A meta-analysis of hairy vetch as a previous cover crop for maize.

Background: The use of hairy vetch (Vicia villosa Roth.) as cover crop is increasing worldwide. Hairy vetch can contribute as a nitrogen (N) source with potential to impact subsequent high N demanding cereals such as maize (Zea mays L.). Contrasting literature results emphasize the need for a global synthesis analysis to quantify changes in maize yield after hairy vetch. Objectives: A meta-analysis was conducted to i) quantify maize yield response to hairy vetch as previous crop, ii) explore hairy vetch influence on fertilized and non-N fertilized maize yields, and iii) assess the tillage and environment factors on maize yield response to hairy vetch. Methods: The global systematic search yielded 23 publications selected by the following criteria, i) hairy vetch dry matter at the end of the season, ii) maize grain yield, and iii) experimental design with (Mzhv) and without (Mzcontrol) hairy vetch treatments. Information such as N fertilization for maize, N accumulation in hairy vetch, organic matter, and tillage before maize sowing were recorded. Hairy vetch effects (effect size) were expressed as a ratio (percentage of grain yield variation in Mzhv/Mzcontrol). Results: Under non-N fertilization (n = 9), results revealed hairy vetch had mostly a positive effect, ranging from 13 to 45% (n = 6). In contrast, N-fertilized maize (n = 20) showed a high chance of neutral effects (n = 12), moderate probability of positive yield impact (7 to 38%, n = 6), and a low likelihood of negative effects (-32 and -17%, n = 2). Notably, maize yields improved by 21-25% when the N accumulation in hairy vetch ranged from 95 to 150 kg ha-1 and N rate from 0 to 120 kg ha-1. Non-N-fertilized maize exhibited a 14% increase in response in no-till systems and a 31% increase with conventional tillage. Conclusion: This study summarizes potential benefits of hairy vetch preceding maize. Yet, the heterogeneous outcomes deserve further exploration in terms of environment and management factors.

Perls/DAB Staining to Examine Iron Distribution in Arabidopsis Embryos.

Iron is accumulated in Arabidopsis embryos during seed maturation. Where iron localizes in seed and embryo is important information for seed research. Iron detection can be performed in an inexpensive manner using Perls staining, based on the Prussian blue complex formation. After this first step, DAB intensification can be performed in order to visualize easily where iron pools are located in isolated embryos.

Growth Developmental Defects of Mitochondrial Iron Transporter 1 and 2 Mutants in Arabidopsis in Iron Sufficient Conditions.

Iron is the most abundant micronutrient in plant mitochondria, and it has a crucial role in biochemical reactions involving electron transfer. It has been described in Oryza sativa that Mitochondrial Iron Transporter (MIT) is an essential gene and that knockdown mutant rice plants have a decreased amount of iron in their mitochondria, strongly suggesting that OsMIT is involved in mitochondrial iron uptake. In Arabidopsis thaliana, two genes encode MIT homologues. In this study, we analyzed different AtMIT1 and AtMIT2 mutant alleles, and no phenotypic defects were observed in individual mutant plants grown in normal conditions, confirming that neither AtMIT1 nor AtMIT2 are individually essential. When we generated crosses between the Atmit1 and Atmit2 alleles, we were able to isolate homozygous double mutant plants. Interestingly, homozygous double mutant plants were obtained only when mutant alleles of Atmit2 with the T-DNA insertion in the intron region were used for crossings, and in these cases, a correctly spliced AtMIT2 mRNA was generated, although at a low level. Atmit1 Atmit2 double homozygous mutant plants, knockout for AtMIT1 and knockdown for AtMIT2, were grown and characterized in iron-sufficient conditions. Pleiotropic developmental defects were observed, including abnormal seeds, an increased number of cotyledons, a slow growth rate, pinoid stems, defects in flower structures, and reduced seed set. A RNA-Seq study was performed, and we could identify more than 760 genes differentially expressed in Atmit1 Atmit2. Our results show that Atmit1 Atmit2 double homozygous mutant plants misregulate genes involved in iron transport, coumarin metabolism, hormone metabolism, root development, and stress-related response. The phenotypes observed, such as pinoid stems and fused cotyledons, in Atmit1 Atmit2 double homozygous mutant plants may suggest defects in auxin homeostasis. Unexpectedly, we observed a possible phenomenon of T-DNA suppression in the next generation of Atmit1 Atmit2 double homozygous mutant plants, correlating with increased splicing of the AtMIT2 intron containing the T-DNA and the suppression of the phenotypes observed in the first generation of the double mutant plants. In these plants with a suppressed phenotype, no differences were observed in the oxygen consumption rate of isolated mitochondria; however, the molecular analysis of gene expression markers, AOX1a, UPOX, and MSM1, for mitochondrial and oxidative stress showed that these plants express a degree of mitochondrial perturbation. Finally, we could establish by a targeted proteomic analysis that a protein level of 30% of MIT2, in the absence of MIT1, is enough for normal plant growth under iron-sufficient conditions.

On the use of carbon blacks as potential low-cost adsorbents for the removal of non-steroidal anti-inflammatory drugs from river water.

The adsorption of two non-steroidal anti-inflammatory drugs (NSAIDs), namely naproxen and ketoprofen, has been studied. Low-cost carbonaceous materials such as carbon blacks have been used as the adsorbents. The influence of temperature (20-60 degrees C), pH (3-11), ionic strength (0.01-0.1M), textural properties of the adsorbents (S(BET) and pore volumes) and aqueous matrix on the adsorption process has been analyzed. The adsorption isotherms have been determined both in milli-Q aqueous solution and water from the Guadiana river. Ionic strength and pH exert a noticeable influence on the process. In general, the removal is favored at low values of temperature and pH. On the contrary, an increase of the ionic strength seems to favor the adsorption process. The use of more porous adsorbents results in a more effective removal of the pollutants. Finally, the use of natural river water results in a noticeable increase of the removal capacity of naproxen and, particularly, ketoprofen. The experimental results proved that, under the optimal operation conditions, up to 517mg/g of naproxen and 400mg/g of ketoprofen may be adsorbed, which demonstrates the promising potential of these adsorbents for the removal of the pharmaceuticals under study.

Removal of chlorophenols in aqueous solution by carbon black low-cost adsorbents. Equilibrium study and influence of operation conditions.

The adsorption process of chlorophenols (CPs) by low-cost adsorbents such as carbon blacks has been studied. The influence of different parameters such as temperature, pH, ionic strength and textural properties of the adsorbents on the adsorption process of pentachlorophenol has been analyzed. The adsorption process is exothermal and parameters such as pH and ionic strength exert a noticeable influence on the adsorption capacity of the solute. These parameters influence the adsorption capacity in an opposite manner. Thus an increase in pH seems to unfavor the adsorption process, whereas the adsorption capacity increases with increasing ionic strength. In order to analyze the influence of the number of chlorine atoms in the molecule of solute the adsorption process of different chlorophenols (i.e., 4-chlorophenol, 3,5-dichlorophenol, 2,4,6-trichlorophenol and 2,3,4,6-tetrachlorophenol) was analyzed. As the number of chlorine atoms (and thus the volume of the molecule) increases, the penetration of the solute through the porous texture of the adsorbent is difficult and, consequently, the adsorption capacity decreases.