Comparaison de deux methodes ?estimation de ľinfection dejeunespeupliersparleMarssoninabrunnea(Ell. et Ev.) P. Magn.

Comparison of two methods for evaluating infection of young poplar leaves by Marssonina brunnea . Two methods for evaluating foliar infection by Marssonina brunnea have been compared on 783 twigs. They appear to be correlated. Distribution in infection classes can be coded and this allows a prediction of the number of spots per square centimeter. Application of the code to two other experiments is discussed.     

Natural Resistance of Two Plantation Woods Populus × canadensis cv. and Cunninghamia lanceolata to Decay Fungi and Termites

Natural durability of two plantation woods, Chinese fir and I-214 poplar, was investigated thoroughly by three testing methods, namely an accelerated laboratory decay test, a fungus cellar test and a field test. After the decay test using Postia placenta and Trametes versicolor, Chinese fir and the I-214 poplar showed 34% and 69% of mass loss, respectively, indicating they should be classified as slightly durable and non-durable wood. This conclusion was confirmed by the fungus cellar test and the field test. Like the performance in the decay test, I-214 poplar showed no resistance to termites either in the laboratory or in the field, whereas Chinese fir would be classified as moderately resistant. [Supported by Sino-Japanese Technical Cooperation Project Titled “Studies on Chinese Plantation Wood” (JICA PROJECT/033-1418-E-O)]     

A new leaf disease on Populus euphratica in south‐western Iran

During the winter of 2012, a leaf spot disease was observed on Euphrates poplar (Populus euphratica) in the forest areas of Khuzestan province, south‐western Iran, causing significant damage in the Karun's riverside forests. Symptoms consisted of necrotic dark brown, circular to oval, 5‐ to 10‐mm spots on both surfaces of the leaves. A fungus having distinct dictyospores similar to those produced by Alternaria spp. was observed. The morphological characteristics, as well as the phylogenetic analysis of the internal transcribed spacer (ITS1‐5,8S‐ITS2) region, confirmed the identity of the strains belonging to the species Alternaria alternata. Pathogenicity tests were conducted on the alive leaves of P. euphratica on the young branches, as well as on the detached leaves in Petri dishes, through inoculation with spore suspension. Target spot symptoms similar to those observed in naturally infected leaves were developed on the inoculated leaves seven to 10 days after inoculation in both the inoculation procedures. A. alternata was consistently re‐isolated from the spots. Interestingly, similar symptoms were observed 7 days after detached leaf treatment with droplets of 15‐day‐old fungal culture filtrate, suggesting the production of pathotoxic compounds by the fungus. To our knowledge, this is the first report of A. alternata causing leaf spot on Euphrates poplar in Iran.     

ITS-based comparison of endophytic mycota in twigs of native <Emphasis Type="Italic">Populus nigra</Emphasis> and cultivated <Emphasis Type="Italic">P. x euramericana</Emphasis> (cv. I-214) stands in Northern Spain

Context  

The European black poplar (Populus nigra) is considered one of the most seriously endangered indigenous tree species. However, the total area covered by monoclonal plantations of hybrid poplar is growing, because of the high profitability of these trees.     

A medium to enhance identification of Septoria musiva from poplar cankers

A series of experiments was conducted to determine the relative tolerance in vitro of an isolate of Septoria musiva (a fungus that causes a severely damaging stem canker disease of poplars) for selected chemicals. Inhibition of diameter growth of this fungus on a V‐8 vegetable juice‐based medium with captan, chlorothalonil, iprodione, mancozeb and streptomycin sulphate at concentrations, respectively, of 50, 1, 10, 10, and 100 mg l^–1 was relatively low compared to inhibition of eight other fungi cultured from cankers on poplars. In addition, the presence of captan stimulated profuse sporulation of the fungus. These properties assisted in the identification of S. musiva from cankers resulting from artificial inoculation of poplar branches in the field.     

Pathological changes and defense responses in poplar tissues caused by Ceratocystis fimbriata1

Structural changes in cells affected by the fungus C. fimbriata, involving the cell wall, cytoplasm and plastids were investigated. In the necrotic tissues a high number of fat drops was observed. The progress of hyphae of the fungus in poplar clones differing in their resistance depended on the presence of a cork layer, tannins and starch content.     

