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Success in evaluating effects of a 75% oxygen atmosphere, containing an ambient concentration of carbon dioxide, on levels of protein and oxidative enzymes in cotton, Gossypium herbaceum L. C.B. 1697, leaf tissue was dependent upon generation of genetically uniform and physiologically similar leaves. Sufficient quantities of 2-4 week old leaves for experimental procedures were obtained from plants grown in a 1:1 perlite:vermiculite potting medium supplied with 20% Hoagland's nutrient and maintained in a controlled environment growth chamber under the following conditions: 16 hr day/8 hr night cycle, irradiances of 200-300 µE m⁻² sec⁻¹, 70% humidity, and 30°. Maximum yields of soluble protein (10-12 mg/g tissue) and active enzymes were obtained when freshly harvested leaves were crushed in liquid nitrogen and then homogenized in 0.1 M Tris-Cl, pH 6.9, containing 0.01 M isoascorbate and polyvinylpyrrolidone [2% (w/v) PVP-10 and 0.5 g dry Polyclar AT/g tissue]. Routinely 90% of the solubilized protein was obtained following centrifugation and chromatography on Sephadex G-50. Introduction of cotton plants into vinyl chambers of 95% humidity resulted in foliar symptoms of physiological stress, including chlorosis, cellular edema, leaf curling, and loss of turgidity. Of the oxidative enzymes analyzed, catalase activity decreased 30%, glycolate oxidase activity decreased 42%, and peroxidase. increased 89% while soluble protein decreased 27% in plants maintained in the high humidity for 5 days. Exposure of plants to 75% oxygen, 350 ppm carbon dioxide for 48 hr under these conditions resulted in a 70% increase in glutathione reductase and a 25% increase in malate dehydrogenase. Other enzymes, superoxide dismutase, catalase, peroxidase, glyoxylate reductase, and acid phosphatase, appeared to be independent of the oxygen treatment. When humidity was carefully controlled at 70%, treatment with 75% oxygen, 350 ppm carbon dioxide resulted in a 180% increase in glutathione reductase, an 85% increase in acid phosphatase, and a 22% increase in peroxidase. In the same experiment, catalase decreased by 32% and total soluble protein decreased by 15%. Activities of glyoxylate reductase and both cyanide-sensitive and insensitive superoxide dismutases appeared to be unaffected by the 75% oxygen treatment after 48 hr. Obviously the impact of humidity as a component of the regulation of metabolism in leaf tissue must be considered. It is concluded that oxidoreductase activities located in the chloroplast, peroxisome, and cytosol are not equally sensitive to high oxygen tensions, and effects of environmental oxygen are not restricted to oxidative enzymes. / Ph. D.

The position of newly expanded shoot leaves in the canopy of apple trees had significant and similar effects on specific leaf weight (SLW), leaf thickness, length of palisade tissue, and number of cell layers in the palisade tissue. Inside canopy leaves had lower SLW, leaf thickness, palisade length, and number of palisade cell layers than middle and outside leaves at each of six sample dates ranging from late May to early October. Outside canopy leaves had the highest values at all sample dates. Differences in SLW, leaf thickness, and palisade length between inside and outside leaves increased as the season progressed, primarily due to a general increasing trend in outside leaves that developed later in the season. Effects of canopy position on spur leaves were not as great as with shoot leaves. Regression analysis showed SLW to be significantly correlated with leaf thickness and palisade length. / M.S.

