RESUMEN

Schinus fasciculata es un árbol de la ecorregión chaqueña argentina. Es una especie de bajo porte, usada como antiséptico, analgésico, antiinflamatorio y antifúngico. Estudios previos registraron baja germinación y deficiente sanidad. El objetivo fue evaluar la germinación y la respuesta de las plántulas in vitro en dos medios de cultivo. Se recolectaron frutos, se desinfectaron por 20 min con HClNa y se sembraron en agar-agua. Las plántulas se repicaron a medio MS en dos diluciones: un cuarto (MS ») y un medio (MS ½). Se hicieron ensayos de germinación y vigor (tiempo medio de germinación máxima en días). Se evaluó % de contaminación. A los 20 días del repique se evaluó % de explantos con hojas, número de hojas y altura de plántulas. Paralelamente se hizo un ensayo de germinación y vigor en arena. La contaminación fue de 16 %, la germinación de 84 %, el vigor de 4,9 días. El 94 y el 100 % de los explantos en MS » y MS ½ presentaron hojas. El número promedio de hojas fue de 7,5 y 7,4 y la altura promedio fue de 3,35 cm y 2,98 cm en MS » y MS ½, observándose diferencias significativas en altura. La germinación en arena fue de 46 % y el vigor de 4,6 días. La utilización de la técnica de cultivo in vitro en S. fasciculata facilita la multiplicación de esta especie de alto valor farmacológico, permitiendo aumentar el porcentaje de frutos germinados y obtener plántulas libres de patógenos todo el año.

Schinus fasciculata is a tree of Argentina Chaco eco-region. It is a low-growing species, used as an antiseptic, analgesic, anti-inflammatory and antifungal. Previous studies reported low germination and poor health. The object of this work was to evaluate the germination and in vitro response of seedlings in two culture media. Fruits were collected, disinfected for 20 min with HClNa and sowing in agar - water. The seedlings were seeded onto MS medium in two dilutions: fourth (» MS) and half (½ MS). Germination and vigor tests (mean time to maximum germination in days) were made. Contamination percentage was evaluated. At 20 days of transplanted were evaluated: % of explants with leaves, leaf number and height of seedlings. Parallel assay germination and vigor in sand was made. Contamination was 16%, germination was 84% and vigor 4.9 days. The 94 % and the 100% of the explants in MS » and ½ MS showed leaves. The average leaf number was 7.5 and 7.4 and the average height was 3.35 cm and 2.98 cm in MS » and MS ½, with a significant difference in height. Germination in sand was 46 % and vigor was of 4.6 days. The technique of in vitro culture in S. fasciculata facilitates the multiplication of this species of high pharmacological value, allowing to increase the percentage of germination and obtain pathogen-free all year seedlings.

RESUMEN

Aspidosperma quebracho-blanco (white quebracho) and Schinopsis balansae (red quebracho) are distinctive trees of the South American Park in Argentina. Quebrachos are found in forests that have been exploited very intensively. The object of this work was the identification of biotic and abiotic factors specially fungal pathogen that affect the quality of both species and its relation with germination. Seeds where evaluated through germination test and the percentage of the incidence of fungal agents in two different years of harvest was determined. In S. balansae the germination rate was 77% and of 27% in 2000 and 2001 harvests, respectively. Associations fungi-germination were found in 2001 for Alternaria spp., Curvularia spp., and Fusarium spp., showing an coefficient of correlation = -0.84; -0.85 and -0.73 (p < 0.00004), respectively. A high percentage of vane seeds (55%) was also found in 2001 harvest, due to adverse environmental factors, specifically higher precipitations during flowering. In A. quebracho-blanco seeds, the germination rate was 50% and 90% in 2000 and 2003 respectively, with a 42% of immature seeds in 2000 harvest that was associated to high precipitations and high temperatures during flowering and ripping of fruits. The incidence of pathogens was low and did not have association to germination.

