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Micronization of maize varieties viz. Nityashree (NAH-2049) and Arjun (EH-434042) was carried out in a near-infrared (NIR) based system. Infrared (IR) processing conditions such as moisture content and time of exposure were standardized to inactivate peroxidase and lipase enzymes and, to improve starch digestibility. Micronization of maize at 200°C for 4 min resulted in 16-20% increase in rapidly digestible starch (RDS) content. The process was effective in completely inactivating peroxidase enzyme and reducing lipase activity by 83-86%. The process did not induce any marked changes in total carbohydrates and protein contents. Reduction in pasting viscosities, peak viscosity (PV), and set back viscosity (SV) of micronized maize flour indicated partial gelatinization of starch. Micronized Arjun flour exhibited higher RDS content, which was correlated with lower viscosity profile values compared to Nityashree flour. Inactivation of enzymes in micronized maize provides the scope for shelf-life extension of flour. Improvement in RDS content increased water absorption capacity, and low viscosity profile provides an opportunity for its inclusion in preparing calorie dense foods having high solids concentration. [ABSTRACT FROM AUTHOR]

Differences between two maize and two triticale genotypes grown in low soil compaction (LSC), moderate soil compaction (MSC) and severe soil compaction (SSC) and with a limited (D) or excess (W) soil water content were observed as a decrease in shoot (S) and root (R) biomass, leaf greening (SPAD) and increase in membrane injury (LI), root and leaf water potential (ψ), photosynthesis (Pn), transpiration (E) and stomata conductance (gS). Close correlations betweenψLandψR,and between differencesψLandψR(Δψ) were found. Drought or waterlogging with LSC conditions in both maize genotypes resulted in higher WUE than in control plants (LSC C), but under the SSC WUE declined. However, for triticale differences in WUE, between treatments were small and insignificant. In general, changes in markers were greater for genotypes sensitive to the soil compaction (Ankora, CHD-12) than in resistant ones (Tina, CHD-247) and were higher in seedlings grown under SSC conditions. Abbreviations:ψR,ψL: root and leaf water potential; C: control; D: drought; E: transpiration rate; FWC: field water capacity; gS: stomatal conductance; LSC, MSC, SSC: low, moderate and severe soil compaction; Pn: photosynthesis rate; W: waterlogging [ABSTRACT FROM PUBLISHER]

Plants respond to abiotic stress through a variety of physiological, biochemical, and transcriptional mechanisms. Many genes exhibit altered levels of expression in response to abiotic stress, which requires concerted action of both cis- and trans-regulatory features. In order to study the variability in transcriptome response to abiotic stress, RNA sequencing was performed using 14-day-old maize seedlings of inbreds B73, Mo17, Oh43, PH207 and B37 under control, cold and heat conditions. Large numbers of genes that responded differentially to stress between parental inbred lines were identified. RNA sequencing was also performed on similar tissues of the F1 hybrids produced by crossing B73 and each of the three other inbred lines. By evaluating allele-specific transcript abundance in the F1 hybrids, we were able to measure the abundance of cis- and trans-regulatory variation between genotypes for both steady-state and stress-responsive expression differences. Although examples of trans-regulatory variation were observed, cis-regulatory variation was more common for both steady-state and stress-responsive expression differences. The genes with cis-allelic variation for response to cold or heat stress provided an opportunity to study the basis for regulatory diversity. [ABSTRACT FROM AUTHOR]

Selenium (Se), regarded as an antioxidant, has been found beneficial for plants growing under stressed conditions. To investigate whether the Se application helps to improve stress tolerance, sodium selenite (Na2SeO3 · 5H2O, 5–15 μM) was hydroponically applied toZea maysvariety OSSK-713-roots under heat and/or PEG-induced osmotic stress (25% PEG-6000) for 8 h. The individual/combined stress caused accumulation of reactive oxygen species (ROS). While only superoxide dismutase (SOD) increased with heat stress alone, the activities of SOD, catalase (CAT) and ascorbate peroxidase (APX) increased under PEG exposure. The combination of these stresses resulted in an induction of both SOD and CAT activities. Lipid peroxidation (TBARS) levels were also high in all the stress treatments, especially under the combination treatment. Addition of Se not only improved the activities of SOD, APX and glutathione reductase (GR) in stress-treated roots, but it also changed the activities of monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR). The findings reveal that Se has a positive effect on heat and/or osmotic stress mitigation mainly by regulating the ascorbate-glutathione cycle, especially in PEG-treated plants. Under the combined stress treatment, addition of 5 µM of exogenous Se was most effective. [ABSTRACT FROM AUTHOR]

In this study the novel biosorbent – raw corn silk (CS) was investigated for Cu 2+ and Zn 2+ removal from aqueous solutions. The physical and chemical properties of CS were determined by SEM – EDX and ATR – FTIR techniques. The SEM micrographs revealed that surface morphology of CS is suitable for metal adsorption, while FTIR analysis confirmed presence of various active groups (O H, C O, C O C, C C and amide II) which could interact with metal ions. The adsorption experiments were performed in batch system. Experimental data were fitted by pseudo – first order and pseudo – second order kinetic models as well as Langmuir and Freundlich isotherm models. Biosorption of the both metals follow pseudo second-order kinetic model. The best fitting adsorption model is Langmuir model and the maximum biosorption capacities (q max ) for Cu 2+ and Zn 2+ at 313 K and pH 5.0 were 15.35 mg g −1 and 13.98 mg g −1 , respectively. The thermodynamic parameters such as Gibbs free energy change (ΔG), enthalpy change (ΔH) and entropy change (ΔS) were studied at different metal concentration and three temperatures. According to thermodynamic study, the biosorption process for both metals is feasible, endothermic and spontaneous. According to thermodynamic study, the biosorption process for both metals is feasible, endothermic and spontaneous. Ion – exchange is the dominant mechanism in adsorption of Cu 2+ and Zn 2+ on the CS with a certain degree of complexation. Desorption study was performed in three adsorption/desorption cycles with diluted nitric acid. Results show that after metal adsorption CS can be efficiently recovered and reused for new adsorption process. Obtained results indicated that corn silk could be used as efficient novel biosorbent for Cu 2+ and Zn 2+ removal from water samples. [ABSTRACT FROM AUTHOR]

Water is essential for plant growth, and water shortage will have an impact on plant yield, growth and quality, therefore, rapid and nondestructive detection of water content in maize leaves is of great significance for scientific guidance of irrigation, and it is also important for improving crop yield. In order to rapidly detect the moisture content of maize leaves, transmission spectrum on the band of 300-1 700 nm was selected to predict moisture content of maize leaves. The testing system included the light source and sensors. The light source part was provided by Wuling Optical Instrument Company. The transmission spectral range of 350-820 nm was obtained with ocean STS-VIS spectrometer, and the spectrum of 900-1 700 nm was measured by Wuling NIRez near-infrared spectrometer. Although the 820-900 nm transmission spectrum was absent, the transmittance curves obtained from different water gradients showed the same trend. Ten maize plants at stage V9 were detected. In order to eliminate the interference of different blade thickness on the experimental results, the first piece of fully expanded leaves from the top of the plant was selected as the experimental sample. The samples were taken back to the laboratory, and 10 cm long strips were cut along the veins from the middle of the leaves. The experiment measured and recorded transmission spectra curve and the moisture content of maize leaves under different water gradient. The moisture content measured by fresh weight moisture content formula, the transmission rate calculated according to Lambert-Beer law. The total number of experimental samples was 98, validation set was 33, and modeling set was 65. The total moisture content of maize leaves was 10%-85% and the average moisture content was 57.9%. In order to eliminate the influence of the noise caused by the spectrometer itself, the Savitzky-Golay method was used for pretreatment. The data was processed using correlation analysis between the transmission spectra and the moisture content, and principal co. As a result, the sensitive wavelengths at 800, 932 and 1 423 nm were selected by the correlation analysis, and the sensitive wavelengths at 478, 748, 1058 and 1323 nm were extracted by principal component analysis. To further improve the determination ability of the model, four sensitive wavelengths were selected, which were 800, 1 323, 1 058 and 1 423 nm. Using the combination of these four wavelengths, 12 vegetation index such as ratio vegetation index, difference vegetation index and normalized difference vegetation index were obtained. In the 12 vegetation indices, the modeling accuracy and prediction accuracy were significantly higher than other vegetation indices, so the DVI (1 423, 800) and DVI (1 423, 1 503) were respectively used to predict the moisture content. The results showed that DVI, which was derived from the combination of strong water absorption band (1 423 nm) and weak water absorption wavelength (800 and 1503 nm), could effectively restrain the disturbance caused by structural changes, and it could sensitively reflect the moisture content of maize leaves. Multivariate linear regression model was established based on DVI (1 423, 800), T1323 and T1058, the calibration R2 reached to 0.968 8, the validation R2 reached to 0.951 9, and the root mean square error of prediction was 0.061. The results showed that water prediction model established by transmission spectroscopy could provide efficient guidance for plant leaf water rapid detecting instrument development. [ABSTRACT FROM AUTHOR]

