那曲东部土壤水分MODIS遥感反演研究

利用那曲东部2014年8月至2015年7月土壤水分观测资料与同期MODIS数据建立了研究区土壤水分遥感监测模型。表观热惯量法(ATI)反演土壤水分结果不理想,基于MODIS 8天合成数据以及晴空数据拟合结果的决定系数分别为0.4503和0.3753,晴空条件下ATI方法监测效果较差。基于单窗方法建立的四种模型中,三次多项式模型拟合效果较好,决定系数为0.5475,分析认为排除冬季数据后建模效果更好。结论:基于单窗方法的三次多项式模型能较好的反演研究区土壤水分,不足之处为对天气要求较高,若无晴空遥感数据,将影响土壤水分监测工作的开展。     

安格斯牛与西藏犏牛杂交生产肉牛试验初报

[目的]犏牛可以生活在海拔2 800~4 200 m,对高寒缺氧的生态环境具有很强的适应能力,是“世界屋脊”的著名牛种,为了提高西藏犏牛资源的综合利用,其后代变废为宝。[方法]在试验区选择200头经产母犏牛通过引进安格斯牛的细管冻精,依靠人工授精技术,应用种间三元杂交技术生产优质商品肉牛试验,测定初生、3月龄的体重、体尺指标,观察高寒气候的适应性。[结果]结果显示:参配母犏牛200头,实配160头,其中104头母犏牛怀孕受胎,98头顺利产犊。实配率80%,人工授精受胎率65%,成活率94.23%。犏牛平均妊娠期(266.81±11.93) d。安格斯与西藏犏牛杂交后代的出生体尺、体重与传统杂交犊牛(多勒)相比,平均体重增加8.95 kg,提高73.23;体高、体斜长、胸围、管围平均分别比传统杂交犊牛(多勒)增加7.491 cm,1.394 cm,8.998 cm,0.063 cm,提高了13.94%,2.56%,15.70%,0.068%。安格斯与西藏犏牛杂交后代的3月龄与传统杂交犊牛(多勒)相比,平均体重增加43.3 kg,提高168.89;体高、体斜长、胸围、管围平均分别比传统杂交犊牛(多勒)增加15.67 cm,16.95 cm,26.31 cm,1.64 cm,提高23.27%,24.76%,34.31%,15.83%。[结论]弥补了犏牛传统杂交后代普遍存在的体躯发育差、生长发育慢等缺陷,且很好地适应西藏高寒生态环境和管理条件,杂种优势十分明显,因此安格斯牛可作为高原环境下繁殖犏牛生产肉牛的理想父本品种使用,并拥有开发高端产品的巨大潜力。     

锌素营养对作物叶片解剖结构的影响

采用水培方法,调节锌素营养供应,观察芹菜、玉米、小麦幼苗生长及幼苗叶片解剖结构。结果看出,锌素营养不足时植株含匀量降低,生长受到抑制:叶肉细胞收缩,细胞间隙增大,叶肉细胞中叶绿体数量减少。禾本科作物维管柬鞘细胞中叶绿体减少尤为明显,但对叶绿体的体积无影响;辅导组织发育受到抑制,机械组织不发达。锌素营养过剩时细胞结构破坏,叶肉细胞严重收缩,叶绿体明显减少。     

Boreal pine forest floor biogenic volatile organic compound emissions peak in early summer and autumn

In boreal forests, canopy-scale emissions of biogenic volatile organic compounds (BVOCs) are rather well characterised, but knowledge of ecosystem-scale BVOC emissions is still inadequate. We used adsorbent tubes to measure BVOCs from a boreal Scots pine (Pinus sylvestris L.) forest floor in southern Finland and analysed the compounds with a gas chromatograph-mass spectrometer. The most abundant compound group was the monoterpenes (averaging 5.04 μg m⁻² h⁻¹), in which α-pinene, Δ³-carene and camphene contributed over 90% of the emissions. Emissions of other terpenoids (isoprene and sesquiterpenes) were low (averaging 0.05 and 0.04 μg m⁻² h⁻¹, respectively). BVOC emissions from the forest floor varied seasonally, peaking in early summer and autumn, with most of the compounds following similar patterns. The emission pattern was sustained throughout the measurement period, suggesting that the main sources of the emissions remained more or less stable. We compared the BVOC fluxes with environmental parameters such as temperature, precipitation and PAR, and with fluxes of other trace gases (CO₂, CH₄, N₂O), as well as with ground vegetation photosynthesis and with litter input. Several of these parameters were correlated with the presence of BVOCs. The sources of soil BVOC emissions are very poorly understood, but our results suggest, that changes in litter quantity and quality, soil microbial activity and the physiological stages of plants are linked with changes in BVOC fluxes.     

