不同密度枣园植草草地生产性能对刈牧的响应

为了探讨混播饲草在不同密度枣园内对刈牧处理的响应,分别于4 m×3 m,4 m×5 m,4 m×7 m枣园内带状混播种植多变小冠花、白三叶、百脉根,2013和2014年度,平均每隔20 d进行刈牧,测定其地上生物量,并且取草样测定CP,NDF和ADF含量,2014年度最后1次刈牧时,在刈牧区和未刈牧区每隔20 cm分层测定地下生物量。结果表明,在枣园密度为4 m×5 m时,饲草地上生物量在2013年和2014年分别达到2169和2008 kg·hm^-2,显著高于低密度枣园（P<0.05）,对应CP产量分别达443和402 kg·hm^-2。刈牧处理,显著降低了饲草根系生物量（P<0.05）,且饲草根系消减系数降低,根系浅层化。虽然刈牧影响饲草的可持续利用,但降低了饲草根系与枣树根系的竞争。     

去叶对菊芋块茎产量及物质分配规律的相关性研究

通过对菊芋（Helianthus tuberosus）进行不同的去叶处理,探讨营养生长期去叶对菊芋块茎生物产量及物质分配规律的影响,为菊芋的高产栽培提供理论参考。结果表明：营养生长期去下1/3叶和去下1/2叶处理条件下块茎生物量均得到提高,剪去倒数1/3叶处理块茎产量达到最高值;营养生长期去叶提高了块茎生物量,降低了分枝数、花数和叶数;去叶提高了菊芋根比重、茎比重、块茎比重和根冠比,降低了叶比重和花比重;块茎干重与块茎数成极显著正相关（P<0.01）,与二级分枝的数量表现为显著正相关关系（P<0.05）;块茎干重与根干重、叶干重和一级分枝干重之间均呈正相关关系,与茎干重、花干重和二级分枝干重呈负相关。     

Biomass Production and Net Ecosystem Exchange Following Defoliation in a Wet Sedge Community

Riparian ecosystems provide many ecosystem services, including serving as an important forage resource for livestock grazing operations. We evaluated defoliation impacts on above- and belowground production, and net ecosystem exchange of CO₂ (NEE), in a wet sedge (Carex nebrascensis Dewey)-dominated plant community. In June or July of 2004–2005, experimental plots were clipped to 10 cm stubble height and paired control plots left unclipped. All plots were clipped to 2.5 cm in mid-September, and end-of-season and season-long aboveground production calculated. Root ingrowth cores were used to estimate annual root production and root length density (RLD). A portable gas exchange system and plexiglass chamber were used to measure NEE in 2005. An elevated water table in 2005 vs. 2004 was associated with higher (P &spilt; 0.001) season-long aboveground production (about double), but lower (P ≤ 0.05) belowground production (about half). Total productivity did not differ between years, but below-:aboveground ratios were 3× higher in 2004 vs. 2005. RLD was not different between years (P &spigt; 0.05). Clipping reduced (P ≤ 0.05) end-of-season aboveground standing crop by 33% to 73% depending on clipping month and year. Effects of clipping month on season-long aboveground production were inconsistent between years; June clipping decreased (P ≤ 0.05) production (-10%) in 2005 and July clipping decreased (P ≤ 0.05) production (-25%) in 2004. NEE for June-clipped plots recovered within 1 mo of clipping, whereas NEE for plots clipped in July remained below unclipped levels at the end of the growing season. Water table levels strongly influenced below-:aboveground ratios, although total production was relatively stable between years. Year effects overwhelmed clipping effects on season-long aboveground production. Defoliation after mid-summer did not allow recovery of photosynthetic capacity by the end of the growing season, suggesting the potential for long-term impact with regular late-season defoliation.     

