Changes in plant population density, composition and sward structure of a hill pasture during a pastoral fallow

Appropriate pre-sowing methods for the introduction of improved forage legume and grass germplasm are an important issue for hill pasture improvement in New Zealand. A pastoral fallow, which involves not defoliating pasture for a period generally from late spring/early summer to autumn, could create a potentially favourable environment for introducing improved germplasm. A field study was conducted on two aspects (shady and sunny) of moist, low-fertility hill country with or without added fertilizer (phosphorus and sulphur) in the southern North Island of New Zealand, to investigate the changes in plant population density and sward structure during a full or partial pastoral fallow, compared with a rotationally grazed pasture. A 7-month (October to May) pastoral fallow dramatically decreased the densities of grass tillers by 72% (P < 0·01), white clover (Trifolium repens L.) growing points by 87% (P < 0·01) and other species by 87% (P < 0·05). The decline in tiller density by pastoral fallow was enhanced on the shady aspect. Fertilizer application increased white clover growing-point density on the shady aspect (P < 0·05) and grass tiller density on the sunny aspect (P < 0·05). Decreased plant density during pastoral fallowing was attributed to aboveground biomass accumulation, which altered sward structure, leading to interplant competition and mortality by self-thinning and completion of the life cycle of some matured plants. The plant size-density relationship during pastoral fallowing in this mixed-species sward followed the serf-thinning rule, particularly when the calculation was based on all plant species rather than grass alone. There was no significant (P > 0·05) difference in final plant population density between the 7-month pastoral fallow and a shorter term (October to December) pastoral fallow. It is concluded that pastoral fallowing effectively reduced the plant population density and altered sward structure of a hill pasture. Such changes create a more favourable environment for the introduction of improved forage species.     

能源植物菊芋在松嫩盐碱地区的栽培试验研究

为探求能源植物菊芋在盐碱地栽培的发展前景,选取栽培菊芋和野生菊芋2份试验材料在松嫩盐碱地上进行了施肥、割草、重度盐碱胁迫及土壤不同开垦年限的处理研究.结果表明:这2份材料均可在中度盐碱地上正常生长和繁殖,施肥、割草对菊芋的生长有促进作用,重度盐碱胁迫会降低菊芋的出苗率,野生菊芋对重度盐碱胁迫表现出更好的抗性,栽培菊芋在中度盐碱地上产量可达到30 000 kg·hm-2以上.通过试验表明菊芋是适合在松嫩盐碱地上发展的优良能源植物.     

苹果果实酶促褐变底物及多酚氧化酶活性的研究

 以5个苹果品种为试材，研究了果实的褐变度，绿原酸、儿茶素和表儿茶素含量及多酚氧化酶(PPO)对不同底物的活性。结果表明，‘富士’果实褐变度最高，其次为‘新红星’，‘金冠’最低。3种酚类物质总量新红星和富士最高，金冠最低。儿茶素仅在‘乔纳金’和金冠果实中检测到少量。富士果实绿原酸含量显著高于表儿茶素，新红星和‘王林’表儿茶素含量显著高于绿原酸。以绿原酸为底物，PPO活性新红星最高，其次是富士和金冠，王林最低。以表儿茶素为底物，富士、乔纳金和王林PP0活性显著高于金冠和新红星。以儿茶素为底物，王林PPO活性最高，其次是富士，新红星最低。     

高校图书馆建立和实施学科馆员制度的研究

“学科馆员”制度在高校图书馆为专业用户提供优质服务,个性化服务和信息资源建设三个方面的需要。实施学科馆员制度,必须明确学科馆员的工作职能;科学制定学科馆员制度建设策略。     

抗弓形虫药物的作用机制和效果的研究进展

弓形虫病是一种危害严重的人畜共患病,人和动物的弓形虫感染呈全球性分布,其感染人可导致孕妇出现流产、死胎、畸胎和弱智儿,能引起免疫功能缺陷或低下病人死亡。且给畜牧业发展造成巨大的经济损失。传统抗弓形虫药物几乎都存在着不能完全杀死虫体及包囊,停药后的复发率较高以及对免疫功能缺陷患者基本无治疗效果等诸多不足。因此,研制和开发一种高效,低毒专用于动物的抗弓形虫药物迫在眉睫。笔者就不同类别抗弓形虫药物的作用机制及效果进行阐述,并对其发展前景进行展望,为新型抗弓形虫药物研制提供参考。     