Histone acetylation plays a critical role in controlling chromatin structure, and reactive oxygen species (ROS) are involved in cell cycle progression. To study the relationship between histone acetylation and cell cycle progression in plants, sodium butyrate (NaB), a histone deacetylase (HDAC) inhibitor that can cause a significant increase in histone acetylation in both mammal and plant genomes, was applied to treat maize seedlings. The results showed that NaB had significant inhibition effects on different root zones at the tissue level and caused cell cycle arrest at preprophase in the root meristem zones. This effect was accompanied by a dramatic increase in the total level of acetylated lysine 9 on histone H3 (H3K9ac) and acetylated lysine 5 on histone H4 (H4K5ac). The exposure of maize roots in NaB led to a continuous rise of intracellular ROS concentration, accompanied by a higher electrolyte leakage ratio and malondialdehyde (MDA) relative value. The NaB-treated group displayed negative results in both TdT-mediated dUTP nick end labelling (TUNEL) and γ-H2AX immunostaining assays. The expression of topoisomerase genes was reduced after treatment with NaB. These results suggested that NaB increased the levels of H3K9ac and H4K5ac and could cause preprophase arrest accompanied with ROS formation leading to the inhibition of DNA topoisomerase. [ABSTRACT FROM AUTHOR]

Carotenoids, a diverse group of colorful pigments, contribute to the development, light harvesting and photoprotection in plants as well as human health. Due to the interesting properties of carotenoids, enhanced carotenoid biosynthesis has been of ongoing interest. Recent advances in computational biology and bioinformatics make it more feasible to understand the transcriptional regulatory network underlying carotenoid biosynthesis. Studies on carotenoid biosynthesis in corn (Zea mays L.) have indicated the pivotal role of the phytoene synthase gene PSY1 (accession: GRMZM2G300348) in endosperm color and carotenoid accumulation in corn kernels. Computational approaches such as Genomatix, PlantPAN, PlantCARE, PlantTFDB and IGDE6 have been used for promoter prediction, regulatory features and transcription factor identification, as well as pairwise promoter comparisons. Four transcripts have been identified for the PSY1 gene. Based on Genomatix and PlantPAN, the promoter predicted for GRMZM2G300348_T01 was different from that predicted for the other three transcripts (GRMZM2G300348_T02, GRMZM2G300348_T03 and GRMZM2G300348_T04). The results indicated that the promoter of GRMZM2G300348_T01 has more diverse motifs involved in hormonal/environmental stress responses. The most significant result obtained from this study is the discovery of two transcription factors belonging to the HB family that are co-expressed with all four transcripts of PSY1 under environmental stresses. It is, therefore, likely that these transcription factors may act as critical regulators of PSY1 gene expression in corn. Identification of the proteins acting upstream of PSY1 within corn will shed light on the fine tuning of PSY1 expression regulation. Such an understanding would also contribute to metabolic engineering aimed at enhanced carotenoid biosynthesis. [ABSTRACT FROM AUTHOR]

Drought stress is one of major factors resulting in maize yield loss. The roles of abscisic acid (ABA) have been widely studied in crops in response to drought stress. However, more attention is needed to identify key ABA-related proteins and also gain deeper molecular insights about drought stress in maize. Based on this need, the physiology and proteomics of the ABA-deficient maize mutant vp5 and its wild-type Vp5 under drought stress were examined and analyzed. Malondialdehyde content increased and quantum efficiency of photosystem II decreased under drought stress in both genotypes. However, the magnitude of the increase or decrease was significantly higher in vp5 than in Vp5. A total of 7051 proteins with overlapping expression patterns among three replicates in the two genotypes were identified by Multiplex run iTRAQ-based quantitative proteomic and liquid chromatography-tandem mass spectrometry methods, of which the expression of only 150 proteins (130 in Vp5, 27 in vp5) showed changes of at least 1.5-fold under drought stress. Among the 150 proteins, 67 and 60 proteins were up-regulated and down-regulated by drought stress in an ABA-dependent way, respectively. ABA was found to play active roles in regulating signaling pathways related to photosynthesis, oxidative phosphorylation (mainly related to ATP synthesis), and glutathione metabolism (involved in antioxidative reaction) in the maize response to drought stress. Our results provide an extensive dataset of ABA-dependent, drought-regulated proteins in maize plants, which may help to elucidate the underlying mechanisms of ABA-enhanced tolerance to drought stress in maize. [ABSTRACT FROM AUTHOR]

Drought occurs at high frequency in maize production zones in Africa. Carefully controlled moisture deficits have been imposed at anthesis and grain filling stages of maize to develop drought tolerant germplasm. The present study was conducted to examine the potential effects of drought tolerant parents selected under such managed drought stress on agronomic performance of their top-cross hybrids across variable growing conditions in the rainy season. Three independent trials consisting of top-cross hybrids involving drought tolerant parents and commercial hybrids were evaluated under manged drought stress (MDS) and well watered (WW) condition at Ikenne in Nigeria for 3 years during the dry season and across 30 stressful (SE) and 52 favourable (FE) rainfed environments in West Africa. The drought stress imposed in the dry season caused a 53-64 % annual average yield reductions in these trials. In spite of these, about 56 % of the top-crosses produced high grain yields under MDS and WW conditions. The rank orders for hybrid grain yields did not change markedly across different years under MDS and WW conditions. Also, nearly 78 % of the top-crosses produced high grain yields across SE and FE environments in the rainy season. Sixteen top-cross hybrids amongst these were present in the top yielding groups under the MDS environment. Some high yielding top-crosses with stable performance across variable rainfed environments were identified in the current study. The phenotypic and genetic correlations between grain yield under MDS and that under SE environment were positive and moderate. Also, the phenotypic and genetic correlations showed that the capacity of top-cross hybrids to produce high grain yields under MDS was independent of the yield potential under FE environment. These results suggest that selection of parents under manged drought stress promotes the development of top-cross hybrids broadly adapted to variable rainfed conditions. [ABSTRACT FROM AUTHOR]

Field trial was conducted in 2011/2012 and 2012/2013 to determine the maize growth parameters under maize-soybean and maize-cowpea intercropping system at different reproductive stages. The varieties used were Umut 2002 (soybean), Karagoz (cowpea) and PR31G98 (maize) while the cropping treatments were sole and intercrop (alternate-rows). The experimental design was a randomized complete block design with three replicates. Results showed that maize planted (alternate-rows) simultaneously with cowpea and soybean recorded significantly higher values of leaf area index (LAI), leaf area ratio (LAR) and net assimilation rate (NAR). Highest values of NAR was recorded at R1 stage; LAI, LAR and relative growth rate (RGR) through at vegetative growth stage. LAI (sole maize) and NAR (1M+1C) showed significant correlation with grain yield. LAR and RGR for maize decreased from VT to R6. The LAI and NAR at silking stage have been identified as the major determinants of grain yield. [ABSTRACT FROM AUTHOR]

Global climate models predict increase in mean daily temperature to be mainly driven by rapid increase in nighttime temperature compared to daytime temperature, leading to narrowing diurnal temperature amplitude. Higher day and night temperatures induce significant negative impact on growth and development of different crops. However, limited studies have focused on quantifying impacts associated with different diurnal temperature amplitudes maintaining the same daily mean temperature. The main objectives were to (i) quantify the impact of diurnal temperature amplitudes on the carbon balance of the plant (photosynthesis versus night respiration rate) and (ii) evaluate the significance of variable day and night temperature with a common mean on the carbohydrate composition and overall plant growth. A maize hybrid (DKC47-27RIB) was grown in controlled environments at two mean daily temperatures (30 °C and 35 °C) with three different combinations of day and night temperatures resulting in diurnal temperature amplitudes of 2 °C, 10 °C and 18 °C. After 42 days of temperature treatments, lower diurnal temperature amplitude led to a linear increase in night respiration and a linear decrease in total sugars, non-reducing sugars, starch concentrations, plant height, total leaf area and total biomass accumulation. However, there was no significant change in photosynthetic rate among the treatment combinations, while photochemical efficiency (Fv/Fm) and chlorophyll index decreased only with diurnal temperature amplitude of 18 °C and 2 °C, respectively. A significant negative relationship was found between night respiration and total biomass accumulation (R 2 = 0.73; P < 0.01 ), total leaf area (R 2 = 0.82; P < 0.01), specific leaf area (R 2 = 0.21; P < 0.01), non-reducing sugars (R 2 = 0.50; P < 0.01) and starch concentrations (R 2 = 0.50; P < 0.01). The results imply that narrowing diurnal temperature amplitude as a result of higher night temperature is the major driver of the negative impact on vegetative growth in maize. [ABSTRACT FROM AUTHOR]

