民勤绿洲天然胡杨林生长季土壤水盐动态

利用经典统计学与地统计学方法研究民勤绿洲天然胡杨林生长季的土壤水盐动态变化规律。结果表明,民勤县双茨科乡和苏武乡土壤含水量随土层深度增加而增大,夹河乡土壤含水量则随土层深度增加先增大后减小。研究区0～20 cm土壤含水量较低,为8.5～34.0 g.kg-1,平均值为18.2 g.kg-1。土壤含水量属中等变异性,且呈中等程度的空间相关性。各季节土壤含水量从高到低依次为春季、秋季和夏季。土壤全盐量属中等变异性,总体变化趋势为随土层深度增加而减小,夹河、苏武和双茨科乡0～20 cm土壤全盐量平均值分别为15.4、28.0和11.1 g.kg-1。各季节土壤全盐量由高到低依次为春季、夏季和秋季。胡杨胸径与土壤水盐含量间呈负相关。     

Heterologous overexpression of Populus euphratica BAK1;1 gene enhanced resistance to Pst DC3000 in tobacco北大核心CSCD

BRI1-ASSOCIATED RECEPTORKINASE1(BAK1), a leucine-rich repeat (LRR) receptor protein kinase, plays a significant role in brassinosteroid (BR) signaling. Furthermore, it combines with other LRR-RLKs protein to initiate immune response in plants. The objective of this study was to (1) investigate the function of the Populus euphratica BAK1;1 gene in the resistance of transgenic tobacco to Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) and (2) discuss the regulation pathway of PeBAK1;1 involved in the resistance to plant pathogen. We cloned the cDNA sequence of the P. euphratica PeBAK1;1 gene, constructed the pBI121-35S::PeBAK1;1 over-expression vector, and then transformed it into wild-type tobacco by Agrobacterium-mediated transformation to obtain PeBA K 1;1-overexpressing transgenic tobacco plants. The bioinformatic analysis showed that the PeBAK1;1 protein contained all the structural features of the plant SERK family. The phylogenetic tree showed that PeBAK1;1 has the highest sequence homology with PtBAK1. The gene expression profile results indicated that the expression of PeBAK1;1 in the root was higher than that in the leaf and stem. The wild-type tobacco plants showed an obvious susceptibility to Pst DC3000, whereas the transgenic plants exhibited enhanced resistance to Pst DC3000. Compared with that of the wild-type (WT), the real-time PCR and quantitative real-time PCR analysis revealed that the expression of pathogenesis-related genes (including PR1, PR3, PR4, and PR5), BAK1-interacting receptor kinase 1 gene, and BONZAI1 gene was upregulated in 35S::PeBAK1;1 transgenic tobacco plants. In conclusion, the PeBAK1;1 gene plays a positive regulatory role in 35S::PeBAK1;1 transgenic tobacco against Pst DC3000, which can enhance the resistance of plants to pathogen. © 2018 Science Press. All rights reserved.     

A survey of antennal responses by five species of coniferophagous bark beetles (Coleoptera: Scolytidae) to bark volatiles of six species of angiosperm trees

Summary. Using Porapak Q traps, we collected the bark volatiles of six angiosperm trees native to British Columbia: black cottonwood, Populus trichocarpa Torr. & A. Gray (Salicaceae), trembling aspen, P. tremuloides Michx. (Salicaceae), paper birch, Betula papyrifera Marsh. (Betulaceae), bigleaf maple, Acer macrophyllum Pursh (Aceraceae), red alder, Alnus rubra Bong. (Betulaceae), and Sitka alder, A. viridis ssp. sinuata (Regel) á. L?ve & D. L?ve (Betulaceae). Utilising coupled gas chromatographic-electroantennographic detection analysis, the captured volatiles were assayed for antennal responses in five species of coniferophagous bark beetles (Coleoptera: Scolytidae), sympatric with most or all of the angiosperm trees: the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, the mountain pine beetle, D. ponderosae Hopkins, the spruce beetle, D. rufipennis (Kirby), the western balsam bark beetle, Dryocoetes confusus Swaine, and the pine engraver, Ips pini (Say). The identities of 25 antennally-active compounds were determined by coupled gas chromatographic-mass spectroscopic analysis, and co-chromatographic comparisons with authentic chemicals. The compounds identified were: hexanal, (E)-2-hexenal, (Z)-3-hexen-1-ol, 1-hexanol, heptanal, α-pinene, frontalin, benzaldehyde, β-pinene, 2-hydroxycyclohexanone, 3-carene, limonene, β-phellandrene, benzyl alcohol, (E)-ocimene, salicylaldehyde, conophthorin, guaiacol, nonanal, methyl salicylate, 4-allylanisole, decanal, thymol methyl ether, (E)-nerolidol, and dendrolasin. A number of these compounds are known semiochemicals that are active in the behaviour of other organisms, including bark beetles, suggesting a high degree of semiochemical parsimony. Antennally-active compounds ranged from seven in A. viridis to 17 in P. trichocarpa. The fewest number of compounds (9) were detected by I. pini and the largest number (24) were detected by D. pseudotsugae. Six compounds excited the antennae of all five species of bark beetles. The large number of antennally-active compounds detected in common by numerous bark beetles and present in common in numerous nonhost trees supports the hypothesis of olfaction-based recognition and avoidance of nonhost angiosperm trees during the process of host selection by coniferophagous bark beetles. Received 13 December 1999; accepted 14 March 2000     

