链霉菌702所产抑真菌物质理化性质的初步研究

用链霉菌702所产的抑真菌物质纯品进行了极性试验和官能团反应。极性试验表明该物质属于中性的非水溶性Ⅰ型抗生素;在官能团反应中,Molisch反应和Hopkins—Col反应呈阳性,表明该物质含有糖基和色氨酸,为进一步对该抑菌物质进行结构鉴定,提供了有益的实验依据。     

《西南林学院学报》高被引论文统计分析

以《西南林学院学报》2002—2006年高被引论文为研究对象,统计分析作者群等相关指标。结果表明：该刊5年的高被引论文中,内稿比例虽然较高,但总体呈下降趋势;国家级基金论文的比例有所提高;作者的地域分布有所扩大,但以高校的作者为主;作者合著率平均为86.7%;在学科分布上,林业基础学科、园艺、生物学等所占比例较高。     

紫云英翻压还田对稻田土壤团聚体组成及其碳氮的影响

紫云英翻压还田是南方传统稻田土壤培肥增产的主要措施。依托连续12年田间定位试验,通过设置CK（不施化肥,紫云英不还田）、单施化肥（GM0）和4个梯度的紫云英翻压量（GM1-4）处理,分析连续多年紫云英翻压还田对稻田土壤团聚体组分、团聚体中碳氮含量和储量,并通过傅里叶红外光谱测定各粒级有机官能团类型及相对含量,探讨连续多年紫云英翻压还田对土壤团聚体组分及其碳氮分布的影响。结果表明,在该土壤中粒级>2 mm土壤团聚体含量最高,占总量的61.12%～68.53%,其次是2～0.25 mm粒级团聚体。紫云英翻压还田较单施化肥处理提高了>2 mm粒级团聚体所占百分比（5.93%～9.91%）。紫云英翻压还田提高了粒级>0.053 mm团聚体中有机碳含量和各个粒级中全氮含量,其中粒级>0.25 mm团聚体的碳氮含量与紫云英翻压量之间呈现出显著正相关关系。紫云英翻压还田分别显著提高了19.42%～37.09%有机碳和22.31%～40.13%氮的总储量,其中粒级>2 mm团聚体中碳氮储量随着紫云英翻压量的增加而增加。>2 mm粒级团聚体中碳氮的分布也随着紫云英的翻压还田而增加。通过傅里叶红外光谱认为土壤各粒级团聚体中脂肪族有机碳和芳香族有机碳以及N-H官能团含量也随着紫云英翻压还田而增加,其中N-H官能团含量与紫云英翻压量之间呈现出显著的正相关关系。紫云英翻压还田同时提高了各团聚体中1 630/2 850+2 940和1 720/2 850+2 940相对比值,其中>2 mm和2～0.25 mm粒级团聚体中1 630/2 850+2 940相对强度比值与紫云英翻压量之间均呈显著性相关关系。综上,紫云英翻压还田不仅有利于改善稻田土壤团聚体组分,增加有机碳和全氮在土壤团聚体中的储存,还提高了团聚体有机碳的活性和稳定性,从而有助于提升稻田土壤肥力。     

Effect of desert plant ecophysiological adaptation on soil nematode communities

Nutrient source limitation in desert ecosystems enhances competition among plant communities, leading to creation of microhabitats beneath the shrubs that can determine composition and abundance of soil organisms. The aim of the study was to determine the effect of plant ecophysiological adaptation on soil nematode communities in the rhizosphere of tightly interweaving shrubby communities. Soil samples were collected monthly under the canopies of three perennial desert shrubs: Artemesia herba-alba, possessing the allelopathic ability to dominate in relationships with other plants; Reaumuria negevensis, a salt-resistant plant; and Noea mucronata, a typical dry desert shrub. An inter-plant area was used as a control. The results demonstrated that soil water content (SWC) and total organic carbon (C_org) were significantly different under different plants and inter-plant areas, with the highest values found under R. negevensis (SWC) and N. mucronata and R. negevensis (C_org). Plant parasite and omnivore-predator nematodes were more sensitive to the ecophysiological individual features of observed plants versus the total number of nematodes and bacteria- and fungi-feeding nematodes. Generally accepted ecological indices such as Wasilewska (WI), trophic diversity (T), maturity (MI, MMI), basal (BI), enrichment (EI), structure (SI), and channel (CI), pointed to specific ecological conditions under canopies of the observed plants.     