A Shark Liver Gene-Derived Active Peptide Expressed in the Silkworm,Bombyx mori: Preliminary Studies for Oral Administration of the Recombinant Protein

Active peptide from shark liver (APSL) is a cytokine from Chiloscyllium plagiosum that can stimulate liver regeneration and protects the pancreas. To study the effect of orally administered recombinant APSL (rAPSL) on an animal model of type 2 diabetes mellitus, the APSL gene was cloned, and APSL was expressed in Bombyx mori N cells (BmN cells), silkworm larvae and silkworm pupae using the silkworm baculovirus expression vector system (BEVS). It was demonstrated that rAPSL was able to significantly reduce the blood glucose level in mice with type 2 diabetes induced by streptozotocin. The analysis of paraffin sections of mouse pancreatic tissues revealed that rAPSL could effectively protect mouse islets from streptozotocin-induced lesions. Compared with the powder prepared from normal silkworm pupae, the powder prepared from pupae expressing rAPSL exhibited greater protective effects, and these results suggest that rAPSL has potential uses as an oral drug for the treatment of diabetes mellitus in the future.     

SM22α inhibits expression of matrix remodeling-related molecules and vascular hypertrophy in rats

AIM：To investigate the effect of smooth muscle protein 22 alpha (SM22α) on the vascular hypertrophy and the expression of matrix remodeling-related molecules in rats. METHODS：Rat carotid arteries were infected with adenovirus, Ad-GFP-SM22α, Ad-GFP-S181D or Ad-GFP-S181A. Two days later, the rats were re-anesthetized and osmotic minipumps were subcutaneously implanted for angiotensin II (Ang II) infusion. The carotid arteries were analyzed using HE staining and the method of immunohistochemistry. RESULTS：Systolic blood pressure significantly increased in the rats receiving Ang II. The vascular medial thickness had a marked increase after Ang II infusion, and was inhibited by the over-expression of SM22α and S181A mutant (inhibition of SM22α phosphorylation). Furthermore, the expression of MMP-2, MMP-9, ICAM-1 and VCAM-1 was also inhibited by SM22α and S181A over-expression. CONCLUSION：Over-expression of SM22α and S181A mutant inhibits vascular hypertrophy, which is associated with the down-regulation of the matrix remodeling-related molecules MMP-2, MMP-9, ICAM-1 and VCAM-1.     

土壤重金属含量的高光谱遥感反演方法综述

随着工业生产规模的扩大、城市环境污染的加剧和农用化学物质种类、数量的增加,土壤重金属污染因其程度加剧、面积扩大而备受关注.重金属污染物在土壤中移动差、滞留时间长、难被微生物降解,并可经水、植物等介质最终影响人体健康,因此对重金属污染的定量监测非常有必要并且意义重大.高光谱遥感技术的发展为宏观、快速获取土壤重金属元素信息提供了新的契机,目前国内外学者基于土壤反射光谱特征,运用多种统计分析方法成功地预测了多种土壤重金属元素的含量.介绍了土壤的光谱特征及光谱特征波段的提取,对利用高光谱遥感技术估算土壤重金属含量的主要方法进行了总结,对影响模型精度的主要因素进行了讨论,介绍了模型在模拟多光谱数据方面的应用,最后对模型反演过程出现的不足及今后的研究方向进行了展望.     

高等教育教学研究项目和教学成果综合管理系统的设计与实现

高校教学研究项目管理手段已经难以适应现阶段教研项目发展的需要,提高教学研究项目的管理水平,促进教学成果的推广和应用,实现信息化势在必行.本系统充分结合项目管理思想和实际需求,进行需求分析、结构设计、功能模块设计和功能实现,以东北林业大学为试点,最终设计出一款适应于普通高校教学研究管理工作的,操作简便、易学易用、科学有效的通用系统.该系统的设计实现和应用有助于高校项目管理实现科学化、规范化和高效化,对推动高校教学改革的深化和教育质量的提高具有重要意义.     

我校学风建设现状调查分析与思考

为全面了解我校学生的学习状况,查找学生缺乏学习热情的根源,我们在二、三年级学生中开展了学风建设问卷调查,通过对调查结果的分析,提出了加强学风建设的对策。