宁夏引黄灌区盐化土壤微生物区系及其指示意义

为了有效防治土壤盐渍化的进一步发展,采用平板稀释法和常规土壤化学性质测定方法,对宁夏惠农不同程度盐渍化土壤微生物区系及其动态变化,土壤化学性质、养分含量及其与土壤微生物的相关关系进行了研究。结果表明：在盐渍化土壤区域,随着盐渍化程度的增加,土壤pH和碱化度以轻度盐渍化土壤最高,且20～40 cm土层高于0～20 cm。不同程度盐渍化土壤养分含量、细菌、真菌和放线菌数量均表现为随着盐渍化程度的加重,而呈现逐渐降低的趋势,即轻度＞中度＞重度,且0～20 cm土层显著高于20～40 cm。细菌、真菌和放线菌数量在不同采样时间上表现为6月＞8月＞9月。土壤微生物区系与土壤养分含量之间相关关系明显,细菌、真菌、放线菌数量除与土壤全钾含量之间没有达到显著水平外,与土壤有机质、全氮、全磷、碱解氮、有效磷、速效钾含量之间均达到显著或极显著正相关关系（P<0.05或P<0.01）。因此,土壤微生物区系可以作为评价盐化土壤质量恢复及演变过程的生物指标。     

规模扩繁夜蛾黑卵蜂的寄主筛选

夜蛾黑卵蜂Telenomus remus Nixon是多种鳞翅目夜蛾科昆虫卵期重要的寄生性天敌。本研究观测了夜蛾黑卵蜂对5种供试寄主卵（斜纹夜蛾Spodoptera litura、草地贪夜蛾Spodoptera frugiperda、甜菜夜蛾Spodoptera exigua、烟青虫Helicoverpa assulta和棉铃虫Helicoverpa armigera）的寄生及子代发育情况,比较了不同寄主卵繁育的夜蛾黑卵蜂在寄生率、羽化率、雌性比和体型大小等生物学指标的差异。结果表明：夜蛾黑卵蜂对斜纹夜蛾的卵粒寄生率最高,为94.48%;其次是草地贪夜蛾（92.11%）;对烟青虫和棉铃虫的卵粒寄生率相对较低,为34.08%和50.75%。草地贪夜蛾卵育出的子代雌蜂的后足胫节长度166.48 μm,比斜纹夜蛾卵繁育的159.22 μm大,但其羽化率较低,仅为68.06%,显著低于斜纹夜蛾的92.40%,斜纹夜蛾的单雌产卵量显著高于其他4种寄主。研究结果显示斜纹夜蛾卵是规模化繁育夜蛾黑卵蜂的理想中间寄主。     

种粮大户应对气象灾害适应性行为综合绩效评价 ——基于AHP-FCE模型

[目的]随着气象灾害越发频繁,如何提升农户气象灾害适应行为能力成为当前亟待解决的问题,了解当前农户应对气象灾害能力现状是提升农户适应能力的前提.以江西省229户种粮大户为例,对其适应行为能力综合绩效进行评价.[方法]以社会绩效、经济绩效、环境绩效为评价指标体系,采用层次分析法确定指标权重,运用模糊综合评价法获取其适应行为能力的绩效评价结果.[结果]社会绩效、经济绩效、环境绩效的最大隶属度为0.5452、0.5992、0.7998,评价结果为"一般"、"一般"、"较差".其中,社会绩效得分最高,为67.6523分,环境绩效得分最低,得分为46分.综合绩效最大隶属度为0.5368,得分为60.5439分,隶属于评价集中的"一般".[结论]环境绩效是阻碍农户适应能力提升的主要因素,而农业收入、政府交流、化肥农药使用程度是提升农户适应能力综合绩效的主要因素.据此提出以下建议:增强农业技术培训力度,提高农业生产效率,促进农业收入增加,提升经济绩效;增强农户与各级政府之间的交流,减少信息壁垒,提升社会绩效,进而提升适应行为能力;推广绿色农业技术,减少化肥使用量,提高环境绩效.     

西双版纳糯玉米地方品种遗传多样性分析

利用SSR标记对西双版纳的36个小糯玉米地方品种和2个对照品种进行遗传多样性研究。从800余对SSR引物中筛选出100对多态性好、稳定性高的SSR引物。结果表明, 这100对SSR引物在36个糯玉米地方品种中共检测出353个等位基因, 每对引物检测出2～8个, 平均为3.53个, 平均多态性息量(PIC)为0.53, 平均标记索引系数(MI)为2.00。聚类分析表明, 糯玉米地方品种聚为6个类群, 与对照品种相比, 地方品种独立成群。     

二穗短柄草CCCH型锌指蛋白基因家族成员的鉴定和分析

CCCH型锌指蛋白基因以基因家族的形式存在,在信号转导调控、形态发生和逆境应答等诸多生物学过程中起着重要作用。为给该基因的克隆及功能研究提供参考信息,本研究针对二穗短柄草的基因组序列,运用多种生物信息学方法在全基因组范围对CCCH型锌指蛋白基因进行了鉴定分析。结果表明,二穗短柄草共有61个含CCCH基序的蛋白质,它们的基因 DNA序列全长825~13 288 bp,内含子数量0~13个,编码区全长498~4 944 bp,编码165~1 007个氨基酸;共检测到145个CCCH基序,以C X₈ C X₅ C X₃ H和C X₇ C X₅ C X₃ H最为常见;基因不均等地分布在5条染色体上,其中2号染色体分布最多,有21个,5号染色体分布最少,仅4个;系统发育分析表明,61个成员可分为8组。     

Suspected inherited rickets in Corriedale sheep

A suspected inherited form of rickets was diagnosed in Corriedale sheep on a commercial sheep farm in Marlborough. Affected lambs were normal at birth but showed a reduced growth rate and a range of skeletal abnormalities, including both varus and valgus deformities and a characteristic dip in the shoulder region. Up to 20 affected lambs had been born on the property over the last two seasons. Skeletal lesions in affected lambs included swollen costochondral junctions, moderate to marked thickening of physes in long bones, and collapse of weakened subchondral bone, particularly in the proximal humerus. These lesions, together with the microscopic changes, strongly suggested a diagnosis of rickets. Affected lambs were hypocalcaemic and hypophosphataemic, consistent with a deficiency of vitamin D.

