假高粱及其近似种同源性研究进展

本文通过形态学、细胞学以及分子生物学3个层次对高粱属的假高粱及其近似种的同源性研究进行了总结,同时归纳了3个不同阶段具有重要影响的理论、试验方法和试验成果.     

假高梁及其近似种同源性研究进展

本文通过形态学、细胞学以及分子生物学3个层次对高粱属的假高粱及其近似种的同源性研究进行了总结，同时归纳了3个不同阶段具有重要影响的理论、试验方法和试验成果。     

假高粱与其近似种组织细胞结构解剖研究

假高粱为世界十大恶性杂草之一,在对外检疫中,由于多种原因,常与其近似种混淆。本研究通过对假高粱及其近似种4种形态的组织细胞结构解剖比较,胚胎的形成与其发育过程的观察,可作为外部形态鉴定的重要补充,克服了往往由于近似种或被鉴定的杂草籽外表损伤所造成的鉴定偏差,鉴定快速准确。     

假高粱与其近似种幼苗形态鉴定研究初报

引言假高粱 Sorghum halepense(L.)Pers 与其近似种苏丹草 S.sudanense Stapf 和拟高粱 S.propinquum Hitchc 等的小穗、颖果特征极为相似,且经常被混杂在进口粮或种子中。又口岸截获的这些杂草种子有的随着装运及运输过程的机械作用等,外观往往被磨损,破坏了其表面的固有形状特征。而且在进口的小麦等原粮中的杂草籽,由于进口地区不同,生态环境差异和杂草个体本身的形态变异以及这些杂草的成熟度不同等,影响了种子鉴定结果的准     

假高粱及其近缘种的鉴别

假高粱(Sorghum halepense)属禾本科蜀黍属(高粱属)。蜀黍属(Sorghum Moench)的主要特征,一年生或多年生草本;秆直立。圆锥花序顶生,由多数含1～5节的总状花序组成。小穗成对,生于穗轴的各节,一具柄,一无柄;穗轴顶端1节有3小穗,一无柄,二具柄;穗轴节间与小穗柄线形,边缘均具纤毛;无柄小穗两性,有柄小穗雄性或中性;无柄小穗的第一颖革质或近革质,成熟时变硬而有光泽,边缘窄内     

加拿大一枝黄花与“黄莺”的ITS同源性分析

根据一枝黄花属核糖体基因转录间隔区(ITS)序列设计引物Y2/Y4,分别扩增了加拿大一枝黄花和“黄莺”的ITS区段,并对PCR产物进行了序列测定和分析。扩增的序列长度为596bp。序列分析的结果表明“黄莺”与加拿大一枝黄花属于同一聚类组,同源性为99.8%~100%,亲缘关系极近。     

几种除草剂防除假高粱药效试验

通过对 6种除草剂除草药效的筛选试验 ,结果表明农民乐是防除假高粱植株有显著效果的除草剂。经对农民乐有效剂量和施药时期试验表明 ,最佳施药期是主株在 1 0片叶前 ,农民乐使用剂量为 0 53g/m2 ;而当假高粱主株进入抽穗结实期后 ,使用剂量则需增至0 6 8g/m     

假高粱与同属几种植物的形态学比较研究

对假高梁与同属７个种的营养器官和结实器官的形态特征作了观察，特别在籽实、花序、叶缘形态及根状茎的有无和特征方面，进行了较为详细的比较研究。明确了假高粱与其他种之间的异同点，并根据籽实和植株的形态特征，对它们进行了归类。     

草甘膦防除假高粱试验

经对几种茎叶除草剂除草效果的筛选 ,结果表明草甘膦为假高粱的有效除草剂 ,草甘膦的最佳剂量为 60 0 0 g .a .i /hm2 ;试验还就假高粱人工除草与化学除草进行比较 ,表明化学除草是对假高粱有效、可行的扑灭方法。     

