4 research outputs found
Allelopathic effect of Baccharis ulicina on germination and initial growth of Avena sativa, Lolium perenne and Raphanus sativus
Baccharis ulicina es una maleza ampliamente
distribuida en los pastizales de la zona semiárida
argentina. A fin de evaluar sus posibles efectos
alelopáticos, se utilizaron extractos acuosos de
B. ulicina (hoja, tallo, raÃz y planta entera) a dos
concentraciones (50 y 150 g tejido/L agua) sobre
la germinación y crecimiento inicial de Avena
sativa, Lolium perenne y Raphanus sativus.
Para cada especie se regaron 100 semillas y se
mantuvieron a 25°C y oscuridad. Se registraron
la germinación de las semillas y la longitud de
coleóptilo / hipocótile (C/H) y radÃcula (R). Con
los datos obtenidos se determinó: porcentaje
de germinación, coeficiente de velocidad de
germinación, vigor de la germinación, inhibición
de la germinación, inhibición de la longitud de
la radÃcula y del coleóptilo / hipocótile e Ãndice
de vigor de radÃcula y de coleóptilo / hipocótile.
Los extractos con alta concentración redujeron
la germinación en promedio 65% mientras que
inhibieron la longitud en 58,8% (C/H) y 93,3% (R)
para A. sativa; 71,5% (C/H) y 87,9% (R) para
L. perenne, y 93,8% (C/H) y 94,5% (R) para
R. sativus. Se registró un evidente efecto fitotóxico
de B. ulicina sobre las especies evaluadas,
indicando que la alelopatÃa serÃa una estrategia
ecológica de la especie.Baccharis ulicina is a weed widely distributed
in pastures of the semiarid zone of Argentina.
With the aim of evaluate potential allelopathic
effects, aqueous extracts of B. ulicina (leaf, stem,
root and whole plant) at two concentrations
(50 and 150 g tissue/L water) were used on
germination and initial growth of Avena sativa,
Lolium perenne and Raphanus sativus. For each
species, 100 seeds were watered and maintained
at 25°C at darkness. Seed germination and length
of coleoptile / hypocotyl (C/H) and radicle (R)
was measured. Then, germination percentage,
germination rate coefficient, germination vigor,
inhibition of germination, inhibition of radicle
length and coleoptile / hypocotyl length, radicle
vigor index and the coleoptile / hypocotyl vigor
index were calculated. High concentration
extracts reduced germination an average of 65%,
in addition, they produced a length inhibition
of 58.8% (C/H) and 93.3% (R) to A. sativa;
71.5% (C/H) and 87.9% (R) to L. perenne, and
93.8% (C/H) and 94.5% (R) to R. sativus. There
was an evident phytotoxic effect of B. ulicina on
evaluated species, indicating that allelopathy
would be an ecological strategy of the species.Fil: Tucat, Guillermo.
Centro de Recursos Naturales Renovables de la Zona Semiárida (Buenos Aires, Argentina).Fil: Bentivegna, Diego.
Centro de Recursos Naturales Renovables de la Zona Semiárida (Buenos Aires, Argentina).Fil: Fernández, Osvaldo.
Universidad Nacional del Sur. Departamento de AgronomÃaFil: Busso, Carlos.
Universidad Nacional del Sur. Departamento de AgronomÃaFil: Brevedan, Roberto.
Universidad Nacional del Sur. Departamento de AgronomÃaFil: Mujica, MarÃa de la Merced.Fil: Torres, Yanina.
Universidad Nacional del Sur. Departamento de AgronomÃaFil: Daddario, Juan.
Centro de Recursos Naturales Renovables de la Zona Semiárida (Buenos Aires, Argentina).Fil: Ithurrart, Leticia.
Universidad Nacional del Sur. Departamento de AgronomÃaFil: Giorgetti, Hugo.
Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental Patagones.Fil: RodrÃguez, Gustavo.
Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental Patagones.Fil: Montenegro, Oscar.
Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental Patagones.Fil: Baioni, Sandra.
Universidad Nacional del Sur. Departamento de AgronomÃaFil: EntÃo, José.Fil: Fioretti, MarÃa Nélida.
