科尔沁沙地差巴嘎蒿——杂类草群落结构、功能的沙漠化演变特征

研究结果表明：在沙漠化发展过程中，差巴嘎蒿－－杂类草群落（1）首先是植物种组成数量和密度大幅度减少，继而植被盖度和地上生物量急剧下降，四项指标受沙漠化影响的强弱顺序是密度＞植物种数量＞工＞地上生物量；（2）结构趋于简单，功能逐渐消退，优势种或亚优势种发生更替，群落最终变性；（3）沙漠化演变既有连续性又有间断性，随着沙漠化的加剧，其连续性变弱，间断性增强，变幅增大；（4）轻度沙漠化时群落稳定性最高，严重沙漠化可导致其稳定性迅速破坏；（5）对沙漠化的危害，表现出一定的时滞效应和自我适应调节能力，这两个问题有等于进一步研究。     

白鱼属鱼类一新种及其营养成份

本文对路南金线白鱼新种作了详细描记，新种体背体侧上方有3条金色带可与该属所有种相区别。文中对其营养成分作了分析，结果表明路南金线白鱼是营养价值很高的优质鱼种，现该物种已处于濒临灭绝状态，应加强保护。     

New genes for disease resistances through somatic hybridization

Somatic hybridization, a process of combining protoplasts from different plants, can provide new sources of disease resistances for plants. In the case of wild and cultivatedSolanum species, the hybrids express resistances from each partner in the fusion and can often be crossed with cultivars to improve agronomic characteristics of the tubers. Restriction fragment length polymorphism (RFLP) analyses can provide a means for determining that the plants being investigated are actually hybrids as well as a means for following the introgression of DNA into progeny lines. These points are addressed in this paper with specific reference to somatic hybrids betweenSolanum brevidens and potato.     

The effects of agricultural fields and human settlements on the use of rivers by wildlife in the mid-Zambezi valley,Zimbabwe

After the eradication of the Tse-Tse fly in the Mid-Zambezi valley, human settlements and fields extended mainly along the main rivers. In order to investigate the consequences of this human development on wildlife diversity we monitored three rivers of the Mid-Zambezi valley in Zimbabwe: Angwa, Manyame and Kadzi. The rivers were divided in segments of 200 m which were checked for spoors in order to assess the number of species and the number of individuals that used the segments. Human settlements were also recorded. We used a GIS to define the spatial characteristics of the fields present along the rivers, and related them to the distribution and abundance of wild species spoors in the river beds and banks. Our results show that the number of species in one segment of the river decreased with the increasing size of the field area bordering the segment. For all the major ungulate species, the numbers of individuals recorded per segment decreased with increasing field area. A similar trend was observed for small and medium-sized carnivores, though they were in lower numbers when present. Our analyses thus confirm that the extension of human agriculture in wildlife areas has an impact on most wild species, but we also define some threshold value of field size above which there seem to be an acceleration of the decrease in wildlife density and diversity: 3.2 ha for medium and small herbivores and carnivores; only the elephant seem to tolerate larger field area with a threshold value of 32 ha.This revised version was published online in May 2005 with corrections to the Cover Date.     

番茄/茄子嫁接对其根际土壤生物学性状及细菌群落结构的影响

以茄子作为砧木,番茄为接穗进行嫁接,并以番茄自根植株和茄子自根植株作为对照,基于传统及现代高通量测序技术分析根际土壤的生物学性状及细菌群落结构特征,旨在揭示嫁接植株抗性增强的机制。结果表明:番茄/茄子嫁接植株根际土壤中可培养细菌、放线菌数量,微生物生物量、酶活性和细菌丰富度、多样性指数均显著高于茄子和番茄自根植株;另一方面,norank_cAcidobacteria、硝化螺菌属(Nitrospira)、芽孢杆菌属(Bacillus)、norank_fGemmatimonadaceae、norank_oGaiellales、norank_fXanthobacteraceae、norank_oSC-I-84、norank_fAnaerolineaceae、norank_fNitrosomonadace...     

不同产地烤烟细菌群落组成与结构研究

为研究不同产地C2F等级烤烟表面细菌微生物的组成和结构,利用高通量测序技术测试了6个不同产地的C2F等级烤烟在醇化初期烟叶表面可培养细菌的组成和结构。结果表明：6个不同产地的烟叶样品表面分别检测到55、39、33、26、24和15个OTU,其中6个烟叶样品共同的OTU为6个。在属分类水平上,大部分烟叶表面可培养的优势细菌微生物是芽孢杆菌属（Bacillus）,部分烟叶表面活跃着肠杆菌属（Enterobacter）,伯克霍尔德菌属（Burkholderia）和罗尔斯通菌属（Ralstonia）。不同品种和产地的烤烟表面细菌结构具有明显差异,同一品种不同产地的烤烟表面细菌结构也存在明显差异。研究结果为利用细菌微生物醇化不同产区烟叶,提高烟叶品质、优化烟叶醇化流程提供理论依据。     

放牧强度对草甸草原植物群落特征及营养品质的影响

【目的】植物群落特征是草地生态系统功能变化的敏感指标,是判别干扰条件下植被退化的重要生态学指标之一。研究不同放牧强度下温性草甸草原植物特征及品质变化情况,以了解放牧作用下草原植物退化的过程和机制,为退化草地生态恢复提供理论依据。【方法】以呼伦贝尔草甸草原肉牛控制放牧试验为平台,分析6种不同放牧强度(对照区G0.00:0,轻度放牧G0.23:0.2 cow.AU/hm²,较轻度放牧G0.34:0.34 cow.AU/hm²,中度放牧G0.46:0.46 cow.AU/hm²,较重度放牧G0.69:0.69 cow.AU/hm²,重度放牧G0.92:0.92 cow.AU/hm²)下温性草甸草原植物群落数量特征、多样性、功能群与营养品质的变化,并探讨他们之间的相关性。【结果】放牧强度大于0.34 cow.AU/hm²时,群落盖度、群落高度、群落地上生物量、原有优势植物(羊草(Leymus chinensis))和贝加尔针茅(Stipa baicalensis)...     

基于强化推流工艺(PFR)的餐厨垃圾堆肥微生物群落结构解析

传统餐厨垃圾好氧堆肥周期长,系统难以稳定连续运行,其中反应器构型和微生物在其处理过程中起到关键作用,但是目前对实际运行条件下的反应器内微生物群落结构的研究较少。通过分析实际运行项目中微生物的多样性与群落结构,为进一步优化餐厨垃圾处理工艺,促进PFR反应器系统的稳定和高效运行,挖掘特定功能微生物,提高资源利用效率提供科学依据。该研究采集德清县11个项目的出料样品,采用Illumina Miseq高通量测序技术,研究其菌群组成、丰度、优势菌群及其相关性。结果表明:1)11个项目的微生物群落组成相似,其中厚壁菌门(Firmicutes)和变形菌门(Proteobacteria)是相对丰度最高的2个菌门,优势菌属为微小杆菌(Exiguobacterium)乳酸杆菌(Lactobacillus),柠檬酸杆菌(Citrobacter),不动杆菌属(Acinetobacter)和假单胞菌(Pseudomonas); 2)底物越丰富,进料量越小,越有利于出料的品质; 3)出料感官品质高,微生物多样性也较高; 4)在OTU水平上,葡萄球菌属与芽孢杆菌属、根瘤菌属均呈负相关,葡萄球菌的迅速增殖抑制了对发酵...