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  • Vermicompost and water stress effects on dry beans (Phaseolus vulgaris L.): productive parameters and water relations
  • Abstract It is documented that vermicompost increases germination and productivity of crops, but little is known of its effect on plant physiological responses under soil water deficit. The aim of this study was to analyze the effect of vermicompost and irrigation interruption on stomatal conductance, gas exchange, and yield of common bean cultivars (drought tolerant -cv. 92 and drought susceptible-cv. 122). Plants were cultivated in unamended soil or soil amended with 1.5 and 3% of vermicompost, with irrigation during the whole cycle but irrigation interruption at the flowering stage. Changes in soil moisture, stomatal conductance (gs), transpiration (E), CO2 assimilation (A),…
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  • Chitinase, chitosanase, and antifungal activities from thermophilic streptomycetes isolated from compost
  • Abstract The Streptomyces genus comprises a large and diverse group of bacteria, many of which are commercially exploited for the production of antibiotics and lytic enzymes. The thermophilic species are less studied than the predominant mesophilic species. However, the first ones are a potential source of thermostable bioactive products and enzymes with novel properties. In this study, two selected thermophilic streptomycetes were identified and their chitinolytic activities were evaluated. The identification of these two isolates was performed by microscopic morphology, partial 16S rDNA sequences, and its phylogenetic analysis. To study the chitinolytic activities of these isolates, the effects of colloidal chitin…
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  • In vitro antagonism of Trichoderma harzianum on Sclerotium cepivorum Berk. and S. rolfsii Sacc., causal agents of onion rot
  • Abstract In vitro tests were carried out, to evaluate the antagonist capacity of a strain of Trichoderma isolated from soil in La Cienega de Chapala, Michoacán, Mexico against Sclerotium cepivorum and Sclerotium rolfsii, casual agents of onion rot, an important disease in Mexico and the rest of the world. Percentages of radial growth inhibition (PRGI) were calculated every 24 h, until a rate of antagonism was obtained according to the Bell’s scale, as well as the percentages of inhibition of the production of sclerotia and their parasitism. The PRGI was 17.4% against S. rolfsii and 22.2% against S. cepivorum after 48…
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  • Experimental evidence of soil bacteria abundance as the primary driver of rhizosphere priming effect
  • Abstract Soil microbial communities are thought to be responsible for the rhizosphere priming effect (RPE). However, because soil microbial communities are comprised of diverse components, very little is known about which component plays the critical role. In this study, soybean and cottonwood were grown at two latitudinal locations with different temperature and light conditions in-situ. We quantified RPE using a natural δ13C method, and measured the abundance, richness and composition of bacteria and fungi communities with DNA-based molecular methods. Among all potential variables, including the three aforementioned indexes of bacteria and fungi communities and soil physicochemical and plant indexes, bacterial abundance…
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  • Application of the random forest algorithm for predicting the persistence of seed banks in the Horqin Sandy Land, China
  • Abstract Persistent seed banks have been detected in the Horqin Sandy Land, China using experimental methods. In this study, we used seed traits (i.e. seed mass and seed shape) to predict the persistence of seed banks using the random forest algorithm. The results showed that the mean decrease in accuracy for seed mass and seed shape was 18.26 and 9.90, respectively, suggesting that seed mass was a better predictor than seed shape. With increasing seed mass, the log of P (where P is the ratio of the number of votes selecting existence of a persistent seed bank to the number of…
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  • Microbial inoculation of Parkinsonia praecox (Ruiz & Pav. ex Hook.) Hawkins for ecological restoration
  • Abstract The use of microbial inocula for the restoration of severely degraded arid environments is of great interest. This is because there is a presumption that growth-favoring microorganisms can facilitate the establishment of seedlings by increasing their ability to withstand both the stress of transplantation in the case of nursery seedlings, and the extreme conditions for natural establishment imposed by the scarce, random and variable rainfall. In this work we analyze the “slenderness index”- the height of the plant divided by its diameter at the height cotyledon node- to analyze the effect of treatments with microorganisms in the nursery. This variable…
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  • Germination of Oenothera odorata, endemic ruderal Onagraceae from Argentina
  • Abstract The Onagraceae are a well-defined family of flowering plants much used by man. Many representatives of this group, which contains 75 species belonging to 8 genera, are indigenous to Argentina, and 19% of these are commonly found throughout the country. Many Onagraceae are ruderal and promote the subsequent establishment of other species, thus contributing to the restoration of degraded areas. Since it is important to know the characteristics of seeds to be used in restoration projects, we studied the basic germination physiology of Oenothera odorata Jacq., a ruderal plant indigenous to Argentina. Material was collected from roadsides and embankments along…
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  • Pre-germination treatments on Senna arnottiana and Senna kurtzii: key contributions for restoration initiatives in Payunia, Patagonia, Argentina
  • Abstract In arid and semi-arid ecosystems, increasing and irreversible degradation in areas of high conservation value has prompted the search for various solutions, such as rehabilitation and ecological restoration. To implement these strategies, it is essential to solve critical issues affecting the establishment of plants in the field and the production of seedlings in nursery gardens. In the present work, the following pre-germination treatments were evaluated for the species Senna arnottiana and S. kurtzii, endemic to the Patagonian steppe (Payunia): (1) Immersion in water at 80 °C for 5 minutes; (2) Immersion in water at 80 °C for 10 minutes; (3)…
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  • Does seed aggrupation and substrate type affect the germination on three native species of Durango, Mexico?
  • Abstract The chemical and physical properties of the substrate produce positive or negative effects on the germination of seeds, and different pre-germination treatments are applied to obtain better results. However, the use of soil as a substrate where the species grows is usually not evaluated or used as a treatment. The objective of the present study was to evaluate the effect of the native substrate [two types of substrate where the woody species grow (clay and sand)] on the germination of Acacia farnesiana, Larrea tridentata and Prosopis laevigata. In addition, two groups were compared in seeds (grouped and not grouped) of…
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  • Regrowth, yield and nutrition of Leymus chinensis and Hordeum brevisubulatum in response to defoliation intensity and frequency
  • Abstract The effects of different defoliation intensities and frequencies were studied on regrowth and herbage mass of Leymus chinensis and Hordeum brevisubulatum in northeast China for two years. Plants were defoliated to 6, 8 or 10 cm stubble height by removing about 40% of growth down to each designated defoliation height. In the first year, L. chinensis was defoliated 22, 17 or 13 times, and in the second year was defoliated 21, 15 or 15 times to reach 6, 8 or 10 cm stubble height treatments, respectively. H. brevisubulatum was defoliated 26, 21 or 15 times in the first year, and…
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