Sources of inoculum of Lophodermium seditiosum on Pinus sylvestris1

A survey of the incidence of Lophodermium seditiosum, L. pinastri and L. conigenum in plantations of Pinus sylvestris in north-east Scotland showed that L. seditiosum predominated on fallen cones and on young needles which tell prematurely in early summer. L. pinastri predominated on old senescent needles which fell in autumn. The incidence of L. conigenum was low on fallen cones and needles and it is not thought that tins species could effectively replace L. seditiosum. It is concluded that the main source of L. seditiosum inoculum for infections in plantations and nearby nurseries is young infected fallen needles on which ascocarps form in late summer and autumn.     

Identification of Lophodermium seditiosum and L. pinastri in Swedish forest nurseries using species‐specific PCR primers from the ribosomal ITS region

Lophodermium seditiosum is a serious needle pathogen on pine, particularly in nurseries, and there is a need to detect the pathogen during its latent phase. The internal transcribed spacer (ITS) regions of the rDNA of L. seditiosum and L. pinastri were amplified with universal primers and sequenced. Sequence comparisons of the two species allowed the design of species‐specific primers for the ITS regions. The primers were between 18 and 24 bp long with a minimum of 3 bp differences between the species. These primer pairs did not give any amplification of DNA from any other of the examined fungal species or from healthy Pinus sylvestris needles. It was also possible to identify either L. seditiosum or L. pinastri in infected needles with and without signs of infection using these primer pairs. The method was found to be very useful for detection of latent infections of L. seditiosum in P. sylvestris needles in nurseries.     

Genetic diversity of Lophodermium piceae in South Finland

Lophodermium piceae, the dominant needle endophyte of Norway spruce (Picea abies), is known to be extremely diverse. This work aimed to test the possible occurrence of cryptic species within the morphological species L. piceae. Genetic variation in 36 South Finnish L. piceae isolates originating from six localities was investigated by comparing DNA sequences of three genetic markers. One of the markers was the internal transcribed sequence (ITS) of the ribosomal DNA and the other two (LP1 and LP2) were based on sequence characterized amplified regions designed for L. piceae. The LP2 marker could be detected only from isolates of L. piceae but not from 20 other ascomycete species tested. This sequence, therefore, is considered as a species‐specific marker for L. piceae. For comparison, ITS sequences of isolates representing two other Lophodermium species, L. pinastri and L. seditiosum, were also investigated. In a neighbor‐joining analysis of ITS sequences all L. piceae isolates fell into one cluster, which was clearly separate from those of L. pinastri and L. seditiosum. Dendrograms of the three markers were incongruent indicating that the L. piceae population examined consisted of a single phylogenetic species. No geographical differentiation was observed. Our results confirm that L. piceae is a genetically highly diverse endophytic species.     

黄山松上的散斑壳

对安徽省岳西县妙道山国家森林公园黄山松上的散斑壳进行了调查研究，共发现６个种，其中岳西散斑壳系一新种；南方散斑壳，扰乱散斑壳为黄山松上的新记录；针叶树散斑壳，库曼散斑壳，松针散斑壳为国内已记载的种。对新种作了汉文和拉丁文描述，记载了已知种的戽性。     

Fungicidal Control of Lophodermium seditiosum on Pinus sylvestris Seedlings in Swedish Forest Nurseries

During the 1990s, there were serious outbreaks of the pathogen Lophodermium seditiosum on pine seedlings in Swedish forest nurseries, even though the seedlings had been treated with the fungicide propiconazole. The present experiment was carried out to evaluate two other fungicides, fluazinam and azoxystrobin, as possible alternatives to propiconazole. In the tests, which were all carried out in the same forest nursery, seedlings were treated with either propiconazole, fluazinam or azoxystrobin, and the proportion of needles with ascocarps of L. seditiosum and the number of ascocarps per needle were recorded over the following 2 yrs. Seedlings treated with azoxystrobin already appeared healthier than control seedlings in September of the first year, and by November all azoxystrobin-treated seedlings had fewer ascocarps per needle compared with control seedlings. In autumn of the second year, there were no ascocarps on seedlings treated with fluazinam or azoxystrobin, whereas seedlings treated with propiconazole had similar numbers of ascocarps to non-treated control seedlings.     