Variability in pathogenicity of Melampsora allii-populina expressed on poplar cultivars

A collection of 42 isolates of Melampsora allii-populina was established. Fourteen isolates were collected from various poplar cultivars over several French localities and 28 isolates from the alternate hosts (Allium spp., Arum spp. and Muscari comosum) obtained from nature or after inoculation. These isolates were inoculated in the laboratory on a large range of poplar cultivars belonging to several species. No isolate proved pathogenic on all cultivars and many qualitative interactions were observed between isolates and cultivars. This is the first evidence for the existence of physiological races within this fungus. No link was found between pathogenicity on poplar and on the alternate hosts. Among the inoculated cultivars, at least three were susceptible to all isolates (Beaupre, Candicans and Robusta), whereas the following showed qualitative reactions to the inoculated isolates: Altichiero, Carpaccio, Cima, Fritzi Pauley, I 154, Isieres, Luisa Avanzo, NL 2842, Rap and Spijk. Race-specific resistance to M. allii-populina (i.e. resistance to some races of the pathogen, but not to the others) has been found in two North American species (Populus deltoides and Populus trichocarpa) which have never coevolved with this fungus. The results are discussed in comparison with Melampsora larici-populina.     

A recommended rate for application of <Emphasis Type="Italic">Chaetomium globosum</Emphasis> ND35 fungus fertilizer on poplar plantations in China

Previous studies showed that Chaetomium globosum ND35 fungus fertilizer can improve the microbial community structure and enzyme activities of replanted soil. However, it remains unclear whether can improve the physiological and ecological characteristics of plants under successive rotation. In this study, we investigated the photosynthetic, physiological, and biochemical indexes including photosynthetic parameters, chlorophyll fluorescence, and chlorophyll content of 1-year-old poplar seedlings under seven different doses (range from 0 to 1.67 g kg^?1) of C. globosum ND35 fungus fertilizer to study the effects of fungus fertilizer on photosynthesis of Poplar. Our results showed that: (1) With increasing application of fungus fertilizer in replanted soil, chlorophyll content of poplar leaves (Chl) increased, while physiological indexes such as electron transport rate (ETR), net photosynthetic rate (P _n), quantum efficiency (Φ), nitrate reductase (NR) activity and root vigor initially increased and then declined. Meanwhile, heat dissipation that depended on the xanthophyll cycle declined and non-photochemical quenching (NPQ) initially increased and then decreased. When the dose of C. globosum ND35 fungus fertilizer was 0.67 g kg^?1 (T3) and 1.00 g kg^?1 (T4), excess light energy of photosynthetic apparatus was reduced, and photosynthetic apparatus distributed more light energy to the direction of photochemical reactions, which improved the efficiency of energy use. Plant height and biomass of leaves, stems, and roots were maximum at T3. We conclude that applying appropriate amounts of C. globosum ND35 fungus fertilizer can improve root physiological activity and capacity for use of light by poplar leaves. This can improve the operating states of the photosynthetic apparatus and lead to increased photosynthetic efficiency of poplar leaves and accumulation of dry matter. This suggests a strategy to alleviate the successive rotation obstacle of soil nutrient depletion.     

Test ?inhibition de ľactivité cambiale du Peuplier par Hypoxylon mammatum: mise au point et application

Test of inhibition of cambial activity of poplar by H. mammatum: development and application. A test was developed in vitro in order to estimate the inhibition of hosts’cambium by H. mammatum and applied to a large number of poplar clones. Toxicity of the culture filtrate appears to be selective but not necessarily specific.     

Tiarosporella durmitorensis sp. nov. – a new pathogenic fungus on needles of Abies alba

A fungus causing necrosis and needle cast has been discovered on fir trees (Abies alba) in a hight of 1700 m above sea level in Yugoslavia. The intensity of infection was very high, and the needles of all age classes were infected. The consequence of the infection is the death of the tree. The pathogen is described as a new species Tiarosporella durmitorensis Karad?i?. So far, this fungus has been found only in European silver fir stands in the National Park Durmitor and in the National Park Biogradska Gora (Montenegro).     

Natural Resistance of Two Plantation Woods Populus × canadensis cv. and Cunninghamia lanceolata to Decay Fungi and Termites

Natural durability of two plantation woods, Chinese fir and I-214 poplar, was investigated thoroughly by three testing methods, namely an accelerated laboratory decay test, a fungus cellar test and a field test. Aft er the decay test using Postia placenta and Trametes versicolor, Chinese fir and the I-214 poplar showed 34% and 69% of mass loss, respectively, indicating they should be classified as slightly durable and non-durable wood. This conclusion was confirmed by the fungus cellar test and the field test. Like the performance in the decay test, I-214 poplar showed no resistance to termites either in the laboratory or in the field,whereas Chinese fir would be classified as moderately resistant.     

