Transcriptional insights into Cu related tolerance strategies in maize linked to a novel tea-biochar.

One-third of maize cultivation in Turkey has been performed in nutrient-rich soils of the coastal agricultural lands of the Black Sea Region, which is among the country's granaries. However, the yield of this chief crop is affected by Cu toxicity due to a decades-long abandoned opencast Cu-mine. As part of the modern agenda, against this problem, we valorized one of the region's signature plant waste by synthesizing a tea-derived biochar (BC) and evaluated for remediation effect on maize Cu tolerance. Among other rates (0%, 0.4%, 0.8%, 1.6%), maximum Cu absorption (168.27 mg kg-1) was found in the 5%BC in in-vitro spiking experiments where natural Cu contamination levels were mimicked. Obvious increasing trends in both root and shoot tissues of maize plantlets growing in Cu-spiked soil (260.26 ± 5.19 mg Cu kg-1) were recorded with proportionally increasing BC application rates. The black tea waste-BC (5%) amendment remarkably reduced the Cu uptake from Cu spiked-soil and showed no phenotypic retardation in maize. Accordingly, it boosted the metabolic and transcriptomic profile owing to up-regulation in the aquaporin and defense genes (PIP1;5 and POD1) by 1.31 and 1.6 fold. The tea-BC application also improved the soil-plant water relations by minimizing cytosolic volume changes between 85 and 90%, increasing chlorophyll intactness (65%) and membrane stability up to 41%. The tea-BC could be a strong agent with potential agronomic benefits in the remediation of the cationic Cu toxicity that occurred in the mining-contaminated agricultural soils.

Preparation, characterization and application of poly(lactic acid)/corn starch/eucalyptus leaf essential oil microencapsulated active bilayer degradable film.

This study aimed to develop a composite bilayer film based on corn starch (CS)/polylactic acid (PLA). The film had a hydrophobic outer layer and an absorbent inner layer. A natural bioactive substance was incorporated into the inner layer, namely, eucalyptus essential oil microcapsules (EOM). This allowed most of the bioactive substance to be released inside the storage environment. The effects of different amounts of EOM on the physical, mechanical, antioxidant, and antimicrobial properties of the films were investigated. Based on the results of scanning electron microscopy (SEM), the addition of 10-15 mL/100 mL of EOM could be uniformly distributed in the film. The addition of less than 15 mL/100 mL of EOM to the film improved its tensile strength, barrier properties, and elongation at break. The addition of too much EOM led to cracks in the film. The addition of EOM also greatly improved the antioxidant and antibacterial properties of the bilayer film. The best performance was obtained when the added amount was 15 mL/100 mL. Films with the best overall properties were used for preserving Agaricus bisporus. In preservation experiments, this film inhibited the respiration rate of A. bisporus, slowed down the consumption of organic matter, and maintained its moisture content. Compared with other cling films, the shelf life of A. bisporus was greatly extended.

Sugar beet extract rich in glycine betaine modulates oxidative defense system and key physiological characteristics of maize under water-deficit stress.

Now-a-days, plant-based extracts, as a cheap source of growth activators, are being widely used to treat plants grown under extreme climatic conditions. So, a trial was conducted to assess the response of two maize (Zea mays L.) varieties, Sadaf (drought tolerant) and Sultan (drought sensitive) to foliar-applied sugar beet extract (SBE) under varying water-deficit conditions. Different SBE (control, 1%, 2%, 3% & 4%) levels were used in this study, and plants were exposed to water-deficit [(75% and 60% of field capacity (FC)] and control (100% FC) conditions. It was observed that root and shoot dry weights (growth), total soluble proteins, RWC-relative water contents, total phenolics, chlorophyll pigments and leaf area per plant decreased under different water stress regimes. While, proline, malondialdehyde (MDA), RMP-relative membrane permeability, H2O2-hydrogen peroxide and the activities of antioxidant enzymes [CAT-catalase, POD-peroxidase and SOD-superoxide dismutase] were found to be improved in water stress affected maize plants. Exogenous application of varying levels of SBE ameliorated the negative effects of water-deficit stress by enhancing the growth attributes, photosynthetic pigments, RWC, proline, glycinebetaine (GB), activities of POD and CAT enzymes and levels of total phenolics, whereas it reduced the lipid peroxidation in both maize varieties under varying water stress levels. It was noted that 3% and 4% levels of SBE were more effective than the other levels used in enhancing the growth as well as other characteristics of the maize varieties. Overall, the sugar beet extract proved to be beneficial for improving growth and metabolism of maize plants exposed to water stress.

