Citrus flavonoids in fruit and traditional Chinese medicinal food ingredients in China

Flavonoids-enriched tissues of citrus such as peel, immature fruit and flower are consumed as culinary seasonings, tea ingredients in China for centuries. This HPLC quantitative study on the five citrus flavonoids, naringin, hesperidin, neohesperidin, sinensetin and nobiletin on a wide range of Chinese citrus fruits and several Traditional Chinese Medicinal food ingredients in East China, revealed a great diversity in flavonoid composition. Huyou peel (C. paradisi cv. Changshanhuyou) was found to be the best naringin (3.25%) and neohesperidin (2.76%) source; C. aurantium, a major ingredient of several citrus-related TCM, is also a suitable source of naringin and neohesperidin, and a good juice source for flavanone glycosides; the peel of Wenzhoumiju (C. unshiu) is one of the richest local species in hesperidin (up to 6.25%); Zaoju (C. subcompressa) has the highest content of nobiletin (0.59%), a polymethoxylated flavone. LC-ES-MS analysis of Zanthoxylum genus for flavonoids revealed for the first time the presence of significant amounts (0.74%) of hesperidin in the root of Liangmianzhen (Z. nitidum (Roxb.) DC), a relative of Sichuan pepper, which is a spice widely used in China.     

Association analysis for detecting significant single nucleotide polymorphisms for phosphorus-deficiency tolerance at the seedling stage in soybean [Glycine max (L) Merr.]

Tolerance to low-phosphorus soil is a desirable trait in soybean cultivars. Previous quantitative trait locus (QTL) studies for phosphorus-deficiency tolerance were mainly derived from bi-parental segregating populations and few reports from natural population. The objective of this study was to detect QTLs that regulate phosphorus-deficiency tolerance in soybean using association mapping approach. Phosphorus-deficiency tolerance was evaluated according to five traits (plant shoot height, shoot dry weight, phosphorus concentration, phosphorus acquisition efficiency and use efficiency) comprising a conditional phenotype at the seedling stage. Association mapping of the conditional phenotype detected 19 SNPs including 13 SNPs that were significantly associated with the five traits across two years. A novel cluster of SNPs, including three SNPs that consistently showed significant effects over two years, that associated with more than one trait was detected on chromosome 3. All favorable alleles, which were determined based on the mean of conditional phenotypic values of each trait over the two years, could be pyramided into one cultivar through parental cross combination. The best three cross combinations were predicted with the aim of simultaneously improving phosphorus acquisition efficiency and use efficiency. These results will provide a thorough understanding of the genetic basis of phosphorus deficiency tolerance in soybean.     

Agronomic traits of soybean cultivars released in different decades after grafting record‐yield cultivar as rootstock

Breeders have seldom considered the selection for root traits during the genetic improvement in soybean. It is hypothesized that grain yield would be increased by the root function improvement, especially for the current cultivars. The objective of this grafting experiment was to determine the effect of record‐yield cultivars L14 or Z35 as rootstocks on agronomic traits of cultivars released in different decades. A total of 11 cultivars, released in different decades, were used to graft onto L14 or Z35 rootstocks. The agronomic traits were measured in the pot‐culture experiments. Grafting cultivars released in different decades onto L14 or Z35 rootstocks resulted in higher yield, 100‐seed mass and apparent harvest index as compared with those of non‐grafted or self‐grafted plants. Grain yield gain of cultivars grafted onto record‐yield cultivar rootstocks was 0.40 g/plant/year from 1966 to 2006, which was larger than that of non‐grafts and self‐grafts (0.27 g/plant/year). The yield of current cultivars should increase more if their root functions were improved.     

