环境友好型杨梅园高效栽培类型与综合效益评价

杨梅园实行精耕细作,会造成生物多样性下降、水土流失加重、杨梅病虫害加剧等不良后果。为克服或缓解这些难题,对杨梅林开展了不同类型的混交栽培模式和抚育方式的研究。结果表明:进行机械割草的杨梅园生物多样性较优,其维管束植物总计达78种,而以药剂除草的,总计仅11种,差异极显著;"杨梅针、阔、竹混交林+自然生草+机械割草"、"杨梅纯林+自然生草+机械割草"和"杨梅纯林+清耕(除草剂除草)"等三种栽培与抚育类型的主要病害有杨梅癌肿病等2种,主要虫害有白蚁类、袋蛾类、栗黄枯叶蛾等7种(类),均以针、阔、竹混交栽培模式受害最轻。对"杨梅+蓝莓"、"杨梅+蕨类(种植)"和杨梅自然生草等3种栽培模式以及机械割草、人工割草和药剂除草等3种抚育方式的"三大效益"进行了综合评价。     

Variation in plant performance in a grassland: Species‐specific and neighbouring root mass effects

Question: What characteristics of local biotic neighbourhood is the best proxy of competitive effects experienced by plants in a herbaceous community: (1) total above‐ground biomass, (2) root mass or (3) relative above‐ground abundance of selected species? Location: Grassland at ca. 1100 m a.s.l. in the Krkono?e Mts., northern Czech Republic. Methods: We implanted two phytometer species, Antho‐xanthum alpinum and Festuca rubra, into a mountain grassland, and examined their response to local variation in (1) total above‐ground biomass, (2) root mass at three soil depths, and (3) relative abundance of individual species above‐ground. Results : Performance of both phytometer species was determined much more consistently by the mass of neighbouring roots and by species composition of neighbours than by the total above‐ground biomass. The two phytometer species showed different responses to these parameters. The most important relationships were (1) negative relationship between performance of Anthoxanthum and mass of neighbouring roots at 0–3 cm, (2) positive relationship between performance of Festuca and mass of neighbouring roots at 3–6 cm, and (3) negative relationship between performance of Festuca and relative abundance of Festuca in the neighbourhood. Conclusions: Neighbouring root mass and above‐ground species composition are better determinants of biotic interactions than total above‐ground biomass of neighbours in the studied mountain grassland. However, the relationships found are not necessarily due to variation in competitive intensity but can be due to other hidden factors as well, e.g. local availability of resources.     

A microsatellite linkage map of the blacklip abalone, Haliotis rubra

There is considerable scope for genetic improvement of cultured blacklip abalone Haliotis rubra in Australia using molecular marker-assisted, selective-breeding practices. Such improvement is dependent on the availability of primary genetic resources, such as a genetic linkage map. This study presents a first-generation linkage map of H. rubra, containing 122 microsatellite markers typed in a single full-sib family. These loci mapped to 17 and 20 linkage groups for the male and female respectively, and when aligned, the consensus map represented 18 linkage groups. The male linkage map contained 102 markers (one unlinked) covering 621 cM with an average intermarker spacing of 7.3 cM, and the female map contained 98 markers (eight unlinked) covering 766 cM with an average intermarker spacing of 9.8 cM. Analysis of markers informative in both parents showed a significantly higher recombination rate in the female parent, with an average male-to-female recombination ratio of 1:1.45 between linked pairs of markers. This linkage map represents a significant advancement in the genetic resource available for H. rubra and provides a framework for future quantitative trait loci mapping and eventual implementation of marker-assisted selection.     

爵床科蛇根叶属一新组合——越南蛇根叶

Staurogyne diandra E. Hossain具能育雄蕊2枚,与叉柱花属（Staurogyne Wall.）能育雄蕊4枚的特征不符,而应属于蛇根叶属（Ophiorrhiziphyllon Kurz）。因此提出新组合——越南蛇根叶（Ophiorrhiziphyllon diandra (E. Hossain) H. J. Xin, D. V. Hai & Y. F. Deng）。     

