中国农田施氮水平与土壤氮平衡的模拟研究

为了估算全国尺度的农田土壤氮素的输入输出平衡状况,并探明土壤氮素的基本去向和氮素污染的可能性,以求合理施用氮肥、保护农田生态环境,该文主要运用农业生态系统生物地球化学模型(DNDC)方法,在GIS区域数据库支持下运行模型,并综合分析模拟结果.研究结果表明,以近20 a来氮肥投入最多的1998年为例,全国农田土壤氮素平衡状况表现为总体过剩,总过剩量为456～962万t N,均值为709万t N.化肥态氮肥投入是土壤氮素收入的主要途径,占到氮素总收入量的近60%,其大量投入是造成农田土壤氮素过剩的主要原因;另外,从氮素的支出途径来看,除了作物生长从土壤中吸取大量的氮素以外,通过NH3挥发和氮淋溶丢失了大量的氮素,分别占总支出量的35%和15%,给环境造成了严重影响.模拟结果显示中国农田氮平衡存在较大的区域差异,减少氮素的无效丢失十分必要.     

区域水土保持监测点布局优化时空模型研究

基于"全国水土保持监测网络和信息系统建设"项目及相关省(自治区、直辖市)的水土保持工作情况,全国初步建设了818个监测点,但目前这些监测点在布局、结构、运维和整体功能发挥等方面仍存在不足,有待调整、优化和完善。分析了区域监测点布局优化的主要影响因素,认为区域自然地理条件异质性决定了监测点的空间布局与类型结构,经济社会发展阶段影响着监测点的密度与结构,物质与人力资源的丰缺影响着监测点建设和升级改造的可行性与功能实现程度。构建了区域监测点布局优化的时空模型、主要指标及其分值、运算法则等,对省级和全国的水土保持监测点布局优化和升级改造具有指导意义,也对相关的资源、环境、生态系统野外监测站点布局的调整、完善具有参考价值。     

Total phenols,flavonoids, and procyanidins levels and total antioxidant activity of different Korean pine(Pinus koraiensis) varieties

Total phenols,flavonoids,procyanidins,and total antioxidant capacity,measured with ferric reducing antioxidant power,radical scavenging capacity,and oxygen radical absorption capacity assays were first evaluated in the extracts of the shells,skins and kernels of 10 varieties of Pinus koraiensis.Results indicate that these varieties had strong radical scavenging capacities,ferric reducing antioxidant power and oxygen radical absorption capacities.Phenolic,flavonoid and procyanidin values ranged from 138.6(#3 kernel)to 518.6(#10 shell)mg GAE/g,from 23.3(#2 kernel)to 70.8(#5 skin)mg RE/g,from 2.5(#2 kernel)to 142.1(#7 skin)mg CE/g,respectively.Radical scavenging capacity and ferric reducing antioxidant power values were positively correlated to the polyphenol contents which play a major role in antioxidant properties.The varieties may be divided into two groups by cluster analysis and the variables being measured.These results will be useful for breeding varieties and guiding their production.     

不同蛋白水平的饲料对中卫山羊羔羊补饲效果的影响

随机选择75只中卫山羊哺乳羔羊,连同母羊分为5组,每组15只羔羊.各组分别饲喂不同蛋白水平的饲料,A组和B组饲喂粗蛋白的质量分数为17%的粉料和颗粒料,C组和D组饲喂粗蛋白的质量分数为19%的粉料和颗粒料,E组为对照组饲喂玉米粉料.试验结果显示:各试验组羔羊增体质量均大于对照组,其中B组羔羊增体质量最快,C组次之.经方差分析显示:B组和C组差异不显著,B组与D组差异显著,A组和E组差异极显著,B组不仅饲喂效果最好而且增体质量成本最低,也最经济.     

真菌诱导子对植物培养物生长和次生代谢产物合成影响之研究进展

真菌诱导子是一类诱导植物细胞生长和次生代谢产物合成的化学物质,包括有真菌菌体、菌液浓缩物、菌丝和菌液提取物、菌丝体高温处理后的可溶性成分、细胞壁降解成分、肽类和蛋白质等.该文对真菌诱导子对植物培养物生长和次生代谢产物合成影响的研究进展进行了综述,并对真菌诱导子在植物细胞培养生产次生代谢产物方面的前景进行了展望.     

