Sulfur-associated polioencephalomalacia in cattle grazing plants in the Family Brassicaceae

Polioencephalomalacia was diagnosed histologically in cattle from two herds on the Darling Downs, Queensland, during July–August 2007. In the first incident, 8 of 20 18-month-old Aberdeen Angus steers died while grazing pastures comprising 60% Sisymbrium irio (London rocket) and 40% Capsella bursapastoris (shepherd's purse). In the second incident, 2 of 150 mixed-breed adult cattle died, and another was successfully treated with thiamine, while grazing a pasture comprising almost 100% Raphanus raphanistrum (wild radish). Affected cattle were either found dead or comatose or were seen apparently blind and head-pressing in some cases. For both incidents, plant and water assays were used to calculate the total dietary sulfur content in dry matter as 0.62% and 1.01% respectively, both exceeding the recommended 0.5% for cattle eating more than 40% forage. Blood and tissue assays for lead were negative in both cases. No access to thiaminase, concentrated sodium ion or extrinsic hydrogen sulfide sources were identified in either incident. Below-median late summer and autumn rainfall followed by above-median unseasonal winter rainfall promoted weed growth at the expense of wholesome pasture species before these incidents.     

Lignin is involved in the reduction of Verticillium dahliae var. longisporum inoculum in soil by crop residue incorporation

Verticillium wilt is an increasing problem in European cauliflower production. In this study, several crop residues were screened for their ability to reduce the viability of microsclerotia when incorporated into soil. In addition, the role of fungitoxic volatiles and lignin in the crop residue-mediated reduction in microsclerotia viability was studied.Broccoli (Brassica oleracea var. italica), cauliflower (B. oleracea var. botrytis), Indian mustard (Brassica juncea), ryegrass (Lolium perenne) and corn (Zea mays) were incorporated in naturally infested soil samples collected from two cauliflower fields in Belgium, labelled Is1 and S3. The effectiveness in reducing the viability of microsclerotia depended on the soil sample and on the type of residue. In the Is1 soil, broccoli, cauliflower and ryegrass incorporation significantly reduced the inoculum level by more than 90%, while Indian mustard significantly reduced numbers of viable microsclerotia by 50%. In the S3 soil, broccoli, cauliflower and Indian mustard were not effective, whereas ryegrass and corn incorporation reduced the microsclerotia level by 50% or more. In conclusion, incorporation of ryegrass and corn was more effective than incorporation of crucifer residues.In the conditions tested, fungicidal volatile compounds did not play an important role in Verticillium microsclerotia reduction in soil. Volatiles from broccoli and cauliflower did not affect microsclerotia viability in an in vitro bioassay, whereas the volatiles from Indian mustard killed the microsclerotia. Indian mustard incorporation in soil, however, only had a minor effect on microsclerotia viability.In the S3 soil, 1% (w/w) Kraft pine lignin, a waste product of the paper industry, had to be added to observe a significant reduction on the viability of microsclerotia, whereas in the Is1 soil, a significant effect was observed when 0.1% (w/w) Kraft pine lignin was added. Acid-insoluble lignin was extracted from all crop residues previously tested. Crop residues with high lignin content seemed to be more effective than crop residues with low lignin content. The reduction of Verticillium microsclerotia viability depended on lignin type and on crop structure, since lignin extracted from cauliflower leaves was more effective than lignin extracted from cauliflower stems and corn leaves were more effective than corn roots. Microsclerotia reduction was higher after fresh residue incorporation than after incorporation of their extracted acid-insoluble lignin, indicating that the effect of crop residue incorporation on microsclerotia viability cannot be explained solely by the effects of lignin.Incorporation of lignin-rich substrates in soil may open up new perspectives for integrated control of Verticillium.     

