Plants that inhabit Antarctica have raised scientific interest due to their resilience to climate change, abiotic tolerance mechanisms and potential biological applications. In vitro propagation is useful for conservation, genetic material availability of these species and avoiding mass collection in their habitat. In vitro culture protocols for the native plants Colobanthus quitensis and Deschampsia antarctica and the non-native Juncus bufonius have been affected by endophytic microorganisms that proliferate when introduced to tissue cultures. This study evaluated the microbicidal and phytotoxic effect of calcium hypochlorite (ca(clo) 2), silver nitrate (AgNO 3) and silver nanoparticles (AgNPs), and their use at different concentrations for different time periods. The Ca(ClO) 2 at 100 mg mL −1 showed the best microbial contamination control in D. antarctica (applied for 20 min) and for the three C. quitensis populations (applied for 15 min). In J. bufonius, AgNO 3 at 10 mg mL −1 for 10 min reduced the microbial growth, but oxidative damage was generated. AgNPs did not prevent contamination or have adverse effects on tissues. Survival plantlets from each treatment, population or species were effectively introduced to the tissue culture and their propagation was successful. these results constitute a fundamental advance for the introduction, propagation and conservation of Antarctic species and their use in scientific research. Global loss of biodiversity has increased considerably in recent years, which has made implementing conservation strategies essential for preserving and propagating plant genetic resources in each geographical region 1-3. One method of conservation is through the use of germplasm banks, or facilities and centers created to conserve genetic resources under favorable conditions to prolong their survival; the final objective is the ex-situ conservation of specific genetic diversity. They are a source of material that enables many possibilities for a species of interest, from developing new cultivable varieties, biological technologies, or to establishing ecological restoration plans 4. The Antarctic continent is an extreme ecosystem due to its adverse environmental conditions. Its organisms are exposed to restricted availability of water and nutrients, very low temperatures, frequent freezing and thawing cycles, prolonged periods of darkness in the winter and exposure to high UV radiation levels during summer. These environmental characteristics are inhospitable to most organisms that live in temperate areas 5. In addition, the increase in human activity in the region, and the confirmation that Antarctica is one of the critical points of global warming, make it a continent of highest priority for the conservation and development of multinational and multidisciplinary scientific challenges 6,7. There are only two native flowering plants that have been able to colonize some ice-free areas in the Antarctic Peninsula: Deschampsia antarctica Desv. (Poaceae) and Colobanthus quitensis (Kunth.) Bartl....

Cocoa is one of the most significant assets in the ecuadorian agricultural structure, which also provides a good source of income for thousands of farmworker families. However, fertilization research works in cocoa cultivation have been relatively scarce. Decades of global research have shown that mycorrhizal fungi determine the fertilization and conservation of agrosystems. Fertilization is considered to be among the cultural and agricultural practices affecting mycorrhizas, which diminishes or prevents the fungal colonization. The objectives of research works were the following: the characterization of mycorrhiza species associated with cocoa, to determine the effects of nitrogen and phosphate fertilization in plant population and to identify the critical dose affecting the fungus development. A factorial design was used (AxBxC), with two (2) application systems, four (4) doses of nitrogen fertilizer, and two (2) doses of phosphate fertilizer with three repetitions. The turkey's test was used to evaluate means with confidence interval of 95%. The evaluated variables were: diameter and length of cocoa pods, number of cocoa pods per tree, index of cocoa beans and almond yield per hectare, as well as, mycorrhizal spore counting, percentage of mycorrhizal fungi colonization, visual density of endophyte, and characterization of mycorrhiza species. The results concluded that the application of 100 Kg/ha N + 70 kg/ha P in the system below the soil surface, achieved yield increments

