Access to maize (zea mays) & its manipulation in hunter-gatherer contexts in central Argentina (c 3000-2500 bp)

2012 ◽  
Vol 2012 (4) ◽  
pp. 1-10 ◽  
Author(s):  
Sebastián Pastor ◽  
Laura López ◽  
Diego Rivero
Keyword(s):  
Zea Mays ◽  
Central Argentina

Weed Communities in Semiarid Rainfed Croplands of Central Argentina: Comparison between Corn (Zea mays) and Soybean (Glycine max) Crops

Weed Science ◽  
2018 ◽  
Vol 66 (3) ◽  
pp. 368-378 ◽  
Author(s):  
Ruth B. Rauber ◽  
Manuel R. Demaría ◽  
Esteban G. Jobbágy ◽  
Daniel N. Arroyo ◽  
Santiago L. Poggio
Keyword(s):  
Zea Mays ◽  
Glycine Max ◽  
Native Species ◽  
Linear Models ◽  
Floristic Composition ◽  
Central Argentina ◽  
Weed Communities ◽  
Agronomic Management ◽  
Starting Point ◽  
Original Vegetation

AbstractThe semiarid Espinal in central Argentina, being recently transformed from natural semiarid grasslands into agriculture, represents an interesting scenario to understand the early stages of weed community assembly and its relationship with crop identity and management. Our aim was to characterize the weed communities in corn (Zea maysL.) and soybean [Glycine max(L.) Merr.], the main crops of the Espinal region, under the dominant rainfed conditions. Weed surveys were carried out in 53 fields, and farmers were interviewed to collect information about crop management. Floristic composition was compared within and between crops by calculating the additive partition of the abundance-based Bray-Curtis dissimilarity. We compared the frequency and mean cover of functional groups between crops through generalized linear models. Finally, canonical correspondence analysis was carried out to analyze the associations between floristic composition and agronomic variables. Mean alpha and gamma diversity was greater in corn (10.0 and 80 species, respectively) than in soybean (7.6 and 46 species, respectively). Furthermore, species composition of weed communities was more similar among soybean fields than among either cornfields or fields of both crops. Hence, floristic differences between crops are potentially the result of different microenvironmental heterogeneity above- and belowground, with corn likely to be more permissive to weed establishment compared with soybean. The higher frequency of annual, dicotyledonous, and native species, and the high proportion of rare species, mostly native, suggest a strong legacy of the original vegetation that thrived in these recently cultivated systems. The functional composition was also affected by agronomic management, with sulfur, nitrogen, and grass herbicide application being the most important factors related to the floristic composition of weed communities. This early description can be used as a starting point for studies concerning trajectories, mechanisms, and processes of weed communities related to environment and management.

Ultrastructure of Plant Leaf Tissue Infected with Mite-Borne Viral-Like Pathogens

1970 ◽  
Vol 28 ◽  
pp. 178-179 ◽  
Author(s):  
O. E. Bradfute ◽  
R. E. Whitmoyer ◽  
L. R. Nault
Keyword(s):  
Triticum Aestivum ◽  
Zea Mays ◽  
Electron Microscope ◽  
Hordeum Vulgare ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Leaf Tissue ◽  
Leaf Ultrastructure ◽  
Double Membrane ◽  
Aceria Tulipae

A pathogen transmitted by the eriophyid mite, Aceria tulipae, infects a number of Gramineae producing symptoms similar to wheat spot mosaic virus (1). An electron microscope study of leaf ultrastructure from systemically infected Zea mays, Hordeum vulgare, and Triticum aestivum showed the presence of ovoid, double membrane bodies (0.1 - 0.2 microns) in the cytoplasm of parenchyma, phloem and epidermis cells (Fig. 1 ).

Identification of maize mosaic virus by immunoelectron microscopy

1986 ◽  
Vol 44 ◽  
pp. 240-241
Author(s):  
O. E. Bradfute
Keyword(s):  
Zea Mays ◽  
Mosaic Virus ◽  
Immunoelectron Microscopy ◽  
Severe Disease ◽  
Maize Mosaic Virus ◽  
The World ◽  
Plant Rhabdovirus

Maize mosaic virus (MMV) causes a severe disease of Zea mays in many tropical and subtropical regions of the world, including the southern U.S. (1-3). Fig. 1 shows internal cross striations of helical nucleoprotein and bounding membrane with surface projections typical of many plant rhabdovirus particles including MMV (3). Immunoelectron microscopy (IEM) was investigated as a method for identifying MMV. Antiserum to MMV was supplied by Ramon Lastra (Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela).

Identification of Maize Rayado Fino Virus by Immunoelectron Microscopy

1985 ◽  
Vol 43 ◽  
pp. 636-637
Author(s):  
O. E. Bradfute
Keyword(s):  
Electron Microscopy ◽  
Zea Mays ◽  
Costa Rica ◽  
Severe Disease ◽  
Rabbit Serum ◽  
Normal Rabbit Serum ◽  
Virus Particles ◽  
Far North ◽  
Maize Rayado Fino Virus ◽  
Antibody Coating

Maize rayado fino virus (MRFV) causes a severe disease of corn (Zea mays) in many locations throughout the neotropics and as far north as southern U.S. MRFV particles detected by direct electron microscopy of negatively stained sap from infected leaves are not necessarily distinguishable from many other small isometric viruses infecting plants (Fig. 1).Immunosorbent trapping of virus particles on antibody-coated grids and the antibody coating or decoration of trapped virus particles, was used to confirm the identification of MRFV. Antiserum to MRFV was supplied by R. Gamez (Centro de Investigacion en Biologia Celular y Molecular, Universidad de Costa Rica, Ciudad Universitaria, Costa Rica).Virus particles, appearing as a continuous lawn, were trapped on grids coated with MRFV antiserum (Fig. 2-4). In contrast, virus particles were infrequently found on grids not exposed to antiserum or grids coated with normal rabbit serum (similar to Fig. 1). In Fig. 3, the appearance of the virus particles (isometric morphology, 30 nm diameter, stain penetration of some particles, and morphological subunits in other particles) is characteristic of negatively stained MRFV particles. Decoration or coating of these particles with MRFV antiserum confirms their identification as MRFV (Fig. 4).

Carotenoid composition in Zea mays developed at sub-optimal temperature and different light intensities

1995 ◽  
Vol 95 (3) ◽  
pp. 409-414 ◽  
Author(s):  
Pierre Haldimann ◽  
Yvan Fracheboud ◽  
Peter Stamp
Keyword(s):  
Zea Mays ◽  
Optimal Temperature ◽  
Light Intensities ◽  
Carotenoid Composition
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