玉米基因型与土壤氮素表观平衡

通过田间试验研究不同基因型玉米产量、N累积量和土壤N素表观平衡.结果表明,3个施N水平处理下不同基因型玉米间的产量、N累积量均存在显著差异.N肥在土壤中的表观残留率平均值由施N112.5kg/hm2水平(Ⅰ)下的36.74%升至施N168.75kg/hm2水平(Ⅱ)下的40.79%和施N225kg/hm2水平(Ⅲ)下的48.36%.应用N累积量较高的玉米基因型可显著减少施用N肥在土壤中的残留率.     

带绒棉种介电分选的试验研究

研制了介电式带绒棉种分选机,对影响分选效果的各因素进行了分析,对不同含绒率的棉种进行了分选电压的单因素试验。结果表明：分选电压是影响分选效果的主要因素之一,随着分选电压的增大,种子的分选效果得到提高;棉种的含绒率是影响分选效果的另一主要因素,为了得到好的分选效果,分选前必须将棉种进行剥绒加工,使其含绒率为１０％左右。     

陆地棉核心种质表型性状遗传多样性分析及综合评价

【目的】分析陆地棉核心种质的遗传多样性和表型性状遗传变异规律,并探讨核心种质的综合评价方法。【方法】利用17个表型性状数据分析419份陆地棉核心种质的遗传多样性。用Shannon-weaver信息多样性指数计算表型性状的遗传多样性,用Nei’s 1973法计算表型性状遗传距离,并使用NTSYS-pc 2.20q软件对核心种质进行聚类分析;用SAS9.2对表型性状数据进行最佳线性无偏估计(BLUE),然后根据最佳线性无偏估计值计算出表型性状的最佳值。同时,结合主成分、回归和相关分析,研究核心种质的综合评价指标和方法。【结果】核心种质表型性状分析发现,单株铃数、单铃重、衣分、子指等性状的变异系数均较大,变异系数超过10%。而断裂比强度、马克隆值以及上半部平均长度的变异程度较小,变异系数均在10%以下。方差分析发现,各表型性状地点间、年份间、地点和年份间、品种间均有极显著差异;不同地理来源的种质表型性状差异较大,长江流域地理来源的种质生育期、伸长率、上半部平均长度、衣分等性状均高于其他的地理来源,西北内陆地理来源的种质纤维强度,单铃重、整齐度指数、株高、纺纱均匀性指数等综合性状最好,美国种质的产量和纤维品质的性状优于其他国家的总和。表型性状的遗传多样性指数范围为0.351—3.796,平均为1.715。分析不同地理来源种质的遗传多样性,发现黄河流域的遗传多样性和遗传丰富度最高,中国南部区域最低。类群聚类结果发现陆地棉整体分散,没有比较明显的类群关系,部分具有相似特点的种质聚类13个组群。核心种质综合评价表明在累计贡献百分比高于85%时,共发现7个主成分,陆地棉核心种质的表型性状综合值(F值)平均为1.740,来自澳大利亚的N74-250F值最高(2.302),辽阳绿绒棉的F值最低(0.624)。对17个表型性状与F值的相关分析,发现除马克隆值、子指和黄度外,单铃重、衣分、断裂比强度、上半部纤维长度等14个表型性状与F值间的相关性具有极显著差异,最后构建了以吐絮期、单铃重、伸长率、花期、马克隆值、株高、果枝数、纺纱均匀性指数8个表型性状为自变量的回归方程,综合评价核心种质资源。【结论】中国保存的陆地棉核心种质具有较为丰富的遗传多样性,不同地理来源遗传变异有较大的差异,不同生态区的核心种质具有独特的性状特性。     

Unravelling pest infestation and biological control in low-input orchards: the case of apple blossom weevil

Low-input farming is an alternative production system that provides a great opportunity to disentangle the natural mechanisms regulating crop pests, since neither pests nor their natural enemies are disrupted by pesticides. Here, we use a key apple pest in Europe, the apple blossom weevil (Anthonomus pomorum), as a model case to unravel the factors driving pest infestation and its biological control in a low-input context, namely the cider apple orchards of NW Spain. We applied a holistic approach based on the complete life cycle of the pest and combined large-scale observation (23 orchards) with small-scale experimental assessment. Weevil attack (0.4–37.4% of flowers) increased with the proportion on apple trees in the immediate orchard neighbourhood and with semi-natural woody habitat in the surrounding landscape and decreased with tree distance to orchard edge and apple bloom level. Thus, the prevalence of the pest depended on the availability of the various resources required for foraging, egg-lying and overwintering. Three types of natural enemies supplied complementary pest control by preying on weevils at different stages in their life cycle: seven parasitoid species attacked immature weevils (6.4–81.5%), while the additive effects of birds and crawling arthropods were evident in terms of the removal of adult weevils (31–44%). We conclude that the effective biological control of A. pomorum can be achieved in low-input systems to maintain the pest at non-harmful levels, through combined management of the pest, its habitat and its natural enemies.     

