不同品系中华绒螯蟹土池生态育苗效果比较

为评估不同品系中华绒螯蟹（Eriocheir sinensis）的繁殖性能和育苗效果,分别采用中华绒螯蟹二龄早熟品系（雌体≥150 g,雄体≥210 g）、“长荡湖1号”A系（雌体≥200 g,雄体≥310 g）、“长荡湖1号”B系（雌体≥250 g,雄体≥360 g）及超大规格品系（雌体≥300 g,雄体≥400 g）作为亲本进行土池生态育苗试验,比较了各品系的抱卵蟹获得率、亲本孵化率、育苗期间的投饵量、幼体变态速度以及大眼幼体产量等指标。试验结果显示：（1）各品系越冬后的抱卵蟹获得率随着亲本规格的增大而明显降低,抱卵蟹成功孵化率随着亲本规格的增大同样呈降低趋势,但组间差异不明显（P>0.05）。（2）各品系投饵量在幼体培育期间呈现先增后减的变化趋势,其中,溞Ⅴ期最高,日投饵量约为75 g/m²;与之相反,幼体蜕皮周期在幼体培育过程中呈现出先降后增的变化趋势,溞Ⅲ-Ⅳ期蜕皮周期最短,仅为5～6 d。（3）除了个别产量异常的池塘外,各品系单蟹产苗量及饵料系数均随着亲本规格的增大而提高,且各品系大眼幼体淡化率差异较小,均在90%左右。结果表明,虽然大规格品系在...     

风幕式喷杆喷雾雾滴粒径与速度分布试验

为了研究风幕出口风速和风幕出风口与喷口的水平距离对雾滴粒径和雾滴速度分布的影响,运用PDPA测试系统对不同条件下的风幕式喷杆喷雾气液两相流场进行了测试,对雾滴粒径、速度分布的测量结果进行了分析和讨论。结果表明:雾滴在气流场的作用下,随着风幕风速的逐步变大,雾滴的粒径变小且分布均匀,有效地增大了雾滴的沉积、减小了飘移。风幕出风口与喷口水平距离越近时,雾滴的穿透性能越好,向后飘移的趋势越弱。     

How much variation in tree mortality is predicted by soil and topography in Central Amazonia?

Tree mortality in Amazonia has been related to regional variation in soil, topography and climatic disturbances, but the magnitude of the effect of these factors on tree mortality at local and mesoscales remains poorly determined. We investigated tree mortality in 72 1-ha permanent plots spanning 64 km² of tropical moist forest in Reserva Ducke, Manaus, Brazil. Plots were censused three times (2000-2003, 2003-2005, and 2005-2008), resulting in two census intervals. The relationships of soil and topography to tree mortality were dependent on tree size. Small- and medium-sized trees (1 ? dbh < 30 cm) had similar relationships of mortality with soil and topography, while large trees (dbh ? 30 cm) showed different (or no) relationships. The effects of soil and topography on tree mortality also varied temporally. In the second census interval after storms, soil and topography explained about one-fourth of the spatial variation in mortality of small- and medium-sized trees (<30 cm dbh), whereas no effects were detected in the first census interval. In particular, soil fertility was the most important predictor of tree mortality in the study area. Topography alone (altitude and slope) was associated with only 12% of the spatial variation in tree mortality and the magnitude of the effect of soil and topography on tree mortality also increased after storms. In general, plots on more fertile soils, on steep slopes and sandy soils in valleys showed greater tree mortality than those on plateau with well-drained clayey soils. Therefore, disturbance history and tree size should be included when scaling up tree mortality from local to regional scales. As much variation remains unexplained, other landscape features, such as watershed morphology and wind exposure, may be necessary to make more precise predictions on patterns of tree mortality in Central Amazonia.     