Sources of Diplodia pinea endophytic infections in Pinus patula and P. radiata seedlings in South Africa

Diplodia pinea, an opportunistic and latent pathogen, can significantly affect Pinus productivity worldwide. Despite being studied in South Africa for almost 100 years, the source of D. pinea inoculum responsible for seedling infection is unknown. The aim of this study was to determine the role of seed in vertical transmission of D. pinea and to investigate sources of inoculum leading to horizontal transmission to pine seedlings. Surface‐disinfected seeds were inoculated with spore and mycelium suspensions of D. pinea to determine its effect on germination. In addition, isolation of the fungus was performed from surface‐disinfected seeds, asymptomatic seedlings collected from nurseries, plantations where pines naturally regenerate and recently established fields, to assess transmission and incidence of endophytic D. pinea infections. Inoculation of seeds with D. pinea spore suspensions affected speed and rate of germination. The fungus was isolated from surface‐disinfected seeds in only a few instances (2–3%) and was not found in healthy seedlings collected from greenhouses and nurseries, suggesting that vertical transmission of the fungus does not occur or is rare. In contrast, D. pinea was isolated from 40% of seedlings obtained from the understory of mature P. patula trees showing that horizontal transmission from mature to young trees sustains the D. pinea inoculum in South African pine plantations.     

白腐菌预处理对杨木硫酸盐法制浆性能的影响

以杨木和白腐菌为研究对象,测定白腐菌预处理前后杨木化学组成与纤维形态的变化,找出合适菌株和最佳的预处理时间,进行硫酸盐法制浆前的预处理,比较制浆后浆料的卡伯值、得率、黏度和纸张的物理性能.结果表明:对木质素降解程度由大到小为香菇菌、云芝菌、杂色木云芝菌、脉射菌、佛罗里达侧耳和糙皮侧耳,香菇菌对综纤维素的降解程度最大,杂色木云芝菌的降解最小;预处理后,杨木纤维平均长度略有降低,纤维的长宽比得到了提高,壁腔比下降;与参照样相比,经脉射菌、杂色木云芝菌和佛罗里达侧耳预处理后制得的浆料,卡伯值降低、得率增加、黏度增加、脱木素选择性提高,纸张的撕裂指数和抗张指数均增加;经过香菇菌预处理后得到的浆料,虽然卡伯值降低、脱木素选择性增加,但是黏度和得率却在下降,纸张的撕裂指数和抗张指数减小.经过这4种白腐菌预处理后,纸张的耐折度和白度均大于对照.     

Compatible and Incompatible Reactions of Melampsora Rust on Willow Leaves

Spore germination, growth and appresssoria formation for Melampsora willow rust were studied for compatible and incompatible hosts to elucidate penetration specificity and prehaustorial events in the infection process. Rust originating from Salix dasyclados was inoculated on a compatible (S. dasyclados) and an incompatible (Salix daphnoides) clone and, for comparison, on the non-host plants tomato, tobacco and poplar. The same experimental procedure was also carried out for rust originating from poplar. Rust development was followed for 5 days at 20 h intervals using a microscope with fluorescent equipment. The study showed that the Melampsora rust can develop on, and penetrate, the leaf regardless of whether the rust was inoculated on compatible or incompatible willow plants. However, the fungus was able to infect and reproduce itself only in compatible interactions. For willow rust in the prehaustorial stage, the study indicated that specific recognition mechanisms were unnecessary to start the infection process.     

Effects of salicylic acid, 1‐aminocyclopropan‐1‐carboxylic acid and methyl jasmonate on the frequencies of endophytic fungi in Quercus serrata leaves

To examine the effects of salicylic acid (SA), the ethylene precursor 1‐aminocyclopropan‐1‐carboxylic acid (ACC) and methyl jasmonate (MJ), which induce defence responses against pathogen in plants, on foliar endophytic fungi, we performed exogenous treatments of Quercus serrata leaves with these chemicals and subsequently isolated endophytic fungi. SA and ACC significantly reduced the isolation frequency of the most dominant fungus, a Xylaria species as identified by sequence analysis of the internal transcribed spacer (ITS) region of the ribosomal DNA. In contrast, the frequency of the second most frequent fungus increased by SA and ACC. A few other fungi were also affected positively or negatively. Shannon diversity indices decreased by all treatments because of the uneven isolation frequencies of the endophytes. Our results imply that host defence responses induced by the chemical treatments reduced the number of infections of some endophytes while the frequency of some other endophytes increased benefiting from the reduction of competitors.     