去叶对不同时期菊芋生物量、株高和生长速率的影响

本文通过对营养期和现蕾期菊芋（Helianthus tuberosus L.）进行去叶处理,探讨去叶对菊芋株高、生长速率和生物量的影响。结果表明：营养期去除1/3叶片菊芋地下生物量达到最高值;现蕾期去叶,地上生物量和总生物量均以去除偶数叶最高;相同叶片去除方式下,不同时期去叶株高均随去叶数量的增加而降低;不同时期各处理菊芋生长速率均随测定时间的延迟而降低。     

Fire,Defoliation, and Competing Species Alter Aristida purpurea Biomass,Tiller, and Axillary Bud Production

Aristida purpurea (purple threeawn) is a competitive native perennial grass with monoculturistic tendencies and poor palatability. We examined effects of fire, defoliation, and interspecific/intraspecific planting for 1) threeawn responses in the presence of threeawn, Bouteloua gracilis, or Pascopyrum smithii, and 2) B. gracilis and P. smithii response with threeawn. Biomass, aboveground production, tillers, and axillary buds were analyzed following two fire and four clipping treatments applied to three species–pair combinations in a completely randomized factorial design with nine replications. Fire killed 36% of threeawn. Fire reduced surviving threeawn biomass 61% and reduced production 27%. Threeawn production was greatest when neither plant was clipped and least when competing species were moderately clipped, or when both plants were severely clipped. Tiller counts of burned threeawn were similar among clipping treatments, and less than non-clipped or moderately clipped plants not burned. Fire decreased threeawn axillary buds on average by 25%. Moderately clipped plants had greater production than those from other clipping treatments across species. Average threeawn percentage of pot biomass was greater with B. gracilis (46 ± 3% SE) than P. smithii (38 ± 3% SE). Fire reduced threeawn from 60 ± 3% to 23 ± 3% of pot biomass, indicating good potential for rapid reductions in threeawn dominance and restoration of plant diversity with fire.     

扎龙保护区不同生境羊草种群生物量的年龄结构

羊草(leymus chinesis)是根茎型禾本科牧草,具有耐干旱、耐瘠薄、耐盐碱、耐短时积水等优良的生物学特性,营养繁殖力极强,在我国东北草原和内蒙古东部草原的羊草分布中心经常形成大面积单优群落.多年来,羊草一直是草地学和生态学学者研究的重点,主要集中在结实率、发芽率、生物量生殖分配、觅养生长格局、遗传分化、密度制约机制、营养繁殖动态等方面,对不同土壤生境下羊草种群生物量的年龄结构报道较少.     

Response of Bluebunch Wheatgrass and Medusahead to Defoliation

Our objective was to determine the short-term response of bluebunch wheatgrass and medusahead to defoliation of wheatgrass designed to stimulate regrowth through tillering. We hypothesized that defoliating bluebunch wheatgrass by 20% at the 3 to 3.5 leaf stage followed by a 50% defoliation at peak standing crop would increase its tillering and biomass production. Consequently, we expected a reduction of the density and biomass of medusahead over that of bluebunch wheatgrass defoliated 50% at peak standing crop. Treatments included four initial medusahead densities (200, 333, 444, 600 plants · m^-2) created by hand-pulling and three defoliation regimes factorially arranged (12 treatment combinations) in a randomized complete-block design and replicated four times at two sites. In 2006 and 2007, defoliation was accomplished by hand-clipping bluebunch wheatgrass 1) by 50% once at peak standing crop (late June); 2) by 20% at the 3 to 3.5 leaf stage, then again to 50% at peak standing crop (mid May, late June); or 3) plants were not clipped. Density was sampled in 2006 and 2007, and biomass was harvested only at Star Mountain (near Riverside, Oregon) in 2007 because Warm Springs (near Drewsey, Oregon) was burned by a wildfire before final 2007 data could be collected. In 2006, no treatments applied at either site detectably altered the number of tillers produced by bluebunch wheatgrass nor did they affect bluebunch wheatgrass density or biomass in 2007 at Star Mountain. Changes in medusahead density were not detected in 2006, but this annual invasive grass increased in density and biomass in 2007 at Star Mountain in plots receiving two defoliations. The relatively short growing period caused by summer drought and the relative intolerance of bluebunch wheatgrass to grazing make the twice-over grazing an unlikely practice for arid rangelands in the western United States. In fact, it could possibly increase the risk of annual grass invasion.     