PCR-RFLP鉴别假高粱和丝克高粱

本文利用PCR特异引物扩增rDNA-18S-26S基因,对PCR产物进行纯化、克隆和测序;分析假高粱与丝克高粱rDNA-18S-26S的酶切图谱,选择合适的限制性内切酶对两者PCR产物进行特异性切割,按照酶切片段的长度来区分两个近似种.被AflIII酶切后,假高粱被切割为674bp、174bp两个片段,而丝克高粱被切割成181bp、174bp、495bp、669bp 4个片段.为建立PCR-RFLP分子鉴定方法有效地区分假高粱与丝克高粱这两个种提供依据.     

In vitro expression of variation of glyphosate tolerance in Sorghum halepense

The in vitro response of five different Sorghum halepense biotypes against the non-selective, broad-spectrum herbicide glyphosate was assessed. Seeds from donor plants (collected in various sites all over Greece) were aseptically germinated on a hormone-free liquid Murashige and Skoog (MS) medium and emerging plantlets were inoculated on a solid MS medium supplemented with 13.6 μM 2.4-dichlorophenoxyacetic acid and 4.6 μM kinetin for callus induction. Exponentially growing calli were initially subcultured twice on induction medium and then transferred to a selection medium containing 10⁻³ M or 10⁻⁴ M (a.i.) glyphosate. The fresh weight of the cultured calli and the callus viability (expressed as callus dehydrogenase activity) were reduced as glyphosate concentration increased. Significant differences were observed among different biotypes. Regenerated plantlets were submitted to a conventional evaluation for glyphosate tolerance. The observed in vitro response of S. halepense to glyphosate was directly related to the in vivo herbicide tolerance observed both on donor and on regenerant plants.     

Dynamic root exudation of phenolic allelochemicals from Johnson grass (Sorghum halepense)

The phenolic allelochemicals from the root exudates of Johnson grass (Sorghum halepense) were collected at different developmental stages and analyzed using high performance liquid chromatography‐ultraviolet/photo‐diode array. The results revealed that three simple phenolic components, p‐hydroxybenzoic acid, p‐hydroxybenzaldehyde and ethyl p‐hydroxybenzoate, along with two flavonoids, diosmetin (3′,5,7‐trihydroxy‐4′‐methoxyflavone) and tricin (5,7,4′‐trihydroxy‐3′,5′‐dimethoxyflavone), were found in the root exudates of Johnson grass. However, the major phenolic compounds varied and the quality of each compound was dynamic at different developmental stages: the only phenolic compound that was detected in the seedling stage was p‐hydroxybenzoic acid; three simple phenolic allelochemicals, p‐hydroxybenzoic acid, p‐hydroxybenzaldehyde and ethyl p‐hydroxybenzoate, were found in the jointing stage; and five compounds, including the two flavonoids, tricin and diosmetin, appeared in the reproductive stage along with the other three simple phenolic allelochemicals. The highest diversity in phenolic constituents was in the reproductive stage, with five allelochemicals. Only p‐hydroxybenzoic acid was found in the whole life cycle of Johnson grass, with a range of 2.9 nmol to 6.8 nmol per plant per day. p‐Hydroxybenzaldehyde had the highest quality among all the compounds, with the highest releasing rate of 26.8 nmol per plant per day. The lowest‐content compounds were the two flavonoids, with the highest quality of 1.8 nmol per plant per day. The results suggest that the temporal dynamic of phenolic allelochemicals in the root exudates of Johnson grass corresponds with the dynamic of development.     