木薯遗传图谱16号连锁群与其细胞学图谱的整合

利用荧光原位PCR技术体系整合木薯的分子遗传图谱,将16号连锁群上的NS376和SSRY86标记定位到华南6号木薯的染色体上,结果表明:这2个标记均能在华南6号不同时期的细胞上检测到1个信号.结合核型分析,将NS376标记定位在华南6号的第4号染色体的短臂上,扩增位点到着丝粒的百分距离是31.25,将SSRY86标记定位在第4号染色体的长臂上,扩增位点到着丝粒的百分距离是75.86.NS376和SSRY86 2个标记位于木薯的同一对染色体上,并且分别位于该染色体的两端,进一步揭示了16号连锁群对应的是木薯的4号染色体.     

Long‐term effects of mulching,traditional cutting and no management on plant species composition of improved upland grassland in the Czech Republic

A shortage of available livestock for utilizing grassland biomass in Central Europe is challenging for the management of both semi‐natural grasslands and previously intensified (limed, fertilized and reseeded) upland grasslands. An alternative method of grassland management is mulching, in which aboveground biomass is cut, crushed and subsequently spread on the surface. This paper reports on an experiment to compare three different mulching frequencies (one, two and three times per year) with an unmanaged treatment and traditional management of two cuts per year (control) on a previously improved upland meadow. Plant species composition was monitored over 13 years. Traditional management of two cuts with biomass removal was the most suitable method for maintaining plant species richness and diversity, and both were reduced significantly in the once‐mulched and especially in the unmanaged treatment. Tall dicotyledonous weeds such as Urtica dioica, Cirsium arvense and Aegopodium podagraria were promoted by the unmanaged treatment and by mulching once a year. Higher frequency of defoliation had positive effects on the spread of short forbs such as Taraxacum spp., Plantago lanceolata and Trifolium repens. After eight years, there were changes in sward structure in the unmanaged and mulched‐once‐a‐year treatments, with increase in the tall/short species ratio. In conclusion, repeated mulching cannot substitute fully for traditional two‐cut management in improved upland meadows without decreasing plant species richness and diversity, and changing the sward structure. Although mulching once a year may prevent invasion by shrubs and trees, it also supports the spread of weedy species similar to no management.     

大小叶种儿茶素在植物油中抗氧化性数据的广义估计方程法的检验和分析

在获得有关大小叶种儿茶素在植物油中的过氧化值数据后,怎样通过摆在人们面前的一大堆数据获得正确的结论,从而揭示一定的规律,并能展示其显著性和统计意义,SAS是目前流行的统计分析软件,应用广义估计方程（GEN-MOD）方法,可以从输出的信息中寻找统计上的参数值,来检验和证实结论可靠程度。     

芝麻产量性状与品质性状的典型相关分析

以15个芝麻品种(品系)为材料,根据生物学意义将15个性状归纳为4个性状组,对性状和性状组基因 型值进行相关分析和典型相关分析,并建立了由多个农艺性状间接改良品质性状的综合选择指数。结果表明:对 单株产量影响最大的因素是农艺性状(株高、果轴长、始蒴部位)和产量构成因子(蒴粒数、千粒重) ,而且农艺性状 与产量构成因子以正相关为主,因此可以同步改良农艺性状和产量构成因子以进一步提高产量潜力;含油量与主 要农艺性状、产量构成因子以及种子容重呈正相关,而与粒宽和蛋白质含量呈显著负相关,因此含油量和产量可以 协调发展,同步提高,而且可以通过籽粒性状间接辅助选择高产、高含油量的芝麻新品种。     

A methodology for characterization and analysis of plant functional composition in grassland‐based farms

Understanding the relationships between farmers' land‐use and management decisions, and plant diversity is a challenge. It requires characterization of plant diversity within and between fields and investigation of land‐use allocation to fields. To analyse how grassland functional composition [mean plant trait and functional diversity index (FD)] varies according to scale (field, land‐use type: cutting, grazing, farm), grasslands were characterized according to leaf dry‐matter content (leaf DM) and FD computed from leaf DM values. A leaf DM‐αFD framework was used to analyse how leaf DM‐based plant strategies were distributed at land‐use type and farm scales (βFD). The study was conducted on eight dairy and beef farms (169 grasslands) differing in their stocking rate. At field and land‐use type scales, leaf DM was significantly decreased and increased with N fertilizer rate and field elevation respectively. It was significantly higher for grazing than for cutting. At the farm scale, the main differences between farms resulted from differences in plant strategy distribution between land‐use types within a farm and among farms for a given land‐use type in relation to management intensity. Farms that contributed the most to αFD had the highest stocking rate, and those which had the most contrasting grasslands for management intensity had the highest βFD. Management practices need to be examined at a land‐use type scale for evaluating the within‐ and between‐field plant functional compositions. By contrast, the value of the analysis was reduced if data were collected and averaged at the farm scale.