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RESUMEN

Schinopsis balansae (quebracho colorado) y Aspidosperma quebracho-blanco(quebracho blanco) son árboles característicos de la región chaqueña deSudamérica. En Argentina, los quebrachos se hallan en bosques que han sidosometidos a una intensa explotación. El objetivo de este trabajo fue identificarfactores abióticos y bióticos, en especial de origen fúngico, que afectan lacalidad de las semillas de ambas especies y su relación con la germinación.Las semillas se evaluaron a través de la prueba de germinación y sedeterminó el porcentaje de incidencia de agentes fúngicos en semillas de dosaños de cosechas distintas. En S. balansae la germinación fue del 77% y del27% en las cosechas de 2000 y 2001, respectivamente, y se encontróasociación con Alternaria spp., Curvularia spp. y Fusarium spp. con lagerminación del año 2001, mostrando un coeficiente de correlación = -0,84;-0,85 y -0,73, respectivamente (p < 0,00004). Asimismo, se halló un elevadoporcentaje de semillas vanas (55%) en la cosecha de 2001, producto defactores ambientales adversos, particularmente abundantes precipitacionesdurante la floración. En las semillas de A. quebracho-blanco la germinaciónfue del 50% y del 90% en los años 2000 y 2003, respectivamente, con un42% de semillas inmaduras en la cosecha de 2000, que se asoció a elevadasprecipitaciones y temperaturas durante la floración y la maduración de losfrutos. La incidencia de patógenos en semillas de esta especie fue mínima yno estuvo asociada a la germinación en ninguno de los dos años evaluados(AU9

Aspidosperma quebracho-blanco (white quebracho) and Schinopsis balansae(red quebracho) are distinctive trees of the South American Park in Argentina.Quebrachos are found in forests that have been exploited very intensively.The object of this work was the identification of biotic and abiotic factorsspecially fungal pathogen that affect the quality of both species and itsrelation with germination. Seeds where evaluated through germination test andthe percentage of the incidence of fungal agents in two different years ofharvest was determined. In S. balansae the germination rate was 77% and of27% in 2000 and 2001 harvests, respectively. Associations fungi - germinationwere found in 2001 for Alternaria spp., Curvularia spp., and Fusarium spp.,showing an coefficient of correlation = -0.84; -0.85 and -0.73 (p < 0.00004),respectively. A high percentage of vane seeds (55%) was also found in 2001harvest, due to adverse environmental factors, specifically higher precipitationsduring flowering. In A. quebracho-blanco seeds, the germination rate was 50%and 90% in 2000 and 2003 respectively, with a 42% of immature seeds in2000 harvest that was associated to high precipitations and high temperaturesduring flowering and ripping of fruits. The incidence of pathogens was low anddid not have association to germination(AU)

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Amazonia and the Gran Chaco are the largest phytogeographic units of the Neotropical Region. The Forest Wedge of the Santa Fe province of Argentina is the southernmost part of the Eastern Chaco, and there are three main types of forest, 1) the mixed dense forests, 2) the Schinopsis balansae "quebrachal" and 3) the Prosopis nigra var. ragonesei forests, distributed along an environmental gradient correlated with topographic elevation. In this paper litterfall and organic matter decomposition of four species were studied in two different microsites in a Schinopsis balansae forest during three years. Litter fall varied along the year following seasonal environmental variation but litterfall variations between years were not significant. Litterfall was not uniform over the whole surface, under close canopy monthly average litterfall amounts 32.67 g/m2, in open gaps 4.47 g/m2 and 15.07 g/m2 under medium density canopy. Organic matter decomposition, like in other forests, was a negative exponential function of time, and the decomposition rate is independent from the microsites where it falls, 0.15 and 0.12 in sunny and shadow microsites respectively for Maytenus vitis-idaea, 0.10 and 0.11 in sunny and shadow microsites respectively for Achatocarpus praecox, 0.04 and 0.03 for Acacia praecox, 0.04 and 0.06 for Schinopsis balansae in sunny and shadow microsites respectively. Shurbs litter was decomposed faster than the tree litter, and the shurbs litter nutrientes level was also higher. Therefore the rate of organic matter decomposition is more correlated with leaf characteristics than with environmental variables.

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