采用Biolog, DGGE 和PLFA三种方法研究利用方式对土壤微生物群落结构的影响

Biolog, 16S rRNA gene denaturing gradient gel electrophoresis （DGGE）, and phospholipid fatty acid （PLFA） analyses were used to assess soil microbial community characteristics in a chronosequence of tea garden systems （8-, 50-, and 90- year-old tea gardens）, an adjacent wasteland, and a 90-year-old forest. Biolog analysis showed that the average well color development （AWCD） of all carbon sources and the functional diversity based on the Shannon index decreased （P 〈 0.05） in the following order： wasteland 〉 forest 〉 tea garden. For the DCCE analysis, the genetic diversity based on the Shannon index was significantly lower in the tea garden soils than in the wasteland. However, compared to the 90-year-old forest, the tea garden soils showed significantly higher genetic diversity. PLFA analysis showed that the ratio of Gram positive bacteria to Cram negative bacteria was significantly higher in the tea garden soils than in the wasteland, and the highest value was found in the 90-year-old forest. Both the fungal PLFA and the ratio of fungi to bacteria were significantly higher in the three tea garden soils than in the wasteland and forest, indicating that fungal PLFA was significantly affected by land-use change. Based on cluster analysis of the soil microbial community structure, all three analytical methods showed that land-use change had a greater effect on soil microbial community structure than tea garden age.     

糯玉米种子活力性状的主基因+多基因混合遗传分析

【目的】探索鲜食型糯玉米种子活力的遗传模型,为糯玉米种子活力研究提供理论基础。【方法】以种子活力有显著差异的糯玉米自交系N34（P₁）和N56（P₂）为亲本,配制F₁、B₁、B₂、F₂群体,利用主基因＋多基因混合遗传模型分析方法,对种子活力3个相关指标（发芽势、电导率和活力指数）的遗传模型进行分析。【结果】鲜食糯玉米发芽势最佳遗传模型为2对加性-显性-上位性主基因＋加性-显性-上位性多基因混合遗传模型,B₁、B₂和F₂主基因遗传率分别为66.62%,49.10%和92.94%;电导率最佳遗传模型为1对加性-显性主基因＋加性-显性多基因混合遗传模型,B₁、B₂和F₂主基因遗传率分别为57.75%,57.96%和65.14%;活力指数最佳遗传模型是2对加性-显性-上位性主基因＋加性 显性多基因混合遗传模型,B₁、B₂和F₂主基因遗传率分别为66.49%,48.02%和89.49%。3个性状均以主基因遗传为主。【结论】在育种实践中,对糯玉米种子活力的遗传改良和选择可在低世代进行,同时可采用聚合回交或轮回选择来积累有效修饰基因和微效基因,以提高育种效率。     

混播比例和施氮肥对箭筈豌豆/燕麦草地根系特性的影响

豆科和禾本科牧草混播是栽培草地的重要模式之一,能显著改善土壤,提升系统可持续生产能力。牧草根系是土壤有机质返还的重要来源,但混播草地中牧草根系特性的变化尚不清楚。以箭筈豌豆和燕麦草地为对象,研究了不同施氮肥水平和混播比例下其根生物量、根性状的变化。结果表明:1)混播比例和施氮肥对草地根生物量和根性状有显著交互作用,混播草地根生物量显著大于单播;与高氮肥处理相比,根生物量在低、中氮肥处理下更高;高氮肥对根长、比根长、根表面积和比根面积在植物生长前期表现为抑制作用,在生长后期随混播中箭筈豌豆比例的增大,抑制作用减轻。2)混播条件下土壤硝态氮含量大于单播,而土壤铵态氮含量仅在乳熟期时大于单播,且随混播中箭筈豌豆比例增大,矿质氮含量增加;施氮肥对0~30 cm土层中的矿质氮含量有显著影响,其含量在施氮肥100 kg·hm^-2下最高,不施肥下最小。3)根生物量与土壤硝态氮含量间显著正相关,根长、根表面积、根体积与土壤硝态氮含量间显著负相关。综上,混播中箭筈豌豆比例的增加有助于改善土壤矿质氮,优化混播草地根性状。     