巴西蕉高效间接器官发生再生体系研究

香蕉间接器官发生再生体系是一种较好的突变育种和基因转化受体再生系统。本研究以巴西蕉低代试管苗茎段薄层切片、中代试管苗茎段薄层切片、吸芽薄层切片、雄花薄层切片为外植体,对巴西蕉间接器官发生再生体系进行了系统研究。研究结果表明,以MS为基本培养基,巴西蕉低代试管苗茎段薄层切片在0.5～1.0mg/L2,4-D+4～6mg/L6-BA激素条件下;雄花薄层切片在0.5～1.0mg/L2,4-D+0.2～0.5mg/LZT激素条件下能通过花菜体间接器官发生途径实现高效再生;同时,花菜体薄层切片在1.0mg/L2,4-D+5mg/L6-BA激素条件下,再次通过花菜体途径实现循环高效再生。本研究为建立香蕉高效间接器官发生再生体系和相关育种技术奠定了基础。     

Motile behaviour of the bloom-forming ciliate Mesodinium rubrum

Mesodinium rubrum (Lohman) (=Myrionecta rubra Jankowsky) swims backwards in jumps of short duration interspersed by longer periods of rest. Cells attain a velocity of up to 1.2 cm s^-1 during jumps and this is probably a speed record for ciliates. The ciliate carries long cirri that serve as mechanoreceptors and for orientating the cell at the initiation of jumps, while the ciliary rows on the posterior part of the cell are responsible for propulsion. The cirri are sensitive to shear so that they can orientate themselves against the current in a siphon flow (such as generated by filter-feeding copepods). Mesodinium cells do not reorientate their body axis during sinking, but they reorientate their direction during the initiation of jumps so that they always tend to move upwards. Because the cells sink between jumps they can regulate their vertical position by modulation of the frequency of jumps. The cells' tendency to drift vertically up or down is light dependent. The jumps are so rapid that these phototrophic organisms can enhance their uptake of dissolved mineral nutrients beyond the limitation of molecular diffusion.     

Soluble and wall-bound phenolics and phenolic polymers in Musa acuminata roots exposed to elicitors from Fusarium oxysporum f.sp. cubense

The accumulation of soluble and wall-bound phenolics and phenolic polymers in Musa acuminata roots exposed to cell wall-derived elicitor from the pathogen, Fusarium oxysporum, f.sp. cubense, race four, was investigated. The root tissue from the banana cultivar "Goldfinger" was found to respond strongly and rapidly towards the elicitor through the increased synthesis of phenolic compounds. Following elicitation, the conjugated and non-conjugated phenolic metabolites in the induced root tissue were extracted and quantified. Induced phenolic synthesis was rapid and reached near maximum values after 16 h. High-performance liquid chromatography revealed both compositional and quantitative differences between induced phenolics (p-coumaric, ferulic, and sinapic acids) and those constitutively present (p-coumaric- and ferulic acid). In addition, vanillic acid was found in the ester-bound fraction and protocatechuic acid in the cell-wall bound fraction of elicited tissue. The deposition and accumulation kinetics of polymerized phenolic monomers as lignin and lignin-like polymers was quantified over a time period of 0-36 h and found to reach maximum values after 24 h. Ionization difference UV spectra of lignin indicated compositional differences in the newly synthesized lignin fraction and correlated with increased concentrations of ferulic acid and sinapic acids esters. The results show that the increased flux through the phenylpropanoid pathway resulted in the synthesis of cinnamic acid and benzoic acid derivatives that were esterified and incorporated into the cell wall fraction as part of the anti-microbial defenses activated in the root tissue.     

Isolation of an alpha-methylene-gamma-butyrolactone derivative, a toxin from the plant pathogen Lasiodiplodia theobromae

Lasiodiplodia theobromae is known as a multi-infectious microorganism that causes considerable crop damage, particularly to tropical fruits. When the fruits are infected by L. theobromae, the typical symptom is the appearance of black spots on the surface of the infected fruit. When injected in to the peel of banana, the culture filtrate of L. theobromae induced formation of black spots. The structure of the isolated compound responsible for this effect was determined to be (3S,4R)-3-carboxy-2-methylene-heptan-4-olide on the basis of analysis of MS, IR, and 1H and 13C NMR spectroscopic data, including HMQC, HMBC, and 1H-1H COSY experiments. The active compound was not only isolated from the culture filtrate derived from potato dextrose medium, but also from the extract of infected peels of bananas.