BiFeO3-SrBi2Nb2O9陶瓷的表征及复阻抗研究

对单相层状钙钛矿结构的xBiFeO3-(1-x)SrBi2Nb2O9(x=0,0.1)陶瓷进行了表征和复阻抗分析。结果表明,BiFeO3的掺入降低了SBN的烧结温度,陶瓷晶粒尺寸减小,致密度提高;在较高温度时,SBFN的电学响应主要来源于晶粒效应,而SBN的电学响应则是晶粒效应、晶界效应和电极与介质界面效应的共同作用。     

CSN3、CSN1S2和β-1g基因多态与西农萨能奶山羊产羔数的相关性研究

 首次利用PCR-RFLP技术探讨κ酪蛋白(CSN3)、αs 2酪蛋白(CSN1S2)和β-乳球蛋白（β-lg）基因多态与69只西农萨能奶山羊产羔数的相关性。结果表明：CSN3-TaqI位点与产羔数之间存在显著相关(P<0.05或P<0.01)，如TC基因型个体第1胎产羔数高于CC型（P<0.01），CC基因型个体第2胎产羔数高于CC型（P < 0.05）；CSN3-HindIII位点与产羔数之间不存在关联（P>0.05）；CSN1S2-Alw26I位点与产羔数间存在显著的相关性(P<0.05或P<0.01)，如NF基因型个体第1胎产羔高于NN型（P<0.05），NN基因型个体第4胎产羔数高于NF型(P<0.01)；β-lg-smaI位点与产羔数间不存在显著相关（P > 0.05）。结果提示CSN3和CSN1S2基因对奶山羊产羔数有显著影响, 从而推测酪蛋白基因可能与FecB基因连锁。因此，认为CSN3-TaqI和CSN1S2-Alw26I位点可作为奶山羊高产羔数标记辅助选择（MAS）的有效分子标记。     

农药飘移状况的室内模拟测定

以硫酸铜代替农药,采用室内恒定风速模拟,结合分光光度法测定和数学模型拟和,研究了不同农药喷雾量及喷雾溶液浓度接近地面飘移情况.结果表明,在本试验条件下,飘移路径上某一点收集到的有效成分比例为常数,该常数与飘移距离高度相关,与喷雾量和喷雾溶液浓度无关.     

丹顶鹤早期生长发育规律的初步研究

对 6只幼鹤 (初生及 1～ 1 3周 )的体重、体尺和 9只成鹤的体尺进行测定 ,将幼鹤体重、体尺测定结果拟合生长曲线方程 ,并与成鹤的体尺指标进行比较。结果表明 :幼鹤早期生长发育阶段可划分为 3个时期 :第 1时期 (0～ 2周龄 )是快速生长期 ,第 2时期 (3～ 7周龄 )是急速生长期 ,第 3时期 (8～ 1 3周龄 )是缓慢生长期。Logistic生长曲线方程能很好地拟合丹顶鹤早期的生长发育 ,拟合精度 (R2 )均大于 0 .9955。幼鹤 1 3周龄时各项体尺指标均达到成鹤的 86%以上 ,并呈现出体长较体宽发育快的特点     

Effects of fractions of coal-derived humic substances on seed germination and growth of seedlings (Lactuga sativa and Lycopersicum esculentum)

Summary Lettuce and tomato seeds were treated in Petri dishes with a humic acid derived from an oxidized coal and with fractions of the same humic acid obtained by ultrafiltration through membranes of known molecular cutoff and by extracting with buffers set at pH 4 and pH 5. The unfractionated humic acid was applied at 40, 100, 1000, and 5000 mg l^-1 whereas the humic fractions were applied at 40, 100, and 200 mg l^-1. Germination parameters such as the number of total germinated seeds, the velocity of seed germination, the fresh weight and dry weight of total seedlings were measured and related to the chemical and physicochemical properties of the humic material. No increase in the germination percentage or the germination rate was observed for either lettuce or tomato seeds. The fresh weight of total seedlings and per seedling increased in treatments with unfractionated humic acid with increasing concentrations for both lettuce and tomato plants without showing signs of growth inhibition up to 5000 mg l^-1. This was attributed to cell elongation and more efficient water uptake. For the lettuce, the fresh weight both of total seedlings and per seedling was enhanced by treating the seeds with fractions of low molecular weight and high content of acidic functions, whereas the dry weight both of total seedlings and per seedling did not change with the humic fraction used. For the tomato seeds in contrast, the dry weight both of total seedlings and per seedling was increased by the use of unfractionated humic acid and by some of the humic fractions. An uptake of humic material by growing tomato seedlings was inferred.     

