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1. Absence of Nanoparticle-Induced Drought Tolerance in Nutrient Sufficient Wheat Seedlings

   https://doi.org/10.1021/acs.est.1c00453  

   Potter, Matthew; Deakin, Justin; Cartwright, Anthony; Hortin, Joshua; Sparks, Dakota; Anderson, Anne J.; McLean, Joan E.; Jacobson, Astrid; Britt, David W. (May 2021, Environmental Science & Technology)

   null (Ed.)

   Strategies to reduce crop losses due to drought are needed as climate variability affects agricultural productivity. Wheat (Triticum aestivum var. Juniper) growth in a nutrient-sufficient, solid growth matrix containing varied doses of CuO, ZnO, and SiO2 nanoparticles (NPs) was used to evaluate NP mitigation of drought stress. NP amendments were at fertilizer levels, with maxima of 30 Cu, 20 Zn, and 200 Si (mg metal/kg matrix). Seeds of this drought-tolerant cultivar were inoculated with Pseudomonas chlororaphis O6 (PcO6) to provide a protective root microbiome. An 8 day drought imposed on 14 day-old wheat seedlings decreased shoot and root mass, shoot water content, and the quantum yield of photosystem II when compared to watered plants. PcO6 root colonization was not impaired by drought or NPs. A dose-dependent increase in the Cu, Zn, and Si from the NPs was observed from analysis of the rhizosphere solution, and this process was not affected by drought. Consequently, fertilizer concentrations of the NPs did not further improve drought tolerance in wheat seedlings under the growth conditions of adequate mineral nutrition and the presence of a beneficial microbiome. These findings suggest that potential NP benefits in promoting plant drought tolerance occur only under certain environmental conditions. 

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2. Enhanced toxicity of environmentally transformed ZnO nanoparticles relative to Zn ions in the epibenthic amphipod Hyalella azteca

   https://doi.org/10.1039/C8EN00755A  

   Poynton, Helen C.; Chen, Chun; Alexander, Shaun L.; Major, Kaley M.; Blalock, Bonnie J.; Unrine, Jason M. (January 2019, Environmental Science: Nano)

   After release into the aquatic environment, engineered nanomaterials (ENMs) undergo complex chemical and physical transformations that alter their environmental fate and toxicity to aquatic organisms. Hyalella azteca are sediment-dwelling amphipods predicted to have a high exposure level to ENMs and have previously shown to be highly sensitive to ZnO nanoparticles (NPs). To investigate the impacts of environmentally transformed ZnO NPs and determine the route of uptake for these particles, we exposed H. azteca to ZnSO 4 , ZnO NPs, and environmental aged ZnO NPs which resulted in three types of particles: 30 nm ZnO–Zn 3 (PO 4 ) 2 core–shell structures (p8-ZnO NPs), micron scale hopeite-like phase Zn 3 (PO 4 ) 2 ·4H 2 O (p6-ZnO NPs), and ZnS nano-clusters (s-ZnO NPs). Treatments included freshwater, saltwater (3 ppt), and the presence of sediment, with a final treatment where animals were contained within mesh baskets to prevent burrowing in the sediment. Dissolution was close to 100% for the pristine ZnO NPs and phosphate transformed NPs, while s-ZnO NPs resulted in only 20% dissolution in the water only exposures. In the freshwater exposure, the pristine and phosphate transformed ZnO NPs were more toxic (LC 50 values 0.11–0.18 mg L −1 ) than ZnSO 4 (LC 50 = 0.26 mg L −1 ) and the s-ZnO NPs (LC 50 = 0.29 mg L −1 ). Saltwater treatments reduced the toxicity of ZnSO 4 and all the ZnO NPs. In the presence of sediment, water column concentrations of Zn were reduced to 10% nominal concentrations and toxicity in the sediment with basket treatment was similarly reduced by a factor of 10. Toxicity was further reduced in the sediment only treatments where the sediments appeared to provide a refuge for H. azteca . In addition, particle specific differences in toxicity were less apparent in the presence of sediment. Bioaccumulation was similar across the different Zn exposures, but decreased with reduced toxicity in the saltwater and sediment treatments. Overall, the results suggest that H. azteca is exposed to ZnO NPs through the water column and NP transformations in the presence of phosphate do not reduce their toxicity. Sulfidized ZnO NPs have reduced toxicity, but their similar level of bioaccumulation in H. azteca suggests that trophic transfer of these particles will occur. 

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3. Analysis of Nutrient Profile of Finger Millet (Eleusine coracana (L.) Gaertn.) for Baby Food Formulation Using Pigeon Pea (Cajanus cajan (L.) Millsp.) as Protein Source

   https://doi.org/10.17265/2161-6264/2020.05.005  

   Britany Font, Anne Osano (January 2020, Journal of agricultural science and technology)

   null (Ed.)