Investigation of the high-amylose maize starch gelatinization behaviours in glycerol-water systems

The effect of glycerol on gelatinization behaviours of high-amylose maize starch was evaluated by confocal laser scanning microscopy (CLSM), scanning electronic microscope (SEM), differential scanning calorimetry (DSC), texture analyzer (TPA) and rheometer. Gelatinization of the high-amylose maize starches with glycerol content of 10% (w/w) began at 95.4 °C (T_o), peaked at 110.3 °C (T_p), and completed at 118.9 °C (T_c). The birefringence began to disappear at around 100 °C and finished at 120 °C which corresponded well to the onset and conclusion temperatures obtained by DSC. The high-amylose maize starch granules maintained original morphological structure at 100 °C and swelled to a great degree at 110 °C. The high-amylose maize starch paste formed at 100 °C showed the lowest hardness (39.92 g), while at 120 and 130 °C, showed the highest hardness (610.89 g and 635.43 g, respectively). It should be noted that in going from 100 °C to 110 °C there is a significant increase in the viscosity of the slurry solution. The identical apparent viscosity was observed when the shear rate exceed 100 s⁻¹, resulting from the high-amylose maize starch granules were completely gelatinized at 120 °C, which was consistent with DSC analysis.     

基于机器视觉的奶牛发情行为自动识别方法

及时检测奶牛发情、适时人工授精、减少空怀奶牛，是奶牛养殖场增加产奶量的关键手段。针对基于运动量和体温等体征的接触式奶牛发情识别方法会造成奶牛应激反应且识别准确率不高的问题，提出了一种非接触式奶牛发情行为自动识别方法。该方法首先使用改进的高斯混合模型实现运动奶牛目标检测，然后基于颜色和纹理信息去除干扰背景，再利用AlexNet深度学习网络训练奶牛行为分类网络模型，识别奶牛爬跨行为，最终实现对奶牛发情行为的自动识别。在供试数据集上的试验结果表明，本文方法对奶牛发情的识别准确率为100%，召回率为88.24%。本文方法可应用于奶牛养殖场的日常发情监测中，为生产管理提供辅助决策。     

混料设计法优化萝卜糕配方的研究

萝卜糕是闽南地区一种传统小吃，其质地柔软，味道鲜美，营养丰富，是一种适宜大众的美食。本文以黏米粉、玉米粉、马铃薯粉为粉料，采用混料设计试验方法优化萝卜糕的原料配比，研究了不同种类及不同配比的淀粉形成的面团的质构特性，比较不同配比的原料对萝卜糕感官品质的影响，确定各原料的最佳添加量。通过质构分析和感官评分法对萝卜糕的配方进行比较。结果表明：当黏米粉、玉米粉和马铃薯粉的混合比例为0.65∶0.10∶0.25时，面团TPA质构特性为硬度较低，黏着性、弹性和内聚性均达到最高值，分别为1 220.834 Pa·s、0.97和0.534，且黏米粉、玉米粉和马铃薯粉比例为0.598、0.176、0.226时，制备的萝卜糕风味最佳，感官品质得分最高。     

混料设计及响应面法优化大黄药渣固态发酵生产漆酶的工艺

通过优化大黄药渣固体培养基的组成及发酵条件,以期最大程度提高发酵生产漆酶的活力。采用D-最优混料设计对固体培养基碳源组成进行优化,优化后得到的固体培养基组成为:小麦麸皮47.2%,大黄药渣47.2%,葡萄糖1.6%,蛋白胨2.5%,氯化钙0.48%,磷酸二氢钾0.5%,硫酸铜0.02%,硫酸镁0.5%。通过中心组合设计响应面试验建立二次回归模型对固态发酵条件进行优化,确定最优发酵条件为发酵初始pH 4.3,发酵温度32.5℃,固液质量体积比1.47∶1,发酵时间7.5 d。在此条件下,发酵生产的漆酶酶活为7 602.1 IU/mL,与模型预测值相对误差在0.6%。     

