect of pH was not found in other years. When applied to corn, acid rain did not affect net photosynthesis, leaf water potentials, leaf chlorophyll content, or pollen germination. Statistically significant linear or quadratic trends due to pH were not detected for these parameters. With few exceptions the pH of the simulated rain did not affect the parameters measured. Within the limits of experimental error, it must be concluded that simulated acid rain of pH 3.0 applied to corn and soybeans does not affect the physiological parameters measured in this study. Issue Date: 1987 Type: Text Description: 151 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987. URI: http://hdl.handle.net/2142/71638 Other Identifier(s): (UMI)AAI8721762 Date Available in IDEALS: 2014-12-16 Date Deposited: 1987
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