Fungi associated with Cyclaneusma needle cast in Scots pine in the west of Poland

Needles of Pinus sylvestris with and without symptoms of Cyclaneusma needle cast, from the west of Poland, were examined for abundance and diversity of fungi using Illumina sequencing. Fungal communities were dominated by Ascomycota (93.6%–98.6% of OTUs). Basidiomycota and non‐culturable fungi were less frequent. Needles were colonized by 260 taxa. Ascomycota, Basidiomycota and Glomeromycota were represented by 149, 39 and 1 taxa. Abundance of fungi was least in 1.5‐year‐old needles attached to twigs and greatest in fallen 2‐year‐old needles. Fungal communities had least diversity in 1.5‐year‐old needles and most diversity in 0.5‐year‐old needles of current growth. It was found that (a) the most common fungi were the needle pathogens Cyclaneusma minus, Lophodermium spp. and Sydowia polyspora; (b) less common potential pathogens were Cenangium ferruginosum, Coniothyrium complex, Desmazierella acicola, Neocatenulostroma germanicum and species in the genera Neodidymelliopsis, Pestalotiopsis, Phoma, Pleurophoma and Pyrenochaeta; (c) common primary or secondary saprotrophs included species of Alternaria, Aureobasidium, Beauveria, Cladophialophora, Cladosporium, Epicoccum, Exophiala, Lecanicillium, Penicillium, Cryptococcus and Kwoniella; (d) Lophodermium was represented mostly by Lophodermium pinastri which occurred 4–72 times more frequently than Lophodermium seditiosum; (e) frequencies of C. minus and C. ferruginosum were lower in the 0.5‐year‐old symptomless needles, increased in the symptomatic and symptomless 1.5‐year‐old needles and decreased after needle fall; (f) frequency of L. seditiosum was highest in 0.5‐year‐old needles; (g) frequency of L. pinastri increased with needle age whereas S. polyspora increased after needle fall; (h) lower frequency of L. pinastrii was associated with higher frequency of S. polyspora. It was concluded that Cyclaneusa needle cast in Poland may be caused by C. minus accompanied by C. ferruginosum, L. seditiosum, L. pinastrii and S. polyspora. Participation of Coniothyrium spp., Epicoccum nigrum, Pestalotiopsis spp. and Phoma spp. in the disease progress cannot be excluded.     

Über Sukzession und pathogene Eigenschaften Kiefernnadeln bewohnender Pilze

Succession and pathogenic properties of fungi inhabiting pine needles . Isolates from healthy and dying pine needles of various age permit conclusions about the relationship of some needle fungi to their host. Of the six most prevalent fungi, only Lopbodermium seditiosum has a pathogenic nature.     

Haustorial morphology of Cronartium conigenum in naturally infected cones of three Pinus species from Guatemala1

Haustorial morphology of the cone-rust pathogen, C. conigenum, was investigated among naturally infected female strobili of three Guatemalan pines, P. maximinoi, P. pseudostrobus, and P. oocarpa. Among the three pine species, haustorial shapes and sizes were more variable in P. maximinoi and P. oocarpa than in P. pseudostrobus. The haustorial shapes and sizes were more variable in parenchyma cells of the cortex, xylem, and pith than in the cells in the phloem, xylem rays, and tracheids. The haustoria were also present in larger numbers in the parenchyma cells of the cortex, xylem, and pith than in phloem parenchyma cells and tracheids. In living cells, the tips of some haustoria were appressed to the host nuclei.     

Histology of Pinus maximinoi cones infected by Cronartium conigenum1

Apparently healthy and C. conigenum infected female strobili of Pinus maximinoi, collected in Guatemala, were histopathologically studied by light microscopy. Scales from infected cones were fused and fertile scales had aborted seeds. Infected cone scales lacked fibre cells in the cortex, which are abundant in healthy cone scales. Intercellular spaces of cortex contained abundant hyphae compared to phloem and xylem. The cell walls of infected tissues in the ovules were darkly stained, while those of comparable healthy tissue were colourless under Pianeze's IIIB stain. Infected ovules of different developmental stages with nucellus, or nucellus plus spongy tissue, were observed. The cells of each tissue type contained many haustoria and did not develop into female gametophyte and embryo. Ovule colonization by hyphae appeared after pollination and subsequently caused their early abortion.     

