Abstract Yerba mate (Ilex paraguariensis St. Hil.) is a species native to the subtropical regions of South America. Despite being an important crop for the region, there are few studies on the use of microorganisms to improve the growth of seedlings in the nursery stage. The objective of this study was to isolate spore-forming endophytic bacteria with plant growth promoting properties associated with yerba mate seedlings and determine their phytobeneficial effect under controlled laboratory conditions. Isolates were selected based on their sporulation capacity and evaluated for in vitro plant growth promoting properties (nitrogen fixation, phosphate solubilization, production of siderophores and synthesis of indolic compounds). Yerba mate seedlings were inoculated with the most promising isolates, which were identified via analyses of the sequence of their 16S rDNA gene as Bacillus circulans (12RS3) and Bacillus altitudinis (19RS3, T5S-T4). After 120 days plants showed higher root dry weight when inoculated with isolate 19RS3 and higher shoot dry weight with 19RS3 and T5S-T4. In conclusion, further studies to determine the ability of these isolates to adapt to the climatic conditions and to survive amidst the native soil microflora in yerba mate cultivated native soils, will be crucial for developing such strains as biofertilizer.

Aspidosperma polyneuron is a climax species of the rainforest tropical forest that has been intensively exploited causing its population decline in the province of Misiones. their reduction in populations of Misiones. To preserve conserve it in gene banks, the behavior and longevity of ultra-dried seeds were studied. The seeds were dehydrated to 3% of moisture content and stored in airtight containers at 8 ± 2 °C. Viability and vigor were measured through germination percentage, and vigor, through mean germination time and germination rate index, at 0, 7, 20, 48 and 60 months of age using the variables germination rate, mean germination time and germination speed index.. Seeds of A. polyneuron behaved as orthodox, preserving its viability and vigor for 60 months when they were subjected to ultra-dry method. This method could solve the shortage of seeds during the long periods between production seasons. The first germination showed no significant difference while the other two presented some deterioration caused by storage. Results indicate that it is possible to extend the longevity of A. polyneuron seeds for long periods solving the shortage of seeds between production seasons.

Aspidosperma polyneuron es una especie climax del bosque tropical que ha sido intensamente explotada provocando su reduccion en las poblaciones de Misiones. Para conservarla en bancos de germoplasma, se estudio el comportamiento y la longevidad de las semillas frente al ultra-secado. Como mostraron comportamiento ortodoxo frente a la deshidratacion, se ultra-desecaron hasta 3% de humedad y se almacenaron en envases hermeticos a 8 ± 2 °C. En estas condiciones se midieron la viabilidad y el vigor a los 0, 7, 20, 48 y 60 meses mediante las variables: porcentaje de germinacion, tiempo medio de germinacion e indice de velocidad de germinacion. La primera de ellas no mostro diferencias significativas mientras que las otras dos, detectaron cierto deterioro causado por el almacenamiento. Estos resultados indican que es posible prolongar la longevidad de las semillas de A. polyneuron durante largos periodos solucionando el faltante de semillas entre temporadas de produccion.