   Finger millet (Eleusine coracana (L.) Gaertn.) is a drought resistant crop with potentially tremendous but under-explored source of nutraceutical properties as compared to other regularly consumed cereals in the era of drawback of nutritional security, these characteristics must be harnessed to develop finger millet as a novel functional food. Under-nutrition caused by inadequate diets, and other factors that influence nutritional status, is the underlying factor in 45% child deaths. In Kenya only 25% of young children are fed adequately diverse diets. The main objective of this study was to prepare baby food formulas using finger millets with pigeon peas as protein source and to analyze their nutritional profiles. Two finger millets varieties (i) Snapping Green Early, low altitude and medium altitude varieties and (ii) U-15) were studied to determine effects of environment on nutrient profiles. This study showed that Snapping Green Early had better nutrient profiles (12.13% protein and is high in Ca, Mg, Fe, Zn and P) than U-15 (11.69% protein and lower nutrients (Ca, Mg, Fe, Zn and P)), and hence was selected for use in the malting process as best variety. As expected, the pigeon peas had the highest protein value (21%). The samples malted for 72 h resulted in reduction of tannin concentration from 0.091% to 0.03% and the amount of nutrients (Ca, Mg, Fe and Zn) doubled and in fact the protein profile increased by 8.31%. The appropriate ratio for the formulation of the baby food was 70:30. The composting resulted in 18.5% increase in protein. 

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4. From Ground to Grain: Tracing Phosphorus and Potassium in Flooded Rice Cultivar Grown on Histosols

   https://doi.org/10.3390/agriculture12081250  

   Amgain, Naba R.; Fan, Yuchuan; VanWeelden, Matthew T.; Rabbany, Abul; Bhadha, Jehangir H. (August 2022, Agriculture)

   To trace the phosphorus (P) and potassium (K) content in flooded rice (Oryza sativa L), 14 rice cultivars commonly grown in the Southern United States were evaluated for their P and K concentration in tissue and grain. Field experiments were conducted at two locations in Everglades Agriculture Area (EAA), where flooded rice was cultivated on organic Histosols. Soil pH and Mehlich-3 phosphorus (M3P) were significantly different between locations. At Site I, soil pH, M3P, and Mehlich-3 potassium (M3K) varied in the range of 6.8–7.1, 21.4–36.4 mg kg−1, and 53.9–151.0 mg kg−1, respectively. At Site II, soil pH, M3P and M3K varied in the range of 6.9–7.3, 11.2–20.5 mg kg−1, and 64.8–104.1 mg kg−1, respectively. Stem potassium was the only measured parameter that was significantly different among rice cultivars at both sites. At Site I and Site II, stem K ranged from 14.2–26.6 mg kg−1 and 10.4–19.4 mg kg−1, respectively. No significant difference in yield among cultivars was observed at Site I, whereas Site II had a significant difference in yield among cultivars. At Site I and Site II, yields ranged from 3745–7587 kg ha−1 and 2627–6406 kg ha−1, respectively. None of the cultivars ranked consistently in the same top and bottom position for each measured parameter. Total phosphorus (TP) concentration was highest in grain, whereas total potassium (TK) concentration was highest in the stem. Results suggest incorporation of rice stem into the soil could potentially add fertilizer back to the soil which helps in fertility management. 

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5. Micropillar compression of single-crystal single-phase (Co, Cu, Mg, Ni, Zn)O

   https://doi.org/10.1063/5.0211263  

   Norman, Jacob_E; Wang, Xin; Dupuy, Alexander_D; Schoenung, Julie_M (July 2024, Applied Physics Letters)

   Bulk, polycrystalline (Co, Cu, Mg, Ni, Zn)O was synthesized using solid-state sintering. Micropillars were prepared and mechanically deformed along three crystallographic orientations: (001), (101), and (111). Pillars (001) and (111) cracked, while Pillar (101) remained intact. Pillars (001) and (101) exhibited activated slip systems, confirmed by a large stress drop, and the presence of slip bands, respectively. Schmid factor (SF) analysis was performed to examine the effect of grain orientations on dislocation activity and slip behavior. SF values range from 0 to 0.5, with non-zero values indicating potential for slip. Six slip systems exist in the (Co, Cu, Mg, Ni, Zn)O rock salt crystal structure: 1/2⟨110⟩11¯0. For the (001) orientation, four slip systems are potentially active (SF = 0.5). For the (101) orientation, there are four potentially active slip systems (SF = 0.25). For the (111) orientation, no potentially active slips systems exist (SF = 0). Dislocation structures, which were observed post-compression via transmission electron microscopy, demonstrated variations in size, number, and distribution across the pillar, depending on micropillar orientation. Entangled dislocations created misorientation in Pillar (001), which led to the possible formation of subgrains, while singular dislocations were observed in Pillar (101), and a lack of dislocations was observed in Pillar (111). Zener–Stroh type dislocation entanglement-mediated cracking is the proposed cause of the transgranular-type cracks in Pillar (001). The possible subgrain formation, or lack of formation, respectively, caused intergranular-type cracks to additionally form in Pillar (001), while Pillar (111) only exhibited transgranular-type brittle fracture. In combination, these findings highlight the importance of dislocation activity, without the need for elevated temperature, and grain orientation in controlling the mechanical deformation response in single-phase (Co, Cu, Mg, Ni, Zn)O. 

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