Glycerophospholipid and triacylglycerol distribution in corn kernels (Zea mays L.)

The distribution of various molecular species of triacylglycerols (TAGs) and phospholipids among three corn kernel parts was determined by LC/ESI-MS. A comparison between three corn kernel parts demonstrated that there was a significant (p < 0.05) difference in their contents of various glycerophospholipid classes. Phosphatidylcholine was the most abundant class in germ and pericarp fractions (51.4–70.6% of the total glycerophospholipids), followed by phosphatidylinositol (11.3–25.1%) and phosphatidylethanolamine (8.4–12.6%). In contrast, phosphatidylethanolamine was found to be the most abundant class in the endosperm fraction (41.4–48.5%), followed by phosphatidylcholine (30.2–33.4%) and phosphatidylinositol (13.2–14.4%). Various molecular species were detected in each class of glycerophospholipid and their levels were significantly (p < 0.05) different among three corn kernel fractions. The major molecular species of triacylglycerol detected in three corn parts were OLL, OOL, LLL, POL, PLL, OOO and POO; where L represents linoleic acid; O, oleic acid; and P, palmitic acid. The TAG composition was significantly different among three corn kernel fractions. In Astro germ fraction, LLL (27.2%) was detected as the dominant TAG molecular species, followed by OLL (21.9%) and PLL (13.4%); however in Astro endosperm fraction, OLL (21.5%) was the major form followed by PLL (18.6%) and LLL (13.5%).     

极早熟玉米杂交种“延单15”选育报告

“延单１５”是１９９０年延边农业科学研究院旱田研究所以自选系甸曲１３７为母本,以外引系４２８为父本,杂交育成的极早熟、高产、多抗、优质的玉米新杂交种．于１９９８年２月经吉林省农作物品种审定委员会审定通过为今后早熟、极早熟区推广品种．     

Preparation of Extruded Snacks with Flavored Flour Obtained from the Carcasses of Nile Tilapia: Physicochemical,Sensory, and Microbiological Analysis

This study aimed to develop extruded snacks including flour obtained from Nile tilápia carcasses, and then evaluate the chemical composition, colorimetry, thiobarbituric acid reactive substances, and microbiology. There was a significant increase in the levels of crude protein, ether extract, ash, and minerals, as well as a reduction in carbohydrates as more flour was included in the snacks. Increased levels of flavored flour caused reduction in the brightness of snacks. Oxidative rancidity was not detected in snacks. The inclusion of flour improved the nutritional value of extruded snacks without changing sensory characteristics. Microbiologically, the snacks are suitable for human consumption.     

3种作物幼苗对空气中苯的吸收和下行传输作用研究

[目的]研究玉米、番茄、空心菜幼苗对空气中苯的吸收和下行传输作用。[方法]采用营养液水培方式,利用玻璃密封箱进行苯污染处理,采用气相色谱法测定不同吸收时间植物根际溶液和玻璃箱中苯浓度变化情况。[结果]玻璃密封箱中空气中苯的浓度为5.90 mg/L,吸收时间为1 h时即可从玉米、番茄、空心菜根际溶液中检测出苯;24 h后玉米、番茄、空心菜幼苗的Cr/Cp值分别为0.46±0.05、0.14±0.02、0.22±0.02;玉米、番茄、空心菜幼苗对空气中苯的传输效率随吸收时间的延长迅速降低,吸收时间为1 h时传输效率分别为(169.52±22.12)、(13.20±0.80)、(1.14±0.52)μg/(h·g)FW。[结论]3种作物幼苗地上部分均可快速吸收空气中的苯,并通过体内下行传输及根释放作用将其转移至根际溶液中,且对空气中的苯均具有较强的传输能力。     

Comparative study of conventional and microwave-assisted liquefaction of corn stover in ethylene glycol

A comparative study on conventional and microwave-assisted liquefaction of corn stover has been carried out using ethylene glycol (EG) as liquefacient and sulfuric acid as catalyst. Microwave dramatically increased the liquefaction extent and rate compared to conventional heating. The liquefied products and residues in both methods have been investigated using gel permeation chromatography (GPC), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM). The GPC results show that the molecular weight of liquefied products with conventional heating is significantly greater than those of microwave-assisted liquefaction. The FTIR spectra indicate that there are significant differences in the hydroxyl and carbonyl group contents in the liquefied products with the two methods. The residue from microwave-assisted liquefaction mainly consisted of mineral matter. Many granules appeared on the surface of microwave liquefied residue according to SEM observation.     

