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 Title: The combined effects of airflow and carbon dioxide on chrysanthemum, dwarf wheat, and soybean Author(s): Korthals, Rodney Lee Doctoral Committee Chair(s): Christianson, Leslie L. Department / Program: Agriculture, Plant CultureEngineering, Agricultural Discipline: Agriculture, Plant CultureEngineering, Agricultural Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Agriculture, Plant Culture Engineering, Agricultural Abstract: Effects of airflow direction and velocity on plant vegetative production were studied. Three plant species were studied: dwarf wheat (Triticum aestivum), chrysanthemum (Chrysanthemum morifolium), and soybean (Glycine max. L.). Specific objectives of this research were to: (1) Evaluate and improve environmental uniformity within plant growth chambers related to airflow velocity, airflow patterns, and CO$\sb2$ availability. (2) Quantify effects of horizontal airflow velocity at ambient and enriched CO$\sb2$, and horizontal versus vertical airflow patterns on plant vegetative growth.A literature review summarizes previous studies on the effects of airflow on plant heat and mass transfer, as well as on mechanical stresses caused by airflow and their effect on plant growth and quality.The development of a proportional and a proportional + integral (PI) CO$\sb2$ controller is described in detail, including the equipment used and control algorithms. The developed controllers maintained average CO$\sb2$ concentrations over a 12 hour period to within 3 and 1 $\mu$mol mol$\sp{-1}$ of set point for the proportional and PI controllers, respectively.Simple chambers were designed to test effects of 0.4, 0.8, and 1.5 m s$\sp{-1}$ airflow velocity on soybeans. Results indicated that velocities between 0.4 and 1.5 m s$\sp{-1}$ affected node number, height, and stem mass after 2 weeks of treatment, but that the plants were of similar size after 4 weeks of treatment.Experiments were performed to compare effects of horizontal and vertical airflow without CO$\sb2$ enrichment and horizontal airflow with 600 $\mu$mol mol$\sp{-1}$ CO$\sb2$ on dwarf wheat, chrysanthemum, and soybean. Soybean had larger leaf and whole plant relative growth rates (RGR) in vertical compared to horizontal airflow, while chrysanthemum had suppressed leaf and plant RGR in vertical compared to horizontal airflow. Vertical airflow appeared to cause mechanical stress in wheat, but evidence of mechanical stress was inconclusive for the other two species. Issue Date: 1991 Type: Text Language: English URI: http://hdl.handle.net/2142/23703 Rights Information: Copyright 1991 Korthals, Rodney Lee Date Available in IDEALS: 2011-05-07 Identifier in Online Catalog: AAI9210876 OCLC Identifier: (UMI)AAI9210876
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