容器规格和养分加载对珍贵树种容器苗生长的影响

容器规格和养分加载量是影响容器苗生长的关键因素。以红豆树、浙江楠、浙江樟和赤皮青冈的2a生容器苗为对象,设置容器规格和缓释肥加载量2因素4水平的析因试验,分析不同容器规格、缓释肥加载量及其交互作用对各珍贵树种生长的影响,筛选适宜的容器规格及缓释肥加载量。结果表明,随容器规格和缓释肥加载量增大,各树种容器苗生长势愈好,容器规格为C3(18cm×20cm)时,各树种容器苗苗高、地径和生物量最大,容器规格增大到C4(20cm×20cm),仅赤皮青冈苗高有显著提高;而容器苗生长量较大时对应的加载量则因树种而不同,红豆树和赤皮青冈为F2(2kg·m^-3),而浙江楠和浙江樟则为F3(3kg·m^-3)。根系生长量亦随容器规格变大而增加,红豆树、浙江楠、浙江樟和赤皮青冈根系分别在容器规格C3、C2(16cm×18cm)、C4和C4时发育较好;红豆树根系随加载量增加变细变长,其根系体积在加载量F2时最大,浙江楠和浙江樟分别在加载量F3和F1时根系各项指标值较大,加载量增加反而抑制浙江樟根系生长,赤皮青冈根系则受加载量的影响不明显。各树种根冠比随容器规格增加变化不大,但随着加载量的增加,均表现出减小的趋势,最小加载量F1(1kg·m^-3)时,根冠比最大。除红豆树外,容器规格和加载量2因素对各树种的交互效应明显,经初步评价,红豆树、浙江楠、浙江樟和赤皮青冈优质容器苗培育的组合分别为C3F2、C3F3、C3F3和C4F2,相对其他3树种,赤皮青冈更适宜于较大规格的容器;浙江楠和浙江樟较红豆树和赤皮青冈要求更多的基质养分。     

兰州大尾羊×小尾寒羊F1代体重和体尺的相关性研究

本研究旨在探讨兰州大尾羊×小尾寒羊F1代羔羊体重和体尺的相关关系,为通过体尺性状估计其体重提供科学的理论依据。试验随机选取80只150日龄兰小杂交F1代羔羊,公、母羔各半,测量其体重（Y）、体长（X₁）、体高（X₂）、胸围（X₃）、管围（X₄）、胸深（X₅）和胸宽（X₆）,运用SPSS 22.0软件分别对公、母羔的体重和体尺数据进行相关性分析、通径分析、逐步线性回归分析和相关系数的分解。结果表明,兰小杂交F1代羔羊的体重与体长、体高、胸围、管围、胸深、胸宽均呈极显著正相关（P<0.01）,公、母羔胸围与体重的相关程度最高,相关系数分别为0.907和0.908,其次为体长,相关系数分别为0.875、0.844。各体尺性状间也呈极显著正相关（P<0.01）,其中胸围和体长的相关系数最高。胸围和体长主要通过直接作用影响体重,胸深、管围、体高、胸宽主要通过间接作用影响体重,胸围对体重的直接作用最大,胸深对体重的间接作用最大。公、母羔体重与体尺的最优回归方程分别为：Y=-43.861+0.675X₃+0.394X₁（r=0.945,P<0.01）和Y=-38.378+0.590X₃+0.397X₁（r=0.948,P<0.01）。综上所述,胸围和体长是影响兰小杂交F1代羔羊体重的两个重要因素,在该品种的选育和肥羔的生产过程中,要加强对胸围和体长的选择力度,同时考虑胸深、管围、体高、胸宽的影响。