醉马草内生真菌共生体对土壤微生物和养分的影响

本研究以我国西北部天然草原广泛分布的烈性毒草醉马草(Achnatherum inebrians)为对象,分析内生真菌共生体对根系土壤中微生物区系和养分的影响。结果表明,采自桑科、甘加和榆中3个地区的醉马草根际土壤中真菌数量为其伴生种根际土壤中对应菌的1.31～1.56倍、细菌数量为1.56～2.65倍。土壤营养成分测定结果表明,醉马草根际土壤中有机质、全氮、速效磷和速效钾的含量均显著高于其伴生种,而全磷和全钾含量差异不显著。     

Legume Forage Quality

Abstract

Legume forage quality research is now concerned not only with nutritive value of forage for ruminant animals, but the impact of these nutrients on environmental quality. If we are to move to a more sustainable agriculture worldwide, more legumes must be incorporated into animal production systems. The goal of forage legume breeders is to tailor legume nutritive value to the needs of the consuming animals. A generalized priority list for legume nutritive value research includes high fiber digestibility, low anti-quality compounds, appropriate condensed tannins, reduced nonprotein nitrogen, and high sulfur amino acids. Although breeders have regularly found a wide range in forage quality within a given legume species, very few varieties with proven forage quality advantages have been released. Yield and persistence issues have dominated forage legume breeding. Improvement in forage quality often is linked to a reduction in yield and/or persistence, and also frequently results in complex genotype X environment interactions. Transgenic technology has almost limitless potential for improving legume forage quality and environmental quality, but only if the public can be convinced that transgenics are an acceptable risk. Structural and functional roles of legume plant cell walls and their relationships to forage quality are poorly understood. Research on the basic processes of forage legume growth and the relationships between growth and forage composition should result in the development of more accurate simulation models, and transgenic technology can provide us with the tools to understand these basic processes.     

HCG与LHRHa对雌性蜂巢石斑鱼产卵期间生理变化的影响及比较

选取日本冲绳地区雌性蜂巢石斑鱼为对象,描述与分析了HCG与LHRHa对该鱼催产效果的差异及注射后所引起的性腺发育变化和排卵相关的性类固醇变化,希望能为蜂巢石斑鱼的人工繁殖提供可靠的理论基础,以及在实践生产中的重要参考。结果表明,HCG与LHRHa均显著促进了决定排卵的性成熟诱导物质MIS的释放以及鱼的产卵; 产卵后的蜂巢石斑鱼雌二酮E2的水平显著下降,验证了蜂巢石斑鱼卵巢发育及产卵随月亮周期变化的周期性; 在渔业生产中注射催产药物前,确定对象鱼卵泡发育阶段对于提高催产成功率十分重要。在LHRHa注射组,完成卵黄化的蜂巢石斑鱼催产效果最佳,卵黄化早期的鱼不产卵; HCG对卵泡发育初期的蜂巢石斑鱼的催产效果优于LHRHa,但催产效果仍不理想,而对于完成了卵黄化鱼的催产效果不如LHRHa。结合LHRHa的其他优势,本研究认为在具备检验鱼体卵巢发育阶段实验技术的条件下,更加推荐LHRHa作为雌性蜂巢石斑鱼的催产药物。     

橡胶树枯草芽孢杆菌Czk1抑菌活性物质的理化性质

采用杯碟法和生长速率法,对橡胶树枯草芽孢杆菌菌株Czk1发酵液中活性物质进行了初步定位。结果表明：活性物质属于胞外分泌型代谢产物,存在于发酵上清液中。理化性质的研究表明,其抗菌物质表现出耐高温,不耐强酸碱,对紫外线和蛋白酶K不敏感,以及对5种常见的金属离子溶液、有机溶剂具有不敏感的特性;采用酸沉淀后甲醇抽提的方法可提取该活性物质。Czk1培养条件的单因子实验结果表明,YPD培养基作为该菌株的发酵液培养基,初始pH值为7.0,以7%接种量接种,摇床培养（28℃,180r·min-1）3d,Czk1表现出对病原菌最佳的拮抗活性。     

堆肥施用量对全株青贮玉米产量和营养价值的影响

【目的】探讨与化学肥料相比施用堆肥对青贮玉米饲料生产能力的影响,为生产中合理施用堆肥进行青贮玉米生产提供理论依据。【方法】采用单因素随机区组试验设计,3个不同堆肥的施用处理分别为20、40和60 t•hm-2,以施用化学肥料（尿素400 kg•hm-2＋过磷酸钙450 kg•hm-2＋钾肥（K2SO4）300 kg•hm-2）为对照组,每个处理3个重复。通过测定各处理单位土地面积的鲜物质产量、干物质产量、营养物质含量、养分瘤胃降解率,得出不同堆肥施用量对青贮玉米单位土地面积生物产量、营养物质产量、可降解营养物质产量等指标的影响,从而对施用堆肥的青贮玉米饲料生产能力进行综合评定。【结果】随堆肥施用量的增加,全株青贮玉米中蛋白质、脂肪、总能含量均显著增高（P＜0.05）,粗纤维的含量显著降低（P＜0.05）,总碳水化合物含量差异不明显（P＞0.05）。同时,提高堆肥施用量增加了全株青贮玉米中蛋白质、脂肪、总碳水化合物、总能的瘤胃降解率（P＜0.05）。各堆肥处理组全株青贮玉米生物产量、营养物质产量、瘤胃可降解营养物质产量和相对饲料价值均高于对照组（P＜0.05）。【结论】与化学肥料相比,施用堆肥提高了青贮玉米的生物产量和饲用品质,本试验条件下最适的堆肥施用量为40 t•hm-2。     

