Dissipation of tembotrione in maize and its effect on biochemical attributes of maize under mid-hill sub-humid zone.

The present study was undertaken to investigate the dissipation behavior of tembotrione in soil and its effect on the biochemical constituents of maize leaves and grain. The average recovery of tembotrione from soil, maize grain, and stover was in the range of 84.0 to 86.0%, 79.3 to 83.0%, and 81.0 to 84.4%, respectively, with RSD less than 10%. Half-life (DT50) of tembotrione ranged from 9 to 14 days at an application rate of 60 to 240 g ha-1. Terminal residues in soil, maize grain, and stover were below detectable levels (≤ 0.025 µg g-1) at studied application rates. The chemical attributes, i.e., total chlorophyll, total carotenoids, and carbohydrate content, of rice leaves were observed at monthly intervals (zero (2 h), 30, 60 days after the herbicide application) and at harvest for biochemical analysis and grain samples at maturity of the crop for carbohydrate content. The results revealed that total chlorophyll, total carotenoids, and carbohydrate content in maize leaves increased significantly with applied tembotrione treatments, and the maximum increase was noticed in treatment 120 g ha-1. A significant increase in total carbohydrate content in maize grain over the control was noticed in all the herbicide-applied treatments. It can be inferred that the application of tembotrione is safe in the production of food with better quality and food safety.

Tracing fossil fuel CO2 by 14C in maize leaves in Guanzhong Basin of China.

Quantifying fossil fuel CO2 (CO2ff) in the atmosphere provides a benchmark method to monitor anthropogenic carbon emissions. Radiocarbon (14C) in atmospheric CO2ff has been widely studied using the 14C in plants to document regional CO2ff patterns. However, annual CO2ff variations, reflecting spatial distributions based on plant samples, are still scarce. In this paper, the spatial distribution and temporal CO2ff changes in the Guanzhong Basin is established using Δ14C measurements from maize leaves collected in 2011 and 2012. With regard to spatial distribution, samples collected around Xi'an City showed lower Δ14C values (more CO2ff), while sites located near the perimeter of the basin showed higher Δ14C values (less CO2ff). This is likely due to the concentration of anthropogenic activities in the center of the Guanzhong Basin. The observed CO2ff mole fractions generally matched with PKU CO2 inventory and the ODIAC CO2 inventory data in the spatial distribution trend. However, it seems that thermal power plants were not well captured by the PKU CO2 inventory. Our results provide useful information for the improvement of the inventory and verification of regional carbon cycle models.

Estimation of amino acid contents in maize leaves based on hyperspectral imaging.

Estimation of the amino acid content in maize leaves is helpful for improving maize yield estimation and nitrogen use efficiency. Hyperspectral imaging can be used to obtain the physiological and biochemical parameters of maize leaves with the advantages of being rapid, non-destructive, and high throughput. This study aims to estimate the multiple amino acid contents in maize leaves using hyperspectral imaging data. Two nitrogen (N) fertilizer experiments were carried out to obtain the hyperspectral images of fresh maize leaves. The partial least squares regression (PLSR) method was used to build the estimation models of various amino acid contents by using the reflectance of all bands, sensitive band range, and sensitive bands. The models were then validated with the independent dataset. The results showed that (1) the spectral reflectance of most amino acids was more sensitive in the range of 400-717.08 nm than other bands. The estimation accuracy was better by using the reflectance of the sensitive band range than that of all bands; (2) the sensitive bands of most amino acids were in the ranges of 505.39-605 nm and 651-714 nm; and (3) among the 24 amino acids, the estimation models of the ß-aminobutyric acid, ornithine, citrulline, methionine, and histidine achieved higher accuracy than those of other amino acids, with the R 2, relative root mean square error (RE), and relative percent deviation (RPD) of the measured and estimated value of testing samples in the range of 0.84-0.96, 8.79%-19.77%, and 2.58-5.18, respectively. This study can provide a non-destructive and rapid diagnostic method for genetic sensitive analysis and variety improvement of maize.

Herbivorous Juvenile Grass Carp (Ctenopharyngodon idella) Fed with Genetically Modified MON 810 and DAS-59122 Maize Varieties Containing Cry Toxins: Intestinal Histological, Developmental, and Immunological Investigations.

