El objetivo de esta revisión se limita a un aspecto particular de Das sustancias húmicas y es el ... more El objetivo de esta revisión se limita a un aspecto particular de Das sustancias húmicas y es el referido a la relación de las mismas con la nutrición mineral de (as plantas superiores a la luz de algunos resultados experimentales obtenidos por este grupo. Se presenta una breve descripción de la materia orgánica del suelo y de uno de sus principales componentes, las sustancias húmicas, algunas características físico-químicas, composición y fraccionamiento. Utilizando métodos de fraccionamiento físicos y la posterior marcación con radioisótopos de las fracciones, se determinaron algunas de sus características fisicoquímicas relacionadas con la nutrición mineral de las plantas. Se postula que las fracciones de bajo peso molecular juegan un papel importante en la movilidad y disponibilidad de los micronutrienies.The objective of this review ís limíted to a particular aspect of the soil humic substances ireferred to their relationship with the mineral nutrition of plants in the light of...
Se analizan las caracteristicas morfologicas y fisiologicas que son importantes para definir el p... more Se analizan las caracteristicas morfologicas y fisiologicas que son importantes para definir el potencial del rendimiento de la planta de girasol . En base a ello se propone un tipo de planta ideal (ideotipo), la cual sea capaz de aprovechar con maxima eficiencia la disponibilidad de recursos provistos con las actuales practicas agronomicas. Se realiza una descripcion del desarrollo del cultivo, poniendo enfasis en los diferentes factores que pueden afectar cada uno de los estados del desarrollo. Dentro de las caracteristicas morfologicas, se propone que las plantas posean un sistema radical extenso y profundo, tallos de porte mediano con alta capacidad de reserva de foto asimilados, los cuales puedan ser redistribuidos al grano durante el periodo de su llenado Hojas con un ritmo de senescencia lento y capaces de alcanzar un IAF no menor de 4 en corto tiempo. Dentro de las caracteristicas asociadas con la formacion del rendimiento, se propone que la superficie meristematica del rece...
En el presente trabajo se informa el efecto de un extracto completo de acidos humicos y su fracci... more En el presente trabajo se informa el efecto de un extracto completo de acidos humicos y su fraccion de medio peso molecular sobre el crecimiento y el nivel endogeno de reguladores del crecimiento en raices de girasol . Los acidos humicos en solucion nutritiva disminuyen el crecimiento de secciones radicales , a diferencia de lo observado at utilizar acidos humicos o solucion nutritiva sola. Cuanto mayor es la concentracion, mayor el efecto Inhibidor . Las secciones radicales tratadas con 285 mg .I de la fraccion de medio peso molecular, mostraron aumento en el crecimiento y en el contenido endogeno de sustancias promotoras del crecimiento . Concentraciones tan altas como 2000 mg fl del extracto completo causaron un aumento en los niveles endogenos de inhibidores . Estos resultados sugieren que los acidos humicos afectan el crecimiento radical , ya sea por alterar el metabolismo de los reguladores del crecimiento o por actuar per se como sustancias reguladoras.
Changes in apple (Malus domestica Bork.) peel PSII photochemical process during fruit development... more Changes in apple (Malus domestica Bork.) peel PSII photochemical process during fruit development under high solar radiation field conditions were analysed by the JIP-test to increase understanding on energy dissipation and susceptibility to photooxidative damage. Fruits growing exposed (E), non-exposed (NE) or suddenly exposed (SU) to high solar radiation were evaluated at three developmental stages. Chlorophyll content and chlorophyll a fluorescence transient (OJIP), were affected by high solar radiation and development. Minimum fluorescence, maximum fluorescence, maximum quantum yield of photochemistry, and specific fluxes per cross section decreased in E and SU fruits. JIP parameters were a sensitive indicator of high solar radiation stress in apple peel. Peroxidative damage was observed in E fruits at each stage of development and in SU fruits at early and mid-stages. By delineating the photochemical events induced by solar radiation in apple fruits at different developmental s...
