Inhibition of Orobanche crenata Seed Germination and Radicle Growth by Allelochemicals Identified in Cereals

Orobanche crenata is a parasitic weed that causes severe yield losses in important grain and forage legume crops. Cereals have been reported to inhibit O. crenata parasitism when grown intercropped with susceptible legumes, but the responsible metabolites have not been identified. A number of metabolites have been reported in cereals that have allelopathic properties against weeds, pests, and pathogens. We tested the effect of several allelochemicals identified in cereals on O. crenata seed germination and radicle development. We found that 2-benzoxazolinone, its derivative 6-chloroacetyl-2-benzoxazolinone, and scopoletin significantly inhibited O. crenata seed germination. Benzoxazolinones, l-tryptophan, and coumalic acid caused the stronger inhibition of radicle growth. Also, other metabolites reduced radicle length, this inhibition being dose-dependent. Only scopoletin caused cell necrotic-like darkening in the young radicles. Prospects for their application to parasitic weed management are discussed. © 2013 American Chemical Society.This research is supported by projects FP7-ARIMNet-MEDILEG and AGL2011-22524 (cofinanced by FEDER funds).Peer Reviewe

Application of Spirulina algae as a food supplementation in the zinc fortification of bread

Background: Zinc is the second only to iron among trace elements in the human body. Approximately 48 of the people worldwide suffer from the zinc deficiency disorders, such as hypogonadism, hypospermia, growth retardation, immune deficiencies. Routinely, the use of food supplementation in daily regiments is common. Use of sea foods as one of the richest source of supplementaries, persuade us to exploit it. Materials and Methods: Academic scientific databases (e.g. Scopus and Elsevier) were researched. Results: A green single-cell algae "Spirulina" is one of these sources. Nowadays this algae has its top position among other microalgae for the production and consumption by man. In addition, Spirulina has 8 essential amino acids and various vitamins (e.g. A,E,C,B1,B2,B6,B12,biotin) and minerals such as Fe, Ca, Mg, Zn. Furthermore this sea source has essential fatty acids such as Omega 6 and Omega 9. Presence of these compounds in Spirulina algae is its unique characteristic comparing to other supplements. Furthermore, this algae has various therapeutic benefits such as amplifying an immunity system, excretion of heavy metals, aiding the food digestion, ulcer repair, improving vision. Conclusion: According to the food pyramid among the cereal products, we choose bread for this fortifying purpose. This bread was prepared in two colors. We inspected and examined this product under laboratorial assessment which proved our hypotheses

Predicting maize yield in a multiple species competition with Xanthium strumarium and Amaranthus retroflexus: Comparing of approaches to modeling herbicide performance

A modeling approach based on weed relative leaf area (RLA) was used to describe the maize yield affected by weed competition and herbicide dose. The change of early RLA with herbicide dose was described using standard dose-response model. The dose response of individual weed species was included in a multivariate rectangular hyperbolic relationship between maize yield and weed relative leaf-area. Final model satisfactorily described the change of the weed relative leaf areas with herbicide dose in a multiple species competition with maize to reach a reasonable estimate of crop yield. Parameter estimates indicated that the maize yield could be about 11.23 t/ha in the absence of weeds. Applying herbicide at 0.29 rate of the recommended dose could decrease the A maranthus retroflexus leaf area by 50%. For X anthium strumarium, increasing the dose up to 0.58 rate of the recommended dose caused 50% reduction in early relative leaf area. The relative leaf area of the X. strumarium was 4.2-fold larger than that of the A. retroflexus at the time of herbicide application. Model validation indicated significantly better predictive ability of the leaf area model than that of the density model. Leaf area model permits to monitor the canopy (with considering the relative ground cover of neighboring plants) and decide that if a competitive crop allows reducing the dose. Recommending the precise required amount of herbicide is achieved using models that account for the interactions among crop and weed species, which survive and persist in the competition after herbicide application. © 2012 Elsevier Ltd.Peer Reviewe

Interactions between reduced rate of imazethapyr and multiple weed species-soyabean interference in a semi-arid environment

Field experiments were conducted to evaluate Xanthium strumarium and Amaranthus retroflexus competitive ability with soyabean under unsprayed and sprayed (half the recommended rate of imazethapyr) conditions. Weed density combinations of 0, 4, 8 or 12plantsm -1 of row for A. retroflexus and 0, 2, 4 or 8plantsm -1 of row for X. strumarium were established alone, and in all possible combinations. When X. strumarium and A. retroflexus were grown at the same density, X. strumarium contributed 60-69% of the total weed biomass depending on weed density. The half rate of imazethapyr reduced the biomass of both weed species by 90% as compared with untreated plots. Untreated A. retroflexus and X. strumarium reduced soyabean yields to 1911kg and 1656kgha -1, respectively, while with the reduced rate of herbicide, the yield only decreased to 3612kg and 3453kg ha -1 respectively. The total weed density required to cause a 5% soyabean yield loss was 0.16 and 0.32plantsm -1 of row with no-herbicide treatment, while with the half rate of imazethapyr, it increased up to 2.78 and 4.32 plantsm -1 in 2007 and 2008 respectively. Owing to the higher competitive ability of X. strumarium, it should be given a greater priority for control than A. retroflexus in soyabean grown in a semi-arid environment. The half rate of herbicide significantly decreased the competitive ability of X. strumarium and A. retroflexus indicating that, in soyabean, application of this rate might be more cost-effective and more environment-friendly than the recommended ones. © 2012 The Authors. Weed Research © 2012 European Weed Research Society.Peer Reviewe