Feeding experiments with juvenile grass carp (Ctenopharyngodon idella) fed with genetically modified maize MON 810 or DAS-59122 dried leaf biomass were carried out with 1-, 3- and 6-month exposures. Dosages of 3-7 µg/fish/day Cry1Ab or 18-55 µg/fish/day Cry34Ab1 toxin did not cause mortality. No difference occurred in body or abdominal sac weights. No differences appeared in levels of inorganic phosphate, calcium, fructosamine, bile acids, triglycerides, cholesterol, and alanine and aspartame aminotransferases. DAS-59122 did not alter blood parameters tested after 3 months of feeding. MON 810 slightly decreased serum albumin levels compared to the control, only in one group. Tapeworm (Bothriocephalus acheilognathi) infection changed the levels of inorganic phosphate and calcium. Cry34Ab1 toxin appeared in blood (12.6 ± 1.9 ng/mL), but not in the muscle. It was detected in B. acheilognathi. Cry1Ab was hardly detectable in certain samples near the limit of detection. Degradation of Cry toxins was extremely quick in the fish gastrointestinal tract. After 6 months of feeding, only mild indications in certain serum parameters were observed: MON 810 slightly increased the level of apoptotic cells in the blood and reduced the number of thrombocytes in one group; DAS-59122 mildly increased the number of granulocytes compared to the near-isogenic line.

Relationships between chemical composition and in vitro gas production parameters of maize leaves and stems.

This study investigated the chemical composition (proximate and Van Soest analysis) and in vitro gas production parameters of maize leaves and stems separately, and related the in vitro gas production parameters with the chemical composition, of thirteen maize cultivars. After harvest in September 2016, all plants were separated into two morphological fractions: leaves and stems. The crude protein (CP) content was greater, and the ratio of acid detergent lignin (ADL) to potentially rumen degradable fibre (calculated as the difference between neutral detergent fibre and ADL; ADL:pRDF) was lower in the leaves than in the stems in all 13 cultivars. For the leaves, the cumulative gas production between 3 and 20 hr (A2), representing cell wall fermentation in the rumen fluid, and the cumulative 72-hr gas production (GP72), representing total organic matter (OM) degradation, were moderately to weakly correlated with the chemical composition, including hemicellulose, cellulose, ADL and CP content (R2  < 0.40), whilst the best relationship between the half-time value (B2), representing the rate of cell wall degradation, and chemical composition had an R2 of 0.63. For the stems, the best relationship between A2, B2 and GP72 with chemical composition was greater (R2  ≥ 0.74) and the best relationship included hemicellulose (A2 only), cellulose and ADL (GP72 and A2 only) contents. In conclusion, maize leaves and stems differed in chemical composition, in particular CP content and ADL:pRDF. The A2 and GP72 of the stems, but not of the leaves, were highly correlated with the chemical composition, indicating that the cell wall and OM degradation of maize stems can be better predicted by its chemical composition.

Long photoperiod affects the maize transition from vegetative to reproductive stages: a proteomic comparison between photoperiod-sensitive inbred line and its recurrent parent.

Maize (Zea mays L.) is a typical short-day plant that is produced as an important food product and industrial material. The photoperiod is one of the most important evolutionary mechanisms enabling the adaptation of plant developmental phases to changes in climate conditions. There are differences in the photoperiod sensitivity of maize inbred lines from tropical to temperate regions. In this study, to identify the maize proteins responsive to a long photoperiod (LP), the photoperiod-insensitive inbred line HZ4 and its near-isogenic line H496, which is sensitive to LP conditions, were analyzed under long-day conditions using isobaric tags for relative and absolute quantitation. We identified 5259 proteins in maize leaves exposed to the LP condition between the vegetative and reproductive stages. These proteins included 579 and 576 differentially accumulated proteins in H496 and HZ4 leaves, respectively. The differentially accumulated proteins (e.g., membrane, defense, and energy- and ribosome-related proteins) exhibited the opposite trends in HZ4 and H496 plants during the transition from the vegetative stage to the reproductive stage. These results suggest that the photoperiod-associated fragment in H496 plants considerably influences various proteins to respond to the photoperiod sensitivity. Overall, our data provide new insights into the effects of long-day treatments on the maize proteome, and may be useful for the development of new germplasm.