施用城市污泥堆肥对土壤理化性质及白三叶生长的影响

通过盆栽试验研究了不同比例城市污泥堆肥对土壤理化性质及白三叶生长的影响。结果表明:施加城市污泥堆肥土壤的pH值相对稳定,比不施肥土壤的变化小,城市污泥堆肥有一定的缓冲作用;施肥土壤的有机质含量比不施肥增加了76.69%～204.80%,施肥土壤的总磷含量比不施肥土壤略有升高,施肥质量分数分别为5%、10%、15%和20%时,土壤中无机氮含量分别是不施肥土壤中的5.6、10.0、5.1和4.5倍,施肥质量分数为10%时,无机氮含量最大,表明城市污泥堆肥土地利用可以提高土壤养分含量;种植白三叶的土壤中施加污泥堆肥后,白三叶地上部分及根的干质量比不施肥分别增加了82.42%～229.95%和10.21%～58.23%,表明污泥堆肥能够促进白三叶的生长;在上述施肥比例下营养元素的利用率不同,氮元素的利用率依次为4.3%、5.8%、2.6%和3.5%,磷元素的利用率依次为1.27%、1.64%、1.21%和1.60%。研究结果说明,施用污泥堆肥可提高土壤有机质含量,改善土壤理化性质,促进白三叶的生长,施肥质量分数为10%时,土壤中无机氮含量最高,总氮和总磷的利用率最高,10%为最佳的施肥比例。      

油茶籽粕提取物中抑菌活性物质的分离纯化研究

以油茶籽粕正丁醇萃取物为原料,通过大孔树脂柱层析、正相硅胶柱层析、高效液相色谱等分离纯化技术将较强抑菌活性的物质进行分离。结果表明,采用60%乙醇进行大孔树脂柱层析,然后以乙酸乙酯、甲醇、甲酸体积比分别为9：1：0.1、8：2：0.1、7：3：0.1 进行正相硅胶梯度洗脱,以30%甲醇作流动相进行高效液相色谱纯化,油茶籽粕正丁醇萃取物能分离出纯度非常高的抑菌活性物质。     

6个燕麦品种(系)在甘肃夏河地区的适应性评价

为了筛选适宜在甘肃高寒牧区种植的高产优质燕麦新品种,对6个燕麦属品种(系)在甘南州夏河桑科草原不同生育时期的生产性能和营养品质进行了分析和比较。结果表明:整个生育期内陇燕2号与陇燕3号生产性能表现相对较好,QO245-7表现最差。各供试品种干草产量在灌浆期最高,其中,陇燕2号高达11917.82kg/hm2,QO245-7最低,为7174.96kg/hm2,差异显著(P<0.05);灌浆期白燕2号营养品质表现最好。为了进一步分析各品种的整体表现,采用基于熵权赋权法的灰色系统理论对灌浆期各品种生产性能及营养品质指标进行综合评价,表现较好的是陇燕2号、陇燕3号和白燕2号,可在高寒牧区推广种植。     

Gorse (Ulex spp.) use by ponies in winter: Is the spatial pattern of browsing independent of the neighbouring vegetation?

Because of the progressive abandonment of agricultural practices, the extension of Atlantic dry gorse/heathlands has increased in the Cantabrian Mountains. However, there is a remarkable lack of knowledge on the spatial use of gorse by grazing animals. This study was designed to examine whether the spatial pattern of gorse browsing was independent of the neighbouring vegetation. In addition, factors that could determine the grazing/browsing pattern were investigated. For this purpose, we conducted a spatially controlled experiment using Basque Ponies (an endangered and rustic horse breed) in winter by simulating short‐term grazing at a moderate stocking rate. Measurements of size and nutritive value of grass and gorse patches were made before and after grazing to analyse grazing pressure and browsing impact. Browsing damage did not occur randomly. Sward height of grass patches was the best predictor of feeding site selection, and gorse patch edges surrounding the most‐used grass patches were browsed with a greater intensity. This foraging strategy appears to be the result of a trade‐off between maximization of intake rate and nutritive benefits. Our results highlight the importance of spatial information for predicting gorse utilization by grazing equids, in particular the effect of utilization of gorse/grass edge. We conclude that these ponies could be a suitable tool for restoring abandoned gorse shrublands.