福建省不同植物群落物种组成及多样性分析

应用物种多样性指数、均匀度和丰富度指数等指标测定福建省阔叶林物种多样性。结果表明:阔叶林在福建省树种中占重要地位,其中硬阔类树种的优势地位更为明显;福建省阔叶林物种分布较均匀,植被保护较完整。     

云南松主分布区天然群体的遗传多样性及保护单元的构建

以20个云南松天然群体为对象,SSR分析表明云南松遗传变异主要存在于群体内,各群体间的遗传多样性水平差异不显著。基于SSR分子标记遗传多样性分析,根据Nei's遗传相似度,采用逐步聚类优先取样法,分别对初始群体、遗传多样性保护单元和剩余群体进行比较、t检验,以此评价遗传多样性保护单元的代表性。结果表明,利用该方法抽样的群体能很好地代表初始群体的遗传多样性,按30%的群体抽样,等位基因数、有效等位基因数、Shannon's信息指数和期望杂合度的保留率分别达到初始群体的98.03%、105.36%、103.99%和105.56%。保护单元的遗传多样性均高于剩余群体,抽样群体组成的遗传多样性保护单元的效果较好。     

抚育间伐对落叶松云冷杉混交林的影响

以15块人工落叶松纯林演化后形成的落叶松云冷杉混交林为对象,间伐后12年观测结果,研究间伐对林分和树木生长、树种组成、物种多样性及土壤等因子的影响。间伐强度分为2级:中度(平均为20%)和强度(平均为30%)。结果表明:间伐促进了保留木生长的显著增加,但不同间伐强度间无显著差异。林分及单木的直径、断面积和蓄积生长率均表现相同的趋势即随间伐强度的增加而增加。但间伐没有显著地增加12年间的总收获量。伐后对照样地表现为较高的枯损,枯死木主要是落叶松和阔叶树。林分进界株数严重不足,进界的主要树种是云冷杉、阔叶树和红松,以耐荫树种为主。从枯损和进界看,如果能对红松和阔叶树进行保护,这种林分很可能逐渐演化为阔叶红松林。建议对红松和阔叶树进行保护,使林分向阔叶红松林方向发展。各林分的树种组成在12年间基本没有发生变化,即间伐没有显著地改变林分的树种组成,目前的树种组成即落叶松、其他针叶树(云杉、冷杉和红松)和阔叶树组成比约为6∶3∶1可能是相对稳定的群落。20%和30%的间伐强度没有显著地改变林分的物种多样性、灌草生物量和土壤物理性质,间伐样地的物种多样性略有提高;间伐样地的土壤物理性质有所改善,总孔隙度和毛管孔隙度都大于对照;林下灌草生物量有所增加。     

广东南澳岛主要森林群落与植物多样性研究

在样方调查的基础上,对南澳岛的主要森林群落进行研究,结果表明,主要森林群落的乔木树种多样性表现为次生林〉人工林,群落各层次植物多样性基本符合灌木层〉乔木层〉草本层的格局;现有的台湾相思、山杜英＋鸭脚木、鸭脚木、珊瑚树等群落为较稳定的群落结构。据此提出了人工林分的改造意见。     

郑州市绿地景观多样性研究

介绍了景观生态学理论中景观多样性的分析方法理论，并在调查的基础上，首次对郑州市绿地系统景观多样性相关指数进行了计算、分析和评价。研究表明，郑州城市绿地系统绿地景观多样性指数为2．08，与理论最大值相差0．5，说明绿地类型面积分布不够均匀，存在一定的改善空间。分城区研究表明，二七区的绿地景观中不同程度地受到某一种类型的控制，绿地景观类型面积分布很不平衡；新建城区存在绿地类型不全，绿地系统生态功能不能很好实现，应建设更多绿地类型。     

大兴安岭湖通河野生五味子药用资源保护区自然生态质量评价分析

从植被类型多样性、物种多样性、生态系统的稳定性和脆弱性、面积适宜性几个方面对大兴安岭湖通河五味子药用资源保护区的自然生态质量进行了评价和分析。     

Genic microsatellite markers for discrimination of spinach cultivars

A set of simple sequence repeat (SSR or microsatellite) markers was used to discriminate a collection of 33 Spinacia oleracea hybrid cultivars from seven different breeding stations all over the world. All SSR markers were genic microsatellite markers located in coding or non-coding regions of genes of known function. Cluster analysis based on 13 of the SSR markers showed that the spinach hybrids grouped into three clusters. The first two clusters consisted of European spinach types, which were well discriminated according to their origin from different breeding stations. The third cluster was a mixture of Asian as well as European types of spinach. Subclusters in this group did not reflect differences in morphology, earliness or company origin. The data show that genic microsatellites are a powerful tool for discrimination of spinach cultivars.     