世界柏科彩叶植物种质资源

柏科植物共有22个属,其中10个属拥有彩叶植物44个种、183个变种。在刺柏属、柏木属和扁柏属中的彩叶植物种数较多,而在扁柏属、刺柏属、崖柏属和柏木属中彩叶植物变种数较多。从柏科植物彩叶种或变种叶色来看,呈黄色的种或变种数最多,达100个,蓝色种或变种60个,白色种或变种16个,灰绿色种或变种3个,紫叶种或变种3个,红棕色种或变种1个。文中介绍了柏科彩叶植物种类、叶色特征,提出了我国繁育和推广利用建议。     

Invasive brown spot needle blight caused by Lecanosticta acicola in Estonia

Lecanosticta acicola (Thüm.) Syd., a serious foliage pathogen of pines in many regions of the world, is an emerging invasive species in northern Europe. After the first record of L. acicola on Pinus ponderosa Dougl. ex Laws. in northern Estonia in 2008, monitoring was started to investigate the spread and host range of the fungus in the country. By the beginning of 2015, L. acicola was also recorded on P. uncinata Mill. ex Mirb., P. mugo Turra and on P. mugo var. pumilio (Haenke) Zenari, being the northernmost records of the fungus in Europe. So far, the single native pine species Pinus sylvestris L. has not been found to be infected. Molecular analysis proved infection of L. acicola on pines in five different localities of Estonia: in Tallinn (mainly in the Botanic Garden, northern Estonia), in Tori and Kärdla (western Estonia), in Vasula and Kärevere (east-central Estonia). The sexual state (teleomorph) of the fungus was not found, but the existence of the both mating types, MAT1-1 and MAT1-2, was confirmed.     

Associations between Tomicus destruens and Leptographium spp. in Pinus pinea and P. pinaster stands in Tuscany,central Italy

The association between Tomicus destruens and fungi of the genus Leptographium was studied in Pinus pinea and P. pinaster forests in Tuscany, central Italy. Fungi were isolated from adult beetles and from pine tissues from infested trees. On average, Leptographium spp. were associated with 18% of beetles in breeding galleries, 35% of emergent brood beetles and 18% of beetles undergoing maturation feeding in pine twigs. The fungal species most frequently identified were Leptographium wingfieldii and L. lundbergii while L. guttulatum and L. serpens were also found.     

Understorey vegetation as an indicator of water content in till soils in Finnish Lapland

Artificial regeneration of Scots pine (Pinus sylvestris L.) has been applied to a variety of forest site in Lapland. Occasional failures in regeneration have been observed on sites with high soil moisture contents and originally dominated by Norway spruce (Picea abies (L.) Karst). Understorey vegetation was studied on four naturally pine-dominated and eight spruce-dominated sites to determine suitable indicator plants for assessing soil moisture regimes. Soil moisture contents were estimated using the in situ dielectric measurements with radar surface arrival detection targeted to a depth of 0-50 cm. The abundance and frequence of plant species were analysed using logistic regression. The most reliable indicators were found to be Stereocaulon and Cladonia lichens for the dry regime (θv<25%), and Polytrichum commune Hedw. and Carex globularis L. for the wet regime (θv>25%). It was concluded that the indicator plants found in this study provide an alternative to the traditional Finnish forest site type approach in recognizing high soil moisture regimes.     

Effects of decomposed leaf litter mixtures from Platycladus orientalis and broadleaf tree species on soil properties

Determining the effects of decomposed leaf litter mixtures, consisting of litter from different tree species, on the properties of soil is important for evaluating nutrient cycling and interspecific relationships. In this study, leaf litter mixtures consisting of Platycladus orientalis (L.) Franco combined individually with eight broadleaf plant species were ground and mixed with soil to analyze the effects of their decomposition on the quantity of soil microbes, the activities of soil enzymes, and the soil chemical properties and to determine the interactions between the different types of litter within a mixture during decomposition. In terms of soil properties as a whole, we found that when P. orientalis litter was mixed separately with litter from Amorpha fruticosa L., Caragana microphylla Lam., Betula platyphylla Suk., or Hippophae rhamnoides L., the resulting litter mixtures showed synergistic interaction effects on soil, but when P. orientalis litter was mixed with litter from Populus simonii Carr., Ulmus pumila L., Robinia pseudoacacia L., or Quercus liaotungensis Koidz. showed antagonistic interaction effects.     