Long-term winter cover cropping effects on corn (Zea mays L.) production and soil nitrogen availability

 This study was conducted to determine effects of long-term winter cover cropping with hairy vetch, cereal rye and annual ryegrass on soil N availability and corn productivity. From 1987 to 1995, with the exception of the first year of the study, the cover crops were seeded each year in late September or early October after the corn harvest and incorporated into the soil in late April or early May. Corn was seeded 10 days to 2 weeks after the cover crop residues had been incorporated, and N fertilizer was applied as a side-dressing at rates of 0, 67, 134, or 201 kg N ha^–1 each year. While the average annual total N input from the above-ground biomass of the cover crops was highest for hairy vetch (72.4 kg N ha^–1), the average annual total C input was highest for cereal rye (1043 kg C ha^–1) compared with the other cover crops. Hairy vetch was the only cover crop that significantly increased pre-side-dressed NO₃ ^–-N (N_i) corn biomass and N uptake at 0 N. At an N fertilizer rate of 134 kg N ha^–1 or higher, the cover crops had a minimal effect on corn biomass. This indicated that even after 9 years of winter cover cropping, the effect of the cover crops on corn growth resulted primarily from their influence on soil N availability. The amount of available N estimated from the cover crops (N_ac) was significantly correlated with relative corn biomass production (r ²=0.707, P<0.001). The total amount of available N, comprising N_ac and N added from fertilizer (N_f), was strongly correlated (r ²=0.820, P<0.001)) with relative corn biomass production. The correlation was also high for the available N comprising N_i and N_f (r ²=0.775, P<0.001). Although cereal rye and annual ryegrass did not improve corn biomass production in the short term, they benefited soil organic N accumulation and gradually improved corn biomass production compared with the control over the long term. Received: 10 August 1999     

兴安盟春玉米生产现状及生态气候应对措施

在深入基层调查和多年实践经验基础上,总结了兴安盟玉米生产中存在的主要问题,并提出了应对措施。结果认为,兴安盟玉米生产中存在的主要问题是没有充分利用气候资源实现高产稳产,玉米越区种植和浪费热量资源问题突出,并提出了合理利用气候资源趋利避害的应对措施和建议,对稳定兴安盟玉米单产、提高玉米总产具有重要意义。     

Optimal Management Practices for Nitrogen Application in Corn Cultivated During Summer and Fall in the Tropics

Optimal management practices for nitrogen (N) fertilization is well defined for corn (Zea mays) cultivated during summer (“summer” corn), but not for corn cultivated during the fall (“fall” corn) in the tropics. Two experiments were carried out to evaluate N rates (50, 100, 200, and 300 kg N ha^?1), N application timing (pre-planting – PP, V2–V3, and V5–V6) and N split application, once (at PP, V3, and V6), two (at V3+ V6) and three times (at PP+ V3+ V6) in corn cultivated during summer (2014/2015) and fall (2015/2016). Data on corn grain yield (CGY), weight of 1000-grains, leaf N content and values of soil-plant analyses development (SPAD) were collected and analyzed using univariate, multivariate (principal component analysis, PCA) and regression analysis. Results showed that corn growth was affected by N rates and splitting. Corn cultivated during summer presented higher CGY and weight-1000 g than corn cultivated during the fall. The highest yields were obtained with higher N rates on “summer” corn (125 kg N ha^?1) than “fall” corn (50 kg N ha^?1). Split N-application at vegetative growth stages, V3+ V6, or PP+ V2+ V6, provided higher yields for “summer” corn, while only PP application was a reliable period of N fertilization for “fall” corn. The finding is that corn cultivated during the fall presented a lower response to N and no obvious advantages to split N fertilization when compared to corn cultivated during summer. These optimal management practices for N fertilization in corn production in the tropics depend on soil water availability.     

玉米“3414”不完全施肥研究

采用"3414"不完全施肥试验方案设计,研究单种玉米在淡灰钙土条件下的土壤供肥量、作物吸收养分量、土壤养分丰缺指标等参数,提出相应的推荐施肥量。结果表明:在该土壤类型条件下单种玉米施纯N 330 kg/hm2、P2O590 kg/hm2、K2O 90 kg/hm2,玉米可获得较好的经济产量。