内生真菌在禾草体内的分布特征

以醉马草(Achnatherum inebrians)、中华羊茅(Festuca sinensis)、野大麦(Hordeum brevisubulatum)及披碱草(Elymus dahuricus)为研究材料,通过光学显微镜和透射电子显微镜对植株茎节间、叶鞘、叶片及种子进行观察,发现Epichloё内生真菌普遍存在于茎节间、叶鞘、叶片及种子中。菌丝体在4种禾草体内分布特点较为相似,茎节间菌丝体分布密集,叶鞘次之,叶片中则分布较为稀疏,均沿细胞伸长方向纵向生长,呈直线或弯曲状,细长无分支;对种子的观察发现,除在醉马草糊粉层内很难观察到菌丝体外,Epichloё内生真菌普遍存在于中华羊茅、野大麦及披碱草的糊粉层中,4种禾草的种皮及胚中均明显的观察到了菌丝体的存在。     

木本克隆植物中国沙棘种群数量与结构对土壤水分的响应

木本克隆植物中国沙棘能够通过克隆生长调节来适应土壤水分有效性或土壤水分异质性,这种调节最终影响其种群数量和结构特征。为了验证这一假设,根据野外调查数据分析了中国沙棘种群数量和结构等对土壤水分有效性的可塑性响应。结果表明,随着土壤水分有效性的提高,中国沙棘克隆种群生物量及个体生长量增大,种群发育进程和个体大小分化加速,而克隆子株密度以及种群增长率呈现先增加后减小的趋势;增长型年龄结构的种群可形成合理的等级结构,其不同高度级的个体数量分布符合直线模型。据此,木本植物克隆可塑性变化最终必然导致种群数和结构改变的假设得以验证。     

Impact of including information from bulls and their daughters in the training population of multiple‐step genomic evaluations in dairy cattle: A simulation study

The objective of this study was to investigate the impact of accounting for parent average (PA) and genotyped daughters’ average (GDA) on the estimation of deregressed estimated breeding values (dEBVs) used as pseudo‐phenotypes in multiple‐step genomic evaluations. Genomic estimated breeding values (GEBVs) were predicted, in eight different simulated scenarios, using dEBVs calculated based on four methods. These methods included PA and GDA in the dEBV (VR) or only GDA (VRpa) and excluded both PA and GDA from the dEBV with either all information or only information from PA and GDA (JA and NEW, respectively). In general, VR and NEW showed the lowest and highest GEBV reliabilities across scenarios, respectively. Among all deregression methods, VRpa and NEW provided the most consistent bias estimates across the majority of scenarios, and they significantly yielded the least biased GEBVs. Our results indicate that removing PA and GDA information from dEBVs used in multiple‐step genomic evaluations can increase the reliability of GEBVs, when both bulls and their daughters are included in the training population.     

A new Leptographium species from the roots of declining Pinus sylvestris in Switzerland

Scots pine (Pinus sylvestris) trees have been declining in the Rhône valley, Switzerland, for almost three decades. In an assessment of the role of fungi in this syndrome, the dominant fungus isolated from stained roots was a Leptographium species, morphologically similar to the asexual state of Grosmannia serpens. We examined isolates of this fungus based on DNA sequences of four protein‐coding genes including actin, β‐tubulin, calmodulin and translation elongation factor‐1 alpha. The results showed that they were of a distinct, undescribed taxon related to species in the Grosmannia serpens and G. wageneri complexes. The fungus, described here as Leptographium rhodanense sp. nov., resembles other species in the two species complexes morphologically, and most probably ecologically, as is suggested by the fact that it was isolated from stained pine roots.     

铬稳定同位素在丛枝菌根蒲公英中的分馏及根外菌丝对铬的吸收

As common soil fungi that form symbioses with most terrestrial plants,arbuscular mycorrhizal(AM) fungi play an important role in plant adaptation to chromium(Cr) contamination.However,little information is available on the underlying mechanisms of AM symbiosis on plant Cr resistance.In this study,dandelion(Taraxacum platypecidum Diels.) was grown with and without inoculation of the AM fungus Rhizophagus irregularis and Cr uptake by extraradical mycelium(ERM) was investigated by a compartmented cultivation system using a Cr stable isotope tracer.The results indicated that AM symbiosis increased plant dry weights and P concentrations but decreased shoot Cr concentrations.Using the Cr stable isotope tracer technology,the work provided possible evidences of Cr uptake and transport by ERM,and confirmed the enhancement of root Cr stabilization by AM symbiosis.This study also indicated an enrichment of lighter Cr isotopes in shoots during Cr translocation from roots to shoots in mycorrhizal plants.     