塔里木河下游胡杨对输水的生态响应

对塔里木河下游不同离河距离成过熟胡杨和输水后更新胡杨胸径、地径、树高、冠幅、枯枝比以及优势胡杨百分比的调查表明:随离河距离增加(地下水埋深增加),胡杨(大树)枯枝比增加,优势胡杨百分比降低;胸径、树高、冠幅随离河距离增加,增减规律不明显。输水后萌蘖更新胡杨的树高、冠幅和地径均随离河距离增加而降低。以上调查指标确定胡杨输水后恢复等级,离河50~300 m胡杨整体恢复"优",离河300~500 m胡杨恢复"良",离河500~1 050m胡杨恢复"中",离河1 050~1 500 m胡杨对输水响应微弱,整体恢复"差"。胡杨具明显的随离河距离增加恢复等级降低的梯度响应特征,生态输水促进了河畔带胡杨的恢复,水是制约塔里木河下游胡杨生长与恢复的关键因子。     

Benefits of Conservation of Plant Genetic Diversity to Arthropod Diversity

Abstract:  We argue that the genetic diversity of a dominant plant is important to the associated dependent community because dependent species such as herbivores are restricted to a subset of genotypes in the host-plant population. For plants that function as habitat, we predicted that greater genetic diversity in the plant population would be associated with greater diversity in the dependent arthropod community. Using naturally hybridizing cottonwoods (  Populus spp.) in western North America as a model system, we tested the general hypothesis that arthropod alpha (within cross-type richness) and beta (among cross-type composition) diversities are correlated with cottonwood cross types from local to regional scales. In common garden experiments and field surveys, leaf-modifying arthropod richness was significantly greater on either the F₁ (1.54 times) or backcross (1.46 times) hybrid cross types than on the pure broadleaf cross type (  P. deltoides Marshall or P. fremontii Watson). Composition was significantly different among three cross types of cottonwoods at all scales. Within a river system, cottonwood hybrid zones had 1.49 times greater richness than the broadleaf zone, and community composition was significantly different between each parental zone and the hybrid zone, demonstrating a hierarchical concentration of diversity. Overall, the habitats with the highest cottonwood cross-type diversity also had the highest arthropod diversity. These data show that the genetics of habitat is an important conservation concept and should be a component of conservation theory.     

Studies in the Biodegradation of 5 PAHs (Phenanthrene,Pyrene, Fluoranthene,Chrysene und Benzo(a)pyrene) in the Presence of Rooted Poplar Cuttings

