Novel polymorphic nuclear microsatellites in Cupressus sempervirens L.

We report the characterization and optimization of nine polymorphic nuclear microsatellites from Cupressus sempervirens L. using an enriched library method. A total of 24 individuals from four different populations were used to estimate genetic diversity parameters. High level of allelic diversity was found with a number of alleles ranging from two to 13. These markers will prove very useful in screening diversity at different geographical scales and in monitoring gene flow in cypress orchards.     

四个不同居群岷江柏叶精油组分比较研究

使用GC-MS仪对大渡河和岷江流域的四个不同居群的岷江柏叶精油进行了化学组分研究.四个居群精油样品化学组成基本相同.精油组分的多变量分析得到汶川县的人工林与其它居群的相似性最小.各组分含量和居群间相关性分析结果显著,此方法可以应用于在岷江柏居群间关系的研究.     

Cupressus arizonica pollen wall zonation and in vitro hydration

The structure of Cupressus arizonica pollen at different degrees of hydration was examined by using cytochemical staining and light (LM) and scanning electron (SEM) microscopy. Most pollen grains are inaperturate and a minority are provided with an operculate pore enveloped by a concave annulus. Intine consists of: 1) a thin polysaccharidic outer layer, 2) a large polysaccharidic middle layer that is spongy and bordered by a mesh of large and branched fibrils, and 3) an inner cellulosic thick layer with callose concentrated on the inner side, which forms a shell around the protoplast. The protoplast is egg-shaped with PAS positive cytoplasm and prominent nucleus. Exine splits during hydration and is cast off according to three major steps: 1) the split opens like a mouth and the underlying intine is expelled by swelling like a balloon, 2) the protoplast enveloped by the inner intine is sucked in the outgrowing side, and 3) the backside of the intine gets rid of the exine shell. In water containing salts, exine is rapidly released and the middle intine may expand up to break the outer layer, with disgregation of the spongy material and release of the intine shell including the protoplast. In water lacking salts, the sporoderm hydration and breaking are negatively influenced by the population effect. Pollen when air dried after the exine release become completely flat owing to disappearance of the middle intine layer which may be restored by dipping pollen in water. The results are discussed in relation to the functional potentialities of the sporoderm.     

Sphaeropsidins D and E, two other pimarane diterpenes, produced in vitro by the plant pathogenic fungus Sphaeropsis sapinea f. sp. cupressi

Two pimarane diterpenes structurally related to sphaeropsidins were isolated from the liquid culture of Sphaeropsis sapinea f. sp. cupressi, a plant pathogenic fungus causing a form of canker disease of Italian cypress (Cupressus sempervirens L.). The two metabolites, characterised by spectroscopic methods, were named sphaeropsidins D (0.40 mg l(-1)) and E (0.16 mg l(-1)). The same fungus produced sphaeropsidins A, B and C, sphaeropsidone and episphaeropsidone, which proved to be phytotoxic to cypress, and chlorosphaeropsidone and epichlorosphaeropsidone showing no phytotoxicity. Sphaeropsidin D assayed at 0.1 mg ml(-1) on severed cypress twigs caused leaf browning and necrosis on Cupressus macrocarpa, but no symptoms were observed on C. sempervirens and C. arizonica. Symptoms appeared in a period of time (6 days after toxin-treatment) shorter than that for sphaeropsidin A. Sphaeropsidin E assayed at 0.2 mg ml(-1) did not produce any symptom on the same cypress species tested with sphaeropsidin D.     

Conifer tree plantations for land rehabilitation: an ecological‐functional evaluation

Plantations of exotic fast‐growing tree species have been widely used for maintaining or restoring ecosystem functions. Despite this, in tropical countries with high biodiversity, these plantations have been the subject of heated debate. We evaluated the long‐term effect of coniferous tree plantations (Cupressus lusitanica, Pinus patula, Pinus elliottii) on the ecological rehabilitation of the Andean highlands in Colombia. To determine degree of rehabilitation, we assessed whether there were differences in the structure or density of native understory vegetation or soil ecological properties between plots established within tree plantations and plots established within other vegetation cover types (secondary forests, ferns, pastures, and abandoned mining areas). Measured variables were combined to create an index of ecological rehabilitation (ERI). We found significant differences in the ERI values among vegetation cover types: secondary forest (11.78) > conifer plantations (P. elliottii: 6.23, P. patula: 5.33, C. lusitanica: 5.24) > ferns (4.16) > pasture (2.50) > abandoned mining areas (0.43). The results obtained showed that, from the structure of native understory vegetation and soil ecological properties, conifer plantations favored the rehabilitation process. However, among them, it was highlighted that the P. elliotii plantations showed significant differences in the density of native understory species, their values being 1.7 and 2.1 times higher than those corresponding to P. patula and C. lusitanica, respectively. Thus, unlike these plantations that could represent an ecological barrier over time, P. elliottii plantations have enabled the advancement of natural succession, showing a high diversity of native species.     