4种氨基糖苷类抗生素联用氯霉素对青海弧菌Q67 联合毒性作用及机制

近年来,氨基糖苷类(Aminoglycoside, AG)抗生素与氯霉素(Chloramphenicol, CHL)联用产生增毒作用而引起的死亡事件屡见不鲜。以4种AG抗生素：盐酸大观霉素(SPC)、硫酸小诺霉素(MCR)、硫酸丁胺卡那霉素(AMK)、妥布霉素(TOB)和氯霉素(CHL)为研究对象,选择青海弧菌(Vibrio qinghaiensis sp.-Q67,Q67)作为指示生物,采用直线均分法设计二元混合物,采用最小二乘法拟合浓度-效应数据,运用浓度加和(CA)模型对药物间的毒性相互作用进行评估,并同步分析抗生素联合毒性作用机理。结果表明：在暴露时间为12 h时,以半数浓度效应(EC₅₀)的负对数pEC₅₀值为毒性指标,5种抗生素的毒性大小顺序为TOB > CHL > MCR > AMK >SPC;4种AG抗生素与CHL的二元混合物的联合毒性作用特点因混合组分的不同而不同,Q67在二元混合物的EC₅₀浓度水平、暴露12 h后,细胞形态均未发生显著变化,而在单个抗生素的EC₅₀浓度、暴露12 h后,细胞明显受损,但损伤程度不同;大部分受混合物作用的Q67的发光相关物质含量在EC₅₀效应下均低于空白组,抗生素及其混合物的作用机制很可能是通过干扰发光菌体内蛋白质合成,进而导致细菌代谢紊乱,最终致其死亡。     

Changes in soil chemical and physical characteristics in Japanese cypress (Chamaecyparis obtusa Endl.) stands by mixture of deciduous broad-leaved trees in the northern Kanto region of Japan

In order to clarify the effects of a mixture of deciduous broad-leaved trees on soil fertility, we investigated litter biomass accumulation, mineral soil chemical and physical characteristics, characteristics of nitrogen mineralization, and the mutual relationships between them in Japanese cypress (Chamaecyparis obtusa) stands mixed with deciduous broad-leaved trees at different ratios (mixture ratio; MR = 0, 16, 33, 43, 100% by basal area) in the northern Kanto region of Japan. Litter biomass in the forest floor and mineral soil was 19.1 Mg ha⁻¹ in MR 0% and decreased approximately 60 % in MR 33%, MR 43% and MR100%. The permeability at 0–5 cm soil depth in MR100% was twice as much as that in MR 0%. Increases in soil permeability were likely due to larger soil pores in the higher MR with much accumulated deciduous broad-leaves. At 0–5 cm soil depth, the differences in carbon concentration among the plots were not clear. On the other hand, carbon concentrations at 5–10 cm depth increased from 90 g kg⁻¹ to 147 g kg⁻¹ with increases in MR from 0% to 100%. Concentrations of exchangeable bases increased two to four times with increases in MR from 0 to 100% at 0–10 cm depth. Soil pH (H₂O) generally increased with increases in MR at each depth. The rates of net nitrogen mineralization at 0–5 cm depthin vitro increased from 25 to 87 mg kg⁻¹ 2 weeks⁻¹ with increases in MR from 0 to 100%. However, increases in nitrification with increases in MR were not clear compared with nitrogen mineralization. These results indicated that a mixture of deciduous broad-leaved trees in a Japanese cypress stand was effective in preventing soil fertility decline. This study was supported by a grant from the Showa Shell Sekiyu Fundation for Promotion of Environmental Research. A part of this study was presented at the 7th International Congress of Ecology (1998).     

香荚兰白绢病土表施药防治试验

白绢病病区土表喷施加量的３００倍波尔多液处理后,发病率（７５％）和病情（部分腐烂）都明显低于一般处理的发病率（１００％）和病情（全部腐烂,长满菌丝,产生菌核）。土表施用菌核净、土菌消、波尔多液、波尔多液＋苯莱特的试验表明,４种农药对防治白绢病,抑制基腐、蔓腐都有明显效果。其中土菌消效果最好,其次为菌核净;波尔多液和波尔多液＋苯莱特效果相近,较差。