Microencapsulated Caraway Essential Oil Affects Initial Growth of Maize Cultivars.

Caraway (Carum carvi L.) essential oil is a candidate for botanical herbicides. A hypothesis was formulated that the sand-applied maltodextrin-coated caraway oil (MCEO) does not affect the growth of maize (Zea mays L.). In the pot experiment, pre-emergence application of five doses of MCEO was tested on four maize cultivars up to the three-leaf growth stage. The morphological analyses were supported by the measurements of relative chlorophyll content (SPAD), two parameters of chlorophyll a fluorescence, e.g., Fv/Fm and Fv/F0, and fluorescence emission spectra. The analyzed MCEO contained 6.5% caraway EO with carvone and limonene as the main compounds, constituting 95% of the oil. The MCEO caused 7-day delays in maize emergence from the dose of 0.9 g per pot (equal to 96 g m-2). Maize development at the three-leaf growth stage, i.e., length of roots, length of leaves, and biomass of shoots and leaves, was significantly impaired already at the lowest dose of MCEO: 0.4 g per pot, equal to 44 g m-2. A significant drop of both chlorophyll a fluorescence parameters was noted, on average, from the dose of 0.7 g per pot, equal to 69 g m-2. Among the tested cultivars, cv. Rywal and Pomerania were less susceptible to the MCEO compared to the cv. Kurant and Podole. In summary, maize is susceptible to the pre-emergence, sand-applied MCEO from the dose of 44 g m-2.

The Influence of Soil Fertilization on the Distribution and Diversity of Phosphorus Cycling Genes and Microbes Community of Maize Rhizosphere Using Shotgun Metagenomics.

Biogeochemical cycling of phosphorus in the agro-ecosystem is mediated by soil microbes. These microbes regulate the availability of phosphorus in the soil. Little is known about the response of functional traits of phosphorus cycling microbes in soil fertilized with compost manure (derived from domestic waste and plant materials) or inorganic nitrogen fertilizers at high and low doses. We used a metagenomics investigation study to understand the changes in the abundance and distribution of microbial phosphorus cycling genes in agricultural farmlands receiving inorganic fertilizers (120 kg N/ha, 60 kg N/ha) or compost manure (8 tons/ha, 4 tons/ha), and in comparison with the control. Soil fertilization with high level of compost (Cp8) or low level of inorganic nitrogen (N1) fertilizer have nearly similar effects on the rhizosphere of maize plants in promoting the abundance of genes involved in phosphorus cycle. Genes such as ppk involved in polyphosphate formation and pstSABC (for phosphate transportation) are highly enriched in these treatments. These genes facilitate phosphorus immobilization. At a high dose of inorganic fertilizer application or low compost manure treatment, the phosphorus cycling genes were repressed and the abundance decreased. The bacterial families Bacillaceae and Carnobacteriaceae were very abundant in the high inorganic fertilizer (N2) treated soil, while Pseudonocardiaceae, Clostridiaceae, Cytophagaceae, Micromonosporaceae, Thermomonosporaceae, Nocardiopsaceae, Sphaerobacteraceae, Thermoactinomycetaceae, Planococcaceae, Intrasporangiaceae, Opitutaceae, Acidimicrobiaceae, Frankiaceae were most abundant in Cp8. Pyrenophora, Talaromyces, and Trichophyton fungi were observed to be dominant in Cp8 and Methanosarcina, Methanobrevibacter, Methanoculleus, and Methanosphaera archaea have the highest percentage occurrence in Cp8. Moreover, N2 treatment, Cenarchaeum, Candidatus Nitrososphaera, and Nitrosopumilus were most abundant among fertilized soils. Our findings have brought to light the basis for the manipulation of rhizosphere microbial communities and their genes to improve availability of phosphorus as well as phosphorus cycle regulation in agro-ecosystems.

