珍稀濒危植物丹霞梧桐种子萌发特性研究

珍稀濒危植物丹霞梧桐（Firmiana danxiaensis）种子存在硬实休眠现象,自然条件下,发芽率极低。试验通过高温浸种（80 ℃）、变温浸种、机械损伤、酸蚀处理和激素处理等不同方法破除其休眠机制。结果表明,除激素处理对破除丹霞梧桐种子休眠无明显作用以外,其他处理均能显著提高其萌发率;其中,酸蚀 20 min 效果最好,丹霞梧桐种子萌发率为 82.29%,发芽势 78.13%,发芽指数 4.59;高温浸种次之,萌发率为 77.52%,发芽势为 68.99%,发芽指数为 3.71。研究表明酸蚀 20 min 和高温浸种能显著促进丹霞梧桐种子萌发。     

原状黄土的地区湿陷特性及其潜在湿陷率

对 3个典型黄土地区的原状黄土样在不同湿度状态下的湿陷特性进行了研究 ,探讨了含水率、干密度、压力对黄土湿陷性的影响规律 ,着重从结构性的角度解释了不同地区间黄土湿陷特性的差异。基于不同地区间黄土湿陷特性的差异这一事实 ,提出了黄土潜在湿陷率的概念。结果表明 ,这一概念可用于对黄土湿陷性的分析 ,并能较好地反映不同黄土种类的结构特性。     

旅游活动对香格里拉景区土壤重金属污染的影响

为了解旅游活动对香格里拉景区土壤重金属的影响,在测定土壤重金属含量的基础上,结合相关分析解析重金属的来源,并采用内梅罗综合污染指数法和污染负荷指数法评价了重金属污染特征.结果表明:(1)研究区混合样中重金属As,Hg,Cd,Cu,Cr,Pb和Zn的平均含量分别为10.16,0.291,0.52,38.67,83.78,42.26,130.27mg/kg,其中Cu,Cd,Cr,Pb和Zn的平均含量超过对照样的13.3%,44.8%,10.6%,15.4%和13.9%,Hg,Cd,Cr以及混合样中的Cu,Zn的含量均超过了迪庆州土壤背景值,各样点Hg含量超过背景值7.45~7.53倍.(2)土壤重金属的单项污染指数从大至小表现为:Hg,Cd,Pb,Zn,Cu,Cr,As,最高污染系数污染程度从大至小表现为:Hg,Cd,Cr,Zn,Cu,Pb,As,Hg为研究区第一污染物.(3)混合样点的平均综合污染指数和污染负荷指数分别为2.7(中度污染)和1.06,对照样平均综合污染指数和污染负荷指数分别为1.54(轻污染)和0.86,研究区混合样的整体污染程度高于对照样.(4)研究区重金属Cu,Cr和Zn的主要污染源可能是旅游活动和生活产生的固体垃圾污染,如塑料制品、玻璃瓶、泡沫、卫生纸等;干湿沉降是Hg进入土壤的主要途径,旅游活动加剧了土壤中Hg的污染,导致研究区土壤Hg污染最严重.     

景电灌区土地利用景观格局变化研究

在GIS、RS技术与景观格局分析软件FRAGSTATS支持下,采用多样性、优势度和均匀度等景观格局指数,分析景电灌区1987、1991、1999年和2003年土地利用景观格局变化。结果表明：土地利用类型总的变化趋势为草地、戈壁、沙地和盐碱地呈减少趋势;耕地、林地、居民点呈增加趋势,耕地的大幅度增加使得景电灌区的景观基质由1987年的戈壁和草地变为2003年的戈壁和耕地。耕地、戈壁、草地和沙地土地类型的平均斑块面积较大,林地、盐碱地和居民点等类型的平均斑块面积较小。随着人类对灌区的开发、建设和利用,景观优势度减少,景观多样性和景观均匀度有所增加。总体上各指数都与人为活动有很强的相关关系。     

Effect of oil contamination on the properties of leached chernozem under model experimental conditions

A model experiment was performed to study the effect of soil contamination with oil on the growth of wheat plants. Neither significant downward migration of oil or oil components, including the most mobile aromatic hydrocarbons, in a column with leached chernozem nor removal of these compounds from the column were observed when the initial oil concentration was below 0.75%. These data confirmed the previous results that oil at a concentration of 0.3% had no negative effect on the growth of wheat. The synergetic effect of oil, soluble salts, and exchangeable sodium should be taken into account in the determination of maximum permissible residual oil content in soils.     

2011年~2012年四川地区J亚型禽白血病分子流行病学调查

为了解2011年~2012年四川地区J亚型禽白血病病毒(ALV-J)流行情况及流行病毒株的分子特征,本研究采集四川地区疑似禽白血病的病料样品784份(血液样品700份,组织样品84份)进行PCR检测,并对部分样品的gp85基因进行序列测定和分析。血液样品和组织样品ALV-J检出率分别为3.1%(22/700)和14.3%(12/84)。核苷酸序列比对结果表明,18个阳性样品的gp85基因核苷酸同源性为87.7%~99.8%,与ALV-J株HPRS-103的核苷酸同源性为87.3%~98.2%,与以前分离的J亚群四川株SCGS-1的核苷酸序列同源性为87.9%~94.4%。遗传进化分析表明,18个样品分别属于不同的分支,其中来自石棉的样品SM与其他样品的遗传距离最远。该调查结果显示四川地区鸡场的ALV-J感染比较普遍,其gp85基因存在明显的遗传多样性,引种是导致这种遗传多样性的重要原因。     