Functional compatibility of two arbuscular mycorrhizae with thirteen fruit trees in Senegal

Functional compatibility between thirteen tropical fruit trees (Afzelia africana Smith., Adansonia digitata L., Aphania senegalensis Radlk., Anacardium occidentale L., Cordyla pinnata (Lepr. ex A. Rich.) Milne-Redhead, Dialium guineensis Wild., Landolphia heudelottii A.DC., Sclerocarya birrea (A.Roch.) Hochst., Saba senegalensis (A. DC.) Pichon and four reference hosts Balanites aegyptiaca (L.) Del., Parkia biglobosa (Jacq.), Tamarindus indica L. and Zizyphus mauritiana Lam.) and two arbuscular mycorrhizal fungi (AMF) (Glomus aggregatum Schenck and Smith emend. Schenck and Glomus intraradices Schenck and Smith), was investigated. Marked differences were found between them in terms of mycorrhizal formation, root colonization, relative mycorrhizal dependency (RMD) and phosphorus concentrations in shoot tissues. A. africana, L. heudelottii and S. senegalensis did not form symbiotic associations, and the growth of A. africana decreased following mycorrhizal inoculation, while L. heudelottii and S. senegalensis showed no dependency. In contrast, A. digitata, A. senegalensis, A. occidentale, B. aegyptiaca and S. birrea were well colonized with AMF, but did not significantly increase in biomass production. Five fruit trees did, however, show dependency by a positive interaction with G. aggregatum, the most effective AMF. Z. mauritiana was found to be very highly dependent (RMD > 75%), T. indica was highly dependent (50–75% RMD), and D. guineensis, P. biglobosa and C. pinnata were moderately dependent (25–50% RMD). Phosphorus absorption probably contributed to this dependency more than the absorption of potassium. These results indicate that some tropical fruit trees do derive benefits from AM inoculation, while others do not.This revised version was published online in November 2005 with corrections to the Cover Date.     

Lophodermium needle cast,insect defoliation and growth responses of young Scots pines in Estonia

Using a retrospective approach, based on historical needle cast disease and insect pest records, data series of needle losses (reconstructed by the use of the needle trace method), tree growth parameters and meteorological data were studied to determine the impact of the appropriate pointer (epidemic or calamity) years on the annual radial and height increment of 46 sample trees in six Scots pine (Pinus sylvestris) stands in Estonia from 1887 to 2006. First, the needle cast epidemics during the last 120 years were retrospectively determined, with resulting 4.6 epidemics per decade as a mean frequency. If the sum of precipitation from May to August reached 300 mm (the mean of 12 epidemic years studied: 361 ± 15 mm), an epidemic of needle cast caused by Lophodermium seditiosum might follow the next year in young plantations. For insect defoliators, similarly clear triggering threshold values of precipitation or temperature could not be determined, although dry and warm summers and mild winters supported the calamities. We separately detected that both larger needle losses and growth reductions in trees related to Lophodermium needle cast epidemic years lasted until the same age of pines, 22–24 years, but for insect pest (diprinoid sawflies) calamity years the growth reduction lasted longer. The relevance of these findings for the prediction of Lophodermium needle cast epidemics is briefly discussed.     

Root lesions in large loblolly pine (Pinus taeda L.) following inoculation with four root‐inhabiting ophiostomatoid fungi

Loblolly pine decline, characterized by deteriorating root systems leading to shortening and thinning of foliage, has been observed throughout portions of the south‐eastern United States. Several root‐inhabiting ophiostomatoid fungi, including Leptographium procerum, Leptographium terebrantis, Leptographium serpens, and Grosmannia huntii are associated with lateral root damage on declining loblolly pine. Trees of various ages were inoculated in primary lateral roots during fall (2006 and 2007) and spring (2007 and 2008). All fungi caused a darkened, resin‐filled lesion on the surface of the phloem, extending into the xylem that was larger than that of controls. Only lesions associated with G. huntii infection were significantly larger in the spring season, compared with the fall. Grosmannia huntii was found to be the most virulent fungus, causing lesions that were longer, deeper and larger than all other fungal species during the spring and larger than L. terebrantis and L. procerum in the fall. Leptographium serpens was the second most virulent fungal species, causing lesions larger than L. procerum and L. terebrantis (with the exception of lesion depth) during both seasons. These tests indicate that G. huntii and L. serpens are significant root pathogens, capable of causing considerable damage, while L. terebrantis and L. procerum may be less virulent. Depending on the actions of their vectors, G. huntii and L. serpens may be responsible for significant root deterioration and tree disease.     

