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Authors = Valdir Marcos Stefenon

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7 pages, 823 KiB  
Communication
Pecan Propagation: Seed Mass as a Reliable Tool for Seed Selection
by Tales Poletto, Valdir Marcos Stefenon, Igor Poletto and Marlove Fátima Brião Muniz
Horticulturae 2018, 4(3), 26; https://doi.org/10.3390/horticulturae4030026 - 11 Sep 2018
Cited by 4 | Viewed by 4589
Abstract
Pecan is one of the most important horticultural nut crops in the world. It is a deciduous species native to the temperate zones of North America, introduced into the subtropical regions of Brazil during the 1870s. High quality seedlings are essential to establishing [...] Read more.
Pecan is one of the most important horticultural nut crops in the world. It is a deciduous species native to the temperate zones of North America, introduced into the subtropical regions of Brazil during the 1870s. High quality seedlings are essential to establishing healthy and productive orchards, and selection of seeds is an important factor in this issue. In this study we evaluated the correlation between seed mass, emergence rate and morphometric traits of seedlings in the pecan cultivar Importada. A significant positive correlation (r > 0.81) between seed mass and plantlet height, stem diameter, emergence rate and number of leaves was observed. Our results suggest that seed mass can be used as a direct method for seed selection towards production of vigorous pecan seedlings. However, since an increase in seed mass is usually associated with a decrease in the number of seeds that a plant can produce per unit canopy, long-duration studies are recommended in order to evaluate the influence of seed selection on a plantation’s production. Full article
(This article belongs to the Special Issue Innovation in Propagation of Fruit, Vegetable and Ornamental Plants)
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10 pages, 758 KiB  
Article
Characterization of Plastidial and Nuclear SSR Markers for Understanding Invasion Histories and Genetic Diversity of Schinus molle L.
by Rafael Plá Matielo Lemos, Cristiane Barbosa D’Oliveira Matielo, Dalvan Carlos Beise, Vanessa Gonçalves Da Rosa, Deise Schröder Sarzi, Luiz Fernando Würdig Roesch and Valdir Marcos Stefenon
Biology 2018, 7(3), 43; https://doi.org/10.3390/biology7030043 - 10 Aug 2018
Cited by 7 | Viewed by 5004
Abstract
Invasive plant species are expected to display high dispersal capacity but low levels of genetic diversity due to the founder effect occurring at each invasion episode. Understanding the history of invasions and the levels of genetic diversity of such species is an important [...] Read more.
Invasive plant species are expected to display high dispersal capacity but low levels of genetic diversity due to the founder effect occurring at each invasion episode. Understanding the history of invasions and the levels of genetic diversity of such species is an important task for planning management and monitoring strategy for these events. Peruvian Peppertree (Schinus molle L.) is a pioneer tree species native from South America which was introduced in North America, Europe and Africa, becoming a threat to these non-native habitats. In this study, we report the discovery and characterization of 17 plastidial (ptSSR) and seven nuclear (nSSR) markers for S. molle based on low-coverage whole-genome sequencing data acquired through next-generation sequencing. The markers were tested in 56 individuals from two natural populations sampled in the Brazilian Caatinga and Pampa biomes. All loci are moderately to highly polymorphic and revealed to be suitable for genetic monitoring of new invasions, for understanding the history of old invasions, as well as for genetic studies of native populations in their natural occurrence range and of orchards established with commercial purposes. Full article
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4 pages, 160 KiB  
Article
In Vitro Growth and Indoleacetic Acid Production by Mesorhizobium loti SEMIA806 and SEMIA816 under the Influence of Copper Ions
by Jéssica Dutra Vieira, Paulo Roberto Diniz da Silva and Valdir Marcos Stefenon
Microbiol. Res. 2017, 8(2), 7302; https://doi.org/10.4081/mr.2017.7302 - 22 Nov 2017
Cited by 3 | Viewed by 578
Abstract
The indoleacetic acid produced by symbiotic bacteria is an important phytohormone signaling microbe-plant interaction, being therefore essential for rhizoremediation. In this study, the effect of different concentrations of copper ions on the bacterial growth and indoleacetic acid production was investigated in two strains [...] Read more.
The indoleacetic acid produced by symbiotic bacteria is an important phytohormone signaling microbe-plant interaction, being therefore essential for rhizoremediation. In this study, the effect of different concentrations of copper ions on the bacterial growth and indoleacetic acid production was investigated in two strains of Mesorhizobium loti in in vitro conditions, aiming to determine critical concentrations of this heavy metal for rhizoremediation of contaminated soils using this bacterium. The experiment consisted on a control culture without copper and three treatments supplemented with 10 mg.L-1, 20 mg.L-1 or 50 mg.L-1 of CuSO4. For both strains, the growth stopped after 48h and no significant difference was observed across treatments. The production of indoleacetic acid by the control treatment without copper was significantly higher in comparison to the copper- containing treatments. Mesorhizobium loti SEMIA806 and SEMIA816 are resistant to up to 50 mg.L-1 of CuSO4 in the culture medium, presenting effective growth. The synthesis of indoleacetic acid was strongly reduced but not excluded by ions copper in the medium. So, it is expected that environmental copper found in the soil up to the concentration of 50 mg.L-1 will not preclude the symbiotic interaction between M. loti and leguminous host plant in rhizoremediation enterprises. Full article
17 pages, 517 KiB  
Review
The Brazilian Pampa: A Fragile Biome
by Luiz Fernando Wurdig Roesch, Frederico Costa Beber Vieira, Vilmar Alves Pereira, Adriano Luis Schünemann, Italo Filippi Teixeira, Ana Julia Teixeira Senna and Valdir Marcos Stefenon
Diversity 2009, 1(2), 182-198; https://doi.org/10.3390/d1020182 - 21 Dec 2009
Cited by 198 | Viewed by 26429
Abstract
Biodiversity is one of the most fundamental properties of Nature. It underpins the stability of ecosystems, provides vast bioresources for economic use, and has important cultural significance for many people. The Pampa biome, located in the southernmost state of Brazil, Rio Grande do [...] Read more.
Biodiversity is one of the most fundamental properties of Nature. It underpins the stability of ecosystems, provides vast bioresources for economic use, and has important cultural significance for many people. The Pampa biome, located in the southernmost state of Brazil, Rio Grande do Sul, illustrates the direct and indirect interdependence of humans and biodiversity. The Brazilian Pampa lies within the South Temperate Zone where grasslands scattered with shrubs and trees are the dominant vegetation. The soil, originating from sedimentary rocks, often has an extremely sandy texture that makes them fragile—highly prone to water and wind erosion. Human activities have converted or degraded many areas of this biome. In this review we discuss our state-of-the-art knowledge of the diversity and the major biological features of this regions and the cultural factors that have shaped it. Our aim is to contribute toward a better understanding of the current status of this special biome and to describe how the interaction between human activities and environment affects the region, highlighting the fragility of the Brazilian Pampa. Full article
(This article belongs to the Special Issue Biodiversity Feature Papers)
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