行距对老芒麦种群地下部及土壤特性的影响

以30cm、45cm、60cm、75cm、90cm行距栽培的第3年的老芒麦人工种群为材料,采用随机取样法,对其根系分布、地下生物量及能量累积、土壤养分及活性进行了研究。结果表明:行距显著影响根系深度与分布范围,对茎基生物量影响不显著,而显著影响根系生物量(P<0.01),使地下生物量存在极显著差异(P<0.01);行距对种群地下能量累积有极显著影响(P<0.01),对茎基能量累积的影响大于根系;30cm行距地下生物量及能量累积显著高于其他行距;行距对土壤pH与有机质含量影响极显著(P<0.01),对养分含量影响由大到小为全N>全K>全P,全P含量无差异;对养分活性影响由大到小为P>K>N,速效P、速效K含量有显著差异(P<0.05),碱解N含量差异较小。行距与根系分布范围、pH值呈极显著正相关(P<0.01);与地下生物量、地下累积能量、土壤有机质含量呈极显著负相关(P<0.01);与土壤速效P、速效K含量呈显著负相关(P<0.05);小行距有利于老芒麦生物量与能量累积,有利提高土壤有机质累积,也有利于土壤养分含量与活性增加。     

59份苜蓿种质材料苗期耐盐性评价及耐盐指标筛选

为了解不同苜蓿种质材料耐盐程度和筛选苜蓿苗期耐盐性评价指标,本研究采用盆栽法对59份苜蓿种质材料苗期进行200 mmol·L^-1 NaCl盐溶液胁迫处理,测定了与苜蓿耐盐性相关的12个生长指标和叶绿素荧光指标,并利用综合评价、相关性分析、灰色关联和聚类分析等方法对其苗期耐盐性进行评价及耐盐指标筛选。结果表明：地上生物量、地下生物量、根冠比、叶面积、叶长、茎粗、叶宽、株高和SPAD（Soil and plant analyzer develotrnent,SPAD,代表相对叶绿素含量）在不同种质材料间变异大,对盐胁迫反应敏感。用加权隶属函数法得到的耐盐性综合度量值（D值）对59份苜蓿材料苗期的耐盐性进行综合评价,基于D值进行聚类分析,可将59份材料划分为5类：第I类有16份种质材料,D值为0.384,属中等耐盐材料;第II类有13份种质材料,D值为0.465,属强耐盐材料;第III类有4份种质材料,D值为0.647,属极强耐盐材料;第IV类有8份种质材料,D值为0.229,属极弱耐盐材料;第V类有18份种质材料,D值为0.305,属弱耐盐材料。综合筛选出耐盐性极强的材料有‘美11’、‘中苜1号’、‘爱开夏’和‘中苜3号’,耐盐性极弱的材料有‘北方SLT’、‘康赛’、‘WL903’、‘WL440HQ’、‘杂6’、‘Natawwakaba’、‘罗默’和‘甘农3号’。通过相关性分析和灰色关联,筛选出叶面积、叶绿素荧光、SPAD和根冠比可作为苜蓿苗期耐盐性鉴定指标。本研究可为耐盐苜蓿新品种选育及利用提供理论依据。     

Fin Condition of Atlantic Salmon Reared at High Densities in Heated Water

Abstract

We assessed the condition of dorsal and pectoral fins of parr of Atlantic salmon Salmo salar that were reared for 70 d at 17.5°C to final densities of 14–55 kg/M² (rearing-unit bottom area) or 80–310 kg/m³ (rearing-unit volume). Pectoral fins were not significantly affected by rearing density, but dorsal fins were more eroded in fish reared at the highest density than in fish checked before the rearing experiments or in those reared at lower densities. Densities as great as 41 kg/m² (229 kg/m³) did not affect fin quality of Atlantic salmon reared at 17.5°C.     