In roots of gramineous plants, lysigenous aerenchyma is created by the death and lysis of cortical cells. Rice ( Oryza sativa) constitutively forms aerenchyma under aerobic conditions, and its formation is further induced under oxygen-deficient conditions. However, maize ( Zea mays) develops aerenchyma only under oxygen-deficient conditions. Ethylene is involved in lysigenous aerenchyma formation. Here, we investigated how ethylene-dependent aerenchyma formation is differently regulated between rice and maize. For this purpose, in rice, we used the reduced culm number1 ( rcn1) mutant, in which ethylene biosynthesis is suppressed. Ethylene is converted from 1-aminocyclopropane-1-carboxylic acid (ACC) by the action of ACC oxidase (ACO). We found that OsACO5 was highly expressed in the wild type, but not in rcn1, under aerobic conditions, suggesting that OsACO5 contributes to aerenchyma formation in aerated rice roots. By contrast, the ACO genes in maize roots were weakly expressed under aerobic conditions, and thus ACC treatment did not effectively induce ethylene production or aerenchyma formation, unlike in rice. Aerenchyma formation in rice roots after the initiation of oxygen-deficient conditions was faster and greater than that in maize. These results suggest that the difference in aerenchyma formation in rice and maize is due to their different mechanisms for regulating ethylene biosynthesis. [ABSTRACT FROM AUTHOR]

Application of some compounds stimulating growth and physiological processes may have favourable effect on maize productivity. The study aimed to assess the response of maize germination and initial growth to soil-applied humic substances, and the effect of these substances and foliar potassium fertilizer on the maize grain yield. The study was based on a single-factorial field experiment conducted over 2006-2008 in Poland, (17o35' E; 53o09' N), on soil classified as mesic Typic Hapludalf, in a randomized block design, in four replications. The effect of the following was evaluated: humus preparation Humistar (12% humic acids and 3% fulvic acids), applied pre-sowing into soil, at a rate of 40 dm3 ha-1 (T1), foliar fertilizer Drakar (25.7% K and 3% N), applied at BBCH 16 and 17, at a rate of 2 dm3 ha-1 (T2), combined application of Humistar and Drakar (T3), and the control (T4). Humistar application resulted in an increase in germination energy, but it did not affect germination capacity or seedlings weight of maize. Humistar or Drakar caused an increase in cob weight, grain proportion in the cob weight and grain yield, as compared with the control. The increase in grain yield in individual years of the study after Humistar application ranged from 1.21 to 8.41% (140-620 kg ha-1), whereas after Drakar from 0.35 to 5.8% (40-430 kg ha-1). Combined application of these preparations caused an increase in grain yield on average from the years in relation to control (by 2.1%), but there was no difference in yield as compared with the application of Humistar or Drakar only. Further studies are necessary to evaluate the effect of these preparations in weak soils with low content of organic matter and nutrients. [ABSTRACT FROM AUTHOR]

In this study we evaluated the leaf surface properties of maize populations native to different water availability environments. Leaf surface topography, wettability and gas exchange performance of five maize populations from the Sahara desert, dry (south) and humid (north-western) areas of Spain were analysed. Differences in wettability, stomatal and trichome densities, surface free energy and solubility parameter values were recorded between populations and leaf sides. Leaves from the humid Spanish population with special regard to the abaxial side, were less wettable and less susceptible to polar interactions. The higher wettability and hydrophilicity of Sahara populations with emphasis on the abaxial leaf surfaces, may favour dew deposition and foliar water absorption, hence improving water use efficiency under extremely dry conditions. Compared to the other Saharan populations, the dwarf one had a higher photosynthesis rate suggesting that dwarfism may be a strategy for improving plant tolerance to arid conditions. The results obtained for different maize populations suggest that leaf surfaces may vary in response to drought, but further studies will be required to examine the potential relationship between leaf surface properties and plant stress tolerance. [ABSTRACT FROM AUTHOR]

Although the remobilization of vegetative nitrogen (N) and post-silking N both contribute to grain N in maize (Zea mays L.), their regulation by grain sink strength is poorly understood. Here we use 15N labeling to analyze the dynamic behaviors of both pre- and post-silking N in relation to source and sink manipulation in maize plants. The results showed that the remobilization of pre-silking N started immediately after silking and the remobilized pre-silking N had a greater contribution to grain N during early grain filling, with post-silking N importance increasing during the later filling stage. The amount of post-silking N uptake was largely driven by post-silking dry matter accumulation in both grain as well as vegetative organs. Prevention of pollination during silking had less effect on post-silking N uptake, as a consequence of compensatory growth of stems, husk + cob and roots. Also, leaves continuously export N even though grain sink was removed. The remobilization efficiency of N in the leaf and stem increased with increasing grain yield (hence N requirement). It is suggested that the remobilization of N in the leaf is controlled by sink strength but not the leaf per se. Enhancing post-silking N uptake rather than N remobilization is more likely to increase grain N accumulation. [ABSTRACT FROM AUTHOR]

We studied assimilation of СО and distribution of С among the products of 3-min-long photosynthesis of maize ( Zea mays L.) leaves. The day before the experiment, half of the plants were fertilized with Ca(NO) (1 g/L of water) at a rate of 6 L/m. Five days before the experiment, some plants were shaded for adaptation (illuminance was reduced by 50%). On the day of the experiment (before the application of СО), several shaded plants were exposed to direct sunlight for 3 min, and some plants grown at full light (light plants) were shaded for 3 min (illuminance of 50%). Unfertilized plants adapted for 5 days to shading showed photosynthesis of 75.9% of control level (full light). If light plants were transferred to shading for 3 min, their photosynthesis decreased to 42.1%. In plants shaded for 5 days and then transferred to full light, photosynthesis in 3 min was 96.3% of control level. At full light, fertilization with nitrate boosted photosynthesis to 132.6% as compared with control material, but photosynthesis decreased to 43.5 and 65.4% of control level in plants shaded for 5 days and those shaded for 3 min, respectively. At the same time, the plants shaded for 5 days and then exposed for 3 min to full light restored photosynthesis to almost control level (95.5%). Analysis of С distribution among the products of 3-min-long photosynthesis showed that, the same as in C plants, a decrease in illuminance (especially a sudden one) in maize reduced the ratio between labeled sucrose and hexoses and elevates incorporation of С into malate, which indicated that its consumption in bundle sheath cells was suppressed. A decrease in the ratio between labeled sucrose and hexoses became more pronounced under the influence of nitrates with this effect also occurring in transport products of photosynthesis (20 cm below С-providing leaf area). In plants fertilized with nitrates, radioactivity of sucrose (% of radioactivity of soluble compounds) decreased in all the types of illumination. When illuminance was suddenly reduced for 3 min, incorporation of С into sucrose was 21.5 against 51.2% in light plants, and radioactivity of aspartate and malate sharply rose to 13.7 and 26.1% (against 2.1 and 8.9% in control material). Incorporation of С into compounds of glycolate pathway was low (less than 2.5%), but it was somewhat greater in nitrate plants. We concluded that the same mechanism of interaction between stomatal apparatus of leaf epidermis, invertase of mesophyll apoplast, and photosynthetic metabolism of carbon with electron flux via electron transport chain in chloroplasts of bundle sheath cells, which governs the rate of photosynthesis and assimilate export from the leaf but is triggered by the extent of consumption in the bundle sheath cells of C acids produced in the mesophyll operates in C plants (the same as in C plants). [ABSTRACT FROM AUTHOR]

A better understanding of the sap flow characteristics of maize plants is critical for improving irrigation water-use efficiency, especially for regions facing water resource shortages. In this study, sap flow rates, related soil-physics and plant-growth parameters, and meteorological factors, were simultaneously monitored in a maize field in two consecutive years, 2011 and 2012, and the sap flow rates of the maize plants were extensively analyzed based on the monitored data. Seasonal and daily variational characteristics were identified at different growth stages and under different weather conditions, respectively. The analyses on the relationships between sap flow rate and reference evapotranspiration (ET), as well as several plant-growth parameters, indicate that the irrigation schedule can exert an influence on sap flow, and can consequently affect crop yield. The ranking of the main meteorological factors affecting the sap flow rate was: net radiation > air temperature > vapor pressure deficit > wind speed. For a quick estimation of sap flow rates, an empirical formula based on the two top influencing factors was put forward and verified to be reliable. The sap flow rate appeared to show little response to irrigation when the water content was relatively high, implying that some of the irrigation in recent years may have been wasted. These results may help to reveal the bio-physical processes of maize plants related to plant transpiration, which could be beneficial for establishing an efficient irrigation management system in this region and also for providing a reference for other maize-planting regions. [ABSTRACT FROM AUTHOR]

