不同杀青工艺对松阳香茶品质的影响

本文针对松阳香茶存在的色泽不绿,香气不高等品质问题,采用不同杀青温度和不同的投叶量处理,研究其对松阳香茶品质的影响。结果表明：其他工艺相同的基础上,采用80型滚筒杀青机杀青,下锅温度以250℃,投叶量在100kg／h时,炒制的香茶品质最佳。     

一种利用流式细胞术鉴定梨倍性的方法

流式细胞术鉴定植物染色体倍性的方法广泛应用于果树多倍体育种中,然而相关流式细胞术鉴定梨染色体倍性的方法还没有系统的研究。以梨树叶片为试材系统优化了各个流式细胞术关键实验节点,结果表明：实验材料选取当年春季新梢第3~5 片梨树嫩叶,尤其是大棚新梢嫩叶最好;叶片前处理时用蒸馏水、去离子水依次洗净叶片表面后,再用去离子水浸泡10 min;使用WPB解离液对梨叶片细胞核进行提取后,用500 目滤膜过滤2 次,离心1 次后用流式细胞仪进行检测可得到理想的实验结果。该方法步骤简单、结果可靠,是一种快速、高效的梨染色体倍性鉴定的方法,可广泛用于梨树多倍体鉴定。     

纵轴流玉米脱粒分离装置喂入量与滚筒转速试验

在玉米籽粒直收过程中,脱粒滚筒转速与联合收获机的额定喂入量相匹配才能发挥出最佳的作业效果。为了获得不同喂入量时玉米联合收获机最优的滚筒转速范围,设计了一种零部件可更换、结构参数和工作参数均可调的纵轴流玉米脱粒分离装置,并在自主研制的试验台上以脱粒滚筒转速、喂入量为影响因素,以籽粒破碎率、未脱净率为性能指标进行玉米脱粒试验。通过台架试验、回归分析和单变量求解,最终确定了不同喂入量的最优滚筒转速范围:喂入量为8 kg/s时,最优的滚筒转速为254~486 r/min;喂入量为10 kg/s时,最优的滚筒转速为278~466 r/min;喂入量为12 kg/s时,最优的滚筒转速为313~445 r/min。在以上条件下籽粒破碎率均小于5%,未脱净率小于2%,达到了国家和相关标准的要求。     

适合草莓倍性鉴定的流式细胞术方法的建立

比较了3种提取液制备红颊、川九1号、吉林草莓细胞核悬液流式细胞术检测效果,结果显示,提取液Ⅲ主峰粒子团清晰而集中,背景碎片少,试剂配方简单配制容易,且3种草莓材料倍性差异区分明显,优于其他2种提取液。对红颊草莓不同部位或不同来源的材料进行流式细胞术检测效果比较,结果表明,组培苗的检测效果明显优于大田试材,组培苗叶片因取材容易、主峰清晰、杂峰少、细胞碎片少而成为最佳试材。     

Effect of Graded Levels of Fiber from Alfalfa Meal on Nutrient Digestibility and Flow of Fattening Pigs

The fiber level and composition have an important effect on nutrient digestibility of swine diets. Little information is known about the effects of fiber level and composition from alfalfa meal on nutrient digestibility of fattening pigs fed a corn-soybean meal-based diet. The objective of this experiment was to determine the effects of alfalfa fiber on the growth performance, intestinal nutrient flow and apparent total tract digestibility（ATTD） of nutrients in fattening pigs. 24 barrows（Duroc×（Large White×Landrace）, body weight=（60.6±0.7） kg） were randomly allotted to 4 treatments with 6 replicates of 1 pig per replicate. The pigs were provided a control diet or a diet containing 5, 10 or 20% of alfalfa meal during a 14-d experiment period. Average daily gain（ADG） and the ATTD of dry matter（DM）, organic matter（OM）, crude protein（CP）, neutral detergent fiber（NDF）, acid detergent fiber（ADF） and gross energy（GE） reduced linearly as the level of alfalfa meal in the diet increased（P〈0.01）. The total tract flow of DM, OM, CP, NDF, ADF, and GE increased with the increase in dietary alfalfa（linear, P〈0.05）. Growth performance and nutrient digestion were not affected by inclusion of 5% alfalfa meal in the diet（P〉0.05）. A multiple linear regression analysis, taking into account both soluble and insoluble fiber intake, explained approximately 70% of the variation in the ATTD of DM, OM, NDF, and GE（P〈0.01）. In conclusion, alfalfa meal should be limited to less than 5% of the diet in fattening pigs to maximize growth performance and nutrient digestion. Soluble and insoluble fiber from alfalfa meal has the differential roles in nutrient digestion, which may help explain the main variation observed in nutrient digestibility. These findings suggest that knowledge of specific fiber components is necessary to accurately predict the effects of dietary fiber on nutrient digestibility.     

Genetic diversity within sea trout population from an intensively stocked southern Baltic river,based on microsatellite DNA analysis

Sea trout, Salmo trutta L., populations in the Slupia River basin have been affected by mass stocking with smolts and fry. This work is focused on a small‐scale differentiation in sea trout populations from one basin with a strong emphasis on the relationship between wild and hatchery origin fish. A total of 216 sea trout were genotyped at 10 microsatellite loci. Global F_ST obtained by amova was low at 0.0165. Pairwise F_ST were significant for all tests except wild and stocked adults. The highest pairwise difference was found between the hatchery sample and Kwacza (F_ST = 0.038). Analysis of the genetic structure revealed micro‐geographical differentiation with four subpopulations. The quality of the artificial spawning was found not to be adequate with a high risk of adverse effects to the whole population. All future stocking actions in the basin should consider the existing population structures.     