12个无芒雀麦种群遗传多样性的RAPD分析

用RAPD分子标记对12个无芒雀麦种群进行遗传多样性分析,结果表明:选用的9条多态性引物共扩增出87个条带,平均每个引物扩增9.67条,其中多态性条带45个,多态性条带百分率为51.72%.无芒雀麦物种水平上的多态性条带数为76个,多态性条带百分率为87.36%,Shannon信息指数为0.2933,Nei s基因多样性指数为0.1843.种群间遗传分化系数为0.2735,说明无芒雀麦的遗传分化主要发生在种群内.聚类结果显示,部分种群间的遗传距离与地理距离有一定的相关性,但也有例外,这可能与人类的广泛栽培加大了种群间的基因交流有关.     

留兰香的抗炎作用研究

采用多种动物模型观察了留兰香对炎性反应的影响，结果显示，留兰香对蛋清、二甲苯引起的局部急性炎症有明显的抑制作用。     

两个呼伦贝尔羊品系不同部位脂肪细胞形态及脂肪代谢相关基因表达差异分析

试验旨在探讨呼伦贝尔羊巴尔虎品系（半椭圆状尾）和短尾品系（小桃状尾）脂肪沉积差异的分子机制。随机选择处于相同饲养管理条件下5月龄呼伦贝尔母羊21只（其中巴尔虎品系11只、短尾品系10只）,测量其体尺、尾型和胴体重指标。组织切片观察8个部位脂肪细胞的形态,测定脂肪组织甘油三酯（TG）含量,并进一步用实时荧光定量PCR检测脂肪代谢相关基因在不同脂肪组织中的表达差异。结果显示,同月龄两品系羊胴体重、体尺及尾型指标差异显著或极显著（P<0.05;P<0.01）。虽然两品系羊同一部位的脂肪细胞形态基本一致,但巴尔虎品系尾部脂肪细胞面积和体积均大于短尾品系（P<0.01）,并且皮下、网膜和尾部脂肪组织中的TG含量在两品系羊间差异显著或极显著（P<0.05;P<0.01）。ATGL、PPARγ、C/EBPα和SREBP 4个脂代谢相关基因在巴尔虎品系个体中的mRNA水平均显著或极显著高于短尾品系（P<0.05;P<0.01）;巴尔虎品系中ATGL和SREBP基因的表达与TG含量分别呈显著负相关和正相关（r=-0.965、0.972）。综上所述,两个呼伦贝尔羊品系在生长和脂肪代谢等方面存在较大差异。本研究结果可为进一步深入解析绵羊脂尾形成的分子机制提供理论依据。     

国内外牛粪生物质资源利用的现状与趋势

随着奶牛养殖业的快速发展,与之伴行的牛粪产量日益增加。不仅严重污染周边环境,而且对人畜健康产生极大影响。如何有效合理地利用牛粪资源,即开展相应资源化研究日益受到国内外学者的重视。本文阐述了目前国内外牛粪的主要利用方式,包括饲料化、能源化和肥料化等,提出适合我国国情的牛粪综合循环利用模式,旨在为牛粪的综合利用提供参考。     

脱落酸、蔗糖和硅对高羊茅和草地早熟禾耐荫性的影响

为探索外源物质对草坪革耐荫性的作用效果及其最佳浓度,在57％遮荫胁迫下,选用脱落酸(ABA) (0,0.02,0.06和0.10mmol·L-1)、蔗糖(0,600,800和1000mg·L-1)和硅酸钠(0,0.50,1.00和1.50 mmol·L-1)对盆栽高羊茅(Festuca arundinacea)和草地早熟禾(Poa pretensis)进行处理.结果表明:各浓度ABA对提高2种草坪草耐荫性没有效果,反而加重胁迫,明显抑制植株的生长,严重影响草坪外观质量;适宜浓度的蔗糖和硅酸钠能不同程度的促进2种草坪草的生长,提高其耐荫性;800 mg· L-1蔗糖和0.50 mmol·L-1硅     