Low nitrogen availability inhibits the phosphorus starvation response in maize (Zea mays ssp. mays L.).

BACKGROUND: Nitrogen (N) and phosphorus (P) are macronutrients essential for crop growth and productivity. In cultivated fields, N and P levels are rarely sufficient, contributing to the gap between realized and potential production. Fertilizer application increases nutrient availability, but is not available to all farmers, nor are current rates of application sustainable or environmentally desirable. Transcriptomic studies of cereal crops have revealed dramatic responses to either low N or low P single stress treatments. In the field, however, levels of both N and P may be suboptimal. The interaction between N and P starvation responses remains to be fully characterized. RESULTS: We characterized growth and root and leaf transcriptomes of young maize plants under nutrient replete, low N, low P or combined low NP conditions. We identified 1555 genes to respond to our nutrient treatments, in one or both tissues. A large group of genes, including many classical P starvation response genes, were regulated antagonistically between low N and P conditions. An additional experiment over a range of N availability indicated that a mild reduction in N levels was sufficient to repress the low P induction of P starvation genes. Although expression of P transporter genes was repressed under low N or low NP, we confirmed earlier reports of P hyper accumulation under N limitation. CONCLUSIONS: Transcriptional responses to low N or P were distinct, with few genes responding in a similar way to the two single stress treatments. In combined NP stress, the low N response dominated, and the P starvation response was largely suppressed. A mild reduction in N availability was sufficient to repress the induction of P starvation associated genes. We conclude that activation of the transcriptional response to P starvation in maize is contingent on N availability.

Silymarin-Enriched Biostimulant Foliar Application Minimizes the Toxicity of Cadmium in Maize by Suppressing Oxidative Stress and Elevating Antioxidant Gene Expression.

For maize, the potential preventive role of foliar spraying with an extract derived from maize grain (MEg, 2%), silymarin (Sm, 0.5 mM), or silymarin-enriched MEg (MEg-Sm) in attenuating the stress effects of cadmium (Cd, 0.5 mM) was examined using a completely randomized design layout. Under normal conditions, foliar spraying with MEg, Sm, or MEg-Sm was beneficial (with MEg-Sm preferred) for maize plants, whereas the benefit was more pronounced under Cd stress. The use of Cd through irrigation water decreased plant growth traits, photosynthetic efficiency, including instantaneous carboxylation efficiency, Fv/Fm, and pigment contents, and hormonal contents (e.g., auxin, gibberellins, cytokinins including trans-zeatin, and salicylic acid). These undesired findings were due to an increase in Cd content, leading to increased levels of oxidative stress (O2•- and H2O2), ionic leakage, and lipid peroxidation. Therefore, this damage resulted in an increase in the activities of nonenzymatic antioxidants, Sm, antioxidative enzymes, and enzyme gene expression. However, under Cd stress, although foliar spray with MEg or Sm had better findings than control, MEg-Sm had better findings than MEg or Sm. Application of MEg-Sm greatly increased photosynthesis efficiency, restored hormonal homeostasis, and further increased the activities of various antioxidants, Sm, antioxidative enzymes, and enzyme gene expression. These desired findings were due to the suppression of the Cd content, and thus the levels of O2•-, H2O2, ionic leakage, and lipid peroxidation, which were positively reflected in the growth and accumulation of dry matter in maize plants. The data obtained in this study recommend applying silymarin-enriched maize grain extract (MEg-Sm at 0.24 g Sm L-1 of MEg) as a spray solution to maize plants when exposed to excess Cd in soil or irrigation water.