Approximately 10-15% of field-grown eastern white pine (Pinus strobus L.) within a nursery plantation expressed foliar characteristics similar to that induced by oxidant pollution. Sensitive genotypes (based on foliar characteristics), had a 50% reduction in needle growth, severe needle tip burn, mottling, and early needle shed during a high O₃, drought-type growing season (1988) compared to a low O₃, non-drought growing season (1989). Tolerant genotypes showed little difference in needle growth or visible injury during the two growing season. Seasonal needle ascorbate concentrations were similar during the two years however, needle glutathione (GSH) content has not. Total GSH content was two-to three-fold greater in both genotypes during the summer of 1989 compared to 1988. Cloned, tolerant trees also had 23% more total GSH when exposed to forced ambient air compared to charcoal-filtered air in open-top chambers. Cloned sensitive trees had similar GSH concentrations when exposed to different chamber treatments. One-year-old needles always had lower ratios of ascorbate/ dehydroascorbate, ascorbate/α-tocopherol and GSH/GSSG than current year needles. One-year-old needles from the tolerant tree also maintained a higher glutathione reductase (GR) activity than the sensitive tree during the late summer. Needles of eastern white pine had two isoforms of GR (GR_A and GR_B). GR_A and GR_B accounted for 17% and 83% of the GR recovered, respectively. GR_A and GR_B had different physical and kinetic properties. Antibody produced from GRR was reactive with both native and denatured GR_B, but was cross-reactive with only native GR_A. Tolerant and sensitive clones exposed to control (< 0.025 ppm) or high (4.5 ppm∙hr total dose) O₃ for O to 72 hr, showed no increase in GR activity. Only in the high-O₃-treated trees did the amount of GR protein increase. Needles from the sensitive clone contained 14, 62, and 464 ng GR mgP⁻¹ and needles from the tolerant clone contained 21, 138, and 2800 ng GR mgP⁻¹ after 0, 24 and 72 hr O₃ exposure, respectively. The results of this dissertation indicate that differential foliar characteristics in eastern white pine may be correlated with GSH turnover and its regulation by GR during periods of high oxidant stress. / Ph. D.

O manejo nutricional adequado é fator determinante na produtividade e na qualidade dos frutos de macieira. Dentre os métodos para diagnóstico nutricional das plantas, destacam-se o critério de faixa de suficiência e o sistema integrado de diagnose e recomendação (DRIS). Este trabalho teve por objetivo avaliar o DRIS como método de interpretação de resultados de análises de folhas de plantas de macieira, estabelecendo normas adequadas para a cultura, e compará-lo com o método de diagnose nutricional, baseado no critério de faixa de suficiência, atualmente utilizado no Sul do Brasil. Buscou-se determinar, também a melhor época de amostragem de folhas de macieira para a aplicação do método DRIS. O estudo foi realizado na região produtora de maçã dos Campos de Cima da Serra, no Rio Grande do Sul, e nas regiões do Alto Vale do Rio do Peixe e Planalto Serrano, em Santa Catarina, em 70 pomares selecionados quanto à produtividade e técnicas de manejo do pomar, onde foram obtidas informações sobre a produtividade, espaçamento, porta-enxertos e realizada a amostragem de folhas e solo. Foram determinadas as concentrações de nitrogênio, fósforo, potássio, cálcio, magnésio, boro, cobre, ferro, manganês e zinco nas amostras de folhas e os valores de pH e os teores de matéria orgânica, fósforo, potássio, cálcio e magnésio nas amostras de solos. Também foram utilizados resultados de experimentos de adubação potássica e nitrogenada para avaliar a eficiência dos métodos DRIS, bem como de resultados de sazonalidade de nutrientes em três cultivares de macieira, para avaliar a época adequada de coleta de folhas para o método DRIS. Os índices DRIS foram calculados utilizando-se dois critérios para a escolha da ordem da razão dos nutrientes (Letzsch, 1985 e Walworth et al., 1986; Nick, 1998) e três formas de cálculo das funções dos nutrientes (Beaufils, 1973; Jones, 1981; Elwali & Gascho, 1984). Os resultados indicaram que: (i) A concentração dos nutrientes apresentou correlação positiva e significativa (p<0,01) com os respectivos índices DRIS, com exceção do N; (ii) O critério do "valor F" (Letzsch, 1985 e Walworth et al., 1986) mostrou-se mais eficiente que o "valor R" (Nick, 1998) para a escolha da ordem da razão dos nutrientes para a cultura da macieira; (iii) O Índice de Balanço Nutricional (IBN), calculado a partir das normas geradas, apresentou correlação negativa e significativa (p<0,01) com a produtividade para a população de referência, em todas as combinações de métodos testados; (iv) O método DRIS descrito por Elwali & Gascho (1984), utilizando o "valor F", quando comparado com o critério de faixas de suficiência, apresentou diagnóstico nutricional mais eficiente que os demais métodos de cálculo do DRIS; (v) O método de cálculo do DRIS, com base no somatório das funções, descrito por Elwali & Gascho (1984), utilizando