Universidad Nacional del Sur. Departamento de AgronomÃ
Root proliferation in native perennial grasses of arid Patagonia, Argentina
Pappophorum vaginatum is the most abundant C4 perennial grass desirable to livestock in rangelands of northeastern Patagonia, Argentina. We hypothesized that (1) defoliation reduce net primary productivity, and root length density and weight in the native species, and (2) root net primary productivity, and root length density and weight, are greater in P. vaginatum than in the other, less desirable, native species (i.e., Aristida spegazzinii, A. subulata and Sporobolus cryptandrus). Plants of all species were either exposed or not to a severe defoliation twice a year during two growing seasons. Root proliferation was measured using the cylinder method. Cylindrical, iron structures, wrapped up using nylon mesh, were buried diagonally from the periphery to the center on individual plants. These structures, initially filled with soil without any organic residue, were dug up from the soil on 25 April 2008, after two successive defoliations in mid-spring 2007. During the second growing season (2008–2009), cylinders were destructively harvested on 4 April 2009, after one or two defoliations in mid-and/or late-spring, respectively. Roots grown into the cylinders were obtained after washing the soil manually. Defoliation during two successive years did reduce the study variables only after plants of all species were defoliated twice, which supported the first hypothesis. The greater root net primary productivity, root length density and weight in P. vaginatum than in the other native species, in support of the second hypothesis, could help to explain its greater abundance in rangelands of Argentina.Facultad de Ciencias Agrarias y Forestale
Efecto fitotóxico de Baccharis ulicina sobre la germinación y crecimiento inicial de Avena sativa, Lolium perenne y Raphanus sativus
Baccharis ulicina is a weed widely distributed in pastures of the semiarid zone of Argentina. With the aim of evaluate potential allelopathic effects, aqueous extracts of B. ulicina (leaf, stem, root and whole plant) at two concentrations (50 and 150 g tissue/L water) were used on germination and initial growth of Avena sativa, Lolium perenne and Raphanus sativus. For each species, 100 seeds were watered and maintained at 25°C at darkness. Seed germination and length of coleoptile / hypocotyl (C/H) and radicle (R) was measured. Then, germination percentage, germination rate coefficient, germination vigor, inhibition of germination, inhibition of radicle length and coleoptile / hypocotyl length, radicle vigor index and the coleoptile / hypocotyl vigor index were calculated. High concentration extracts reduced germination an average of 65%, in addition, they produced a length inhibition of 58.8% (C/H) and 93.3% (R) to A. sativa; 71.5% (C/H) and 87.9% (R) to L. perenne, and 93.8% (C/H) and 94.5% (R) to R. sativus. There was an evident phytotoxic effect of B. ulicina on evaluated species, indicating that allelopathy would be an ecological strategy of the species.Baccharis ulicina es una maleza ampliamente distribuida en los pastizales de la zona semiárida argentina. A fin de evaluar sus posibles efectos alelopáticos, se utilizaron extractos acuosos de B. ulicina (hoja, tallo, raÃz y planta entera) a dos concentraciones (50 y 150 g tejido/L agua) sobre la germinación y crecimiento inicial de Avena sativa, Lolium perenne y Raphanus sativus. Para cada especie se regaron 100 semillas y se mantuvieron a 25°C y oscuridad. Se registraron la germinación de las semillas y la longitud de coleóptilo / hipocótile (C/H) y radÃcula (R). Con los datos obtenidos se determinó: porcentaje de germinación, coeficiente de velocidad de germinación, vigor de la germinación, inhibición de la germinación, inhibición de la longitud de la radÃcula y del coleóptilo / hipocótile e Ãndice de vigor de radÃcula y de coleóptilo / hipocótile. Los extractos con alta concentración redujeron la germinación en promedio 65% mientras que inhibieron la longitud en 58,8% (C/H) y 93,3% (R) para A. sativa; 71,5% (C/H) y 87,9% (R) para L. perenne, y 93,8% (C/H) y 94,5% (R) para R. sativus. Se registró un evidente efecto fitotóxico de B. ulicina sobre las especies evaluadas, indicando que la alelopatÃa serÃa una estrategia ecológica de la especie
Root proliferation in native perennial grasses of arid Patagonia, Argentina
Pappophorum vaginatum is the most abundant C4 perennial grass desirable to livestock in rangelands of northeastern Patagonia, Argentina. We hypothesized that (1) defoliation reduce net primary productivity, and root length density and weight in the native species, and (2) root net primary productivity, and root length density and weight, are greater in P. vaginatum than in the other, less desirable, native species (i.e., Aristida spegazzinii, A. subulata and Sporobolus cryptandrus). Plants of all species were either exposed or not to a severe defoliation twice a year during two growing seasons. Root proliferation was measured using the cylinder method. Cylindrical, iron structures, wrapped up using nylon mesh, were buried diagonally from the periphery to the center on individual plants. These structures, initially filled with soil without any organic residue, were dug up from the soil on 25 April 2008, after two successive defoliations in mid-spring 2007. During the second growing season (2008–2009), cylinders were destructively harvested on 4 April 2009, after one or two defoliations in mid-and/or late-spring, respectively. Roots grown into the cylinders were obtained after washing the soil manually. Defoliation during two successive years did reduce the study variables only after plants of all species were defoliated twice, which supported the first hypothesis. The greater root net primary productivity, root length density and weight in P. vaginatum than in the other native species, in support of the second hypothesis, could help to explain its greater abundance in rangelands of Argentina.Fil: Torres, Yanina Alejandra. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico BahÃa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina; Argentina. Universidad Nacional del Sur. Departamento de AgronomÃa; ArgentinaFil: Busso, Carlos Alberto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico BahÃa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina. Universidad Nacional del Sur. Departamento de AgronomÃa; ArgentinaFil: Montenegro, Oscar A.. Provincia de Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental de Patagones; ArgentinaFil: Ithurrart, Leticia Soledad. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico BahÃa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina; Argentina. Universidad Nacional del Sur. Departamento de AgronomÃa; ArgentinaFil: Giorgetti, Hugo D.. Provincia de Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental de Patagones; ArgentinaFil: RodrÃguez, Gustavo. Provincia de Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental de Patagones; ArgentinaFil: Bentivegna, Diego Javier. Universidad Nacional del Sur. Departamento de AgronomÃa; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico BahÃa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina; ArgentinaFil: Brevedan, Roberto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico BahÃa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina; Argentina. Universidad Nacional del Sur. Departamento de AgronomÃa; ArgentinaFil: Fernandez, Osvaldo Alberto. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico BahÃa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina; Argentina. Universidad Nacional del Sur. Departamento de AgronomÃa; ArgentinaFil: Mujica, MarÃa M.. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; ArgentinaFil: Baioni, Sandra S.. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico BahÃa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina. Universidad Nacional del Sur. Departamento de AgronomÃa; ArgentinaFil: EntÃo, José. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; ArgentinaFil: Fioretti, MarÃa N.. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico BahÃa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina; Argentina. Universidad Nacional del Sur. Departamento de AgronomÃa; ArgentinaFil: Tucat, Guillermo. Universidad Nacional del Sur. Departamento de AgronomÃa; Argentina. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico BahÃa Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina; Argentin