Cultivable and metagenomic approach to study the combined impact of nanogypsum and Pseudomonas taiwanensis on maize plant health and its rhizospheric microbiome.

In the present study we examined the effect of nanogypsum and Pseudomonas taiwanensis strain BCRC 17751on plant and soil health using conventional and metagenomics approaches. Soil physicochemical properties and agronomical parameters of maize plants were reported to be better when applied with nanogypsum and bacterial inoculum together. When compared to control a significant increase in total bacterial counts, nitrogen, phosphorus, potassium (NPK) solubilizing bacterial population and soil enzyme activities (fluorescein diacetate, alkaline phosphatase, dehydrogenase, ß-glucosidase, arylesterase and amylase) was reported in treatments. The metagenomics studies revealed dominance of beneficial bacteria such as Proteobacteria, Bacteriodetes, Planctomycetes, Acidobacteria and Nitrospirae in treated soil. On the other hand some novel bacterial diversity was also reported in treated soil which was evident from presence of taxonomically unclassified sequences. Hence, it can be concluded that combined application of nanogypsum and Pseudomonas taiwanensis in maize help in improving the structure and function of soil which affects the plant health without causing any toxic effect. However, in situ validation of the prescribed treatment is required under field conditions on different crops in order to give maximum benefits to the farmers and the environment.

Transcriptome dynamic landscape underlying the improvement of maize lodging resistance under coronatine treatment.

BACKGROUND: Lodging is one of the important factors causing maize yield. Plant height is an important factor in determining plant architecture in maize (Zea mays L.), which is closely related to lodging resistance under high planting density. Coronatine (COR), which is a phytotoxin and produced by the pathogen Pseudomonas syringae, is a functional and structural analogue of jasmonic acid (JA). RESULTS: In this study, we found COR, as a new plant growth regulator, could effectively reduce plant height and ear height of both hybrids (ZD958 and XY335) and inbred (B73) maize by inhibiting internode growth during elongation, thus improve maize lodging resistance. To study gene expression changes in internode after COR treatment, we collected spatio-temporal transcriptome of inbred B73 internode under normal condition and COR treatment, including the three different regions of internode (fixed, meristem and elongation regions) at three different developmental stages. The gene expression levels of the three regions at normal condition were described and then compared with that upon COR treatment. In total, 8605 COR-responsive genes (COR-RGs) were found, consist of 802 genes specifically expressed in internode. For these COR-RGs, 614, 870, 2123 of which showed expression changes in only fixed, meristem and elongation region, respectively. Both the number and function were significantly changed for COR-RGs identified in different regions, indicating genes with different functions were regulated at the three regions. Besides, we found more than 80% genes of gibberellin and jasmonic acid were changed under COR treatment. CONCLUSIONS: These data provide a gene expression profiling in different regions of internode development and molecular mechanism of COR affecting internode elongation. A putative schematic of the internode response to COR treatment is proposed which shows the basic process of COR affecting internode elongation. This research provides a useful resource for studying maize internode development and improves our understanding of the COR regulation mechanism based on plant height.

Induction of defense-related enzymes and enhanced disease resistance in maize against Fusarium verticillioides by seed treatment with Jacaranda mimosifolia formulations.