Vitamin D assays revealed significantly higher 1,25(OH) vitamin D concentrations in affected lambs than in controls, suggesting a defect in the vitamin D receptor as the likely mechanism. DNA testing revealed that 4/10 Corriedale rams used during the previous season had sired affected lambs. Studies aimed at confirming the genetic nature of the disease and the mechanism are continuing at Massey University.     

Management of gastrointestinal nematode parasites on sheep farms in New Zealand

AIM: To report current farmer opinions and farming practices relating to control of gastrointestinal nematodes and anthelmintic resistance on sheep farms in New Zealand.

METHODS: An interview-based cross-sectional study of grazing management and anthelmintic useage was conducted by veterinarians on 80 randomly selected sheep farms in New Zealand.

RESULTS: Useable data were returned by 74/80 (92%) farmers who participated in the study. However, despite contacting 400 farmers the target sample size of 100 farms was not reached. The results indicated that only 31% of farms had previously tested for drench resistance, that effective quarantine-drenching of imported stock was not always carried out, and that farmers were more likely to integrate cattle than ewes into their grazing management of lambs. Furthermore, the number of drenches given to lambs had changed little in 25 years. The use of faecal egg counting by farmers has increased.

CONCLUSIONS: Dependence on anthelmintics continues to be high on sheep farms in New Zealand. Whilst the number of drench treatments has changed little, there is more widespread use of persistent or long-acting treatments. Farmers need to be encouraged to monitor the resistance status of nematode populations on their farms and use this information to develop strategies aimed at maintaining susceptible alleles within the parasite populations and conserving the efficacy of existing drug families.     

亚硒酸钠对小鼠附植前胚胎发育能力的影响

为探讨不同浓度的亚硒酸钠对小鼠体重、超排效果及其胚胎后续发育的影响,将6～7周龄的小鼠随机分为4组,1组为对照组,其余3组按小鼠每千克体重分别注射0.30 mg(低剂量组)、1.50 mg(中剂量组)和2.25 mg(高剂量组)的亚硒酸钠溶液,再分别测量各组小鼠的体重及观察、记录各组小鼠的超排效果和胚胎体外发育情况.结果显示:(1)高剂量组小鼠体重变化量(-0.31 g)显著低于低剂量组(7.95 g)、中剂量组(8.65 g)和对照组(11.06 g)(P＜0.05),而低剂量组、中剂量组与对照组之间无显著差异(P＞0.05);(2)不同剂量亚硒酸钠处理的小鼠经超排后回收的平均可用胚胎数,各组之间相比均无显著差异(P＞0.05),但高剂量组冲出的胚胎经体外培养后的囊胚发育率(17.6％)显著低于对照组(27.6％)(P＜0.05),而与低剂量组(24.3％)和中剂量组(20.6％)差异不显著(P＞0.05).以上结果表明,高剂量的亚硒酸钠不利于小鼠胚胎的发育,其作用机制需要从细胞和分子水平做更深入的研究.     

不同复混基质对双孢蘑菇产量和质量的影响

为了克服单纯利用杏鲍菇菌渣和金针菇菌渣栽培双孢蘑菇的缺陷,以漳州市角美农业发展有限公司批量生产的一次发酵料(60％杏鲍菇菌渣+20％王老吉茶渣+20％牛粪+豆粕0.25 kg/m2+过磷酸钙0.5 kg/m2+轻质碳酸钙0.5 kg/m2)为对照,开展了复混基质(金针菇菌渣添加稻草)对双孢蘑菇产量和质量影响的研究.结果...     

基于改进Faster R-CNN和Deep Sort的棉铃跟踪计数

棉铃作为棉花重要的产量与品质器官,单株铃数、铃长、铃宽等相关表型性状一直是棉花育种的重要研究内容。为解决由于叶片遮挡导致传统静态图像检测方法无法获取全部棉铃数量的问题,提出了一种以改进Faster R-CNN、Deep Sort和撞线匹配机制为主要算法框架的棉铃跟踪计数方法,以实现在动态视频输入情况下对盆栽棉花棉铃的数量统计。采用基于特征金字塔的Faster R-CNN目标检测网络,融合导向锚框、Soft NMS等网络优化方法,实现对视频中棉铃目标更精确的定位;使用Deep Sort跟踪器通过卡尔曼滤波和深度特征匹配实现前后帧同一目标的相互关联,并为目标进行ID匹配;针对跟踪过程ID跳变问题设计了掩模撞线机制以实现动态旋转视频棉铃数量统计。试验结果表明：改进Faster R-CNN目标检测结果最优,平均测量精度mAP₇₅和F1值分别为0.97和0.96,较改进前分别提高0.02和0.01;改进Faster R-CNN和Deep Sort跟踪结果最优,多目标跟踪精度为0.91,较Tracktor和Sort算法分别提高0.02和0.15;单株铃数计数结果决定系数、均方...