Impacto de la inoculación con micorrizas y el riego en la sobrevivencia de It is grown mainly in Central Chile, where precipitations are predicted to drop in 40% and change in frequency in the future due to climate change. Rhizopogon luteolus is an ectomycorrhizae usually associated with Pinus species and has been found to increase drought tolerance. We addressed the effect of R. luteolus inoculation on survival and functional traits of P. radiata seedlings exposed to two watering treatments. These treatments simulated control (50 ml) and 40% reduced precipitations (20 ml). We also evaluated the combined effect of watering quantity (20 and 50 ml) and frequency (every 5, 10 and 30 days) on the same variables. R. luteolus inoculation increased seedling survival, but reduced plant size. Watering quantity affected plant survival only at intermediate watering frequencies, but not at the high and low frequencies. The lowest frequency, normal for the summer of Central Chile, resulted in ∼80% seedling mortality. Most of the functional traits measured were not affected neither by watering frequency nor quantity, but they were affected by mycorrhization. Mycorrhizae inoculation, together with some sort of artificial watering could be a possible strategy to cope with prolonged drought events. KEYWORDS:Pinus radiata, Rhizopogon luteolus, climate change, ectomycorrhizae, drought tolerance. RESUMENEn condiciones de sequía, las plantas aumentan la probabilidad de sobrevivir ajustando sus rasgos funcionales y por medio de asociaciones biológicas. Las asociaciones micorrícicas y el riego artificial aumentan la sobrevivencia en condiciones de sequía, especialmente en etapas tempranas del desarrollo, cuando las plantas son más sensibles. En Chile, Pinus radiata es la especie forestal más importante. Se planta principalmente en Chile central, donde se predice que las precipitaciones disminuirán en un 40% y cambiará su frecuencia en el futuro debido al cambio climático. Rhizopogon luteolus es una ectomicorriza usualmente asociada a especies de Pinus y se ha encontrado que aumenta la tolerancia a la sequía. Se analizó el efecto de la inoculación de R. luteolus en la sobrevivencia y rasgos funcionales de plántulas de P. radiata expuestas a dos tratamientos de riego. Estos tratamientos simulan precipitaciones control (50 ml) y reducidas a un 40% (20 ml). También se evaluó el efecto combinado de la cantidad (20 y 50 ml) y frecuencia (cada 5, 10 y 30 días) de riego en las mismas variables. La inoculación con R. luteolus aumentó la sobrevivencia pero redujo el tamaño de las plántulas. La cantidad de riego afectó la sobrevivencia de las plantas sólo en la frecuencia intermedia de riego, pero no en las frecuencias alta y baja. La frecuencia más baja, normal para el verano de Chile central, resultó en ∼80% de mortalidad de plántulas. La mayoría de los rasgos funcionales no fueron afectados por la frecuencia o cantidad de riego, pero si por la micorrización. La inoculación ISSN 0016-5301 Gayana Bot. 69(2): [296][297][298][299][300][301][302...

In Chilean temperate forest, the fern Blechnum chilense has a wide ecological breath, but occur mainly in full sun habitats, while Blechnum mochaenum is restricted only to shady sites. We evaluated if the species with different ecological breath behave similarly in their anatomical and physiological traits. Maximal photosynthetic rate (Amax), Stomatal conductance (g s ), evapotranspiration (E), and SLA (specific leaf area) were measured in situ in 20 individuals of each fern species. Additionally, we estimated the stomatal density (SD), stomatal index (SI), and stomatal size in leaves of each sampled individual. B. mochaenum, the shade-tolerant species, had lower SD, SI, A, and E, and higher stomatal size and SLA than B. chilense. Higher stomatal frequency could result in greater gas exchange in open sites for B. chilense. The leaf physiology of these fern species seems to depend partially on their stomatal traits. KEYWORDS:Blechnum, stomatal density, stomatal index, stomatal size, gas exchange, evergreen temperate forest. RESUMENEn el bosque templado de Chile, el helecho Blechnum chilense se encuentra principalmente en lugares abiertos y soleados, mientras que el helecho Blechnum mochaenum está restringido a lugares sombríos. En este estudio se evalúa si ambas especies de Blechnum, de lugares abiertos y sombreados, se comportan de manera similar respecto de sus rasgos anatómicos y fisiológicos, y si existe diferencia en la correlación entre estos rasgos. Se midió la tasa fotosintética máxima (Amax), conductancia estomática (g s ), evapotranspiración (E) y SLA (área foliar específica) in situ en 20 individuos de cada especie de helecho. Adicionalmente, se estimó la densidad estomática (SD), el índice estomático (SI) y el tamaño de los estomas en hojas de cada individuo muestreado. Blechnum mochaenum, la especies sombra-tolerante, presentó menor SD, SI, Amax y E, y mayor tamaño de estomas y SLA que B. chilense. Una frecuencia estomática mayor podría resultar en una mayor tasa de intercambio de gases en los sitios abiertos para B. chilense. La fisiología de las hojas de estas especies de helechos parece depender, en parte, de las características estomáticas. PALABRAS CLAVE:Blechnum, densidad estomática, índice estomático, tamaño de estomas, intercambio de gases, bosque templado siempreverde.

The research was carried out on the Property “El Cartan” that is located in Km 4 way at Puebloviejo-Ventanas, county of Los Ríos. A test was conducted on the hybrid corn DK-1040. This test measures the response of the larvae of insects Spodoptera frugiperda and Elasmopalpus lignosellus to the application of dose of biological and organic insecticides. Also, the most appropriate dose in products was determined with an economic analysis. The experimental design used was random complete blocks with seven treatments and three replicates. The variables evaluated are: percentage of larvae control, number of larvae per plant, corn damage, and yield for hectare. The evaluated variables were subjected to the analysis of variance, and Tukey test was applied to 95 % probability. The analyzed results were determined to apply Neem (Azadirachtina indica) in dose of 1,0 L ha -1 . It diminishes the populations of S. frugiperda and E. lignosellus in relationship to the other active matters applied in the test. Higher doses lead to migration of pests to nearby hosts. The highest yield per hectare was found in the Neem 1.0 L ha-1 treatment with 8,940 kg ha-1.