o "valor F" é o mais indicado para a cultura da macieira, por apresentar valores de IBN que melhor indicam o estado nutricional das plantas e pela eficiência no diagnóstico nutricional da cultura; (vi) A melhor época de coleta de folhas para o método DRIS esta situada entre a quinta e a décima quinta semana após a plena floração; (vii) As normas DRIS geradas neste trabalho foram adequadas para o diagnóstico nutricional da macieira, para as condições do Sul do Brasil. / The appropriate nutritional management is a decisive factor in fruit productivity and quality of apple trees. Among the several methods for nutritional diagnosis of the plants, the most important are the sufficiency range approach and the diagnosis and recommendation integrated system (DRIS). The objective of this work was evaluate DRIS as an interpretation method of results of analyses of apple tree leaves, establishing appropriate norms for the culture and comparing it with the sufficiency range approach currently used in the Southern Brazil, and determine the best sampling time of apple tree leaves for the application of the DRIS method. The study was carried out in the apple producing area of Campos de Cima da Serra (RS, Brazil), and in the areas of Alto Vale do Rio do Peixe and Planalto Serrano (SC, Brazil), in 70 orchards selected on basis of productivity and management techniques, where information on productivity, spacing, rootstock was obtained and leaf and soil sampling were performed. The concentrations of nitrogen, phosphorus, potassium, calcium, magnesium, boron, copper, iron, manganese and zinc were determined in the leaf samples as well as the pH values and the concentrations of organic matter, phosphorus, potassium, calcium and magnesium in the samples of soils. Results of fertilization experiments with potassium and nitrogen were also used to evaluate the efficiency of DRIS methods, as well as results of nutrient seasonally in three apple tree cultivars, to evaluate the appropriate leaf collection time for the DRIS method. The DRIS indices were calculated using two criteria to choose the order of the nutrient ratio (Letzsch, 1985 and Walworth et al., 1986; Nick, 1998) and three forms of calculating of the nutrient functions (Beaufils, 1973; Jones, 1981; Elwali & Gascho, 1984). The results indicated that: (i) the nutrient concentration presented positive and significant correlation (p<0.01) with the respective DRIS indices, except for N; (ii) the criterion of the "F value" (Letzsch, 1985 and Walworth et al., 1986) was shown to be more efficient than the "R value" (Nick, 1998) to choose the order of the nutrient ratio for apple tree culture; (iii) the Nutritional Balance Index (NBI), calculated from the generated norms, presented a negative and significant correlation (p <0.01) with productivity for the reference population in all combinations of methods tested; (iv) the DRIS method described by Elwali & Gascho (1984), using the "F value", when compared with the sufficiency range approach, presented a more efficient nutritional diagnosis than the other methods of DRIS calculation; (v) the method of DRIS calculation, based on the sum of the functions, described by Elwali & Gascho (1984), using the "F value" is the most suitable for apple tree culture, for presenting NBI values that best indicate the nutritional state of the plants and for the efficiency in the nutritional diagnosis of the culture; (vi) the best leaf sampling time for the DRIS method is between the fifth and the fifteenth week after full blossom; (vii) The DRIS norms generated in this work were appropriate for the nutritional diagnosis of apple trees, for the conditions of Southern Brazil.

O manejo nutricional adequado é fator determinante na produtividade e na qualidade dos frutos de macieira. Dentre os métodos para diagnóstico nutricional das plantas, destacam-se o critério de faixa de suficiência e o sistema integrado de diagnose e recomendação (DRIS). Este trabalho teve por objetivo avaliar o DRIS como método de interpretação de resultados de análises de folhas de plantas de macieira, estabelecendo normas adequadas para a cultura, e compará-lo com o método de diagnose nutricional, baseado no critério de faixa de suficiência, atualmente utilizado no Sul do Brasil. Buscou-se determinar, também a melhor época de amostragem de folhas de macieira para a aplicação do método DRIS. O estudo foi realizado na região produtora de maçã dos Campos de Cima da Serra, no Rio Grande do Sul, e nas regiões do Alto Vale do Rio do Peixe e Planalto Serrano, em Santa Catarina, em 70 pomares selecionados quanto à produtividade e técnicas de manejo do pomar, onde foram obtidas informações sobre a produtividade, espaçamento, porta-enxertos e realizada a amostragem de folhas e solo. Foram determinadas as concentrações de nitrogênio, fósforo, potássio, cálcio, magnésio, boro, cobre, ferro, manganês e zinco nas amostras de folhas e os valores de pH e os teores de matéria orgânica, fósforo, potássio, cálcio e magnésio nas amostras de solos. Também foram utilizados resultados de experimentos de adubação potássica