Dynamics of Moraxella bovis infection and humoral immune response to bovine herpes virus type 1 during a natural outbreak of infectious bovine keratoconjunctivitis in beef calves

Infectious bovine keratoconjunctivitis (IBK) is an acute disease caused by Moraxella bovis (Mb). Several factors may predispose animals to an IBK outbreak; one commonly observed is infection with bovine herpes virus type 1 (BHV-1). The aim of this study was to investigate the dynamics of BHV-1 virus infection and its relation with clinical cases of IBK in weaned calves from a beef herd with a high prevalence of lesions caused by Mb. Sampling was carried out in six stages and included conjunctival swabs for isolating Mb as well as blood samples for identifying antibodies specific for BHV-1. A score for IBK lesions after observing each eye was determined. The findings of this study showed a high prevalence of BHV-1 virus infection (100% of animals were infected at the end of the trial); 67% of animals were culture-positive for Mb, but low rates of clinical IBK (19% of calves affected) were detected at the end of the trial. These results suggest that infection with BHV-1 did not predispose these animals to IBK, and that Mb infection produced clinical and subclinical disease in the absence of BHV-1 co-infection.     

2种烟草种植模式种植成本分析

分析了我国烟草生产不同发展阶段的传统烟草种植和现代烟草种植模式下烟农种植过程中的成本投入,结果表明:因烟草专业化服务组织农业机械化水平和专业化程度的提高,烟草种植的人工投入数、人工成本分别由传统烟草种植模式的15.01个/667 m2和758元/667 m2降低到现代烟草种植模式的2.41个/667 m2和120.25元/667 m2;由于人工成本的大幅度降低,烟草种植总成本由传统烟草种植模式的798元/667 m2降低到现代烟草种植模式下的307.25元/667 m2。     

不同细度类型细羊毛纤维直径变异研究

共采集150个中国美利奴羊（新疆型）3个细度类型（18 μm以下、18～20 μm及20 μm以上）羊毛样本，分析了沿毛丛长度方向及毛丛内纤维间直径变异。结果表明，不同细度类型羊毛沿毛丛方向纤维直径有相似的变异规律且与饲草料资源的季节性变化吻合，但细度18 μm以下羊毛纤维直径变异最小（P<0.01）；相反地，毛丛内纤维间直径变异随羊毛细度的降低而增大（P<0.01）。     

典型黑土环境下的高、低镉积累白菜品种筛选及耐性比较

为探究不同白菜(Brassica pekinensis L.)品种在典型黑土环境中的镉敏感程度和镉积累特性,筛选出具备高镉、低镉积累特征的耐镉品种。试验以东北地区20种主栽白菜品种为材料进行盆栽模拟试验,研究基于不同白菜品种镉胁迫下的剂量-效应、镉积累特征,对得到的高、低镉积累品种的浓度积累效应及氧化损伤程度进行评估。结果显示:供试品种间剂量-效应差异明显,JF和BCCRQJ为镉耐性最强两个品种,耐受阈值分别为1.204 mg·kg~(-1)和1.036 mg·kg~(-1)。高镉浓度下(≥0.6 mg·kg~(-1))JF叶镉含量最低,根向叶迁移系数(TF)、叶富集系数(BCF)均小于1;BCCRQJ净化率最高。土壤镉含量与两者根、叶积累量、过氧化氢(H_2O_2)、超氧阴离子(O_2~-)、丙二醛(MDA)、游离脯氨酸(FPRO)均呈正相关,与净化率呈负相关(P0.05),此外高浓度下BCCRQJ氧化损伤程度较JF更高。综合试验结果表明,JF是镉耐性极高的低积累品种,而BCCRQJ为镉耐受力略逊于JF的高积累品种。