Revista De La Facultad De Agronomia De La Universidad Del Zulia, 2017
El objetivo de esta revision se limita a un aspecto particular de las sustancias humicas y es el ... more El objetivo de esta revision se limita a un aspecto particular de las sustancias humicas y es el referido a la relacion de las mismas con la nutricion mineral de las plantas superiores a la luz de algunos resultados experimentales obtenidos por este grupo. Se presenta una breve descripcion de la materia organica del suelo y de uno de sus principales componentes, las sustancias humicas, algunas caracteristicas fisico-quimicas, composicion y fraccionamiento. Utilizando metodos de fraccionamiento fisicos y la posterior marcacion con radioisotopos de las fracciones, se determinaron algunas de sus caracteristicas fisicoquimicas relacionadas con la nutricion mineral de las plantas. Se postula que las fracciones de bajo peso molecular juegan un papel importante en la movilidad y disponibilidad de los micronutrientes.
En el sudoeste bonaerense de la República Argentina, avena fatua es una maleza que ocupa una sign... more En el sudoeste bonaerense de la República Argentina, avena fatua es una maleza que ocupa una significativa proporción del banco de semillas presentes en el suelo, causando severas pérdidas de rendimiento en los cultivos de trigo, lo cuál la caracteriza como una maleza invasora. A pesar de que en los cultivos, se utilizan normalmente prácticas de control com graminicidas selectivos, se observa una alta incidencia de la población de Avena fatua a través de la determinación del número de panojas y semillas por metro cuadrado remanentes de las plantas que escapan al control y que alcanzan el estado reproductivo antes de la cosecha del cereal. El objetivo de este estudio fue evaluar el efecto de varios graminicidas postemergentes selectivos para el cultivo de trigo sobre el crecimiento de la población de Avena fatua por metro cuadrado en un diseño estadístico de bloques al azar con cuatro repeticiones. Los tratamientos fueron los siguientes: testigo sin control, tralkoxydim (150 y 200 g/...
Classically, soil humic substances have been divided into three main fractions: (a) fulvic acid (... more Classically, soil humic substances have been divided into three main fractions: (a) fulvic acid (FA); (b) humic acid (HA); and (c) humin'. However, there are no clear differences among these three fractions, as a continuous gradation appears to exist within FA, HA and humin fractions. Further, it has been postulated that no two humic substances are exactly similar 2. Modern analytical techniques such as chromatography, gel permeation and electrophoresis have been used to study this problem, but only a few sub-fractions have been obtained so far. We report in this paper the separation of FA and HA into-everal sub-fractions by isotachophoresis and isoelectric focusing, which is helpful in the' elucidation of the structure and physical, chemical and biological properties of these soil humic substances.
Lithospermum arvense is an increasing annual weed in winter crops of the semiarid region of south... more Lithospermum arvense is an increasing annual weed in winter crops of the semiarid region of southern Argentina under low impact tillage systems, an agricultural practice that has become popular in recent years. Seed distribution in the soil profile under conventional tillage will change when reduced tillage is implemented, thus affecting the germination microenvironment. The effect of seed burial depth and soil water regime on field germination, enforced dormancy, innate dormancy and seed decay was studied in relation to burial time in a field experiment. In addition, the effect of burial depth on seed germination and seedling emergence was examined under laboratory controlled conditions. Field germination of buried seed ranged from 55% to 65% for shallow (2 cm) and from 5% to 30% for greater depths (20 cm). Enforced dormancy levels were significantly higher among deeper seeds. The amount of innate dormant seeds was reduced to <10% after a year of burial. Lithospermum arvense seedbanks can be classified as short-term persistent. Germination in the laboratory was unaffected by burial depth, while seedling emergence reduction was adequately described by a sigmoidal model. Results indicate that agricultural practices that accumulate L. arvense seeds near the soil surface enhance seedling recruitment.