Fusarium verticillioides is an important fungal pathogen of maize, causing stalk rot and severely affecting crop production. The aim of this study was to characterize the protective effects of formulations based on Jacaranda mimosifolia leaf extracts against F. verticillioides in maize. We compared different seed treatments comprising J. mimosifolia extracts, chemical fungicide (mefenoxam) and salicylic acid to modulate the defense system of maize host plants. Both aqueous and methanolic leaf extracts of J. mimosifolia (1.2% w/v) resulted in 96-97% inhibition of mycelial growth of F. verticillioides. While a full-dose (1.2%) extract of J. mimosifolia provided significant protective effects on maize plants compared to the inoculated control, a half-dose (0.6% w/v) application of J. mimosifolia in combination with half-strength mefenoxam was the most effective treatment in reducing stalk rot disease in pot and field experiments. The same seed treatment significantly upregulated the expression of genes in the leaves encoding chitinase, glucanase, lipid transfer protein, and pathogenesis-related proteins PR-1, PR-5 and PR-10, 72 h after inoculation. This treatment also induced the activities of peroxidase, polyphenol oxidase, protease, acid invertase, chitinase and phenylalanine ammonia lyase. We conclude that seed pre-treatment with J. mimosifolia extract with half-strength chemical mefenoxam is a promising approach for the management of stalk rot in maize.

Activated sludge treatment for promoting the reuse of a synthetic produced water in irrigation.

Large volumes of produced water are generated as a byproduct in activities of oil and gas exploitation, which can be reused in agriculture after a treatment process. Activated sludge treatment has been successfully used to remove oil from wastewater, but systematic studies on the toxicity of this effluent using this treatment are scarce in the literature. In this study, it was investigated the performance of an activated sludge system in the treatment of a synthetic produced water under different initial conditions in terms of salinity and oil and grease concentration. Furthermore, it was evaluated this effluent phytotoxicity in the germination, and seedling and plant growths of sunflower and corn seeds using untreated and treated synthetic produced water. Results revealed the activated sludge effectiveness in oil and grease and salinity removal from produced water, viz. high removal efficiency of 99.01 ± 0.28 and 91.07 ± 0.39%., respectively. Untreated produced water showed considerable toxic effects on the germination (74.67 ± 2.31% and 82.67 ± 2.31 for sunflower and corn seeds, respectively) and growth stages of sunflower and corn seed plants. The germination percentage was approximately 100% for both types of seed. The seedling and plant growth of the two seeds irrigated with treated produced water had similar performance when used tap water. These results highlighted the potential reuse as an unconventional water resource for plant irrigation of the synthetic produced water treated by an activated sludge process, which technology has showed high removal performance of salinity and oil.

Phosphorus fertilization and mycorrhizal colonization change silver nanoparticle impacts on maize.

Environmental risks of silver (Ag) nanoparticles (NPs) have aroused considerable concern, however, their ecotoxicity in soil-plant systems has yet not been well elaborated, particularly in agroecosystems with various fertility levels and soil biota. The aims of the present study were to determine AgNPs impacts on maize as influenced by mycorrhizal inoculation and P fertilization. A greenhouse pot experiment was conducted determine the effects of mycorrhizal inoculation with Rhizophagus intraradices and P fertilization (0, 20, and 50 P mg/kg soil, as Ca(H2PO4)2) on plant growth, Ag accumulation and physiological responses of maize exposed to AgNPs (1 mg/kg), or an equivalent Ag+. Overall, AgNPs and Ag+ did not significantly affect plant biomass and acquisition of mineral nutrients, activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), chlorophyll contents and photosystem (PS) II photochemical efficiency. In most cases, AgNPs and Ag+ caused similar Ag accumulation in plant tissues. P fertilization significantly increased Ag bioavailability and plant Ag accumulation, but only promoted the growth and P uptake of nonmycorrhizal plants. AM inoculation produced positive impacts on plant biomass, nutritional and physiological responses, but slightly affected extractable Ag in soil and Ag accumulation in plants. Mycorrhizal responses in plant growth and P uptake were more pronounced in the treatments without P but with Ag. By and large, AgNPs exhibited similar phytoavailability, phytoaccumulation and low phytotoxicity compared to Ag+, but higher fungitoxicity (i.e., lower root colonization). In conclusion, both AM inoculation and P fertilization can improve plant performance in the soil exposed to Ag, but P increases environmental risk of Ag. Our results indicate a beneficial role of arbuscular mycorrhizal fungi but a dual role of P in soil-plant systems exposed to AgNPs or Ag+.