不同海拔梯牧草生物型种群构件的生物量分配策略

为了解不同海拔条件下梯牧草各构件的生物量分配特征,在梯牧草分布区域,按照不同海拔梯度设置样地,对成熟期梯牧草种群个体构件生物量分配策略进行分析.结果 表明:(1)不同海拔地段,梯牧草各构件生物量大小均表现为茎＞根＞穗＞叶;生物量分配为营养分配＞储藏分配＞繁殖分配;(2)不同海拔地段,根、茎、叶及穗生物量对梯牧草株体生物...     

微卫星座位多态性与两个肉用绵羊群体眼肌性状的关系

根据绵羊18号染色体遗传连锁图谱及相关报道,选择了可能与Carwell基因连锁或与眼肌性状有关的10个高度多态微卫星基因座,研究它们与眼肌性状的关系。应用非变性聚丙烯酰胺和复合银染技术分析了这些基因座的多态性,并分别对Dorset和Suffolk与新疆细毛羊级进杂交F2代两个肉羊群体的遗传特性进行了分析。应用最小二乘拟合线性模型分析了10个微卫星基因座多态性与超声波测量的眼肌性状(眼肌面积,眼肌厚度,眼肌宽度)的关系。结果表明:(1)Dorset群体中,BM3413基因座对眼肌厚度有显著影响(P<0.05),TGLA122基因座对眼肌宽度有显著影响(P<0.05),MCMA26基因座对眼肌厚度和宽度均有显著影响(P<0.05),从而影响眼肌面积;(2)Suffolk群体中,MCM38、CSSM18、ILSTS54和BM3413对眼肌厚度和宽度同时具有影响而显著或极显著地影响眼肌面积(P<0.05或P<0.01)。同时,本研究还发现了一些显著影响绵羊眼肌面积的最有利基因型:Dor-set群体中,微卫星基因座MCMA26的基因型FN(196 bp/222 bp)和基因型EM(192 bp/220 bp);Suffolk群体中,微卫星基因座CSSM18的基因型AE(124 bp/134 bp),ILSTS54的基因型AD(130 bp/148 bp)和CD(134 bp/148bp)以及BM3413的基因型BF(190 bp/232 bp)。综合分析表明:(1)微卫星MCMA26-CSSM18区域可能为Carwell基因的存在位点,而BM3413可能是一个除Callipyge与Carwell之外新的影响绵羊后臀和眼肌性状QTL或基因的存在区域;(2)本研究发现的一些最有利基因型在今后的肉羊选育中有望作为相应群体早期辅助选择的标记基因型。     

刈割对羊茅黑麦草和无芒雀麦蘖转化的影响

根据种群生命统计分析原理，进行了刈割对羊茅轩麦草和无芒雀麦蘖转化的影响的研究。结果表明，羊茅黑草经元芒雀麦有较低的蘖死亡率和较高的蘖出现率，在营养期对刈 茅黑麦草优于繁殖期，应避免频繁强度利用元芒雀麦，羊茅黑草则适合频敏地强度与轻度结合刈牧。     

梨叶早衰脱落主要类型表现与防控对策

梨叶早衰脱落现象的严重发生,成为困扰部分梨产区提高产量、增进品质的重大生产技术难题。本文综合作者长期调查研究结果与相关报道资料,将梨叶早衰脱落现象归纳为水分失调型、营养失调型、病虫为害型、郁闭寡照型、肥害药害型五大类型,并对类诱发因素、症状表现、发生规律及关键防控对策进行分别阐述,以助相关从业者鉴别区分和更加有效地开展防控。