e nitrogenada para avaliar a eficiência dos métodos DRIS, bem como de resultados de sazonalidade de nutrientes em três cultivares de macieira, para avaliar a época adequada de coleta de folhas para o método DRIS. Os índices DRIS foram calculados utilizando-se dois critérios para a escolha da ordem da razão dos nutrientes (Letzsch, 1985 e Walworth et al., 1986; Nick, 1998) e três formas de cálculo das funções dos nutrientes (Beaufils, 1973; Jones, 1981; Elwali & Gascho, 1984). Os resultados indicaram que: (i) A concentração dos nutrientes apresentou correlação positiva e significativa (p<0,01) com os respectivos índices DRIS, com exceção do N; (ii) O critério do “valor F” (Letzsch, 1985 e Walworth et al., 1986) mostrou-se mais eficiente que o “valor R” (Nick, 1998) para a escolha da ordem da razão dos nutrientes para a cultura da macieira; (iii) O Índice de Balanço Nutricional (IBN), calculado a partir das normas geradas, apresentou correlação negativa e significativa (p<0,01) com a produtividade para a população de referência, em todas as combinações de métodos testados; (iv) O método DRIS descrito por Elwali & Gascho (1984), utilizando o “valor F”, quando comparado com o critério de faixas de suficiência, apresentou diagnóstico nutricional mais eficiente que os demais métodos de cálculo do DRIS; (v) O método de cálculo do DRIS, com base no somatório das funções, descrito por Elwali & Gascho (1984), utilizando o “valor F” é o mais indicado para a cultura da macieira, por apresentar valores de IBN que melhor indicam o estado nutricional das plantas e pela eficiência no diagnóstico nutricional da cultura; (vi) A melhor época de coleta de folhas para o método DRIS esta situada entre a quinta e a décima quinta semana após a plena floração; (vii) As normas DRIS geradas neste trabalho foram adequadas para o diagnóstico nutricional da macieira, para as condições do Sul do Brasil. / The appropriate nutritional management is a decisive factor in fruit productivity and quality of apple trees. Among the several methods for nutritional diagnosis of the plants, the most important are the sufficiency range approach and the diagnosis and recommendation integrated system (DRIS). The objective of this work was evaluate DRIS as an interpretation method of results of analyses of apple tree leaves, establishing appropriate norms for the culture and comparing it with the sufficiency range approach currently used in the Southern Brazil, and determine the best sampling time of apple tree leaves for the application of the DRIS method. The study was carried out in the apple producing area of Campos de Cima da Serra (RS, Brazil), and in the areas of Alto Vale do Rio do Peixe and Planalto Serrano (SC, Brazil), in 70 orchards selected on basis of productivity and management techniques, where information on productivity, spacing, rootstock was obtained and leaf and soil sampling were performed. The concentrations of nitrogen, phosphorus, potassium, calcium, magnesium, boron, copper, iron, manganese and zinc were determined in the leaf samples as well as the pH values and the concentrations of organic matter, phosphorus, potassium, calcium and magnesium in the samples of soils. Results of fertilization experiments with potassium and nitrogen were also used to evaluate the efficiency of DRIS methods, as well as results of nutrient seasonally in three apple tree cultivars, to evaluate the appropriate leaf collection time for the DRIS method. The DRIS indices were calculated using two criteria to choose the order of the nutrient ratio (Letzsch, 1985 and Walworth et al., 1986; Nick, 1998) and three forms of calculating of the nutrient functions (Beaufils, 1973; Jones, 1981; Elwali & Gascho, 1984). The results indicated that: (i) the nutrient concentration presented positive and significant correlation (p<0.01) with the respective DRIS indices, except for N; (ii) the criterion of the "F value" (Letzsch, 1985 and Walworth et al., 1986) was shown to be more efficient than the "R value” (Nick, 1998) to choose the order of the nutrient ratio for apple tree culture; (iii) the Nutritional Balance Index (NBI), calculated from the generated norms, presented a negative and significant correlation (p <0.01) with productivity for the reference population in all combinations of methods tested; (iv) the DRIS method described by Elwali & Gascho (1984), using the "F value", when compared with the sufficiency range approach, presented a more efficient nutritional diagnosis than the other methods of DRIS calculation; (v) the method of DRIS calculation, based on the sum of the functions, described by Elwali & Gascho (1984), using the "F value" is the most suitable for apple tree culture, for presenting NBI values that best indicate the nutritional state of the plants and for the efficiency in the nutritional diagnosis of the culture; (vi) the best leaf sampling time for the DRIS method is between the fifth and the fifteenth week after full blossom; (vii) The DRIS norms generated in this work were appropriate for the nutritional diagnosis of apple trees, for the conditions of Southern Brazil.