Nitric oxide and hydrogen sulfide protect plasma membrane integrity and mitigate chromium-induced methylglyoxal toxicity in maize seedlings.

The present study aims to analyse the potential crosstalk between nitric oxide (NO) and hydrogen sulfide (H2S) in triggering resilience of maize (Zea mays L.) seedlings to hexavalent chromium (Cr VI). Exogenous application of 500 µM sodium nitroprusside (SNP, as a NO donor) or sodium hydrosulfide (NaHS, as a H2S donor) to 9-day-old maize seedlings, countered a Cr (200 µM) -elicited reduction in embryonic axis biomass. Cr caused cellular membrane injury by enhancing the levels of superoxide and hydroxyl radicals as well as methylglyoxal, and 4-hydroxy-2-nonenal. The application of SNP or NaHS considerably improved the endogenous NO and H2S pool, decreased oxidative stress and lipid peroxidation by suppressing lipoxygenase activity and improving some antioxidant enzymes activities in radicles and epicotyls. Radicles were more affected than epicotyls by Cr-stress with enhanced electrolyte leakage and decreased proton extrusion as indicated by lesser H+-ATPase activity. H2S appeared to mitigate Cr toxicity through up-regulated H+-ATPase and glyoxalase pathways and by maintaining optimal GSH levels as downstream effects of ROS and MG suppression. Hence, H2S-mediated the regeneration of GSH pool is associated with the attenuation of MG toxicity by enhancing S-lactoglutathione and D-lactate production. Taken together, our results indicate complementary roles for H2S and GSH to strengthen membrane integrity against Cr stress in maize seedlings.

Pre- sowing seed treatment with salicylic acid and sodium hydrosulfide confers Pb toxicity tolerance in maize (Zea mays L.).

In the present study, impact of salicylic acid (SA), sodium hydrosulfide (NaHS) and concomitant application of SA and NaHs seed priming was investigated in alleviation of the lead stress adverse effects on growth parameters, total chlorophyll content, dicarbonyl stress, and lead-induced iron deficiency in maize. Maize seeds were soaked in 0.5 mM SA and 0.5 mM NaHS individually and in 0.25 mM SA and 0.25 mM NaHS concomitantly for 12 h. The 6 day old plants were subjected to 2.5 mM Pb(NO3)2 for 9 days. Lead stress caused a significant decrease in growth parameters and total chlorophyll and shoot iron contents, whereas increased lead and methylglyoxal accumulation significantly. The cysteine and methionine contents elevated in shoots of lead stressed plants; probably due to redirection of sulfur assimilation requirement for lead detoxification. The SA, NaHS and SA+NaHS applications modulated glyoxalase I activity and resulted in remarkable reduction in methylglyoxal accumulation during lead stress. Lead induced iron deficiency was reverted under SA, NaHS and SA+NaHS seed priming in shoots, probably through reduction in lead uptake and increase in nitric oxide content. Lead imposition activated iron starvation pathway via elevation in methionine content and expression of iron uptake and hemostasis-related genes including Yellow Stripe1 (ZmYS 1), S-adenosylmethionine synthase (ZmSAMS) and 2'-deoxymugineic acid synthase (ZmDMAS1) in roots. However, the ZmSAMS and ZmDMAS1 transcript levels did not change under lead exposure in shoots. The SA, NaHS and SA+NaHS seed primed plants displayed downregulation of ZmSAMS and ZmDMAS1 in shoots and roots under lead stress. In conclusion, seed priming with SA and NaHS could improve lead tolerance in maize via reduction in the Pb uptake, consequently lowering lead toxicity in the food chain.

Nanoparticle treatment of maize analyzed through the metatranscriptome: compromised nitrogen cycling, possible phytopathogen selection, and plant hormesis.