Ilus. Tab. Bib. Sum. (En, Es)Se investig? la absorci?n foliar de sulfato en plantas de frijol cua... more Ilus. Tab. Bib. Sum. (En, Es)Se investig? la absorci?n foliar de sulfato en plantas de frijol cuando se variaban algunas condiciones fisiol?gicas, y la forma qu?mica en que ?ste se traladaba dentro de la planta, usando para ello azufre-35. Se utilizaron plantas de 10 a 15 d?as de edad de Phaseolus vulgaris L., cultivadas en arena de r?o o soluci?n nutritiva de Hoagland No 1 con micro-elementos. Se trabaj? en invernadero o en cuarto de crecimiento con control de luz y temperatura. Se hicieron seis experimentos: a) lavado de hojas tratadas b) ritmo de absorci?n y transporte de sulfato c) absorci?n de sulfato a distintos valores de pH d) absorci?n y transporte del sulfato a distintos reg?menes de intensidad lum?nica e) efecto del CNK sobre la absorci?n y transporte y f) forma qu?mica de traslaci?n del azufre. Las soluciones radioactivas aplicadas ten?an una concentraci?n de 0.05 M y una actividad espec?fica que vari? en cada experimento. La aplicaci?n se realiz? siempre en la capa supe...
Models based on thermal-time approaches have been a useful tool for characterizing and predicting... more Models based on thermal-time approaches have been a useful tool for characterizing and predicting seed germination and dormancy release in relation to time and temperature. The aims of the present work were to evaluate the relative accuracy of different thermal-time approaches for the description of germination in Lithospermum arvense and to develop an after-ripening thermal-time model for predicting seed dormancy release. Seeds were dry-stored at constant temperatures of 5, 15 or 24 degrees C for up to 210 d. After different storage periods, batches of 50 seeds were incubated at eight constant temperature regimes of 5, 8, 10, 13, 15, 17, 20 or 25 degrees C. Experimentally obtained cumulative-germination curves were analysed using a non-linear regression procedure to obtain optimal population thermal parameters for L. arvense. Changes in these parameters were described as a function of after-ripening thermal-time and storage temperature. The most accurate approach for simulating the...
A computer simulation model was developed to describe Anoda cristata (L.) Schlecht seedbank dynam... more A computer simulation model was developed to describe Anoda cristata (L.) Schlecht seedbank dynamics in soybeans. The model considers different weed management strategies: absence of control, control with the recommended rate and with glyphosate at half the recommended rate, and two soybean row spacings (35 and 70 cm). The model was evaluated using data from previous experiments obtained for four consecutive years. The model accurately reproduced the seedbank dynamics. The seedbank decreased more in weed management strategies without seed production. In absence of control, the seedbank reached an equilibrium density. When seeds were produced every year, the model output was more sensitive to changes in the rate of predation; but without seed production, seed mortality was the most important process. Simulation demonstrated that long-term eradication may occur with continuous use of glyphosate at the recommended rate or with the combination of soybean at 35 cm between rows and glypho...
A computer simulation model was developed to describe Anoda cristata (L.) Schlecht seedbank dynam... more A computer simulation model was developed to describe Anoda cristata (L.) Schlecht seedbank dynamics in soybeans. The model considers different weed management strategies: absence of control, control with the recommended rate and with glyphosate at half the recommended rate, and two soybean row spacings (35 and 70 cm). The model was evaluated using data from previous experiments obtained for four consecutive years. The model accurately reproduced the seedbank dynamics. The seedbank decreased more in weed management strategies without seed production. In absence of control, the seedbank reached an equilibrium density. When seeds were produced every year, the model output was more sensitive to changes in the rate of predation; but without seed production, seed mortality was the most important process. Simulation demonstrated that long-term eradication may occur with continuous use of glyphosate at the recommended rate or with the combination of soybean at 35 cm between rows and glypho...