自走式柠条饲料联合收获机设计

设计了一种自走式柠条饲料联合收获机。该机可一次性完成柠条的平茬、输送、切断和装箱联合作业,采用了自动化程度较高的液压行走系统和基于DSP的满负荷喂入与行走速度匹配的智能化控制技术。介绍了该机的工作原理,并对主要工作部件结构进行了设计。田间测试证明,整机性能指标达到任务书要求,符合国家有关标准和地方标准的要求。      

辽宁苗期玉米根叶对水分胁迫的响应

为了提炼辽宁春玉米苗期干旱胁迫影响的定量化评价指标,以‘丹玉39’为试验材料,采用盆栽称重控水法,对不同水平土壤含水量对春玉米苗期根叶生长的影响进行研究。结果表明：正常（75%）和偏湿（85%）水分条件下玉米具有较高的株高,茎粗和叶面积。干旱胁迫下,玉米生长发育受到抑制,株高降低、茎粗变细、根系和地上部的生物量降低,叶片光合面积减小,根冠比增大。但一定程度的干旱（55%）有利于根系下扎,增大根冠比。干旱胁迫对玉米的株高和根系的生长发育有较大的影响,地上生物量受干旱胁迫影响大于根系。     

Effect of conformation on the properties of uniaxially drawn polylacide films upon drawing temperature

Polylactide(PLA) films were drawn at various drawing temperature of 65, 90 and 120 °C. The effects of drawing temperature on structural conformation and properties of PLA films were investigated. It was confirmed that the PLA films at drawing temperature of 65 and 90 °C were composed of α′ phase crystal form. The strain-induced crystallization and molecular orientation increased with increasing the draw ratio, which result in improving the mechanical and thermal properties of α′ phase PLA films. However, at drawing temperature of 120 °C, the strain-induced crystallization and molecular orientation of PLA films were not distinctly detected. It was supposed that the rate of the chain relaxation was faster than chain orientation and strain-induced crystallization during uniaxial drawing process.     

山羊传染性胸膜肺炎支原体和绵羊肺炎支原体对抗菌药物敏感性的研究

测定了环丙沙星、氧氟沙星、单诺沙星、红霉素、罗红霉素、泰乐菌素、泰妙菌素、四环素等8种药物对羊肺炎支原体两个标准株Y-98和Y-goat的体外抑菌浓度以及红霉素与氧氟沙星、泰乐菌素对Y-goat和四环素与氧氟沙星、泰乐菌素对Y-98的联合药敏作用.结果表明,这8种抗菌药物对Y-goat和Y-98的MIC(μg/mL)分别为:环丙沙星0.223、0.002 23,氧氟沙星0.281、0.014 0,单诺沙星0.136、0.014 0,红霉素0.021 8、无效,罗红霉素0.032 7、无效,泰乐菌素0.042 2、0.039 0,泰妙菌素0.021 7、0.052 0,四环素0.195、0.052 0.红霉素与氧氟沙星的联合药敏指数为1,是相加作用;红霉素与泰乐菌素对Y-goat的联合药敏指数为1.5,是无关作用;四环素与氧氟沙星、泰乐菌素对Y-98的联合药敏试验指数均为0.375,是协同作用.     

羊支原体性肺炎两标准株对抗菌药物敏感性的研究

本实验测定了环丙沙星、氧氟沙星、单诺沙星、红霉素、罗红霉素、泰勒菌素、泰妙菌素、四环素等8种药物对羊肺炎支原体两个标准株Y98和Y-goat的体外抑菌浓度以及红霉素与氧氟沙星、泰勒菌素对Y-goat和四环素与氧氟沙星、泰勒菌素对Y98的联合药敏作用。对羊肺炎支原体两个标准株对抗菌药物的敏感性进行了分析。     

Earthworm (<Emphasis Type="Italic">Metaphire guillelmi</Emphasis>) effects on rice photosynthates distribution in the plant–soil system

An experiment was conducted to investigate the effects of earthworm (Metaphire guillelmi) activities on rice photosynthates distribution in plant–soil system through ¹⁴C pulse-labelling method. Rice was planted in pots, and maize straw was mulched on the surface with or without earthworms. Rice plants at tillering stage or heading stage were labelled with ¹⁴CO₂. Plant and soil were sampled 15 days after labelling at the tillering or heading stage and at harvest. Rice growth was inhibited by earthworms (M. guillelmi) at early stage, but the inhibition disappeared at later stage. Earthworms significantly (P < 0.01) increased the ¹⁴C percentage in root at day 15 after tillering stage labelling, but the effect disappeared at harvest. Earthworms (M. guillelmi) significantly (P < 0.01) increased the ¹⁴C percentage in root at day 15 after heading stage labelling and increased ¹⁴C percentage in soil at harvest. Earthworms decreased the percentages of total organic ¹⁴C (TO¹⁴C) present as microbial biomass ¹⁴C (MB¹⁴C) and increased the percentages of total organic ¹⁴C present as dissolved organic ¹⁴C (DO¹⁴C) at all sampling times. It is suggested that earthworms might alter the transfer of plant photosynthates from the aboveground to the belowground, and thus, soil active C pool. However, these data should be also confirmed in the field.