BACKGROUND: The beneficial use of nanoparticle silver or nanosilver may be confounded when its potent antimicrobial properties impact non-target members of natural microbiomes such as those present in soil or the plant rhizosphere. Agricultural soils are a likely sink for nanosilver due to its presence in agrochemicals and land-applied biosolids, but a complete assessment of nanosilver's effects on this environment is lacking because the impact on the natural soil microbiome is not known. In a study assessing the use of nanosilver for phytopathogen control with maize, we analyzed the metatranscriptome of the maize rhizosphere and observed multiple unintended effects of exposure to 100 mg kg-1 nanosilver in soil during a growth period of 117 days. RESULTS: We found several unintended effects of nanosilver which could interfere with agricultural systems in the long term. Firstly, the archaea community was negatively impacted with a more than 30% decrease in relative abundance, and as such, their involvement in nitrogen cycling and specifically, nitrification, was compromised. Secondly, certain potentially phytopathogenic fungal groups showed significantly increased abundances, possibly due to the negative effects of nanosilver on bacteria exerting natural biocontrol against these fungi as indicated by negative interactions in a network analysis. Up to 5-fold increases in relative abundance have been observed for certain possibly phytopathogenic fungal genera. Lastly, nanosilver exposure also caused a direct physiological impact on maize as illustrated by increased transcript abundance of aquaporin and phytohormone genes, overall resulting in a stress level with the potential to yield hormetically stimulated plant root growth. CONCLUSIONS: This study indicates the occurrence of significant unintended effects of nanosilver use on corn, which could turn out to be negative to crop productivity and ecosystem health in the long term. We therefore highlight the need to include the microbiome when assessing the risk associated with nano-enabled agriculture. Video Abstract.

Assessment of the N- and P-Fertilization Effect of Black Soldier Fly (Diptera: Stratiomyidae) By-Products on Maize.

To meet the growing demand for an alternative animal protein source, the Black Soldier Fly (BSF) (Hermetia illucens) industry is expanding. Thus, the valuation of its byproducts, foremost BSF frass, is getting more economic and ecological weight. Three different residues, BSF frass, larval skins, and dead adult flies, were compared with a mineral and an organic commercial fertilizer in a pot trial with maize (Zea mays L., [Poales: Poaceae]). byproducts were applied in three nutrient-based application rates (180; 215 kg N/ha; 75 kg P2O5/ha), and plant nutrients, physiological and yield parameters were measured at harvest date. Ground flies had the highest N-fertilizing effect of all byproducts, similar to commercial mineral and organic fertilizers used as controls, whereas its proportion of the BSF production systems' output is low. Frass as the abundant byproduct showed comparably low N-fertilization effects. Its low N availability was attributed to volatilization losses, mainly driven by high pH and ammonium contents. BSF frass as the main byproduct output is more suited as a basic fertilizer or potting substrate amendment than as a short-term organic fertilizer. Postprocessing of frass seems reasonable. For a profound assessment of frass as fertilizer, several aspects (e.g., the overall impact of postprocessing, plant strengthening and plant protection potential, effects on microbial processes) must be clarified.

Organic manure input improves soil water and nutrients use for sustainable maize (Zea mays. L) productivity on the Loess Plateau.

Long-term chemical fertilizer input causes soil organic matter losses, structural compaction, and changes in soil water and nutrient availability, which have been subdued in the most of dry farmland in China. The concept of "more efficiency with less fertilizer input" has been proposed and is urgently needed in current agriculture. Application of chemical fertilizer combined with organic manure (OM) could be a solution for soil protection and sustainable production of dry-land maize (Zea mays. L). Field research over three consecutive years on the Loess Plateau of China was conducted to evaluate the integrated effects of chemical fertilizer strategies and additional OM input on soil nutrients availability and water use in maize. The results showed that, after harvest, soil bulk density decreased significantly with OM application, concomitant with 11.9, 18.7 and 97.8% increases in topsoil total nitrogen, organic matter, and available phosphorus contents, respectively, compared with those under equal chemical NPK input. Water use in the 1.0-1.5 m soil profile was improved, therefore, the soil conditions were better for maize root growth, leaf area and shoot biomass of individual maize plants increased significantly with OM application. Optimized NPK strategies increased grain yield and water use efficiency by 18.5 and 20.6%, respectively, compared to only chemical NP input. Furthermore, additional OM input promoted yield and water use efficiency by 8.9 and 5.8%, respectively. Addition of OM promotes sustainable soil and maize grain productivity as well as friendly soil environmental management of dry land farming.