El objetivo de esta revisión se limita a un aspecto particular de Das sustancias húmicas y es el ... more El objetivo de esta revisión se limita a un aspecto particular de Das sustancias húmicas y es el referido a la relación de las mismas con la nutrición mineral de (as plantas superiores a la luz de algunos resultados experimentales obtenidos por este grupo. Se presenta una breve descripción de la materia orgánica del suelo y de uno de sus principales componentes, las sustancias húmicas, algunas características físico-químicas, composición y fraccionamiento. Utilizando métodos de fraccionamiento físicos y la posterior marcación con radioisótopos de las fracciones, se determinaron algunas de sus características fisicoquímicas relacionadas con la nutrición mineral de las plantas. Se postula que las fracciones de bajo peso molecular juegan un papel importante en la movilidad y disponibilidad de los micronutrienies.The objective of this review ís limíted to a particular aspect of the soil humic substances ireferred to their relationship with the mineral nutrition of plants in the light of...
Se analizan las caracteristicas morfologicas y fisiologicas que son importantes para definir el p... more Se analizan las caracteristicas morfologicas y fisiologicas que son importantes para definir el potencial del rendimiento de la planta de girasol . En base a ello se propone un tipo de planta ideal (ideotipo), la cual sea capaz de aprovechar con maxima eficiencia la disponibilidad de recursos provistos con las actuales practicas agronomicas. Se realiza una descripcion del desarrollo del cultivo, poniendo enfasis en los diferentes factores que pueden afectar cada uno de los estados del desarrollo. Dentro de las caracteristicas morfologicas, se propone que las plantas posean un sistema radical extenso y profundo, tallos de porte mediano con alta capacidad de reserva de foto asimilados, los cuales puedan ser redistribuidos al grano durante el periodo de su llenado Hojas con un ritmo de senescencia lento y capaces de alcanzar un IAF no menor de 4 en corto tiempo. Dentro de las caracteristicas asociadas con la formacion del rendimiento, se propone que la superficie meristematica del rece...
En el presente trabajo se informa el efecto de un extracto completo de acidos humicos y su fracci... more En el presente trabajo se informa el efecto de un extracto completo de acidos humicos y su fraccion de medio peso molecular sobre el crecimiento y el nivel endogeno de reguladores del crecimiento en raices de girasol . Los acidos humicos en solucion nutritiva disminuyen el crecimiento de secciones radicales , a diferencia de lo observado at utilizar acidos humicos o solucion nutritiva sola. Cuanto mayor es la concentracion, mayor el efecto Inhibidor . Las secciones radicales tratadas con 285 mg .I de la fraccion de medio peso molecular, mostraron aumento en el crecimiento y en el contenido endogeno de sustancias promotoras del crecimiento . Concentraciones tan altas como 2000 mg fl del extracto completo causaron un aumento en los niveles endogenos de inhibidores . Estos resultados sugieren que los acidos humicos afectan el crecimiento radical , ya sea por alterar el metabolismo de los reguladores del crecimiento o por actuar per se como sustancias reguladoras.
Changes in apple (Malus domestica Bork.) peel PSII photochemical process during fruit development... more Changes in apple (Malus domestica Bork.) peel PSII photochemical process during fruit development under high solar radiation field conditions were analysed by the JIP-test to increase understanding on energy dissipation and susceptibility to photooxidative damage. Fruits growing exposed (E), non-exposed (NE) or suddenly exposed (SU) to high solar radiation were evaluated at three developmental stages. Chlorophyll content and chlorophyll a fluorescence transient (OJIP), were affected by high solar radiation and development. Minimum fluorescence, maximum fluorescence, maximum quantum yield of photochemistry, and specific fluxes per cross section decreased in E and SU fruits. JIP parameters were a sensitive indicator of high solar radiation stress in apple peel. Peroxidative damage was observed in E fruits at each stage of development and in SU fruits at early and mid-stages. By delineating the photochemical events induced by solar radiation in apple fruits at different developmental s...