A field experiment was conducted for two years (2013 and 2014) to study the effect of foliar spray of potassium and zinc on maize crop under rainfed environment. Nine treatments were examined as: control, recommended rate of zinc (RRZn) to soil @ 15 kg Zn2SO4 ha-1, foliar zinc spray (FZS) @ 0.1%, recommended rate of potassium to soil (RRK) @ 75 kg K2O ha-1, RRK + RRZn, RRK+ FZS, foliar potassium spray (FKS) at 1% concentration, FKS + RRZn, FKS + FZS. The experiments were arranged in split plot with three replications. All integrated and individual foliar sprays of potassium and zinc surpassed all other treatments. Among all foliar treatments, integrated use of foliar potassium and zinc spray at 25 and 50 days after sowing (DAS) @ 1.0 and 0.1%, respectively enhanced all plant growth, yield, physiological and quality traits of maize. The highest 1000 grain weight (g) and grain yield (kg ha-1) were recorded under the combined foliar spray of potassium and zinc (FKS + FZS), followed by FKS + RRZn and RRK+ FZS. Greater net benefit and benefit cost ration were examined under all foliar sprays. Foliar spray of potassium and zinc is a fertilizer use efficient technique for increasing the maize yield attributes and net income under rainfed conditions. [ABSTRACT FROM AUTHOR]

The role of salicylic acid in Cd tolerance has attracted more attention recently but no information is available on the efficiency of different forms of salicylic acid. The aim was thus to investigate whether both the acid and salt forms of salicylic acid provide protection against Cd stress and to compare their mode of action. Young maize plants were grown under controlled environmental conditions. One group of 10-day-old seedlings were treated with 0.5 mM SA or NaSA for 1 day then half of the pants were treated with 0.5 mM Cd for 1 day. Another group of seedlings was treated with 0.5 mM CdSO4 for 1 day without pre-treatment with SA or NaSA, while a third group was treated simultaneously with Cd and either SA or NaSA. Both salicylic acid forms reduced the Cd accumulation in the roots. Treatment with the acidic form meliorated the Cd accumulation in the leaves, while Na-salicylate increased the phytochelatin level in the roots and the amount of salicylic acid in the leaves. Furthermore, increased antioxidant enzyme activity was mainly induced by the acid form, while glutathione-related redox changes were influenced mostly by the salt form. The acidic and salt forms of salicylic acid affected the two antioxidant systems in different ways, and the influence of these two forms on the distribution and detoxification of Cd also differed. The present results also draw attention to the fact that generalisations about the stress protective mechanisms induced by salicylic acid are misleading since different forms of SA may exert different effects on the plants via separate mechanisms. [ABSTRACT FROM AUTHOR]

In this study, some morphological and physiological parameters of three maize (Zea mays L.) cultivars, cv. FR13, FRB73 and TTM815, were analysed to investigate their tolerance to drought stress. Twenty-one-day old plants were subjected to three different regime of drought stress by withholding Hoagland's nutrient solution for 2 (mild drought stress), 5 (moderate drought stress), and 8 (severe drought stress) days. Root growth in cultivars FR13 and TTM815 was significantly inhibited by moderate and severe drought stress while shoot growth in all maize cultivars was not affected under all drought treatments. Our results showed that inhibited root growth under mild and severe drought conditions was responsible for decreased total plant lenght in all cultivars although FRB73 was less affected. Fresh and dry biomass increased in all cultivars under all drought treatments, however it was more significant in FRB73. These results may indicate that water relations in FRB73 can be regulated more properly under drought stress, as indicated by relatively constant water content. “Chlorophyll a” content in FR13 and TTM815 was decreased at the end of the treatments while it was not affected in FRB73 by drought stress. “Chlorophyll b” content in FR13 and FRB73, on the other hand, was less affected by drought treatments. Malondialdehyde accumulation in all cultivars increased considerably as a result of all drought treatments, however to a less extent in FRB73. Total phenolic contents in all cultivars were increased especially by moderate and severe drought stress. Total soluble sugar contents in FR13 and TTM815 were decreased significantly by mild and severe drought stress while it remained constant in FRB73 under all drought treatments. According to our results, it may be concluded that FRB73 is more drought tolerant maize cultivar because of the ability of maintaining root and shoot growth, accumulation of phenolics, fresh and dry biomass, relatively less affected water, photosynthetic pigment (chlorophyll a and b) and sugar content and lower level of malondialdehyde under drought stress when compared to FR13 and TTM815. [ABSTRACT FROM AUTHOR]

In plants, Vacuole H+-PPases (VPPs) are important proton pumps and encoded by multiple genes. In addition to full-length VPPs, several truncated forms are expressed, but their biological functions are unknown. In this study, we functionally characterized maize vacuole H+-PPase 5 ( ZmVPP5), a truncated VPP in the maize genome. Although ZmVPP5 shares high sequence similarity with ZmVPP1, ZmVPP5 lacks the complete structure of the conserved proton transport and the inorganic pyrophosphatase-related domain. Phylogenetic analysis suggests that ZmVPP5 might be derived from an incomplete gene duplication event. ZmVPP5 is expressed in multiple tissues, and ZmVPP5 was detected in the plasma membrane, vacuole membrane and nuclei of maize cells. The overexpression of ZmVPP5 in yeast cells caused a hypersensitivity to salt stress. Transgenic maize lines with overexpressed ZmVPP5 also exhibited the salt hypersensitivity phenotype. A yeast two-hybrid analysis identified the ZmBag6-like protein as a putative ZmVPP5-interacting protein. The results of bimolecular luminescence complementation (BiLC) assay suggest an interaction between ZmBag6-like protein and ZmVPP5 in vivo. Overall, this study suggests that ZmVPP5 might act as a VPP antagonist and participate in the cellular response to salt stress. Our study of ZmVPP5 has expanded the understanding of the origin and functions of truncated forms of plant VPPs. [ABSTRACT FROM AUTHOR]

The higher photosynthetic potential of C4 plants has led to extensive research over the past 50 years, including C4-dominated natural biomes, crops such as maize, or for evaluating the transfer of C4 traits into C3 lineages. Photosynthetic gas exchange can be measured in air or in a 2% Oxygen mixture using readily available commercial gas exchange and modulated PSII fluorescence systems. Interpretation of these data, however, requires an understanding (or the development) of various modelling approaches, which limit the use by non-specialists. In this paper we present an accessible summary of the theory behind the analysis and derivation of C4 photosynthetic parameters, and provide a freely available Excel Fitting Tool (EFT), making rigorous C4 data analysis accessible to a broader audience. Outputs include those defining C4 photochemical and biochemical efficiency, the rate of photorespiration, bundle sheath conductance to CO2 diffusion and the in vivo biochemical constants for PEP carboxylase. The EFT compares several methodological variants proposed by different investigators, allowing users to choose the level of complexity required to interpret data. We provide a complete analysis of gas exchange data on maize (as a model C4 organism and key global crop) to illustrate the approaches, their analysis and interpretation. © 2015 John Wiley & Sons Ltd [ABSTRACT FROM AUTHOR]

ABSTRACT In a polifactorial long-term experiment, the effects of the year and the agrotechnical factors on the yields and plant physiological parameters (LAI, SPAD) of winter wheat and maize were studied on chernozem soil in the period of 2011-2013. Results of our long-term experiments proved that the yield of winter wheat was influenced both by the fertilization and the crop rotation. The productivity of the C[sub 4]-type maize was higher than that of the C[sub 3]-type winter wheat. Our results proved that the plant physiological parameters (LAI, SPAD) of winter wheat (C[sub 3]) and maize (C[sub 4]) were not different, however, there were great differences in productivity between the two crops. A new parameter (Ph.C.) was developed for the characterization of the photosynthetic capacity in winter wheat and maize. The Ph.C. values of winter wheat (C[sub 3]) and maize (C[sub 4]) were significantly different (300-400 Ph.C. and 800-1200 Ph.C.). The Ph.C. values can also be well used for the characterization of the agrotechnical elements (fertilization, crop rotation, irrigation). A close correlation was found between the yields of maize and winter wheat and the Ph.C. values (r = 0.671-0.938**, r = 0.792-0.934**). [ABSTRACT FROM AUTHOR]