8种十字花科短命植物的物候及其对荒漠环境的适应

对8种广泛分布于新疆北部荒漠的十字花科早春短命植物物候特征及其对荒漠环境的适应进行了观测与分析。结果表明，8种植物的种子均在3月中、下旬萌发，5月下旬至6月上旬果实成熟，生活周期均在54～79d，其营养生长期约占整个生活周期的1／3，而生殖生长期约占2／3。植株的生长发育与温度及降水存在密切的联系，说明8种植物均属于典型的避旱型早春短命植物，其短的生活周期是逃避准噶尔荒漠夏季干热气候的一种适应对策。     

中国十字花科果实微形态及其系统学意义

采用GMA半薄切片法,首次深入研究了中国十字花科(Brassicaceae)76种及7变种(包括9族35属)果实的微形态,结果显示十字花科果实分两侧压扁及背腹压扁。除乌头荠族、紫罗兰族的果实无毛状体外,其他7个族均具单细胞毛。毛状体分为4种类型:单毛不分枝、丁字毛、分叉毛及星状毛。独行菜族果实具翅,包括微翅、周翅、宽翅及披针形翅。中果皮通常由薄壁细胞层及纤维层构成,少数物种的中果皮细胞木化(如南芥族、独行菜族、香花芥族)。维管束多数,分布于果皮薄壁组织。假隔膜通常为2层薄壁细胞,但南芥族及香花芥族少数属种的假隔膜细胞木化,三肋菘蓝及厚壁荠未见明显假隔膜。十字花科果实特征通常在属内是稳定的,具有重要的分类学价值。本研究完善了十字花科果实形态学,为该科族或属的划分提供了形态学依据,为分子系统学的研究提供了形态学支持,并为进一步深入研究十字花科系统学提供了基础资料。     

十字花科植物17个物种PIN3基因的系统进化分析

为了探明十字花科植物不同物种PIN3基因之间的进化差异,运用Brassica Database数据库及十字花科基因数据库在线平台,对拟南芥(Arabidopsis thaliala)、红花荠菜(Capsella rubella)、芜青(Brassica rapa)、油菜(Brassica napus)、甘蓝(Brassica oleracea)等17个已完成基因组测序的十字花科物种的18个(油菜含有2个)PIN3同源性基因进行分析,并对其推导的编码蛋白(PIN3)进行了系统进化分析。结果表明,18个PIN3序列间的相似性为86.74%,PIN3推导蛋白之间的相似度为90.93%,蛋白等电点约为7.15~9.44,芜青PIN3等电点明显偏高。PIN3的氨基酸比对分析结果表明,在多个糖基化位点出现具有种属差异性和符合进化关系的氨基酸替换现象,盐芥属植物中条叶蓝芥(Thellugiella parvula)PIN3在更多的位点出现氨基酸的替换,这可能是导致十字花科不同种属PIN3蛋白的功能和活性出现差异的原因。     

Photosystem II and cellular membrane stability evaluation in hexaploid wheat seedlings under salt stress conditions

Salinity limits crop production in large areas of the world. The application of in vitro Photosystem II (PS‐II) activity measurements to screen hexaploid wheat (Triticum aestivum, L.) genotypes for NaCl tolerance has been investigated by comparing their responses under stress and control (no added NaCl) conditions. One of the four cultivars used in the study was ‘Kharchia’ known for its high salt tolerance. Wheat seedlings were grown hydroponically in environmental chambers and treated with a range of NaCl concentrations (0.034 M, 0.17 M, 0.68 M, or 3.42 M) over a 1, 3, and 5‐day period. The salt treatments were started in the appropriate time so that they were all ten‐day‐old during harvest. Cellular membrane stability (CMS) as measured by a conductivity method and PS‐II activity values were affected adversely by NaCl concentration and duration of treatment. Both methods clearly distinguish between salt‐sensitive and salt‐tolerant genotypes. Statistical analysis showed that PS‐II activity and CMS measurements are well correlated (r=0.7589) suggesting that PS‐II activity would be used as an additional screening method besides CMS to evaluate salt tolerance of wheat.     