山苍子精油对白纹伊蚊的生物活性及其成分分析

研究了山苍子Litsea cubeba果实精油对白纹伊蚊Aedes albopictus成蚊的驱避活性和对其幼虫的毒杀活性;采用GC-MS定性分析了精油的化学成分,并定量分析了其中9种活性成分。结果如下：在1．5mg·cm^-2的涂抹剂量下,山苍子精油对白纹伊蚊的100％保护时间为3．70h,对白纹伊蚊4龄期幼虫的24h毒杀Lc50值为82．48μg·mL^-1。定性分析共鉴定出17种化合物,其中E-柠檬醛的相对含量最高,其峰面积百分比为44．65％,其它相对含量较高的成分分别是Z-柠檬醛（34．60％）、柠檬烯（11．70％）、甲基庚烯酮（2．28％）、芳樟醇（1．28％）等。定量分析9种活性成分在精油中的总含量为238．70mg·mL^-1,其中E-柠檬醛106．20mg·mL^-1、Z-柠檬醛68．79mg·mL^-1、桉叶油素40．90mg·mL^-1的含量较高。研究结果表明,山苍子精油对白纹伊蚊具有良好的成蚊驱避和幼虫毒杀活性,这些生物活性与精油的化学成分密切相关。     

湘西桤木人工林蓄积量模型及适宜经营密度研究

密度是表达林分结构的重要指标,立地条件、树种及林龄不同时,其林分最佳密度也不相同。笔者以湘西桤木人工林为研究对象,采用数量化方法I和非线性回归分析方法,对2009年和2010年调查的78块标准地数据进行数据分析处理与建模。结果表明：（1）平均高、公顷株数、土层厚度、龄组、坡向、坡位、自然灾害、海拔、树种组成8种因子中,平均高、公顷株数、土层厚度和龄组对湘西桤木人工林平均木材积和单位面积蓄积量均有显著性影响,而海拔和树种组成对湘西桤木人工林平均木材积和单位面积蓄积量均无显著性影响。这对建立桤木人工林蓄积量与密度、平均高收集数据时提供理论指导,同时既能节省外业调查费用,又能保证建模数据的科学性。（2）建立了湘西8~10年桤木人工林蓄积量与密度、平均高相关关系模型： ,建模精度为96.8458%,平均相对误差为1.1334%。模型适应性检验表明,残差值呈对称均匀分布,其平均相对误差为-1.2156%。（3）该地区8~10年桤木人林的最佳经营密度为800~1000株/hm2。这对于合理地经营和管理湘西桤木人工林具有重要的理论和实际指导意义。     

晚播对大豆产量及性状的影响

通过对7月5日至7月25日晚播条件下大豆生长发育研究表明，每晚播5d，株荚数分别降低19．7％、29．6％、51．9％、56．3％。株粒数分别降低14．6％、24．8％、47．6％、60．3％。而对百粒重影响不大。减产率19．0％-72．3％，达极显著水平。7月15日以前播种，可获得70％以上的产量，且能正常成熟，7月20日后播种，仅能获得50％以下的产量，且不能正常成熟。     

气门弹簧的可靠度计算

论述了一种实用有效的计算气门弹簧可靠度的方法。在基本随机变量概率特性已知的情况下，使用二阶矩技术计算了气门弹簧的可靠度，并编制了实用的计算机程序，可以迅速准确地得到气门弹簧的可靠度。     

激振式扭转疲劳试验台载荷波形畸变分析

针对行星式离心激振扭转疲劳试验台在进行汽车传动轴扭转疲劳试验时出现的载荷波形畸变现象,分析了试验台扭振系统并建立了数学模型,导出交变扭矩幅值变化的数学表达式。通过试验分析和计算机模拟验证了数学模型,找到了扭矩波形畸变的根本原因,并提出了消除波形畸变的方法,为合理使用原有这类试验台及新设计这类试验台提供了理论依据。     

Isothermal and non-isothermal shrinkage behaviors of highly oriented PET yarns

The isothermal and non-isothermal shrinkage behaviors of highly oriented Poly(ethylene terephthalate) yarns were investigated. In isothermal measurements, shrinkage and shrinkage stress firstly monotonously increased due to more and more activated frozen molecular segments with increasing time and temperature, and then relaxed at high temperature resulting from intermolecular slipping of micro-fibrils. According to the different contributions of amorphous and crystalline regions to shrinkage behavior, non-isothermal shrinkage and shrinkage stress curves were fitted by Gauss curves and the entire shrinkage process was divided into three stages: contraction of micro-fibrils, contraction of extended interfibrillar tie molecules and relative displacement of micro-fibrils.