Comparative Proteomic Analysis of the Response of Maize (Zea mays L.) Leaves to Long Photoperiod Condition.

Maize (Zea mays L.), an important industrial material and food source, shows an astonishing environmental adaptation. A remarkable feature of its post-domestication adaptation from tropical to temperate environments is adaptation to a long photoperiod (LP). Many photoperiod-related genes have been identified in previous transcriptomics analysis, but proteomics shows less evidence for this mechanism of photoperiod response. In this study, we sampled newly expanded leaves of maize at the three- and six-leaf stages from an LP-sensitive introgression line H496, the donor CML288, LP-insensitive inbred line, and recurrent parent Huangzao4 (HZ4) grown under long days (15 h light and 9 h dark). To characterize the proteomic changes in response to LP, the iTRAQ-labeling method was used to determine the proteome profiles of plants exposed to LP. A total of 943 proteins differentially expressed at the three- and six-leaf stages in HZ4 and H496 were identified. Functional analysis was performed by which the proteins were classified into stress defense, signal transduction, carbohydrate metabolism, protein metabolism, energy production, and transport functional groups using the WEGO online tool. The enriched gene ontology categories among the identified proteins were identified statistically with the Cytoscape plugin ClueGO + Cluepedia. Twenty Gene Ontology terms showed the highest significance, including those associated with protein processing in the endoplasmic reticulum, splicesome, ribosome, glyoxylate, dicarboxylate metabolism, L-malate dehydrogenase activity, and RNA transport. In addition, for subcellular location, all proteins showed significant enrichment of the mitochondrial outer membrane. The sugars producted by photosynthesis in plants are also a pivotal metabolic output in the circadian regulation. The results permit the prediction of several crucial proteins to photoperiod response and provide a foundation for further study of the influence of LP treatments on the circadian response in short-day plants.

Non-dioxin-like PCB and PBDE deposition on Zea mays L. leaves: modelled contamination in milk from dairy animals fed on silage.

Maize (Zea mays L.) can intercept airborne pollutants before their deposition on soil. Selected non-dioxin-like polychlorinated biphenyls (Σ6NDL-PCBs) and polybrominated diphenyl ethers (Σ8PBDEs) with feed and food safety relevance were measured on maize leaves harvested for silage in dairy animals from 28 fields in Italy. Analyses were carried out by gas chromatography coupled to high- and low-resolution mass spectrometry. Contamination ranged from 0.65 to 5.3 ng g(-1) with 12% moisture for Σ6NDL-PCBs, and from 2.7 to 6.2 for Σ8 PBDEs. Modelled contamination in cow's milk was estimated to fall within the range 0.27-16 ng g(-1) for PCBs, 0.17-1.9 for PBDE number 47, and 0.22-2.1 for PBDE number 99 on a lipid basis. The results indicate that maize silage alone may raise Σ6NDL-PCB contamination in dairy milk up to the 95th percentile in the European Union. Results are discussed in terms of air quality standards able to support food safety.

Expression of zma-miR169 miRNAs and their target ZmNF-YA genes in response to abiotic stress in maize leaves.

The miR169 miRNA family is highly conserved in plants. Its members regulate the expression of genes encoding the universal transcription factor subunit NUCLEAR FACTOR-Y subunit A (NF-YA) via transcript cleavage. NF-YA regulates gene expression by binding the CCAAT box sequence in target promoters. The miR169/NF-YA module plays a critical role during plant development and in plant responses to abiotic stress. We characterized the secondary structures of maize pre-miR169 miRNAs and predicted their potential gene targets. Coexpression of zma-miR169 and ZmNF-YA in Nicotiana benthamiana demonstrated that mutations in or deletion of target sites abolished regulation by zma-miR169. Maize seedlings were subjected to short-term (0-48h) and long-term (15days) drought, abscisic acid (ABA), or salt stress. Long-term exposure to PEG (drought stress) or NaCl (salt stress) repressed seedling growth. We investigated the expression patterns of zma-miR169s and their target ZmNF-YA genes in maize leaves and found diverse changes in expression in response to the three stress treatments. The expression of most zma-miR169 genes was downregulated by PEG and upregulated by ABA. In response to salt stress, zma-miR169 genes were upregulated initially and subsequently downregulated. Most ZmNF-YA genes were upregulated during the short term and downregulated by 15days in response to the three stress treatments.