Detection and features of wetwood in Quercus mongolica var. grosseserrata

To elucidate the location of water in wetwood, variations in moisture content within a tree of Quercus mongolica var. grosseserrata were observed macroscopically by determination of moisture content and by soft x-ray photography. Then the typical wetwood, which had been precisely located by such macroscopic analysis, was examined further by cryo-scanning electron microscopy. The moisture content varied considerably within the tree trunk, and typical wetwood was detected in limited regions of the heartwood. The distribution of the wetwood did not always correspond to the discoloration of the wood. In the wetwood, almost all the lumina of vessels and fibers were filled with water, while the lumina of ray and axial parenchyma cells were often cavitated. Intercellular spaces produced by deformation of cell walls and radial shakes were filled with water. In addition, tyloses were collapsed and torn in the wetwood, and they did not block the vessel lumina. These results suggest the possibility that vessels and fibers might serve as effective pathways for the accumulation of water in the wetwood.     

Stand dynamics during a 12-year period in a second-growth stand in a cool temperature forest in northern Japan

In 1981 and 1993, trees over 2 m high were measured and mapped to clarify stand dynamics in two permanent plots of 0.1 ha in a secondary, cool temperate, mixed broadleaf/conifer forest after logging in the Tomakomai Experiment Forest, central Hokkaido, northern Japan. The species could be placed in two groups according to the change in basal area and density, and annual height growth:Quercus mongolica var.grosseserrata, Phellodendron amurense, Prunus sargentii andTilia japonica (Group I: GI) showed episodic regeneration and/or fast height growth;Acer mono, Acer palmatum var.matsumuae andSorbus alnifolia (Group II: GII) showed continuous regeneration and/or slow height growth. The age distribution of stems over 10 cm in d.b.h. suggests synchronous regeneration of GI and GII species. Vertical stratification was promoted during the 12-year period by the difference in annual height growth between the two species groups. Additional tree censuses in both remnant old-growth stands and second-growth stands after large scale blowdowns demonstrated thatQ. mongolica var.grosseserrata is most dominant in stands varying in the stages of development. Disturbance history and successional trends in dominant species implied that stand-devastating disturbances were responsible for the regeneration ofQ. mongolica var.grosseserrata in the study forest.     

Ophiostomatoid fungi isolated from Japanese red pine and their relationships with bark beetles

We isolated ophiostomatoid fungi from bark beetles infesting Pinus densiflora and their galleries at 24 sites in Japan. Twenty-one ophiostomatoid fungi, including species of Ophiostoma, Grosmannia, Ceratocystiopsis, Leptographium, and Pesotum, were identified. Among these, 11 species were either newly recorded in Japan or were previously undescribed species. Some of these fungal species were isolated from several bark beetles, but other species were isolated from only a particular beetle species. Thus, it is suggested that some ophiostomatoid fungi have specific relationships with particular beetle species. In addition, fungus-beetle biplots from redundancy analysis (RDA) summarizing the effects of beetle ecological characteristics suggested that the association patterns between bark beetles and the associated fungi seemed to be related to the niches occupied by the beetles.     

Guild structures of seed insects in relation to acorn development in two oak species

We investigated patterns of acorn growth in Quercus variabilis Blume and Quercus serrata Thunb., seasonal trends in emergence of seed insects found in the acorns, oviposition periods of the insects and falling periods of insect-infested acorns. In Q. variabilis, two insect guilds were associated with acorn development: (i) the immature acorn feeding (IAF) guild [Curculionidae sp., Poecilips cardamomi (Schaufuss), and Characoma ruficirra (Hampson)]; and (ii) the mature acorn feeding (MAF) guild [Curculio robustus (Roelofs), Curculio sikkimensis (Heller), and Cydia glandicolana (Danilevsky)]. In Q. serrata, there were three guilds: (i) the pistillate flower feeding (PFF) guild (cynipid wasp); (ii) the IAF guild [sap absorption by Mechoris ursulus (Roelofs)]; and (iii) the MAF guild (M. ursulus, C. sikkimensis, Cydia danilevskyi (Kuznetzov), C. glandicolana and Autostichidae sp.). The succession of guilds during acorn development may be a consequence of the use by different species of the limited food resource. The lack of a PFF guild in Q. variabilis that was found in our field site would have a positive effect on IAF guilds in utilizing the acorns.     