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The objective of this study was to evaluate the role of PGPR consortium and fertilizer alone and in combination on the physiology of maize grown under oily sludge stress environment as well on the soil nutrient status. Consortium was prepared fromBacillus cereus(Acc KR232400),Bacillus altitudinis(Acc KF859970),Comamonas(Delftia) belonging to family Comamonadacea (Acc KF859971) andStenotrophomonasmaltophilia(Acc KF859973). The experiment was conducted in pots with complete randomized design with four replicates and kept in field. Oily sludge was mixed in ml and Ammonium nitrate and Diammonium phosphate (DAP) were added at 70 ug/g and 7ug/g at sowing. The plant was harvested at 21 d for estimation of protein, proline and antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD). To study the degradation, total petroleum hydrocarbon was extracted by soxhelt extraction and extract was analyzed by GC-FID at different period after incubation. Combined application of consortium and fertilizer enhanced the germination %, protein and, proline content by 90,130 and 99% higher than untreated maize plants. Bioavailability of macro and micro nutrient was also enhanced with consortium and fertilizer in oily sludge. The consortium and fertilizer in combined treatment decreased the superoxide dismutase (SOD), peroxidase dismutase (POD) of the maize leaves grown in oily sludge. Degradation of total petroleum hydrocarbon (TPHs) was 59% higher in combined application of consortium and fertilizer than untreated maize at 3 d. The bacterial consortium can enhanced the maize tolerance to oily sludge and enhanced degradation of total petroleum hydrocarbon (TPHs). The maize can be considered as tolerant plant species to remediate oily sludge contaminated soils. [ABSTRACT FROM PUBLISHER]

Prior studies with Nicotiana and Arabidopsis described failed assembly of the chloroplastic NDH [NAD(P)H dehydrogenase] supercomplex by serial mutation of several subunit genes. We examined the properties of Zea mays leaves containing Mu and Ds insertions into nuclear gene exons encoding the critical o- and n-subunits of NDH, respectively. In vivo reduction of plastoquinone in the dark was sharply diminished in maize homozygous mutant compared to normal leaves but not to the extreme degree observed for the corresponding lesions in Arabidopsis. The net carbon assimilation rate (A) at high irradiance and saturating CO2 levels was reduced by one-half due to NDH mutation in maize although no genotypic effect was evident at very low CO2 levels. Simultaneous assessment of chlorophyll fluorescence and A in maize at low (2% by volume) and high (21%) O2 levels indicated the presence of a small, yet detectable, O2-dependent component of total linear photosynthetic electron transport in 21% O2. This O2-dependent component decreased with increasing CO2 level indicative of photorespiration. Photorespiration was generally elevated in maize mutant compared to normal leaves. Quantification of the proportion of total electron transport supporting photorespiration enabled estimation of the bundle sheath cell CO2 concentration (Cb) using a simple kinetic model of ribulose bisphosphate carboxylase/oxygenase function. The A versus Cb relationships overlapped for normal and mutant lines consistent with occurrence of strictly CO2-limited photosynthesis in the mutant bundle sheath cell. The results are discussed in terms of a previously reported CO2 concentration model [Laisk A, Edwards GE (2000) Photosynth Res 66: 199-224]. [ABSTRACT FROM AUTHOR]

Rainfed maize ( Zea mays , L.) crops in temperate semi-arid regions with high inter-annual variation of summer precipitation, are commonly cultivated at low population densities. During seasons with favorable conditions for plant growth (e.g., summer rainfalls above normal records), the number of kernels of sub-apical ear can contribute significantly to total kernel number per plant (TKN). However, there is no information of the determinant traits of kernel setting at sub-apical ear, or the effects of breeding on these traits. We used a crop physiology model with an individual plant approach in attempt to describe genotypic differences in those traits related to kernel setting at the apical (KNE 1 ) and the sub-apical ear (KNE 2 ) of older and newer Argentinean maize hybrids. Four representative hybrids of the decades of 80′, 90′, 00′ and 10′ were cultivated during two growing seasons at three densities (4, 8 and 12 pl m −2 ). Nondestructive techniques were used to estimate the growth rate of individual plant (PGR PC ), apical (E 1 GR CP ) and sub-apical (E 2 GR CP ) ear during the period bracketing silking (critical period), biomass partitioning to reproductive sinks (E 1 GR CP PGR CP −1 and E 2 GR CP PGR CP −1 ) and the efficiency to set kernels of the plant (TKN PGR CP −1 ) and the ears (KNE 1 E 1 GR CP −1 and KNE 2 E 2 GR CP −1 ). Differences among tested hybrids in KNE 1 (ca. 400–600 k ear −1 ) were mainly determined by KNE 1 E 1 GR CP −1 (ca. 230–280 k d −1 g −1 ) while newer hybrids had the highest E 1 GR CP PGR CP −1 (>0.50). By contrast, hybrids had similar KNE 2 (ca. 124 k ear −1 ) due to their similar E 2 GR CP PGR CP −1 (ca. 0.08) and KNE 2 E 2 GR CP −1 (ca. 93 k d −1 g −1 ). These results suggest that breeding effect on TKN was mainly determined by KNE 1 E 1 GR CP −1 and for the newest hybrid this trait did not interact with plant density. Hence, the newest hybrid exhibited a positive linear response of TKN to PGR PC ( r 2 = 0.82) reaching the highest TKN among hybrids at low, mid and high density. A better performance of maize crops at low densities could be obtained by breeding for E 2 GR CP PGR CP −1 . [ABSTRACT FROM AUTHOR]

Ustilago maydis is a biotrophic plant pathogenic fungus that leads to tumor development in the aerial tissues of its host, Zea mays . These tumors are the result of cell hypertrophy and hyperplasia, and are accompanied by the reprograming of primary and secondary metabolism of infected plants. Up to now, little is known regarding key plant actors and their role in tumor development during the interaction with U . maydis . Polyamines are small aliphatic amines that regulate plant growth, development and stress responses. In a previous study, we found substantial increases of polyamine levels in tumors. In the present work, we describe the maize polyamine oxidase (PAO) gene family, its contribution to hydrogen peroxide (H 2 O 2 ) production and its possible role in tumor development induced by U . maydis . Histochemical analysis revealed that chlorotic lesions and maize tumors induced by U . maydis accumulate H 2 O 2 to significant levels. Maize plants inoculated with U . maydis and treated with the PAO inhibitor 1,8-diaminooctane exhibit a notable reduction of H 2 O 2 accumulation in infected tissues and a significant drop in PAO activity. This treatment also reduced disease symptoms in infected plants. Finally, among six maize PAO genes only the ZmPAO1 , which encodes an extracellular enzyme, is up-regulated in tumors. Our data suggest that H 2 O 2 produced through PA catabolism by ZmPAO1 plays an important role in tumor development during the maize- U . maydis interaction. [ABSTRACT FROM AUTHOR]

We have developed a novel hybridization platform that utilizes nuclear male sterility to produce hybrids in maize and other cross-pollinating crops. A key component of this platform is a process termed Seed Production Technology (SPT). This process incorporates a transgenic SPT maintainer line capable of propagating nontransgenic nuclear male-sterile lines for use as female parents in hybrid production. The maize SPT maintainer line is a homozygous recessive male sterile transformed with a SPT construct containing (i) a complementary wild-type male fertility gene to restore fertility, (ii) an α-amylase gene to disrupt pollination and (iii) a seed colour marker gene. The sporophytic wild-type allele complements the recessive mutation, enabling the development of pollen grains, all of which carry the recessive allele but with only half carrying the SPT transgenes. Pollen grains with the SPT transgenes exhibit starch depletion resulting from expression of α-amylase and are unable to germinate. Pollen grains that do not carry the SPT transgenes are nontransgenic and are able to fertilize homozygous mutant plants, resulting in nontransgenic male-sterile progeny for use as female parents. Because transgenic SPT maintainer seeds express a red fluorescent protein, they can be detected and efficiently separated from seeds that do not contain the SPT transgenes by mechanical colour sorting. The SPT process has the potential to replace current approaches to pollen control in commercial maize hybrid seed production. It also has important applications for other cross-pollinating crops where it can unlock the potential for greater hybrid productivity through expanding the parental germplasm pool. [ABSTRACT FROM AUTHOR]