新疆十字花科区系地理成分分析

新疆地处欧亚大陆腹地，十字花科植物有76属，180余种，从垂直分布的情况来看，主要分布于阿尔泰山和天山的亚高山草甸和森林草甸带、昆仑山的高寒荒漠和荒漠草原及帕米尔高原的高山草甸带。从水平分布来看，有5个分布较集中的区域：阿尔泰山地、准噶尔西部山地、天山中西部山地、天山东部山地、昆仑山和帕米尔高原，其它地区零散分布。其区系地理组成分中76个属归入7个分布区类型和9个变型。其中以地中海区、西亚至中亚分布型、北温带和中亚分布型为主，单种属、寡种属比例偏高，其种类又以新疆北疆偏多。可认定该区是十字花科的分布中心。与邻区的比较发现，新疆与周边植物区系关系密切，物种交流的机会较多，尤其是东西方向是植物区系交流的重要通道。新疆十字花科分布规律在一定程度上反映了新疆植物区系的特点。     

十字花科8种植物叶表皮微形态特征

利用光学显微镜观察了十字花科8种植物的叶表皮形态。结果表明,菘蓝属3个种与鸟头荠族的5个单种属植物叶的上下表皮细胞均存在着多边形和不规则形的特征,差异不显著。8种材料的气孔器类型表现的非常一致,即上下表皮的气孔器类型均为不等细胞型并有少量的无规则型。在气孔的大小、气孔指数和气孔密度上表现出一定差异,但没有明显的规律。通过研究证实了菘蓝属与鸟头荠族的亲缘关系较近。     

Occurrence and molecular characterization of Turkish isolates of Turnip mosaic virus

A total of 142 samples of plants showing symptoms of Turnip mosaic virus (TuMV) were collected from fields planted to Brassicaceae and non‐Brassicaceae crops in the southwest Marmora region of Turkey, during the 2004?06 growing seasons. Using enzyme‐linked immunosorbent assay (ELISA) TuMV was detected in the main brassica‐crop fields of Turkey, with an overall incidence of 13·4%. TuMV was detected in samples from Brussels sprouts, cabbage, wild mustard, radish and wild radish, but not cauliflower or broccoli. The full‐length sequences of the genomic RNAs of two biologically distinct isolates, TUR1 and TUR9, were determined. Recombination analyses showed that TUR1 was an intralineage recombinant, whereas TUR9 was a non‐recombinant. Phylogenetic analyses of the Turkish isolates with those from the rest of the world showed that the TUR1 and TUR9 isolates belonged to world‐Brassica and Asian‐Brassica/Raphanus groups, respectively. This study showed that TuMV is widely distributed in the Asia Minor region of Turkey.     

DNA sequences identify invasive alien Cardamine at Lake Constance

The shores of Lake Constance in southwest Germany inhabit an endemic and highly endangered lake-shore community. In spring 2004, a so far unknown Cardamine (Brassicaceae) was detected at the lake-shores. In the subsequent years, this taxon has spread rapidly, 95 locations have been recorded until spring 2007. We tested the utility of DNA sequences to distinguish between two alternative hypotheses regarding the appearance of this new invasive taxon: a local formation via hybridization between native species versus an introduction of a non-native taxon. The relative DNA contents was analysed as an additional independent character. DNA sequences provided substantial evidence that the unknown Cardamine taxon, recently discovered at Lake Constance in southwest Germany, is a non-native species introduced from abroad. Sequences of the internal transcribed spacer of the large subunits of nuclear ribosomal DNA and two noncoding regions of chloroplast DNA (trnL intron, trnL/F spacer) were distant from sequences of all native Cardamine species providing evidence against a hybridization hypothesis. In contrast, DNA sequences of the unknown Cardamine were identical to one accession of Cardamine flexuosa auct. non With. (Asian C. flexuosa) from Japan. The introduction history of Asian C. flexuosa at Lake Constance and the potential threat to the native lake-shore vegetation is discussed. Our study highlights the potential of DNA sequences to identify invasive genotypes and source regions.