Flooding effects on starch partitioning during early growth of two oak species

Pedunculate (Quercus robur L.) and sessile (Q. petraea [Matt.] Liebl.) oaks are the most common oak species in Western Europe. They are known to display different ecological requirements, particularly relative to root hypoxia induced by flooding: In a glasshouse study of seedlings, we quantified the effects of flooding on starch mobilization from cotyledons and starch partitioning. Growth and distribution of lateral roots were also measured. The above-ground growth of Q. robur was less affected by flooding than that of Q. petraea which failed to develop a second flush. Root growth was also severely inhibited, particularly in Q. petraea. In Q. robur, lateral root initiation as well as elongation was restricted to the soil surface layer. Flooding markedly reduced total growth and concentrations of in all components except stems. Starch mobilization from cotyledons was delayed by flooding, especially in Q. robur seedlings. Under flooding, the decrease of cotyledons dry mass and starch content in Q. robur was lower than in Q. petraea, whereas Q. robur displayed larger growth than Q. petraea. The features of carbohydrate management may be crucial in the observed differences in flooding tolerance of these species.     

Comparative study of leaf carbon gain in saplings ofThujopsis dolabrata var.hondai andQuercus mongolica var.grosseserrata in a cool-temperate deciduous forest

Seasonal courses of leaf CO₂ gas exchange in a growing season were examined in saplings ofThujopsis dolabrata var.hondai andQuercus mongolica var.grosseserrata in a cool temperate deciduous forest. Between the two tree species there were no large differences in the light compensation point of leaf photosynthesis, except for the season of new leaf expansion. However, light-saturated rates of net photosynthesis were obviously high inT. dolabrata var.hondai. EvergreenT. dolabrata var.hondai saplings had large photosynthetic production in two seasons, before the emergence of new foliage and after foliage fall of the overstory deciduous trees, because of the significantly high solar radiant energy penetrating under the forest canopy during the seasons. Saplings of deciduousQ. mongolica var.grosseserrata were heavily shaded throughout the growing season by foliage of the overstory trees, which resulted in a low daily surplus production. The annual surplus production of leaves in the growing season was estimated to be 2300 mmol CO₂ m⁻² inT. dolabrata var.hondai and −100 mmol CO₂ m⁻², slightly negative, inQ. mongolica var.grosseserrata. These results supported the high survivability ofT. dolabrata var.hondai saplings and the high mortality ofQ. mongolica var.grosseserrata in the deciduous forest.     

Raffaelea quercivora sp. nov. associated with mass mortality of Japanese oak, and the ambrosia beetle (Platypus quercivorus)

 A hyphomycete consistently isolated from dead oak trees (Quercus serrata and Q. mongolica var. grosseserrata) attacked by the ambrosia beetle Platypus quercivorus in Japan is described and illustrated as Raffaelea quercivora sp. nov. The new species is characterized by having small obovoid to pyriform sympodioconidia and slender, long conidiophores that taper to a point. The fungus has been isolated from the body surfaces and mycangia of the beetle. It is likely that the fungus was transferred to oak trees by P. quercivorus. Received: August 20, 2001 / Accepted: March 14, 2002     

Phytophthora quercetorum sp. nov., a novel species isolated from eastern and north-central USA oak forest soils

Isolates belonging to an undescribed Phytophthora species were frequently recovered during an oak forest soil survey of Phytophthora species in eastern and north-central USA in 2004. The species was isolated using an oak leaf baiting method from rhizosphere soil samples collected from Quercus rubra, Q. macrocarpa, and Q. phellos. This species is formally described as P. quercetorum. It is homothallic and has aplerotic oogonia and paragynous antheridia. It produces papillate sporangia (occasionally bipapillate) of ovoid-elongated shapes. Its temperature optimum for growth is ca 22.5 °C with the upper limit of ca 32.5 °C. P. quercetorum differs from the morphologically related P. quercina in producing distinct submerged colony-patterns, different growth-temperature requirements, and oogonial shapes and sizes. Phylogenetic analyses using seven nuclear loci supported P. quercetorum as a novel species within clade 4, closely related to P. arecae, P. palmivora, P. megakarya, and P. quercina.     

Rodent acorn selection in a Mediterranean oak landscape

Quercus suber, Quercus ilex and Quercus coccifera (Cork, Holm and Kermes oaks, respectively) are common evergreen oak species that coexist in the landscapes of the western part of the Mediterranean basin. Rodents are the main acorn predators and thus one of the main factors for understanding recruitment patterns in oaks. In this paper we analyse to what extent mice prefer acorns from one oak species over another in three oak species studied using acorn removal experiments and video tape recordings. Twenty labelled acorns from each of the three Quercus species (60 acorns) were placed in 40 cm×40 cm quadrats on each plot. Because selection might vary as a result of the vegetation context, we performed the trials in the five main vegetation types within the study area (four replicates in each vegetation type) in order to control for habitat influences on rodent acorn preferences (a total of 20 plots). The removal of 1,200 acorns occurred within 68 days. Mice removed 98.7% of the acorns. Q. ilex acorns were preferred over Q. suber and Q. coccifera in all vegetation types except in pine forest, where no acorn preferences were detected. Acorn removal rates differed with vegetation type, correlating positively with shrub cover. The distance at which acorns were displaced by rodents (mean =4.6 m±5.1 SD) did not differ between acorn species, but varied among vegetation types. Bigger acorns of Q. coccifera were selected only after Q. ilex and Q. suber acorns were depleted, while no size selection was detected for the latter two species. Thus, we conclude that rodents show preference for some oak acorns and that landscape context contributes significantly to rodent activities and decisions.     