Information concerning corn plant development within predicted environmental constraints and the possibility of alleviating their negative influence by ecological compounds is limited. Thus the aim of our research was to evaluate the physiological activity, growth, and development of corn plants under the expected climate-change conditions and treated with Biojodis (certificated extract of humus and active iodine; Jodavita, Lithuania) and Cyanobacteria (a mixture of monocultures of Microcystis aeruginosa MKR 0105 and Anabaena sp. PCC 7120). 'Cyrkon' corn plants (Zea mays L.) were cultivated in several simulated predicted climate conditions, including constant or periodically changing temperature and soil moisture content. During the vegetative season they were treated at three-week intervals using Biojodis at concentrations of 1.0, 2.0, or 3.0%, and Cyanobacteria, and then assessed using growth and physiological parameters. The obtained results showed the corn's different reactions to the applied conditions. Plants that grew at constant or periodically changing different temperatures (0 to 40°C) or in unsatisfactorily (20% m.c.) or excessively (60% m.c.) watered soils, developed slowly in comparison with those growing at 20°C and in optimally moistened media (30% m.c.). Watering, spraying, or watering and spraying of corn plants with Biojodis (1, 2, 3%) and a foliar application of Cyanobacteria increased their growth at optimal or unfavourable temperature and in unsatisfactory or excessively moistened soil. The three times spraying with Biojodis (1 or 2%) and with Cyanobacteria was most promising. The plant development changes related to the used compounds and simulated environmental constraints were associated with the changes in indexes of chlorophyll content in leaves, stability of membranes, gas exchange, and activity of acid or alkaline phosphatase and RNase. The above indicates that foliar and soil application of Biojodis and plant sprayings with Cyanobacteria increased growth of corn cultivated under optimal temperature and soil moisture content and partly restored the harmful effects of artificial temperature and water stress on plant development and physiological activity. Biojodis also can increase the iodine content in corn and uptake of nutrients from the soil, and thus decrease environmental pollution. [ABSTRACT FROM AUTHOR]

The mechanism of compensatory growth in corn after post-drought rewatering at the seedling stage was explored by investigating the levels and effects of several plant hormones. This study consisted of two treatment conditions: nitrate (NO 3 − ) addition to the roots and cytokinin addition to the leaves. Results showed that drought stress reduced the biomass of aboveground parts and the whole plant, but increased root soluble carbohydrate concentration and root activity. Post-drought rewatering under the addition of NO 3 − to the roots increased corn growth. Biomass values of the aboveground parts and the whole plant were similar between the rewatering and wetness at 10 days after rewatering conditions. Upon addition of NO 3 − to roots, post- drought rewatering increased the cytokinin contents of leaves and its delivery rate from roots to leaves. Addition of cytokinin to leaves without the addition of NO 3 − to roots increased the growth rate of corn seedlings upon post-drought rewatering and simultaneously caused high leaf cytokinin concentration. Thus, increase in concentration of root-derived cytokinin concentration in leaves was closely related to compensatory growth in corn upon post-drought rewatering at the seedling stage. [ABSTRACT FROM AUTHOR]

Increases in nitrogen (N) availability reduce decay rates of highly lignified plant litter. Although microbial responses to N addition are well documented, the chemical mechanisms that may give rise to this inhibitory effect remain unclear. Here, we ask: Why does increased N availability inhibit lignin decomposition? We hypothesized that either (1) decomposers degrade lignin to obtain N and stop producing lignin-degrading enzymes if mineral N is available, or (2) chemical reactions between lignin and mineral N decrease the quality of lignin and limit the ability of decomposers to break it down. In order to test these hypotheses, we tracked changes in carbon (C) mineralization, microbial biomass and enzyme activities, litter chemistry, and lignin monomer concentrations over a 478-day laboratory incubation of three maize genotypes differing in lignin quality and quantity (Fbm (high lignin) < F (medium lignin) < Fbm (low lignin)). Maize stem internodes of each genotype were mixed with either an acidic or neutral pH sandy soil, both with and without added N. Nitrogen addition reduced C mineralization, microbial biomass, and lignin-degrading enzyme activities across most treatments. These dynamics may be due to suppressed fungal growth and reduced microbial acquisition of lignin-shielded proteins in soils receiving N. However, N addition alone did not significantly alter the quantity or quality of lignin monomers in any treatment. Our results suggest that abiotic interactions between N and phenolic compounds did not influence lignin chemistry, but mineral N does alter microbial enzyme and biomass dynamics, with potential longer-term effects on soil C dynamics. [ABSTRACT FROM AUTHOR]

Maize is the 3rd major crop grown all over the world that fulfills the needs of millions of people. Various biotic and abiotic factors caused reduction in grain yield of maize, among them weeds show most adverse effects. Objective of this study was to develop glyphosate resistance maize for developing maize hybrids and synthetic varieties with high grain and fodder yield potential. Glyphosate is a broad spectrum herbicide and resistance of crop against the herbicide, allows post emergence application, which otherwise is impossible. Higher GTG crude protein (479.94µg/g) was recorded for CIL 194-975 plant. The plant CIL 194-1786 showed higher expression level of GTG protein, indicated that transformation efficiency was better for line CIL-194 than CIL-123. GTGene stably integrated to the genome of the maize lines CIL-194 and CIL-123, these transformed lines showed more ability to cope with herbicides as compared with non-transformed lines in greenhouse and field trials. The transgenic lines were sown in field and data was recorded for various morpho-physiological, grain, fodder yield and quality traits. Data was statistically analyzed to check significance of results at <0.05% probability level. It was concluded from heritability, genetic advance, stepwise multiple linear regression, principle component and factor analysis that the selection on the basis of grain yield, green fodder yield, stem diameter, cob weight, stomata conductance, chlorophyll contents, photosynthetic rate, cob length, grain protein, grain oil, embryo percentage and grain starch may be fruitful keeping in view as the major contributing traits to improve crop yield and production. It was suggested that the transgenic lines for glyphosate resistance may be used to develop transgenic hybrids and synthetic varieties with higher grain yield with high quality. [ABSTRACT FROM AUTHOR]

Late embryogenesis abundant (LEA) proteins are identified as a large and highly diverse group of polypeptides accumulating in response to cellular dehydration in many organisms. However, there are only very limited reports of this protein family in maize until this study. In the present paper, we identified 32 LEA genes in maize. A total of 83 LEA proteins including 51 members in Arabidopsis and 32 putative members in maize were classified into nine groups. Gene organization and motif compositions of the LEA members are highly conserved in each of the groups, indicative of their functional conservation. The predicted ZmLEA genes were non-random distributed across chromosomes, and transposition event and segmental duplication contributed to the expansion of the LEA gene family in maize. Some abiotic stress-responsive cis-elements were also found in the promoters of ZmLEA genes. Microarray expression analyses revealed different accumulation patterns of ZmLEA family members. Moreover, some members of ZmLEAs were regulated under IAA and some abiotic stresses. This study will provide comprehensive information for maize LEA gene family and may pave the way for deciphering their functions in further studies. [ABSTRACT FROM AUTHOR]

The dehydration-responsive element-binding (DREB) transcription factors play important roles in regulation of plant responses to abiotic stresses. In the present study, ZmDBF3, a novel DREB transcription factor gene from maize ( Zea mays L.), was cloned and characterized. Sequence analyses revealed that ZmDBF3 is classified into A-4 group. It was demonstrated that ZmDBF3 was induced in by salt, drought, cold, and high temperature, as well as by signaling molecules abscisic acid (ABA), but no significant changes were observed under salicylic acid (SA) and methyl jasmonate (MeJA) conditions. The results of transient expression assays and transcriptional activity analysis revealed that ZmDBF3 is a nuclear protein with transcriptional activity. Overexpression of ZmDBF3 in yeast ( Saccharomyces cerevisiae) exhibited increased survival rate under NaCl, KCl, NaCO, NaHCO, PEG6000, freezing, and sorbitol treatment, compared with the control. Furthermore, ectopic expression of ZmDBF3 in Arabidopsis significantly enhanced tolerance to salt, drought, and freezing tolerance. Taken together, the findings indicated that the ZmDBF3 is a novel member of DREB transcription factor which may act as a regulatory factor involved in multiple stress response pathways. [ABSTRACT FROM AUTHOR]

Carotenoids are health-promoting organic molecules that act as antioxidants and essential nutrients. We show that chickens raised on a diet enriched with an engineered corn variety containing very high levels of four key carotenoids (β-carotene, lycopene, zeaxanthin and lutein) are healthy and accumulate more bioavailable carotenoids in peripheral tissues, muscle, skin and fat, and more retinol in the liver, than birds fed on standard corn diets (including commercial corn supplemented with colour additives). Birds were challenged with the protozoan parasite Eimeria tenella and those on the high-carotenoid diet grew normally, suffered only mild disease symptoms (diarrhoea, footpad dermatitis and digital ulcers) and had lower faecal oocyst counts than birds on the control diet. Our results demonstrate that carotenoid-rich corn maintains poultry health and increases the nutritional value of poultry products without the use of feed additives. [ABSTRACT FROM AUTHOR]