Biology of Septoria musiva and Marssonina brunnea in hybrid Populus plantations and control of Septoria canker in nurseries

Spore dispersal and symptom development of Septoria musiva and Marssonina brunnea were studied in hybrid poplar plantings in the north central United States. Ascospores or conidia were present within the plantings throughout the growing season. Results of Septoria canker control in nurseries are discussed in relation to the biology of the fungus and use of resistant clones.     

超量表达FBL1对84K杨根系和生长量影响研究

生长素及其信号转导系统对植物的生长发育具有重要的影响。本研究从银腺杨'84K'(Populus alba × P. glandulosa cl. '84K')中分离了生长素受体基因PtrFBL1,利用PMDC32构建了PMDC32-PtrFBL1超量表达载体,并通过遗传转化获得了超量表达植株17个。对温室定植的3个转基因株系和对照植株的根系、生长量和光合指标等性状分析结果显示:转基因株系总根长和总根面积达到显著或极显著差异,而根系干质量、平均不定根系长度、平均不定根直径差异不显著;株高、平均节间长、地径和高径比皆高于对照,且大多数转基因株系达到显著差异;除气孔限制值(Ls)低于对照外,气孔导度(Cd)、水分利用效率(WUE)、光能利用效率(LUE)和叶绿素相对含量皆高于对照,且大多数转基因株系达到显著或极显著差异。以上结果表明,可能是FBL1超表达增加了转基因株系根系面积,提高了水分和养分的吸收利用,进而导致转基因株系光能吸收和转化效率提高,引起转基因株系生长加快。     

A new record of Rhizoctonia butinii associated with Picea glauca ‘Conica’ in Slovenia

In 2013, the death of needles of dwarf Alberta spruce (Picea glauca ‘Conica’) seedlings was observed in an arboretum in Slovenia. Needles on infected P. glauca ‘Conica’ twigs were covered with thick, yellowish brown hyphal cushions. The outgrowing mycelium was white and had completely overgrown some needles and connected them to each other. To definitively identify the fungus affecting P. glauca ‘Conica’, morphological examinations of isolated pure cultures were performed, and the internal transcribed spacer (ITS) region of the rDNA was sequenced. Based on morphological and molecular phylogenetic analyses together with the performed pathogenicity trial, we identified the causal agent of the observed symptoms as Rhizoctonia butinii – a recently described species. This report connects this fungus to a new locality and a new host plant.     

Structure and Function of <Emphasis Type="Italic">Populus deltoides</Emphasis> Agroforestry Systems in Eastern India: 1. <Emphasis Type="Italic">Dry matter dynamics</Emphasis>

Agroforestry systems based on poplar (Populus deltoides) are becoming popular in eastern and northern parts of India. Therefore studies on the structure and function of the systems are important. The investigations included allometric equations for above- and belowground tree components, crop and plantation floor biomass and litter fall estimation at Pusa, Bihar, India. Biomass, floor litter mass, litter fall and net primary productivity (NPP) of plantations increased with an increase in age of trees whereas, crop biomass for any specific crop interplanted with poplar decreased with the age of the plantation. The total plantation biomass increased from 12.08 to 90.59 Mg ha⁻¹ and NPP varied from 5.69 to 27.9 Mg ha⁻¹ year⁻¹. The biomass accumulation ratio ranged from 2.1 to 3.2. Total annual litter fall was in between 1.95 and 10.00 Mg ha⁻¹ year⁻¹, of which 92–94% was contributed by leaf litter. Compartmental models were developed for dry matter distribution in agroforestry systems involving young (3-year-old) and mature (9-year-old) poplar trees interplanted with various crops, the crops being grown in two rotations maize (Zea mays) – wheat (Triticum aestivum) – turmeric (Curcuma domestica) and pigeonpea (Cajanus cajan) – turmeric. This study substantiates the potential of Populus deltoides G₃ under agroforestry combinations.     

Isolierung und Identifikation des Sesquiterpenalkohols (+/−)-Torreyol aus Reinkulturen des Ektomykorrhizapilzes Cortinarius odorifer Britz

Isolation and identification of the sesquiterpene (+/?)-Torreyol from pure cultures of the ectomycorrhizal fungus Cortinarius odorifer Britz . Several strains of the ectomycorrhizal fungus Cortinarius odorifer produce in pure culture crystals of the sesquiterpene (+/?)-Torreyol. The identification has been made on the basis of spectral evidence.