皮埃蒙特牛与秦川牛杂交效果试验报告

为提高秦川牛生长发育和产肉性能,引进意大利著名肉牛品种皮埃蒙特牛与非保种我秦川牛进行杂交试验。并与同期同龄的短角红牛、利水赞牛杂种后代进行比较。试验结果表明,皮秦Ｆ１生长发育,产肉性能明显优于秦川牛、杂交效果也好地短角牛和利木赞牛的杂交后代。     

大豆种衣剂有效成分配比优选及应用研究——Ⅱ大豆种衣剂有效成分分配比优选

由植物竹长调节剂Cc、杀虫杀菌i、多元络合态微肥Mi三种组分配制的各种衣剂处理大豆，使大豆出苗率增加，病株率降低，苗期株斋降低，叶片数增多，叶绿素含量增加，叶面积增大，光合速率增强，总根长增加，根系活力增强，大豆地睚部，地下部干重均有不同程度的增加。     

环式剥皮机主要参数的设计计算及效能分析

本文论述了我国常用的环式剥皮机主要参数的设计计算,并对影响木材剥皮质量和生产率的各种因素,以及环式剥皮机在生产中使用的经济效益等进行了分析。为有关生产部门推广应用环式剥皮机提供了有价值的参考。     

INSL-3 protein expression in normal and cryptorchid testes of Ziwuling black goats

Ziwuling black goats are typically found in loess plateaus regions and the Ziwuling Nature Reserve. Cryptorchidism is a common disease in this inbred goat, and its pathogenesis has been linked with the expression of insulin-like factor 3 (INSL-3). Therefore, this study aimed to investigate anatomical alterations caused by cryptorchism and the expression and distribution of INSL-3 in normal and cryptorchid testicular tissues. The testicular tissues of 6-month-old Ziwuling black goats were collected for microscopic analyses using histochemical, immunohistochemical, immunofluorescence and biometrical methods, as well as Western blotting to compare the expression and distribution of INSL-3. A lower expression of INSL-3 was observed in cryptorchid compared with normal testicular tissues (p < .01). Cryptorchidism caused a significant reduction in layers of spermatogenic epithelium and tubule areas in Ziwuling black goat (p < .01). The interstitial to seminiferous tubule area ratio was larger in cryptorchid than in normal group. Periodic Acid-Schiff (PAS) staining revealed pronounced positive bands in the interstitial tissue, while positive Alcian blue (AB) staining was not clear, and AB-PAS staining revealed a positive red band in the basement membrane of cryptorchid group. Immunofluorescence revealed a strong signal of INSL-3 expression in Sertoli and peritubular myoid cells, and moderate signal in Leydig and spermatogenic cells in the normal group. However, in cryptorchid testicular tissues, the signal of INSL-3 expression was strong in primary spermatocytes, occasional in Sertoli cells, limited in Leydig cells and absent in peritubular myoid cells. Furthermore, immunohistochemistry showed that INSL-3 expression was higher in normal testes compared with cryptorchid testicular tissues (p < .05), especially in primary spermatocytes and Sertoli cells. Collectively, our results indicate that cryptorchidism is closely related to the disorder of acid glycoprotein metabolism and the reduction in release of INSL-3 from Leydig cells. Moreover, Sertoli and peritubular myoid cells are crucial for INSL signalling and could underpin further research on the mechanism of cryptorchidism in animal.     

中国天然橡胶主产区橡胶树品种区域配置建议

中国橡胶树育种工作经过半个多世纪的发展,通过引进国外优良无性系与自主培育适合不同生态区的橡胶树优良品种,培育出数十个橡胶树优良品种在海南、云南、广东等3大植胶区种植。本文通过对中国植胶区主要育成或引进橡胶树品种,以及相关品种的适宜种植区域进行初步总结与分析,结合橡胶树品种特性与植胶生态类型区,提出主产区橡胶树品种区域配置建议,以期为确定不同橡胶树优良品种的区域试验、适应性范围、以及为相关品种的区域配置、扩大试种及对口推广应用提供参考和依据。