4个枫香家系在不同环境下的叶色变化

[目的]对不同遗传材料在不同环境条件下叶片色素含量变化及其呈色响应开展试验研究,从生理生化角度探寻影响秋季枫香叶片呈色的关键因素,为枫香叶色改良、新品种选育和应用环境选择提供理论依据。[方法]以4个不同家系的1年生枫香幼苗为试材,测定其在不同环境下叶片叶绿素、类胡萝卜素、花青素和可溶性糖含量并分析其相关性。[结果]结果表明:试验期间,枫香叶片逐渐由绿色变成红色、深红色。同时4个家系叶色变化差异显著,其中17号家系叶片主要为深红色,14号家系叶片颜色以黄绿色为主。叶片中的叶绿素、叶绿素a、叶绿素b和类胡萝卜素含量变化呈下降趋势,特别在平均温度最低、平均昼夜温差大的3号试验点下降幅度最大。4个家系叶片花青素含量显著升高。同时4个家系叶片可溶性糖含量在各试验点均较试验前有不同程度增加。相关分析表明花青素含量与可溶性糖含量呈显著正相关,与叶绿素含量、平均温度和平均呈显著负相关。多因素方差分析表明家系和不同环境对叶片叶绿素、类胡萝卜素、花青素、可溶性糖和叶片红色面积比例变化产生极显著影响(p0.01)。[结论]不同家系枫香叶片颜色在不同环境下有不同的变化趋势,同一环境下不同枫香家系叶片变化也显著不同,温度变化的差异和枫香叶片色素比例的改变是导致其颜色改变的主要原因。     

Beeting in Picea abies (L) karst. Growth and damage in a field experiment

A field experiment was established in two Picea abies (L.) Karst. plantations in southern Sweden to study yield and effects of competition on growth in beeted stands. Beeting was carried out in gaps where originally planted seedlings had been removed. Tree species used for beeting were P. abies, Pinus sylvestris L., Pinus contorta Dougl. and Larix decidua Mill × L. leptolepis Gord. The plantations were beeted when mean heights were 95 cm (Ullasjo) and 40 cm (Knäred). Effects of competition on diameter growth of P. abies were found when originally planted stands were 2.5 and 3.5 m in height. On both sites, diameter growth in stump height was significantly lower for seedlings beeted in small gaps (approx. 20 m²) than for seedlings beeted in the middle of large gaps (approx. 155 m²). This difference was larger at Ullasjo than at Knared. About 50 % of the P. sylvestris 70 % of the P. contorta and 80% of the L. decidua x L. leptolepis were dead or severely damaged six years after beeting. The main causes of damage were fraying and browsing by moose and roe‐deer.     

Co‐occurrence of the ascomycete Lophodermium piceae and the rust fungus Chrysomyxa abietis in Norway spruce needles

The frequency of needles and the proportion of needle segments infected by Lophodermium piceae were compared in symptomless and Chrysomyxa abietis‐infected, 1‐year‐old needles of Picea abies. In late spring, symptomless needles from both rust‐infected and healthy saplings were sampled. In addition, rust‐infected, totally chlorotic needles and needles with chlorosis along about half their length from the diseased trees were examined. In all three stands, the proportion of segments infected by L. piceae was larger in the rust‐infected half of the needle than in the symptomless half; but the difference was statistically significant in only one of the stands. The proportion of L. piceae‐infected segments among the nonrust‐infected needles was the same as that found for the uninfected half of rust‐infected needles (after correction for size differences). No differences in the proportion of L. piceae‐infected segments were found between the totally chlorotic, rust‐infected needles and the green needles of diseased or healthy trees.