基于CFD-DEM耦合的网式过滤器水沙运动数值模拟

过滤器内部的水沙运动复杂且多变,初始状态下沙粒分布的不均导致滤芯产生局部堵塞,改变了水流流态并进一步影响后续沙粒运动和分布。本文以CFD-DEM(Computational fluid dynamics,CFD;Discrete element method,DEM)耦合模拟Y型网式过滤器内部流场变化与沙粒运动及分布,直观地反映了滤芯对水流的流动阻力特性与对沙粒运动分布影响。结果表明,过滤器内部存在明显的回流区、旋涡区及滞流区,导致各过滤面流速不均,出口一侧流速大,进口一侧流速小,两者相差39%;随着时间的变化,过滤器内流场变化明显,沙粒堆积依次出现在出口侧下端面、出口侧上端面、进口侧下端面、进口侧上端面上,最终布满整个滤芯;在滤芯的4个过滤面中,出口侧上端面流速大而沙粒堆积最少,进口侧上端面流速小而沙粒堆积最多,由此可见出口侧上端面具有更好的过滤性能,可适当提高该处过水面积,以提高过滤器过滤效率。     

拖拉机液压底盘液控比例流量阀设计与试验

为提高液压驱动拖拉机行驶时的调速稳定性和低速行驶时的平顺性,设计了一种液控比例流量阀。该阀设计有压力补偿功能,以消除压力波动对流量的影响,提高了流量控制精度。通过传统计算和仿真验证的方法对该阀进行结构参数设计。基于阀口迁移理论设计了阀芯节流槽,以增大调速区间。仿真结果表明:该阀控制流量范围为0~5.67×10-3m3/s,流量变化平稳,流量调速控制压力区占总控制压力区间的68.4%;压力补偿阀控制补偿压力在0.3~0.7 MPa的范围内,可使比例换向阀流量稳定。试验结果表明:拖拉机空载、发动机怠速工况时,流量调速控制压力区占总控制压力区间的45%;拖拉机空载、发动机高速工况时,流量调速控制压力区占总控制压力区间的62%;拖拉机重载、发动机怠速工况时,流量调速控制压力区占总控制压力区间的49.5%;拖拉机重载、发动机高速工况时,流量调速控制压力区占总控制压力区间的48.5%;当控制压力为0.78 MPa时,液控比例阀流量稳定在8.33×10-5m3/s;当控制压力为0.84 MPa时,液控比例阀流量稳定在2.5×10-4m3/s。     

Stimulation in the movement and uptake of phosphorus in response to magnetic P solution and arbuscular mycorrhizal fungi in Ocimum basilicum

A greenhouse experiment was conducted to assess the effects of magnetic field, arbuscular mycorrhizal fungi (AMF), and phosphorus (P) concentration in the nutrient solution (0, 5, 10, 20, or 40 mg L^?1) on the mobility and accumulation of P in soil and plant tissues of basil (Ocimum basilicum L.). The experiment was designed as a factorial combination and treatments were arranged in a completely randomized design with four replicates. Magnetic field increased water-soluble P in the soil and P concentration in plant shoot by 30.0% and 13.0%, respectively, in comparison to the control. The application of magnetic field and inoculation of AMF at 10 mg P L^?1 increased the P translocation efficiency by 23.3% and 17.8%, respectively. Overall, our results demonstrated that the use of magnetic field and AMF could be an effective tool for enhancing of uptake and movement efficiency of P even at low concentrations.     

稻田—田埂过渡区土壤优先流特征研究

为揭示田埂对稻田—田埂过渡区土壤水分渗漏的影响,对比不同位点(田内、过渡带和田埂)优先流特征差异,采用室外亮蓝染色示踪方法,对江汉平原典型稻田—田埂过渡区进行研究。结果表明:过渡区土壤染色面积比(SAR)随深度的增加呈波动下降,其中0~20cm土层SAR较高,占剖面总SAR的53.85%~88.55%。不同位点土壤SAR差异明显,0~20 cm土层平均SAR由大到小依次为田内、过渡带、田埂,20 cm以下各位点SAR均较低,但田埂平均SAR高于田内。各位点水平剖面染色结果与垂直染色结果能较好对应,且随着深度增加,土壤染色区域急剧减少。各位点染色路径数(SPN)与SAR显著相关,田埂中、下层土壤SPN均高于田内。染色路径宽度(SPW)结果显示,0~20 cm田内以10~80 mm和大于80 mm SPW为主,过渡带和田埂大于80 mm SPW较少,均以小于10 mm和10~80 mm为主。各位点SPW的差异反映在水流类型上,田内为非均质指流—高相互作用大孔隙流,过渡区和田埂以混合作用大孔隙流—高相互作用大孔隙流为主。水分渗漏路径结果显示,田内水分由过渡带和田埂的垂直和侧向渗漏较强,且田沟田埂侧向流较田间田埂明显。田埂是稻田水分快速流失的主要区域,加剧了稻田水肥流失和水环境污染风险。本研究可为稻田水分保持和制定合理施肥、灌溉等措施提供依据。