日本血吸虫子胞蚴群体侵占钉螺肝脏的动态的研究

本文首次报告应用计算机扫描及测量面积软件观察和定量分析感染日本血吸虫的钉螺组织学切片，从而描述子胞蚴群体侵犯钉螺肝脏的动态。自感染后４０天至１８０天内，子胞蚴群体呈现增长－稳定－再增长－再稳定的过程。血吸虫与钉螺的寄生关系体现了两者既斗争又相适应的动态平衡。单个毛蚴感染钉螺，其寄生侵占指数即寄生虫占阳性肝脏总面积的百分比阈值（Ｐ／ＰＤＧＧＣＴ％）可达６９．６％。     

平菇菌丝耐碱性研究初报

本试验对平菇菌丝在同一培养基pH6～13范围内的生长速度、生长势和形态结构进行了观测,并对棉子皮生料与发酵料在其范围内抑制杂菌污染情况进行了比较。试验结果表明平菇菌丝在pH6～13范围内均可生长,但pH10以上生长势显著减弱。因此可为驯化耐碱性菌种和提高栽培成功率提供依据。     

The ash wilt disease: A preliminary investigation of wood anatomy

A macroscopical, microscopical and SEM examination of wood samples, taken from diseased ash trees, was undertaken to probe into the cause of an ash wilt disease considered to be identical with dieback. The symptoms, particularly the obstruction of the vessels by tyloses and the occurrence of fungal hyphae in one specimen, bear a strong resemblance to those found in Dutch elm disease.Samenvatting Houtmonsters van zieke essen werden macroscopisch, microscopisch en met de SEM onderzocht om de oorzaak van de esseverwelkingsziekte op te sporen. Deze ziekte, ook wel aangeduid met essensterven, vertoont grote overeenkomsten met de in de Verenigde Staten van Amerika en in Groot-Brittanië al langer bekende ash dieback. De gevonden verschijnselen, in het bijzonder de verstopping van vaten door thyllen en het vóórkomen van schimmeldraden in een van de monsters, vertonen veel overeenkomsten met karakteristieke symptomen van de iepeziekte en van de eikeverwelking.     

Underground communication of root hormones by common mycorrhizal network between trifoliate orange and white clover

Common mycorrhizal network (CMN) links up several coexisting plant individuals via underground root communication for resource sharing, while it is not known whether phytohormones participate in such communication. A two-chambered rootbox separated through 37-μm mesh was used to establish the CMN by Diversispora spurca between trifoliate orange (TO) and white clover (WC). After 20 weeks of inoculation, the CMN was established, as evident from high mycorrhizal buildup under supplier (mycorrhizal inoculation) TO–target (non-mycorrhizal inoculation) WC association. This CMN was eventually responsible for the significant increase in plant biomass of these associated plants. CMN decreased root abscisic acid (ABA) level in supplier and target plants, but increased root indole-3-acetic acid (IAA) level in supplier plant alone. CMN mediated significantly higher gibberellins (GAs) and zeatin riboside (ZR) concentration in roots of target plant, leaving supplier plant unaffected. Root ZR was bidirectionally transferred through the CMN. A higher root methyl jasmonate (MeJA) concentration was observed in supplier WC–target TO or supplier TO–supplier WC association, indicating an unidirectional communication from WC to TO. It suggested that except IAA, GAs, brassinosteroid (BR), and ABA, root MeJA and ZR were apparently involved in the underground communication by CMN.     

三唑类杀菌剂对苹果轮纹病菌超微结构的影响

为了研究三唑类杀菌剂对苹果轮纹病菌形态和结构的影响,选择在生产上常用的防治苹果轮纹病的三唑类杀菌剂:戊唑醇和苯醚甲环唑,对苹果轮纹病菌进行处理。用光学显微镜和扫描电镜技术研究新型三唑类杀菌剂对苹果轮纹病菌发育的组织学和超微形态结构的影响。结果表明:光学显微镜和扫描电镜观察发现三唑类杀菌剂处理能导致苹果轮纹病菌发生一系列变化:菌丝的生长明显受到抑制,不再匍匐生长,而是向上生长。菌丝干瘪、畸形,分枝增多,分枝有长有短,很不规则,且不均匀膨大。一些菌丝出现不同程度的龟裂现象。这些变化会导致苹果轮纹病菌菌丝的生长严重受阻,最终菌丝细胞解体死亡。