Herbicide safener, a diverse group of chemicals, is an important tool used to protect plants from herbicidal injury. With the aim of decreasing drift injury of haloxyfop-P-methyl to sensitive plants, the protective effect of four safeners (R-28725, 3-dichloroacetyl oxazolidine and its two optical isomers) was evaluated. Physiological and biochemical tests were conducted under laboratory conditions in Northeast Agricultural University, China, by using seed treatment with safener and soil treatment with haloxyfop-P-methyl, respectively. The maize seeds treated with these safeners were safe from haloxyfop-P-methyl treatment. A positive correlation between growth level and endogenous glutathione (GSH) content, glutathione S-transferases (GST) activity was observed in this research. Enhancement of GSH content, GST activity and affinity of GST to 1-chloro-2,4-dinitrobenzene (CDNB) in maize treated by R-28725 was maximum. However, the detoxification of herbicide was not accompanied by the increase of acetyl-CoA-carboxylase (ACC) activity in maize. [ABSTRACT FROM AUTHOR]

The addition of selenate or selenite to common fertilizers for crop production could be an effective way of producing selenium-rich food and feed. However, this would be feasible only if the increase in plant selenium (Se) content did not negatively influence the uptake of other essential elements. We therefore need to understand the interactions between Se and other major and trace elements during uptake by the plant. This study aimed to evaluate the influence of inorganic forms of Se on the accumulation of selected macronutrients (Ca and Mg) and micronutrients (Fe, Zn, Mn and Cu). Those essential elements are involved in the oxidative balance of cells. Zea mays seedlings were grown hydroponically in growth chambers in nutrient solutions to which we added 10, 50 or 1000 μg.L −1 of selenate and/or selenite. Cation accumulation was significantly affected by the addition of 50 μg.L −1 or 1000 μg.L −1 Se, but not by the presence of 10 μg.L −1 of Se in the nutrient solution. The highest concentration (1000 μg.L −1 ) of Se in the nutrient solution affected the accumulation of essential cations in Zea mays : selenate tended to increase the accumulation of Mg, Zn and Mn, whereas a selenate/selenite mixture tended to decrease the accumulation of Ca, Mg, Zn and Mn. Only Fe accumulation was unaffected by Se whatever its form or concentration. Selenium may also affect the distribution of cations on Zea mays . For example, levels of Mg and Zn translocation to the shoots were lower in the presence of selenite. [ABSTRACT FROM AUTHOR]

In this study, the characteristics of maize biochar produced at different pyrolysis temperatures (300, 450 and 600 °C) and its effects on organic carbon, nitrogen and enzymatic activities after addition to fluvo-aquic soil were investigated. As pyrolysis temperature increased, ash content, pH, electrical conductivity, surface area, pore volume and aromatic carbon content of biochar increased while yield, ratios of oxygen:carbon and hydrogen: carbon and alkyl carbon content decreased. During incubation, SOC, total N, and ammonium-N contents increased in all biochar-amended treatments compared with the urea treatment; however, soil nitrate-N content first increased and then decreased with increasing pyrolysis temperature of the applied biochar. Extracellular enzyme activities associated with carbon transformation first increased and then decreased with biochars pyrolyzed at 450 and 600 °C. Protease activity markedly increased with increased pyrolysis temperatures, whereas pyrolysis temperature had limited effect on soil urease activity. The results indicated that the responses of extracellular enzymes to biochar were dependent on the pyrolysis temperature, the enzyme itself and incubation time as well. [ABSTRACT FROM AUTHOR]

Background and aims: Few studies have addressed the effects of root physiological plasticity on interspecific interactions. The present study aimed to investigate the plasticity of wheat and maize roots and their responses to nitrogen (N) application rates and neighboring species in wheat/maize intercropping. Methods: The roots of wheat and maize were sampled three times by auger after about 90 days of co-growth in the intercropping treatment with five levels of N application and sole crops at one N application rate. Results: Intercropped wheat altered its root length density (RLD) and lateral root distribution with different N application regimes, while lateral root distribution of intercropped maize was less sensitive to N application regimes. In addition, wheat had a 54.5 % (38-69 days) −375 % (0-37 days) higher N uptake rate per unit root length (NURl) when intercropped with maize compared with sole cropping but intercropped maize had either 58.3 % lower (0-37 days) or similar NURl than did sole cropped maize at the same N application rate. Conclusions: Our findings suggest that the competitive ability of the plant species for underground resources is conducive to plasticities in RLD, lateral root distribution in response to soil N, and N uptake efficiency to neighboring species. [ABSTRACT FROM AUTHOR]

Maize (Zea maysL.), grown in different Asian countries, undergoes drought stress during the hot summer periods, which is the most common cause for reduced growth and yield of maize worldwide. A greenhouse experiment was conducted to investigate the prompting role of ascorbic acid (AsA) in maize drought-tolerant (Agaiti-2002) and drought-sensitive (EV-1098) cultivars under two drought stress levels (control and 65% field capacity). Ascorbate is essential for plants due to its function as antioxidant and protector against environmental stresses. The results showed that drought stress reduced the plant growth, fresh and dry biomass, and photosynthetic pigments of maize plants. Exogenous application of ascorbic acid lowered the drought stress-induced reduction in growth, biomass, and photosynthetic pigments. Drought stress enhanced the activities of superoxide dismutase (SOD) and peroxidase (POD) in maize plants, and application of AsA further enhanced the activity of these enzymes. The results indicate that foliar application of AsA alleviated the detrimental effects of drought stress in maize plants by improving the antioxidative defense system. The cultivar EV-1098 was found to be relatively resistant to drought stress. Our research suggested that foliarly applied AsA may be useful for the sustainable maize production under drought-stressed ecologies. [ABSTRACT FROM AUTHOR]

Main conclusion: Effects of a low aluminum (Al) dose were characterized. The Al supplement inhibited root growth but enhanced leaf growth in maize lines with different Al sensitivities. High levels of Al are phytotoxic especially in acidic soils. The beneficial effects of low Al levels have been reported in some plant species, but not in maize. Maize is relatively more sensitive to Al toxicity than other cereals. Seedlings, at the three leaf stage, of four Chinese maize foundation parent inbred lines with different Al tolerances, were exposed to complete Hoagland's nutrient solution at pH 4.5 supplemented with 48 μM Al under controlled growth conditions, and then the Al stress (AS) was removed. The leaf and root growth, root cell viability, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ions (K, Ca and Mg), photosynthetic rate and chlorophyll, protein and malondialdehyde contents in tissues were assayed. In conclusion, a low Al dose inhibits root growth but enhances leaf growth in maize. The Al-promoted leaf growth is likely a result of increased protein synthesis, a lowered Ca level, and the discharge of the growth-inhibitory factors. The Al-promoted leaf growth may be a 'memory' effect caused by the earlier AS in maize. Al causes cell wall rupture, and a loss of K, Ca and Mg from root cells. CAT is an auxiliary antioxidant enzyme that works selectively with either SOD or POD against AS-related peroxidation, depending on the maize tissue. CAT is a major antioxidant enzyme responsible for root growth, but SOD is important for leaf growth during AS and after its removal. Our results contribute to understanding how low levels of Al affect maize and Al-resistant mechanisms in maize. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effects of partially replacing dry ground corn with glycerin on ruminal fermentation using a dual-flow continuous culture system. Six fermenters (1,223 ± 21 ml) were used in a replicated 3x3 Latin square arrangement with three periods of 10 d each, with 7 d for diet adaptation and 3 d for sample collections. All diets contained 75% concentrate and three dietary glycerin levels (0, 15, and 30% on dry matter basis), totaling six replicates per treatment. Fermenters were fed 72 g of dry matter/d equally divided in two meals/d, at 0800 and 2000 h. Solid and liquid dilution rates were adjusted daily to 5.5 and 11%/h, respectively. On d 8, 9, and 10, samples of 500 ml of solid and liquid digesta effluent were mixed, homogenized, and stored at -20°C. Subsamples of 10 ml were collected and preserved with 0.2 mL of a 50% H2SO4 solution for later determination of NH3-N and volatile fatty acids. Microbial biomass was isolated from fermenters for chemical analysis at the end of each experimental period. Data were analyzed using the MIXED procedure in SAS with α = 0.05. Glycerin levels did not affect apparent digestibility of DM (PLin . = 0.13; PQuad . = 0.40), OM (PLin . = 0.72; PQuad . = 0.15), NDF (PLin . = 0.38; PQuad . = 0.50) and ADF (PLin . = 0.91; PQuad . = 0.18). Also, glycerin inclusion did not affect true digestibility of DM (PLin . = 0.35; PQuad . = 0.48), and OM (PLin . = 0.08; PQuad . = 0.19). Concentrations of propionate (P < 0.01) and total volatile fatty acids (P < 0.01) increased linearly and concentrations of acetate (P < 0.01), butyrate (P = 0.01), iso-valerate (P < 0.01), and total branched-chain volatile fatty acids, as well as the acetate: propionate ratio (P < 0.01) decreased with glycerin inclusion. Linear increases on NH3-N concentration in digesta effluent (P < 0.01) and on NH3-N flow (P < 0.01) were observed due to glycerin inclusion in the diets. Crude protein digestibility (P = 0.04) and microbial N flow (P = 0.04) were greater in the control treatment compared with the other treatments and responded quadratically with glycerin inclusion. Furthermore, the inclusion of glycerin linearly decreased (P = 0.02) non-ammonia N flow. Glycerin levels did not affect the flows of total N (PLin . = 0.79; PQuad . = 0.35), and dietary N (PLin . = 0.99; PQuad . = 0.07), as well as microbial efficiency (PLin . = 0.09; PQuad . = 0.07). These results suggest that partially replacing dry ground corn with glycerin may change ruminal fermentation, by increasing total volatile fatty acids, and propionate concentration without affecting microbial efficiency, which may improve glucogenic potential of beef cattle diets. [ABSTRACT FROM AUTHOR]