Formononetin accelerates mycorrhization and increases maize production at low phosphorus application rates.

The formononetin biostimulant may be an option for reducing P fertilization once it stimulates mycelial growth of arbuscular mycorrhizal fungi and increases plant ability to take up nutrients through the roots, especially phosphorus. The objective of this study was to evaluate the effect of formononetin associated with phosphorus fertilization in maize. Field experiments were conducted in a randomized block design with a 3 × 4 factorial arrangement (0, 50 or 70, and 140 kg ha-1 P2O5; and formononetin application rates: 0, 25, 50, and 100 g ha-1), with four replications. Formononetin (100 g ha-1) increased the mycorrhizal colonization rate up to 30% in maize in the first four weeks after emergence when no P fertilizer was applied, and to 17% when 50 or 70 kg ha-1 of P2O5 were applied. The application of 50 and 100 g ha-1 of formononetin significantly increased plant height, ear height, and grain yield (22% - 76%) when no P fertilizer was applied. The use of formononetin in the field stimulates mycorrhizal colonization, has a positive effect on maize yield, and reduces the need for P fertilizer application in maize. However, this effect was evident only at low P soil contents.

Phosphorus addition increased carbon partitioning to autotrophic respiration but not to biomass production in an experiment with Zea mays.

Plant carbon (C) partitioning-the relative use of photosynthates for biomass production, respiration, and other plant functions-is a key but poorly understood ecosystem process. In an experiment with Zea mays, with or without arbuscular mycorrhizal fungi (AMF), we investigated the effect of phosphorus (P) fertilization and AMF on plant C partitioning. Based on earlier studies, we expected C partitioning to biomass production (i.e., biomass production efficiency; BPE) to increase with increasing P addition due to reduced C partitioning to AMF. However, although plant growth was clearly stimulated by P addition, BPE did not increase. Instead, C partitioning to autotrophic respiration increased. These results contrasted with our expectations and with a previous experiment in the same set-up where P addition increased BPE while no effect on autotropic respiration was found. The comparison of both experiments suggests a key role for AMF in explaining these contrasts. Whereas in the previous experiment substantial C partitioning to AMF reduced BPE under low P, in the current experiment, C partitioning to AMF was too low to directly influence BPE. Our results illustrate the complex influence of nutrient availability and mycorrhizal symbiosis on plant C partitioning.

Bioactive seco-Sativene Sesquiterpenoids from an Artemisia desertorum Endophytic Fungus, Cochliobolus sativus.

A series of seco-sativene sesquiterpenoids (1-11) including two new natural products (2 and 3), four new analogues (4-7), and six known analogues, helminthosporic acid (1), drechslerine A (8), drechslerine B (9), helminthosporol (10), helminthosporal acid (11), and isosativenediol (12), were purified from the endophytic fungus Cochliobolus sativus isolated from a desert plant, Artemisia desertorum. The stereochemistry of helminthosporic acid (1) was established for the first time by X-ray diffraction, and the structures including relative and absolute configurations of these new compounds were determined by NMR and CD spectra together with biosynthetic considerations. Compounds 5-7 are the first seco-sativene sesquiterpenoids possessing a glucose group on C-15, C-15, and C-14, respectively. Compounds 1, 7, 9, and 11 displayed strong phytotoxic effects on corn leaves by producing visible lesions, and helminthosporic acid (1) was shown to promote division of leaves and roots of Arabidopsis thaliana with a dose-dependent relationship.