Revista De La Facultad De Agronomia De La Universidad Del Zulia, 2017
El objetivo de esta revision se limita a un aspecto particular de las sustancias humicas y es el ... more El objetivo de esta revision se limita a un aspecto particular de las sustancias humicas y es el referido a la relacion de las mismas con la nutricion mineral de las plantas superiores a la luz de algunos resultados experimentales obtenidos por este grupo. Se presenta una breve descripcion de la materia organica del suelo y de uno de sus principales componentes, las sustancias humicas, algunas caracteristicas fisico-quimicas, composicion y fraccionamiento. Utilizando metodos de fraccionamiento fisicos y la posterior marcacion con radioisotopos de las fracciones, se determinaron algunas de sus caracteristicas fisicoquimicas relacionadas con la nutricion mineral de las plantas. Se postula que las fracciones de bajo peso molecular juegan un papel importante en la movilidad y disponibilidad de los micronutrientes.
En el sudoeste bonaerense de la República Argentina, avena fatua es una maleza que ocupa una sign... more En el sudoeste bonaerense de la República Argentina, avena fatua es una maleza que ocupa una significativa proporción del banco de semillas presentes en el suelo, causando severas pérdidas de rendimiento en los cultivos de trigo, lo cuál la caracteriza como una maleza invasora. A pesar de que en los cultivos, se utilizan normalmente prácticas de control com graminicidas selectivos, se observa una alta incidencia de la población de Avena fatua a través de la determinación del número de panojas y semillas por metro cuadrado remanentes de las plantas que escapan al control y que alcanzan el estado reproductivo antes de la cosecha del cereal. El objetivo de este estudio fue evaluar el efecto de varios graminicidas postemergentes selectivos para el cultivo de trigo sobre el crecimiento de la población de Avena fatua por metro cuadrado en un diseño estadístico de bloques al azar con cuatro repeticiones. Los tratamientos fueron los siguientes: testigo sin control, tralkoxydim (150 y 200 g/...
Classically, soil humic substances have been divided into three main fractions: (a) fulvic acid (... more Classically, soil humic substances have been divided into three main fractions: (a) fulvic acid (FA); (b) humic acid (HA); and (c) humin'. However, there are no clear differences among these three fractions, as a continuous gradation appears to exist within FA, HA and humin fractions. Further, it has been postulated that no two humic substances are exactly similar 2. Modern analytical techniques such as chromatography, gel permeation and electrophoresis have been used to study this problem, but only a few sub-fractions have been obtained so far. We report in this paper the separation of FA and HA into-everal sub-fractions by isotachophoresis and isoelectric focusing, which is helpful in the' elucidation of the structure and physical, chemical and biological properties of these soil humic substances.
Lithospermum arvense is an increasing annual weed in winter crops of the semiarid region of south... more Lithospermum arvense is an increasing annual weed in winter crops of the semiarid region of southern Argentina under low impact tillage systems, an agricultural practice that has become popular in recent years. Seed distribution in the soil profile under conventional tillage will change when reduced tillage is implemented, thus affecting the germination microenvironment. The effect of seed burial depth and soil water regime on field germination, enforced dormancy, innate dormancy and seed decay was studied in relation to burial time in a field experiment. In addition, the effect of burial depth on seed germination and seedling emergence was examined under laboratory controlled conditions. Field germination of buried seed ranged from 55% to 65% for shallow (2 cm) and from 5% to 30% for greater depths (20 cm). Enforced dormancy levels were significantly higher among deeper seeds. The amount of innate dormant seeds was reduced to <10% after a year of burial. Lithospermum arvense seedbanks can be classified as short-term persistent. Germination in the laboratory was unaffected by burial depth, while seedling emergence reduction was adequately described by a sigmoidal model. Results indicate that agricultural practices that accumulate L. arvense seeds near the soil surface enhance seedling recruitment.