An experiment was conducted to investigate the effect of phytase transgenic corn (PTC) on intestinal microflora, and the fate of transgenic DNA and protein in the digesta and tissues of broilers. A total of 160 1-day-old Arbor Acres commercial male broilers were randomly assigned to 20 cages (8 chicks per cage) with 10 cages (replicates) for each treatment. Birds were fed with a diet containing either PTC (54.0% during 1–21 days and 61.0% during 22–42 days) or non-transgenic isogenic control corn (CC) for a duration of 42 days. There were no significant differences (P>0.05) between birds fed with the PTC diets and those fed with the CC diets in the quantities of aerobic bacteria, anaerobic bacteria, colibacillus and lactobacilli, or microbial diversities in the contents of ileum and cecum. Transgenic phyA2 DNA was not detected, but phyA2 protein was detected in the digesta of duodenum and jejunum of broilers fed with the PTC diets. Both transgenic phyA2 DNA and protein fragments were not found in the digesta of the ileum and rectum, heart, liver, kidney, and breast or thigh muscles of broilers fed with the PTC diets. It was concluded that PTC had no adverse effect on the quantity and diversity of gut microorganisms; Transgenic phyA2 DNA or protein was rapidly degraded in the intestinal tract and was not transferred to the tissues of broilers. [ABSTRACT FROM AUTHOR]

The embryo defective (emb) mutants in maize genetically define a unique class of loci that is required for embryogenesis but not endosperm development, allowing dissection of two developmental processes of seed formation. Through characterization of the emb14 mutant, we report here that Emb14 gene encodes a circular permuted, YqeH class GTPase protein that likely functions in 30S ribosome formation in plastids. Loss of Emb14 function in the null mutant arrests embryogenesis at the early transition stage. Emb14 was cloned by transposon tagging and was confirmed by analysis of four alleles. Subcellular localization indicated that the EMB14 is targeted to chloroplasts. Recombinant EMB14 is shown to hydrolyze GTP in vitro (Km = 2.42 ± 0.3 µM). Emb14 was constitutively expressed in all tissues examined and high level of expression was found in transition stage embryos. Comparison of emb14 and WT indicated that loss of EMB14 function severely impairs accumulation of 16S rRNA and several plastid encoded ribosomal genes. We show that an EMB14 transgene complements the pale green, slow growth phenotype conditioned by mutations in AtNOA1, a closely related YqeH GTPase of Arabidopsis. Taken together, we propose that the EMB14/ AtNOA1/YqeH class GTPases function in assembly of the 30S subunit of the chloroplast ribosome, and that this function is essential to embryogenesis in plants. [ABSTRACT FROM AUTHOR]

Considering Iran and Azerbaijan to be origin countries in the Astara region, and in order to study the effects of salt stress on morphological and physiological characteristics, changes to eight maize cultivars were experimented on in three replications on the basis of randomized complete block design over three years. Cultivars included K3615/1, S.C704, B73, S.C302, Waxy, K3546/6, K3653/2, and Zaqatala-68, and they were cultivated in two pieces of land in Astara: one with normal soil and the other with salty soil. During the experiment, Na+ accumulation in leaves, chlorophyll a, chlorophyll b, leaf relative water content (LRWC), proline content, biomass per plant, harvest index, and grain yield per hectare were measured. Results from the experiment showed that, between locations (normal and saline) in most traits, significant differences were seen. And between varieties in all traits, significant differences were seen. The interaction between years and varieties for all traits was not significant. Comparison traits in different salinities showed that in most traits there are significant differences between genotypes. Proline content increased with increasing soil salinity. With increasing salinity, Na+ accumulation in leaves severely increased and the biggest accumulation was observed in S.C704. Maximum LRWC in B73 was measured in normal conditions. The highest amount of chlorophyll a, in normal conditions, was observed in S.C704 with 1.873 mg/g fresh weight of leaves, which was not significantly different from B73. Between chlorophyll a and chlorophyll b, Na+ and LRWC positive correlations were observed in non-stress conditions. Between chlorophyll a and chlorophyll b, yield per plant, and yield grain, significant positive correlations were observed in salty conditions. [ABSTRACT FROM AUTHOR]

PREMISE OF THE STUDY: Although anthers of Zea mays, Oryza sativa, and Arabidopsis thaliana have been studied intensively using genetic and biochemical analyses in the past 20 years, few updates to anther anatomical and ultrastructural descriptions have been reported. For example, no transmission electron microscopy (TEM) images of the premeiotic maize anther have been published. Here we report the presence of chloroplasts in maize anthers. METHODS: TEM imaging, electron acceptor photosynthesis assay, in planta photon detection, microarray analysis, and light and fluorescence microscopy were used to investigate the presence of chloroplasts in the maize anther. KEY RESULTS: Most cells of the maize subepidermal endothecium have starch-containing chloroplasts that do not conduct measurable photosynthesis in vitro. CONCLUSIONS: The maize anther contains chloroplasts in most subepidermal, endothecial cells. Although maize anthers receive sufficient light to photosynthesize in vivo and the maize anther transcribes >96% of photosynthesis-associated genes found in the maize leaf, no photosynthetic light reaction activity was detected in vitro. The endothecial cell layer should no longer be defined as a complete circle viewed transversely in anther lobes, because chloroplasts are observed only in cells directly beneath the epidermis and not those adjacent to the connective tissue. We propose that chloroplasts be a defining characteristic of differentiated endothecial cells and that nonsubepidermal endothecial cells that lack chloroplasts be defined as a separate cell type, the interendothecium. [ABSTRACT FROM AUTHOR]

The present study focuses on effects of untreated and treated ink industry wastewater on germination of maize, barley and sorghum. Wastewater had a high chemical oxygen demand (COD) and metal content compared to treated effluent. Germination decreased with increasing COD concentration. Speed of germination also followed the same trend, except for maize seeds exposed to untreated effluent (E), which germinated slightly faster than controls. These alterations of seedling development were mirrored by changes in soluble protein content. E exerted a positive effect on soluble protein content and maximum levels occurred after 10 days with treated effluent using coagulation/flocculation (TE) process and treated effluent using combined process (coagulation/flocculation/biosorption) (TE). Likewise, activity of α-amylase was influenced by effluent composition. Its expression depended on the species, exposure time and applied treatment. Nevertheless, current results indicated TE had no observable toxic effects on germination and could be a beneficial alternative resource to irrigation water. [ABSTRACT FROM AUTHOR]

This experiment aimed to evaluate plant growth promoting rhizobia in combination with biochar for improving the growth and physiology of maize (Zea mays L.). Three rhizobia isolated from different legumes (RH1, RH2, and RH3) were used to inoculate maize growing in soil amended with different levels of biochar (0.0, 0.5, 1.0, and 1.5%) under controlled conditions. The magnitude of improvement in the growth and physiology of maize varied due to rhizobial inoculation and application of biochar, either alone or in combination. Combined application of different rhizobia and biochar caused significant improvement in the growth and physiological attributes of maize over their sole use. The performance of all tested rhizobia was comparatively better at the 1.0% biochar level for improving maize growth compared with the other biochar levels (0.5 and 1.5%). Rhizobial strain RH1 showed the most prominent results for improving the growth of maize among all the tested rhizobia either used alone or in combination with biochar. Phosphatase, dehydrogenase, and microbial biomass C were also improved in the rhizosphere due to rhizobial inoculation and biochar. This work clearly indicates that the rhizobia from different legumes variably improved the growth and physiology of maize. However, the performance of rhizobia could be further improved when used in combination with an appropriate level of biochar. [ABSTRACT FROM AUTHOR]