Cuttings of Populus nigra L. cv. Loenen were cultivated in sand treated with one of the following PAHs: phenanthrene (Phen), fluoranthene (Flt), pyrene (Pyr), chrysene (Chr) and benzo[a]pyrene (BaP). The PAHs were applied at varying levels of concentration to each test series. After 6 weeks the concentration and the distribution of the PAHs in the substrate of the various sets of tests were compared with the concentration in the substrate of the control. Additionally the substrate and the plant roots were tested for evidence of degradation products of PAHs. The results revealed that the levels of concentration of Phen and Pyr detected in the substrate surrounding the roots was in some cases significantly lower than in the corresponding section of substrate in the unplanted set (= control). This phenomenon did not occur for Flt and BaP and in the case of Chr only in those substrates, which had been treated with the highest levels of concentration. As the presence of lesser amounts of Phen and Pyr in the plant pots cannot only be attributed to their accumulation and metabolism in the roots, it is fair to assume that the chemical transformation of these three PAHs took place outside the roots. The set of tests treated with Phen revealed the presence of 2- or 3-hydroxy-Phen (main components), a hydroxy-methoxy-Phen, 9,10-Phenanthrenequinone and one unidentified compound in metabolite form. Altogether eleven metabolites of Pyr were identified in the root extracts, which can be divided into three groups: 1-Hydroxy-Pyr and derivatives, dihydroxy-Pyr and derivatives and ring fission products (4-Hydroxy-Pyr and a derivative of the 4-Phen-carbonic acid). However, the metabolite mass detected for Phen and Pyr represents only an insignificant percentage in comparison with the lesser amounts of PAHs observed in the planted set of tests. This indicates that the three PAHs were reduced to lower molecular compounds, which are methodically impossible to record, and subsequently translocated to other parts of the plant and integrated into the biomass. Although no lesser amount for Flt and BaP was found in the plant pots, 1-Hydroxy-Flt, an unidentified compound of Flt and 1-Methoxy-BaP were detected. These are presumably end products which were enhanced in the roots. It was not possible to identify any transformation products of Chr. It can be assumed that the majority of metabolites were not synthesised in the roots but are a result of microbial degradation in the rhizosphere. The test plants improved the conditions for the biotransformation of Phen and Pyr significantly and accumulated Flt, Pyr, Chr and BaP in their roots. It can therefore be concluded that the use of plants in the bioremediation of contaminated soils is a promising option.     

塔克拉玛干绿洲外围胡杨林的水分特征研究

塔克拉玛干沙漠南缘地区年均降水量不足50mm,胡杨在这一地区绿洲外围自然植被中占有重要地位.对塔克拉玛干沙漠绿洲外围胡杨林水分特征的研究表明,在生境地下水含量较稳定的条件下,胡杨林受到的水分胁迫程度不大,干旱胁迫未对胡杨林的持续存在构成主要威胁.胡杨的水分生理特点显示植物更加依靠稳定的水分供应来应对极端干旱的环境条件,并且在蒸腾作用中形成了细胞水平上的生理适应策略.因此,保持地下水的稳定是维持绿洲前沿天然胡杨林持续存在的关键因素.     

几种可利用多氯联苯和多溴联苯醚植物内生菌的分离及初步鉴定

采用PDA、NA以及高氏一号培养基,分别从毛白杨、绦柳、荻以及二穗短柄草植株内分离、纯化出37株内生菌,其中34株为细菌,3株为放线菌.以分离纯化得到菌株各自对应的营养培养基并添加不同浓度的污染物对获得的37株内生菌进行污染物的耐受筛选,发现24株分别对20 mg·L-1的aroclor1254和BDE209具有一定的耐受性.利用无机盐培养基并添加污染物作为微生物唯一碳源筛选,发现菌株CPY-4和菌株SGL-1可以在只提供4-BDE的无机盐培养基中存活,菌株CPY-4,SGL-1、菌株4、菌株13可以在提供BDE209和aroclor1254的无机盐培养基中存活.形态学观察和16Sr DNA序列同源性分析,初步确定菌株SGL-1为克雷伯氏菌属,菌株CPY-4为地衣芽胞杆菌,菌株4和菌株13为肠杆菌属.     

干旱区荒漠植被的特点及恢复问题的研究--以塔里木河流域胡杨林生态系统为例

干旱区除存在唯一的真正森林-胡杨(Populuseuphratica)林外,植被普遍极其稀疏,以降水稀少,蒸发显著为特点的干旱区,荒漠植被的存在对于生态环境的保护和良性发展起到极大的作用,干旱区的荒漠植被表现出特有的生理特征,本文研究塔里木河流域胡杨林的特征及对生态环境的适应规律,进一步提出了扩展荒漠植被的可能性及其措施。     

Biodegradation of anthracene in the roots and growth substrate of poplar cuttings

Following their exposure to anthracene, the roots of Populus nigra L. Loenen showed traces of 9 substances classed as products of biodegradation. The main substances detected were phthalic acid and 9,10-anthraquinone, followed by hydroxyanthracene and methoxyanthracene and five other compounds which could not be identified. Due to the relatively low concentration of degradation products found in the roots, further degradation to lower molecular compounds are discussed. The presence of 9,10-anthraquinone as the main product of the degradation of anthracene was also evident in the control tests with unplanted sandy substrate, although the content was higher in the planted series of tests. As a non-sterile approach was chosen, it may be assumed that a microbial degradation for 9,10-anthraquinone took place in the control series. However, it is difficult to differentiate clearly between a microbial degradation of anthracene in the substrate and metabolization in the roots due in part to the absence of specific degradation products in the various reaction areas.