Lorenza Costa

La Selva Paranaense destaca por su biodiversidad y los frutales nativos representan un grupo relevante porque son un elemento fundamental de los procesos de restauración ecológica y catalizan la rehabilitación de las funciones ecológicas de dispersión, refugio y alimentación. Recientemente, en el marco de proyectos de fomento del uso sustentable del bosque nativo, los frutales nativos de la familia Myrtaceae han sido centrales para favorecer acciones tendientes al desarrollo territorial del noreste de Argentina. En este sentido, el conocimiento ecofisiológico resulta escaso a pesar de ser crucial para poder desarrollar propuestas técnicas para el aprovechamiento en bosque nativo y cultivo fuera del bosque. En esta revisión sistematizamos la información disponible sobre los requerimientos y estrategias de manejo. Destacamos la oportunidad de plantar frutales nativos en cultivos de yerba mate, sistemas típicos de la región, para diversificar los monocultivos. En conclusión, los frutales nativos son una oportunidad para la reconexión cultural a través de la producción de cultivos con identidad territorial y novedosos para otras localidades, que deberán generar impacto ambiental, social y económico positivo en sus sitios de origen.

Productive systems management and forest conservation require innovation to produce sustainably. Non-timber forest products, especially native fruit trees, are promising platforms for rural economic development. Nevertheless, the limited and recent domestication of these species requires a considerable investment of time and effort until scientific knowledge is effectively translated into cultivation practices. Our objective was to propose strategies for use, crop diversification and postharvest management for the domestication of two Atlantic Forest native fruit trees: Campomanesia xanthocarpa, guavirá, and Campomanesia guazumifolia, siete capotes. For this purpose, we studied the composition and natural regeneration of these species in the native forest to assess the impact of harvest from wild trees; the establishment in different growing conditions, to define cultivation practices; the postharvest behavior of the fruits, and conservation strategy to extend the postharvest life. C. xanthocarpa and C. guazumifolia are very rare in the native forest and natural populations may have different composition depending on the site. The establishment of guavirá is successful under low canopy coverage, while siete capotes is sensitive to interspecific competition and thermical- and light-stress, so the best planting site was in minimally managed yerba mate plantations. The C. xanthocarpa fruits can be harvested at physiological maturity depending on the surface color. In the case of C. guazumifolia, maturity can be determined by the firmness of the fruit. For both species, refrigeration can extend the postharvest life. It is feasible to domesticate both species and extend the postharvest life of their fruits.

Background Kale is a leafy vegetable rich in phytochemicals that promote health. After harvest, leaf senescence is induced, and kale turns yellow due to the degradation of chlorophyll. Previous studies have shown that low-intensity red light pulses delay postharvest senescence in kale. This effect may be mediated by phytochromes activated by red light. The effect of low-intensity red-light LED treatment on the expression of genes involved in chlorophyll degradation (NYC1, NOL, SGR, PPH, and PAO) and genes encoding senescence-associated transcription factors related to the phytochrome signaling cascade (PIF4, ORE1, and WRKY6) was examined in this work. Methods and results Kale leaves were treated daily with red-light-LED (22 ± 3 µmol m⁻² s⁻¹) for 1 h and then were stored in the dark together with untreated leaves. Samples were taken during storage to perform biochemical and gene analysis. A close correlation was found between chlorophyll degradation and the gene expression of NYC1, SGR, and PAO in control leaves. Red light treatment caused a strong inhibition of these gene expressions, which explains the retention of chlorophylls. PIF4 and WRKY6 were not upregulated at the expression level in the dark, while red light induced that expression only for a short time. ORE1 expression increased in darkness and was inhibited by red treatment. Conclusion Red light treatment preserved chlorophyll by the strong inhibition of NYC1, SGR, and PAO expression in irradiated leaves. The expression of ORE1 increased in darkness and was inhibited by red treatment, as was expected in the red light-activated phytochrome signaling cascade. Graphical abstract

En este trabajo se presentan los estudios de una muestra de macrorrestos vegetales del sitio alero Los Cipreses, en el norte del Lago Traful, Neuquén. Se estudiaron hojas, escamas ovulíferas, conos-semillas, semillas, frutos, leños y órganos subterráneos en diferentes estados de conservación. Se comparó el registro arqueobotánico con la colección de referencia y se observaron caracteres diagnósticos bajo lupa binocular. Se realizaron cortes diagnósticos delgados para la identificación de las maderas y su observación a través de microscopio óptico. Además, se realizó un estudio químico de extracción de antocianinas sobre los leños desecados que presentaban coloración rojiza. Entre los taxa identificados se encuentran Maytenus sp., cf. Maytenus boaria, cf. Podocarpaceae, Podocarpus nubigenus, Nothofagus dombeyi, Austrocedrus chilensis. Estos resultados contribuyen a comprender las prácticas de recolección en el bosque andino patagónico por parte de las sociedades cazadoras recolectoras. Los mismos son relevantes debido a su difícil preservación en este tipo de ambiente. Este registro sugiere el uso, al menos, estival del sitio Alero Los Cipreses, y un rango de movilidad local para la recolección de las plantas.

Chlorophyll (Chl) loss is the main visible symptom of senescence in leaves. The initial steps of Chl degradation operate within the chloroplast, but the observation that “senescence‐associated vacuoles” (SAVs) contain Chl raises the question whether SAVs might also contribute to Chl breakdown. Previous confocal microscope observations (Martínez et al. 2008) showed many SAVs containing Chl. Isolated SAVs contained Chl a and b (with a Chl a/b ratio close to 5) and smaller amounts of chlorophyllide a. Pheophytin a and Pheophorbide a were formed after incubation of SAVs at 30°C in darkness, suggesting the presence of Chl‐degrading activities in SAVs. Chl in SAVs was bound to a number of “green bands”. In the most‐abundant green band of SAVs, Western blot analysis showed the presence of PSI Chl‐binding proteins, including the PsaA protein of PSI reaction center and the apoproteins of light‐harvesting complexes (Lhca 1‐4). This was confirmed by ‐1 measurements of 77K fluorescence emission spectra showing a single emission peak at around 730 nm in SAVs, ‐2 mass spectrometry of the most prominent green band with the slowest electrophoretic mobility, and ‐3 immunofluorescence detection of PsaA in SAVs observed through confocal microscopy. Incubation of SAVs at 30°C in darkness caused a steady decrease in PsaA levels. Overall, these results indicate that SAVs may be involved in the degradation of PSI proteins and their associated chlorophylls during senescence of leaves.