外来入侵植物假高粱在我国的潜在分布区分析

［目的］ 预测假高粱在我国的潜在分布区,为控制其在我国进一步传播扩散提供依据。［方法］ 基于采样后的假高粱(Sorghum halepense)全球分布数据,以19个生物气候因子作为预测的环境因子,MaxEnt模型作为物种适生性预测模型,同时结合假高粱的生态学参数,预测假高粱在我国的潜在分布。［结果］ 假高粱在我国有广泛的潜在分布区,目前的实际分布远没有达到其最大潜在分布范围,因此仍有可能继续扩散。最冷季节平均气温、年平均气温、最干季节降水量和最冷季节降水量等环境要素对假高粱的生长和分布具有重要影响。［结论］ 必须采取有效措施阻止假高粱的扩散。     

Shift of allelochemicals from Sorghum halepense in the soil and their effects on the soil's bacterial community

Johnsongrass (Sorghum halepense [L.]Pers.), an exotic invasive weed in China, secretes the phenolic compounds, p‐hydroxybenzoic acid (p‐HBA) and p‐hydroxybenzaldehyde (p‐HBAL), as the dominant allelochemicals in the root exudates. To better understand how these two allelochemicals affect the soil microbial community in the rhizosphere of S. halepense, the fate of these compounds in the invaded soil and the effect of these phytotoxins on the soil bacterial community were evaluated. The concentrations of the allelochemicals in the soil were determined by a high‐performance liquid chromatography‐ultraviolet/photodiode array after 1, 2, 4, 6, 12 and 24 h of treatment. MiSeq sequencing was undertaken to understand how the bacterial populations in the soil were affected by the allelochemicals. The HPLC results indicated that p‐HBA was degraded by the microorganisms that were present in the soil after 1 h and disappeared after 6 h of incubation. The compound, p‐HBAL, initially was converted to p‐HBA and then the p‐HBA broke down, disappearing after 12 h of incubation in non‐sterile soil. Both p‐HBA and p‐HBAL were stable under sterile soil conditions for up to 24 h. The relative abundance of Proteobacteria was significantly inhibited. However, those of Acidobacteria, Chloroflexi, Verrucomicrobia and Cyanobacteria were increased by the p‐HBAL treatment. These findings suggest that allelochemicals from S. halepense might affect the bacterial community composition in the soil.     

少毛钝绥螨的生物学特性及rDNA ITS序列分析

少毛钝绥螨Proprioseiopsis asetus是在国内有分布的一种捕食螨,其研究尚不深入。为明确其生物学特性,在25℃室内条件下研究了少毛钝绥螨对芦笋蓟马1龄若虫、柑橘全爪螨低龄若螨、椭圆食粉螨1龄若螨和丝瓜花粉的食性。结果表明:少毛钝绥螨可以取食以上4种食物,其中对粉螨和芦笋蓟马的捕食量较大,对柑橘全爪螨捕食量较小。少毛钝绥螨及其近缘种的rDNA ITS序列在61~85、116~159、177~198、224~254、277~317、531~549、438~445 bp和580~594 bp等ITS区段存在差异性碱基。少毛钝绥螨及其近缘种分为两个组群。Proprioseiopsis、Neoseiulus、Amblyseius聚为一个组群(GroupⅠ),而Euseius单独聚为一个组群(GroupⅡ)。少毛钝绥螨与N.womersleyi和N.agrestis亲缘关系较近。     

Phylogenetic Analysis of Sugarcane Rusts Based on Sequences of ITS, 5.8 S rDNA and D1/D2 Regions of LSU rDNA

Phylogenetic analysis of sugarcane rusts based on sequences of ITS and the 5.8 S rDNA revealed two highly divergent ITS groups among isolates of Puccinia sp. sensu Muta, 1987 and P. kuehnii specimens. Although there is sufficient divergence (exceeding normal intraspecific variation) between the ITS regions of the two groups to support separation into different species, unusually high homology of the ITS group I sequences with those of members of Cronartium and identical sequences of the D1/D2 regions of the LSU rDNA for all the isolates of “Puccinia sp.” and P. kuehnii that otherwise exhibited different ITS sequences, suggest that the two highly divergent sequences may have resulted from abnormal genetic events leading to non-orthologous, intraspeciflc polymorphisms. The other sugarcane rust, P. melanocephala and the grass rusts, P. miscanthi and P. rufipes, were separated from “Puccinia sp.” and P. kuehnii and from each other in D1/D2 region analyses, indicating that D1/D2 region sequences may more correctly reflect phylogenetic relationships in these rusts than do the ITS regions. Further studies to examine differences in patho-genicity or finer morphological features within P. kuehnii that may be correlated with the high divergence in ITS sequences and experiments to determine if these two sequence types represent intraspeciflc polymorphism are necessary. Received 11 October 2000/ Accepted in revised form 24 November 2000     