Using Bacillus subtilis E20‐fermented soybean meal as replacement for fish meal in the diet of orange‐spotted grouper (Epinephelus coioides,Hamilton)

The potential of Bacillus subtilis E20‐fermented soybean meal (FSBM) as a partial alternative component of fish meal (FM) in fed diets of orange‐spotted grouper (Epinephelus coioides) was evaluated in this study. An FM‐based diet and seven diets containing 10%, 20% and 30% and 10%, 20%, 30% and 40% of FM replaced by soybean meal (SBM) and FSBM, respectively, were fed to grouper for 84 days to evaluate possible substitution levels of FM by tracking growth performance, digestive enzyme activity and morphological changes in the liver and distal intestine. No significant differences in survival and muscle composition of grouper were found between controls and treatments. Growth performance and feed efficiency of fish fed diets with FM replaced by FSBM up to 30% were not significantly different from controls, whereas significantly decreased growth performance and feed efficiency occurred with diets containing >20% of SBM. Based on the feed efficiency, the maximum substituted levels of FM by SBM and FSBM in grouper diets were 18.36% and 29.32%, respectively, based on broken‐line analyses. Histopathological changes in the liver and distal intestine, and significantly lower activity levels of digestive enzymes, including pepsin in the stomach and trypsin, chymotrypsin, amylase and lipase in the distal intestine, were found in fish fed a diet containing 30% of FM replaced by SBM. However, these parameters were improved by the substitution of FSBM. It is therefore believed that FSBM has great potential to be used as a protein source in grouper diets in partial replacement of FM.     

褐黄血蜱中肠内容物菌群结构分析

为了解褐黄血蜱的带菌情况及其公共卫生意义,本研究在无菌条件下采集褐黄血蜱中肠内容物,提取细菌总DNA为模板,采用通用引物PCR扩增细菌16S r DNA V3区,经DGGE电泳回收DGGE 16个优势条带,并选取其中13个条带进行测序分析,结果显示,选取条带分别与立克次氏体属、柯克斯氏体属、假单胞菌属、葡萄球菌属、大肠杆菌属等高度相似。采用传统细菌学方法,从中肠内容物培养分离到2株细菌,经鉴定其中1株为蜡样芽胞杆菌。对各地区褐黄血蜱半饱血雌成蜱和吸血雄成蜱中肠菌群结构分析结果表明其带菌情况基本相同,但饱血雌成蜱3个地区间具有较大的差异;而饱血雌蜱和其它两种状态下的蜱肠道菌群也有差异。贝纳柯克斯氏体、菊欧文氏菌、肺炎克雷伯菌及软腐果胶杆菌是褐黄血蜱中肠内的优势菌。本研究利用PCR-DGGE技术分析褐黄血蜱中肠内容物,为蜱传播疾病的研究奠定基础。     

珠穆朗玛峰北坡土壤脲酶和中性磷酸酶活性初步研究

研究了珠穆朗玛峰北坡地区沿绒布河谷海拔4400～5550m的夏季土壤中水解酶类脲酶、中性磷酸酶活性,并探讨了这两种土壤酶与土壤有机质和海拔高度的相互关系。结果表明:(1)随着海拔升高,土壤脲酶、中性磷酸酶活性呈高低波动变化,在研究区域出现多个峰值,总的趋势是上升的,其最大值分别出现在海拔5500m和5450m处。(2)偏相关分析表明,土壤脲酶活性与有机质含量呈正相关,土壤中性磷酸酶活性与有机质含量呈显著正相关;土壤脲酶活性与海拔的相关性不具显著性意义,中性磷酸酶活性与海拔呈极显著正相关。     

Assessing the Antagonistic Potential and Antibiotic Resistance of Actinomycetes Isolated from Two Zheltozems of Southeastern China

Forty streptomycete strains have been isolated into pure culture from two eroded zheltozems (yellow soils) of the Fujian province. Their antagonistic activities and contributions to the formation of soil resistome have been characterized. The estimation of the antimicrobial effect of natural isolates allowed revealing 6 strains simultaneously inhibiting the growth of the fungi Fusarium oxisporum, Alternaria alternata, Paecilomyces sp., Trichoderma sp., and Candida albicans. One strain (Streptomyces aburaviensis F2-6) with a wide range of antifungal actions was also active against the bacteria Pseudomonas putuda, P. fluorescens, P. sepacia, Streptococcus sp., and Escherichia coli. It has been shown that the share of isolates with a wide range of antimicrobial effects (44%) and a high antagonistic activity (77%) in zheltozem of the urban Zhangzhou district is significantly higher than in the soil of the village of Hongkeng (22 and 39%, respectively). According to the resistome concept, determinants of resistance to antibiotics first appeared in their producers; they can be transmitted to other bacteria in the soil due to horizontal drift. Tests of streptomycetes for resistance to antibiotics with different acting mechanisms (inhibitors of the synthesis of cytoderm, protein, and metabolic pathways) has shown that the share of cultures with multiple resistance in zheltozems does not exceed 25–31%. No resistance to all of the studied antibiotics is characteristic of 15–16% of the strains isolated from zheltozems. The obtained data can be used for assessing the risks related to the transfer of antibiotic resistance genes from the environment to clinically valuable pathogenic species.