Effect of photoperiod on development and reproduction of Megacopta cribraria(Hemiptera:Plataspidae)

Megacopta cribraria (Hemiptera: Plataspidae) continually outbreaks due to suitable photoperiod in recent years. Effect of photoperiod on growth, development and reproduction of M. cribraria were assessed in this study. Results indicated that developmental duration, nutrient accumulation efficiency, and adult fecundity of M. cribraria were significantly different under 6 photoperiodical conditions. Developmental duration of nymph stage gradually tended to be shorter as day time increase. Body weights of 5th instar nymphs for 16 h and 4 h day time photoperiods were 5.2 mg and 4.6 mg, respectively. Moreover, longevity of adults tended to be longer as day time increase. However, for the short day photoperiod (4 L:20 D and 8 L:16 D), population showed no reproductive behaviors. Index of population trend increased with photoperiod extension and adults showed stronger reproductive capacity and longer longevity. This research identified the favorable photoperiodical conditions before outbreak. It may provided reference for ecological adaptability of M. cribraria, and contribute to the scientific basis for forecasting and controlling of M. cribraria.     

Influence of rotation system on siderophere-producing microorganism(SPM) in rhizosphere soil of southern China

Soil siderophores are important for crop growth,benefit ferric iron absorption of root,and are affected by cropping patterns.The objective of this study was to evaluate the quantity of siderophores in soil of 2 continuous crop rotation patterns over 30 years in Anren country,China.Quantity and siderophore-producing capability of microorganisms in rice-riceoilseed rape(DDY)rotation and rice-rice(DD)rontinuous cropping rhizosphere soil were tested and analyzed by chrome azurol S method.Isolated strains were used to identify siderophore-producing microorganism(SPM)by PCR amplification and DNA sequencing.Results showed that 9 siderophore-producing bacteria strains were isolated from DDY rhizosphere soil while 7 strains were identified from DD rhizosphere soil.The mean solubility index which representing siderophore-producing capability of strains was 3.05.PCR amplification results indicated that bacterial were the major SPM in soil.This research indicates that crop rotation systems could drive microorganisms to produce siderophores and enrich them in bacterial communities.     

集体林地不同经营模式对林地经营投入的影响——以江西省为例

【目的】试图回答集体林地不同经营模式对农户林地资金投入和劳动力投入的影响,以促进森林资源增长和林业可持续发展。【方法】基于江西省集体林区10个样本县50个样本村500户农户调查数据,运用计量模型分析联户经营、股份合作经营对农户林地资金投入和劳动力投入的影响。【结果】联户经营对农户是否参与资金投入具有显著促进作用,其影响系数为1.013,且联户经营对农户资金投入规模也具有显著正向影响,对资金总投入和单位面积投入的影响系数分别为4.174 和1.909;股份合作经营对农户劳动力投入规模具有显著正向影响,对劳动力总投入和单位面积投入的影响系数分别为0.521 和0.180;股份合作经营对采伐政策具有正向调节作用,联户经营和股份合作经营能够减轻偏远山区交通不便对劳动力投入的限制;农户家庭人力资本、林地状况、经济能力等禀赋对农户林地经营投入也具有不同程度影响。【结论】联户经营和股份合作经营能够促进农户林地经营投入,但目前发展程度较低,对林地资金投入和劳动力投入的影响存在较大差异。为促进林业可持续发展,应引导联户经营和股份合作经营的规范化、程序化,尤其在交通偏远的地区,倡导联户经营和股份合作经营,发挥其成员多、信息广等优势;同时,加强集体林权配套改革和林区基础设施改善,增强农户营林积极性。     

Safety evaluation of an oak-flavored milk powder containing ellagitannins upon oral administration in the rat

Ellagitannins are phenolic compounds that occur in a number of dietary sources such as walnuts, raspberries, pomegranate, strawberries, and oak-aged wines. Ellagitannins have been acknowledged to have antioxidant and cancer chemopreventive activities. However, ellagitannins have also been considered to be "antinutrients" and have been reported to provoke adverse effects in animals. In this context, risk assessment studies are demanded to ensure that chemicals present in food do not compromise food safety. Oak-flavored milk can be obtained by thermal treatment of milk in the presence of oak shavings. The oak-flavored milk can be used to impart wood-like flavor to different recipes. The present study evaluated, under a subchronic approach, the safety of an oak-flavored milk powder containing ellagitannins in rats upon repeated oral administration for 96 days. The effect of 30% oak-flavored milk powder in the diet was evaluated. This amount involved a margin of safety equivalent to the daily intake of 134 yogurts by a 70 kg person for 96 days. Growth rate, food utility index, 9 hematological, and 13 serobiochemical parameters as well as the metabolism and tissue distribution of ellagitannins and derived metabolites were studied. Overall, no significant differences were found in oak-milk-fed rats in any blood parameter analyzed. No effect was found on growth rate and food utility index. Urolithin A was identified in feces of rats fed oak-flavored milk and the glucuronide derivative in urine. No metabolites were found in the liver, kidney, or uterus. Histopathological analysis of liver and kidney corroborated the absence of toxicity. Therefore, these results suggest that the intake of the oak-flavored milk powder assayed in this study is safe and does not involve potential hazard to human health.     