Phylogenetic and morphological analyses of Pythium graminicola and related species

Isolates of Pythium graminicola and related species were differentiated using restriction fragment length polymorphism (RFLP) analyses of the internal transcribed spacer (ITS) regions of rDNA and the cytochrome c oxidase subunit II (COX II) gene. These sequences were used in subsequent phylogenetic analyses. Finally, the phylogenetic placement of species was compared to that determined from morphological characteristics. The 62 isolates tested were divided into seven groups, A–G, based on RFLP analysis of the rDNA-ITS region. In the RFLP analysis of the COX II gene, isolates were divided into groups similar to those based on ITS-RFLP. Groups A and B were each separated into two additional subgroups. Grouping of isolates based on RFLP analyses agreed with the morphological differentiation. Groups A, B, D, E, F, and G were identified as P. graminicola, P. arrhenomanes, P. aphanidermatum, P. myriotylum, P. torulosum, and P. vanterpoolii, respectively. Group C was closely related to group B based on phylogenetic analysis of the rDNA-ITS region and the COX II gene and is similar to P. arrhenomanes. Each of the other species occupied their own individual clades. Although P. arrhenomanes is morphologically similar to P. graminicola, our phylogenetic analyses revealed that it was evolutionarily distant from P. graminicola and more closely related to P. vanterpoolii. Our analysis also revealed that P. torulosum with smaller oogonia is more closely related to P. myriotylum with large oogonia than to P. vanterpoolii, which forms smaller oogonia and is morphologically similar to P. torulosum. P. aphanidermatum with large oogonia and aplerotic oospores was not related to the morphologically similar species P. myriotylum. Results suggest that P. graminicola and related species are phylogenetically distinct, and molecular analyses, in addition to morphological analyses, are necessary for the accurate taxonomic placement of species in this complex.     

Phylogenetic relationships of Ralstonia solanacearum species complex strains from Asia and other continents based on 16S rDNA, endoglucanase, and hrpB gene sequences

The 16S rDNA, endoglucanase, and hrpB genes were partially sequenced for Asian strains of Ralstonia solanacearum spp. complex, including 31 strains of R. solanacearum and two strains each of the blood disease bacterium (BDB) and Pseudomonas syzygii. Additional sequences homologous to these DNA regions, deposited at DDBJ/EMBL/GenBank databases were included in the analysis. Various levels of polymorphisms were observed in each of these DNA regions. The highest polymorphism (approximately 25%) was found in the endoglucanase gene sequence. The hrpB sequence had about 22% poly-morphism. The phylogenetic analysis consistently divided the strains into four clusters, as distinctly shown on the phylogenetic trees of 16S rDNA, hrpB gene, and endo-glucanase gene sequences. Cluster 1 contained all strains from Asia, which belong to biovars 3, 4, 5, and N2. Cluster 2 comprised the Asian strains of R. solanacearum (as biovars N2 and 1) isolated from potato and clove, as well as BDB and P. syzygii. Cluster 3 contained race 3 biovar 2 strains from potato, race 2 biovar 1 strains from banana, and race 1 biovar 1 strains isolated from America, Asia, and other parts of the world. Cluster 4 was exclusively composed of African strains. The results of the study showed the distribution and diversity of the Asian strains, which are present in three of the four clusters. The similarity of Asian strains to those in the other regions was also observed.The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under accession numbers AY464950 to AY465050