Thesis (Ing.)--Universidad Mayor de San Andrés, Facultad de Agronomía, Carrera de Ingeniería Agronómico, 2004. / Reproduced from copy at BYU's Benson Institute. Includes bibliographical references (leaves 101-106).

Thesis (M.S. in soil science)--Washington State University, May 2010. / Title from PDF title page (viewed on July 7, 2010). "Department of Crop and Soil Sciences." Includes bibliographical references.

Ethanolamine kinase (EC 2.7.1.82) catalyses the reaction of ethanolamine and Mg^2+-ATP to produce phosphoethanolamine and Mg^2+ -ADP. For spinach (Spinacia oleracea) the activity of ethanolamine kinase is increased in leaf extracts of salinized plants. A comparison of ethanolamine kinase activity between extracts from control and salinized plants after native polyacrylamide gel electrophoresis shows that ethanolamine kinase activity migrates to the same position on a gel. This observation suggests that salinization does not induce the activity of a novel ethanolamine kinase isozyme. Ethanolamine kinase has been purified 6,537 fold to apparent homogeneity from spinach leaves by ammonium sulphate fractionation and sequential fractionation by both open-bed and HPLC chromatography, using ion-exchange and hydrophobic interaction matrices. The enzyme has an estimated molecular weight of 80,000 D by gel filtration chromatography and a subunit size of 38,000 D by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Ethanolamine kinase has a broad pH optimum between pH 7 and 9 and the optimal ratio of Mg^2+:ATP for the reaction is 1: 1 at 5 mM. The apparent K^m value for the substrate ethanolamine is 16 μM and the V^max is 438 nmol • min^-1 •mg^-l protein. Monomethylethanolamine and dimethylethanolamine serve as substrates for. ethanolamine kinase but not trimethylethanolamine (ie choline). Enzyme activity is slightly stimulated by NaCl and KCl and inhibited to varying degrees by phosphate, ammonium, phosphoethanolamine and phosphodimethylethanolamine. Not surprisingly enzyme activity is also inhibited by ADP and to varying degrees by the divalent cations Mn^2+, Ca^2+, Co^2+, Ba^2+ and Ni^2+. This work is the first purification and biochemical characterization of ethanolamine kinase in spinach and is the first step towards understanding the contribution ethanolamine kinase makes towards the synthesis of choline. / Thesis / Master of Science (MSc)

Two field studies were conducted to evaluate metolachlor (Dual®) for preemergence weed control in spinach to provide support to gain registration through the IR-4 program. Dual® at 1.0 to 1.5 lb a.i./A gave acceptable control of London rocket, black mustard, lambsquarters, and knotweed. Nettleleaf goosefoot, cheeseweed, and yellow sweetclover control was not acceptable. In one test, dimethenamid (Frontier® or SAN -582H, Sandoz) controlled London rocket, lambsquarters, knotweed, and goosefoot at 0.25 lb ai. /A and did not control cheeseweed or sweetclover. Spinach was not injured by Dual® or Frontier®.

Several newly introduced insecticides that have potential for use in vegetable crops for aphid control were evaluated and demonstrated very good efficacy against green peach aphid (Myzus persicae). Field testing in spinach showed that CGA-293343 (Novartis) at the two rates tested significantly reduced the number of aphids relative to the untreated check. CGA-215944 (pymetrozine -Novartis) effectively reduced the number of aphids after two applications. Aphistar (RH- 7988 - Rohm and Haas) demonstrated the greatest reduction in the number of aphids per plant after each application. Provado (imidacloprid) and Thiodan (endosulfan) were applied as commercially available standard treatments and effectively reduced the number of aphids relative to the untreated check. Pirimor (pirimicarb) numerically reduced the number of aphids but was not significantly different relative to the untreated check.

Graduation date: 1948

Thesis (Ph. D.)--Universiteit te Amsterdam, 1910. / Includes bibliographical references.

Baby spinach is a relatively new crop in South Africa with both commercial significance and reputed health benefits. It is known to assist in combating degenerative conditions associated with ageing, such as heart disease, cardiovascular disease, Alzheimer’s disease, cataracts and several forms of cancer. Three parallel NPK trials were conducted to investigate the effects of nitrogen (N), phosphorus (P) and potassium (K) on the growth and development of baby spinach. N and P treatments were arranged as (0, 45, 75, 105, 120 kg.ha -1 N and P), and K treatments were arranged as (0, 63, 85, 127, 148 kg.ha -1) in a randomised complete block designed with four replicates. Results showed that yield, dry matter, chlorophyll content and Leaf Area Index (LAI) were significantly increased by increasing the N application, while K had a significant effect on the LAI but not on yield, dry matter, chlorophyll content or stomatal conductance. Nitrogen treatments quadrupled fresh yield, dry matter and chlorophyll content, reaching maximum impact at 75 kg.ha-1 N. Phosphorus application showed significantly increased yields, dry matter and chlorophyll content, reaching maximum impact at 75 kg.ha-1 P. Therefore, to achieve optimum growth with N and P, 75 kg.ha-1 is recommended. The optimum rates of N, P and K were then used to formulate a NPK combined trial which was arranged as 0, 30:30:40, 45:45:60, 60:60:70, 75:75:90 kg.ha-1 in a randomised complete block design with three replicates. The results showed that maximum impact on yield, chlorophyll content, fresh and dry matter was achieved when combined NPK was applied at 45:45:60 / Agriculture and  Animal Health / M. Sc. (Agriculture)

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