Unique gliadin patterns in Chinese winter wheat cultivars

Cultivated Chinese wheat germplasm has been a valuable genetic resource in international plant breeding. Patterns of gliadin among cultivated Chinese accessions are unknown, despite the proven value and potential novelty. The objective of this work was to analyse the diversity within improved Chinese wheat germplasm. The electrophoretic banding patterns of gliadin in winter wheat cultivars and advanced lines were determined by acid-polyacrylamide gel electrophoresis. For 148 leading commercial cultivars and promising advanced lines used in this study, 48 patterns were identified, 29 corresponding to ω -gliadin, nine to γ -gliadin, five to β -gliadin and five to α -gliadin. The most frequent patterns were A6 in ω ; B in γ ; B in β and A in the region of α . A total of 116 band types appeared in the 148 samples: 94 accessions had unique gliadin types, and 22 gliadin, types while not unique, were found in 54 accessions. The gliadin patterns of Chinese wheat cultivars and lines greatly differed from the patterns of wheat lines from other countries. Three patterns, E, J, H, M, N and O in the ω -zone had not been reported previously. Three wheat zones of China, the Northern Winter Wheat Region, the Yellow and Huai Valley River valleys Winter Wheat Region and the Southwestern Winter Wheat Region, showed different frequencies in their gliadin patterns. This information can be used to monitor genetic diversity with Chinese wheat germplasm.     

皖北小麦主栽品种遗传多样性的系统聚类法分析

采用系统聚类分析法对淮北地区近50年来推广面积在6.67hm2以上的20个主栽小麦品种遗传差异进行了初步探讨。以株高、穗长、小穗数、小穗密度、千粒重、护颖长短、粒长和粒宽等农艺性状为依据,计算20个品种间遗传距离,采用类平均分析法对供试材料进行聚类分析。结果表明：供试的20个品种共划分为8个类群,Ⅰ类为扬麦12、皖麦47;Ⅱ类为皖麦33;Ⅲ类为皖麦48、阜麦938、济麦21、皖麦44、皖麦55、荔高6号、豫麦49ck2、浏虎98、豫农035、百农AK58;Ⅳ类为豫麦49、皖麦38;Ⅴ类为郑麦366、衡观35;Ⅵ类为皖麦50;Ⅶ类皖蒙118;Ⅷ类为豫麦70。划分结果与系谱分析基本一致,并把系谱来源不清的品种划分到相应的杂种优势群。形态学形状检测是研究品种间遗传差异的一种方法,可为小麦育种亲本选配提供初步的理论依据。     

Marker assisted polycross breeding to increase diversity and yield in perennial ryegrass (Lolium perenne L.)

Summary In this study, the application of molecular markers to optimise genetic diversity in a polycross breeding program of perennial ryegrass (Lolium perenne L.) was evaluated. The genetic diversity among 98 potential parental plants from three maturity groups (early, intermediate and late flowering) was investigated using amplified fragment length polymorphism (AFLP) markers. For each maturity group, two polycrosses of six parental plants with contrasting levels of genetic diversity were composed. Average genetic diversity among parents selected for narrow polycrosses was 36% lower than among parents selected for wide polycrosses. Diversity within first generation synthetic progenies (Syn1) was proportional to the diversity within the respective parental polycrosses. However, differences were less pronounced with Syn1 progenies from narrow polycrosses showing 16% reduced diversity when compared to Syn1 progenies from wide polycrosses. Multivariate analyses allowed for a clear separation of the six Syn1 progenies based on AFLP markers and demonstrated their genetic distinctness. Evaluation of dry matter yield, date of ear emergence and stem length of Syn1 and Syn2 progenies showed progenies from wide polycrosses to be constantly higher yielding when compared to progenies from narrow polycrosses. On the other hand, there was no significant difference in variability for the two morphological traits between progenies of narrow- and wide polycrosses. The results presented here provide evidence for an efficient application of molecular markers to select genetically diverse polycross parents which resulted in an average yield increase of 3.8%.