Karyotype Analyses in Cupressus gigantea

The chromsomal number and karyotype of Cupressus gigantea Cheng et L. K. Fu is reported for the first time. The number of somatic chromosome in root tip cell of the species was found to be 2n=22. According to the terminology defined by Levan et al, the karyotype is 2n=22= 4m(SC)+16m+2sm, belonging to Stebbin's "A" type of karyotypic symmetry which is generally considered as primitive one. By comparing karyotypes of Cupressus gigantean with other four species of Cupressaceae, the author discovered that Cupressus gigantea is a primitive species in Cupressaceae.     

The Peroxidase Isoenzymes of Cupressus Linn.

By means of disc polyacrylamide gel electrophoresis, peroxidase isoenzymes of 9 species of Cupressus Linn, were analysed. The interspecific zymogramatic differences are obvious. Each species possesses its specific zymogram, distinguishable form the others. According to the zymogramatic similarity among these species calculated with the method of polar ordination, they may be grouped into 5 groups, which may be grouped in turn into two categories. C. gigantea Cheng et L. K. Fu, C. torulosa D. Don, C. duclouxiana Hichel, C. chengiana S. Y. Hu, and C. jiangeensis N. Chao. fall into one category. The second category contains C. sempervirens, C. arizonica Greene, C. lusitanica and C. funebris Endl. The experimental result about peroxidase comfirms the interspecific relationships of Cupressus suggested by the previous works. A positive relation is found between the peroxidases isoenzyme zymogramatic similar degree and the geographical vicarism of the related species, which has been used for analysing the regularity of phytogeographical vicarism. The mean zymogram distance of Cupressus Linn. among species is 0.75, from which it is inferred that the divergency took place the Jurassic. The advantage of polar ordination method in the study of iso-enzyme zymogram is discussed.     

Application of petG-tm P sequence to systematic study of Chinese Cupressus species

Chinese Cupressus L.includes five species.The molecular phylogenetic relationships of the Cupressus species and Chamaecyparis L.were determined by comparing 417-479 bp of chloroplast petG-trnP intergenic spacer sequence.In PAUP* analysis,Platycladus orientalis was used as the functional out group.By using the maximum likelihood method 1077 trees were examined and the result showed that one tree had a best score of -Ln=2 232.47.The phylogenetic tree clearly showed that Chamaecyparis nootkatensis was diverged from other Chamaecyparis species.Based on the results,together with evidences from other aspects,we consider that Cupressus funebris and Chamaecyparis nootkatensis should be placed in the genus Cupressus.The use of cpDNA intergenic spacer petG-trnP in Cupressus was also discussed.     

林分密度对云顶山柏木人工林林下物种多样性和土壤理化性质的影响

以成都云顶山柏木(Cupressus funebris)人工林为对象,采用典型样地法研究不同林分密度(1100、950、800、650、500株/hm~2)对林下物种多样性和土壤理化性质及林下物种多样性与土壤理化性质相关性的影响。结果表明:共发现维管植物168种,隶属75科140属。随林分密度的降低,灌木层多样性指数呈先增后减的单峰变化,在密度650株/hm~2出现峰值,草本层多样性指数呈先增后减再增再减的双峰变化,在密度950株/hm~2和650株/hm~2出现峰值。同时发现光照为影响林下植物多样性的重要因素。林分密度对土壤全氮、全钾、速效钾、有机质影响显著,有机质、全氮、全钾、速效钾随林分密度降低呈先增后减的变化趋势。钾、氮、有机质与林下植被物种多样性关系最密切。结论:林分密度650株/hm~2为云顶山柏木人工林最适密度,该密度能较好的提高林下物种多样性和土壤肥力。