Ilus. Tab. Bib. Sum. (En, Es)Se investig? la absorci?n foliar de sulfato en plantas de frijol cua... more Ilus. Tab. Bib. Sum. (En, Es)Se investig? la absorci?n foliar de sulfato en plantas de frijol cuando se variaban algunas condiciones fisiol?gicas, y la forma qu?mica en que ?ste se traladaba dentro de la planta, usando para ello azufre-35. Se utilizaron plantas de 10 a 15 d?as de edad de Phaseolus vulgaris L., cultivadas en arena de r?o o soluci?n nutritiva de Hoagland No 1 con micro-elementos. Se trabaj? en invernadero o en cuarto de crecimiento con control de luz y temperatura. Se hicieron seis experimentos: a) lavado de hojas tratadas b) ritmo de absorci?n y transporte de sulfato c) absorci?n de sulfato a distintos valores de pH d) absorci?n y transporte del sulfato a distintos reg?menes de intensidad lum?nica e) efecto del CNK sobre la absorci?n y transporte y f) forma qu?mica de traslaci?n del azufre. Las soluciones radioactivas aplicadas ten?an una concentraci?n de 0.05 M y una actividad espec?fica que vari? en cada experimento. La aplicaci?n se realiz? siempre en la capa supe...
Models based on thermal-time approaches have been a useful tool for characterizing and predicting... more Models based on thermal-time approaches have been a useful tool for characterizing and predicting seed germination and dormancy release in relation to time and temperature. The aims of the present work were to evaluate the relative accuracy of different thermal-time approaches for the description of germination in Lithospermum arvense and to develop an after-ripening thermal-time model for predicting seed dormancy release. Seeds were dry-stored at constant temperatures of 5, 15 or 24 degrees C for up to 210 d. After different storage periods, batches of 50 seeds were incubated at eight constant temperature regimes of 5, 8, 10, 13, 15, 17, 20 or 25 degrees C. Experimentally obtained cumulative-germination curves were analysed using a non-linear regression procedure to obtain optimal population thermal parameters for L. arvense. Changes in these parameters were described as a function of after-ripening thermal-time and storage temperature. The most accurate approach for simulating the...
A computer simulation model was developed to describe Anoda cristata (L.) Schlecht seedbank dynam... more A computer simulation model was developed to describe Anoda cristata (L.) Schlecht seedbank dynamics in soybeans. The model considers different weed management strategies: absence of control, control with the recommended rate and with glyphosate at half the recommended rate, and two soybean row spacings (35 and 70 cm). The model was evaluated using data from previous experiments obtained for four consecutive years. The model accurately reproduced the seedbank dynamics. The seedbank decreased more in weed management strategies without seed production. In absence of control, the seedbank reached an equilibrium density. When seeds were produced every year, the model output was more sensitive to changes in the rate of predation; but without seed production, seed mortality was the most important process. Simulation demonstrated that long-term eradication may occur with continuous use of glyphosate at the recommended rate or with the combination of soybean at 35 cm between rows and glypho...
A computer simulation model was developed to describe Anoda cristata (L.) Schlecht seedbank dynam... more A computer simulation model was developed to describe Anoda cristata (L.) Schlecht seedbank dynamics in soybeans. The model considers different weed management strategies: absence of control, control with the recommended rate and with glyphosate at half the recommended rate, and two soybean row spacings (35 and 70 cm). The model was evaluated using data from previous experiments obtained for four consecutive years. The model accurately reproduced the seedbank dynamics. The seedbank decreased more in weed management strategies without seed production. In absence of control, the seedbank reached an equilibrium density. When seeds were produced every year, the model output was more sensitive to changes in the rate of predation; but without seed production, seed mortality was the most important process. Simulation demonstrated that long-term eradication may occur with continuous use of glyphosate at the recommended rate or with the combination of soybean at 35 cm between rows and glypho...
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Papers by Gustavo Orioli