Effects of various cooking processes on the concentrations of arsenic, cadmium, mercury, and lead in foods

The effects of cooking processes commonly used by the population of Catalonia (Spain) on total arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) concentrations in various foodstuffs were investigated. All food samples were randomly acquired in local markets, big supermarkets, and grocery stores of Reus (Catalonia). Foods included fish (sardine, hake, and tuna), meat (veal steak, loin of pork, breast and thigh of chicken, and steak and rib of lamb), string bean, potato, rice, and olive oil. For each food item, two composite samples were prepared for metal analyses, whose levels in raw and cooked (fried, grilled, roasted, and boiled) samples were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The highest concentrations of As, Hg, and Pb (raw and cooked samples) were mainly found in fish, with a clear tendency, in general, to increase metal concentrations after cooking. However, in these samples, Cd levels were very close to their detection limit. In turn, the concentrations of metals in raw and cooked meat samples were detected in all samples (As) or only in a very few samples (Cd, Hg, and Pb). A similar finding corresponded to string beans, rice, and olive oil, while in potatoes, Hg could not be detected and Pb only was detected in the raw samples. In summary, the results of the present study show that, in general terms, the cooking process is only of a very limited value as a means of reducing metal concentrations. This hypothetical reduction depends upon cooking conditions (time, temperature, and medium of cooking).     

Classification of Peruvian highland maize races using plant traits

The maize of Latin America, with its enormous diversity, has played an important role in the development of modern maize cultivars of the American continent. Peruvian highland maize shows a high degree of variation stemming from its history of cultivation by Andean farmers. Multivariate statistical methods for classifying accessions have become powerful tools for classifying genetic resources conservation and the formation of core subsets. This study has two objectives: (1) to use a numerical classification strategy for classifying eight Peruvian highland races of maize based on six vegetative traits evaluated in two years and (2) to compare this classification with the existing racial classification. The numerical classification maintained the main structure of the eight races, but reclassified parts of the races into new groups (Gi). The new groups are more separated and well defined with a decreasing accession within group × environment interaction. Most of the accessions from G1 are from Cusco Gigante, all of the accessions from G3 (except one) are from Confite Morocho, and all of the accessions from G7 are from Chullpi. Group G2 has four accessions from Huayleño and four accessions from Paro, whereas G4 has four accessions from Huayleño and five accessions from San Geronimo. Group G5 has accessions from four races, and G6 and G8 formed small groups with two and one accession each, respectively. These groups can be used for forming core subsets for the purpose of germplasm enhancement and assembling gene pools for further breeding.     

子午岭次生林区土壤持水力及其与土壤有机碳的关系

通过野外调查和室内分析,就子午岭次生植被辽东栎、山杨、沙棘、狼牙刺、白羊草的土壤持水力及其与土壤有机碳含量的关系进行研究.结果表明,①植被间土壤持水力为:辽东栎＞山杨＞狼牙刺＞白羊草＞沙棘,除沙棘外,各植被土壤持水力和供水力随植被的正向演替而提高.②土壤比水容量即释水能力表现为乔木林大于灌木林和草地.③土壤水分特征曲线Gardner模型参数A、土壤有效水、土壤无效水含量与土壤有机碳含量有很好的相关性,相关系数分别达到0.83,0.80,0.79.     

计算机测定茶树叶片受害面积及其受害面积百分率的方法研究

建立了通过对茶树叶片进行扫描,利用Photoshop软件同时获得多张叶片及其受害部位的像素值,从而快速计算茶树叶片受害面积以及受害面积百分率的测定方法,并对此方法进行了系统的研究,结果表明：扫描分辨率为150dpi时,扫描时间和存储占用空间较优,测定效果和高分辨率扫描效果基本一致,该方法测定结果与人工测定结果无显著差异,其效率远远高于人工测定。     

基于区间线性规划理论的水稻土重金属Cd形态限量标准研究

应用生态环境效应法,借助区间线性规划理论,以稻谷Cd与活性形态(可交换态、碳酸盐结合态、铁锰氧化物结合态和有机物结合态)Cd含量间的线性回归模拟方程为目标函数,以稻谷Cd限量卫生标准为限制条件,筛选各约束条件下的最大最优值为各活性形态Cd含量的限量标准,为成都平原土壤重金属污染控制提供参考,为深入研究基于生物有效性的土壤重金属限量标准的制定提供科学依据。结果表明,土壤Cd活性形态限量标准分别为:可交换态Cd≤0.0865 mg/kg,碳酸盐结合态Cd≤0.2641 mg/kg,铁锰氧化物结合态Cd≤0.2461 mg/kg,有机物结合态Cd≤0.0760 mg/kg。     

中国荷斯坦奶牛乳脂中miR-2285f生物信息学分析及靶基因验证

旨为探索bta-miR-2285f和宿主基因TANK结合激酶1(TANK binding kinase 1,TBK1)的生物学功能,以及bta-miR-2285f与靶基因互作调节奶牛乳脂代谢的潜在机制,本研究通过生物信息学方法分析bta-miR-2285f在不同物种间的保守性,并通过上游序列CPG岛分析、启动子预测、进一步进行组织表达谱分析,预测靶基因并进行GO功能和KEGG通路富集分析。利用双荧光素酶报告试验验证bta-miR-2285f调控的下游靶基因钙结合蛋白39(Calcium binding protein 39,CAB39),并在乳腺上皮细胞水平探究bta-miR-2285f的功能作用。结果表明：1)bta-miR-2285f是牛特异性miRNA,属于内含子miRNA;2)bta-miR-2285f与宿主基因TBK1上游序列2 kb处均不含有CPG岛。bta-miR-2285f在上游586 bp处为转录起始位点。宿主基因TBK1在上游105 bp处为转录起始位点;3)TargetScan和miRWalk预测miR-2285f有172个交集靶基因,主要参与新陈代谢、遗传信息传...