A new species ofClohiesia from Hong Kong

Clohiesia lignicola sp. nov. (freshwater ascomycetes) is introduced based on a specimen collected on submerged wood in the Tung Chung River, Hong Kong. Ascomata are clypeate, asci are cylindric-clavate with a relatively massive apical apparatus and ascospores are fusoid-ellipsoidal.Clohiesia lignicola differs fromC. corticola in having wider asci and wider fusoid-ellipsoidal ascospores, and larger ascomata.Clohiesia lignicola is described and illustrated with light micrographs and is also compared with species in the genus,Annulatascus.     

Conidial development in selected ambrosial species of the genus <Emphasis Type="Italic">Raffaelea</Emphasis>

Conidiogenesis of the type species and two additional species of the genus Raffaelea Arx & Hennebert are described. In contrast to previous conclusions based on light microscopy that indicate sympodial production of the conidia, we found that conidium development was by annellidic percurrent proliferation in the type species Raffaelea ambrosiae, as well as in Raffaelea arxii and Raffaelea albimanens. Consequently, this mode of conidium development is similar to the conidiogenesis of anamorphs within the Ophiostomatales, but distinguished by sporodochia formed within the genus Raffaelea. These findings reduce the differences between Raffaelea and other anamorphs with annellidic percurrent proliferation of the conidiogenous cells within the Ophiostomatales to different conidiomata and conidiophores, and they support previous reports of the close phylogenetic relationship between Raffaelea and Ophiostoma.     

Japanese species of Hypomyces and its anamorph III

Three new species of Hypomyces with KOH-negative subiculi occurring on the Aphyllophorales are described. Hypomyces pseudocorticiicola is characterized by a grayish-yellow to brown subiculum, fusiform ascospores, always with one septum, and its Cladobotryum-anamorph. Hypomyces laeticolor is characterized by a bright-colored subiculum, small apiculi on the ascospores, and well-developed verticillate conidiogenous cells. Hypomyces penicillatus forms a Trichothecium-like anamorph with well-developed verticils of conidiogenous cells.     

A new species ofAppendicospora from Hong Kong

A new species ofAppendicospora, A. honkongensis, occurring on fronds ofLivistona chinensis in Hong Kong is described and illustrated with interference contrast micrographs. It differs fromA. coryphae in having larger ascomata and ascospores, and a peridium of brown-walled cells. The differences betweenApiospora andAppendicospora are reexamined in the light of the cultural characteristics of the latter.     

Three new <Emphasis Type="Italic">Ophiostoma</Emphasis> species isolated from Japanese red pine

Three new species of Ophiostoma found on Japanese red pine are described as Ophiostoma pusillum sp. nov., O. botuliforme sp. nov., and O. nigrogranum sp. nov. Ophiostoma pusillum is characterized by oblong ascospores and a Hyalorhinocladiella anamorph. Ophiostoma botuliforme has ostioles covered with a hyaline gelatinous cap, allantoid ascospores, and a Pesotum anamorph with hyaline to pale brown stipes. Ophiostoma nigrogranum has hyaline ostiolar hyphae with rounded tips, allantoid ascospores, and sclerotium-like structures.Contribution no. 172, Laboratory of Plant Pathology and Mycology, Institute of Agriculture and Forestry, University of Tsukuba     

外生菌根菌对樟子松苗木生长的影响

以内蒙古大兴安林樟子松分布区较典型的6个乡土菌种与本实验室从法国引进的宿主范围较广的2个菌种及内蒙古地区分布广泛的土生空团菌为研究对象,采用固体和液体两种菌剂类型,对出苗30d左右的樟子松实生苗进行外生菌根菌接种试验,接种130d后观察菌根侵染情况及生长特性,同时对菌根化的樟子松苗木进行自然干旱胁迫,研究外生菌根菌接种对樟子松苗木生长及抗逆性的影响。结果显示:(1)5个乡土菌种和1个法国引进菌种均能够与樟子松实生苗共生菌根,菌根化苗木较对照的苗高增长10.5%～111.4%、地茎增长4.55%～92.8%、苗木干重增加6.8%～184.5%,且固体菌剂效果优于液体菌剂。(2)在干旱胁迫下,菌根化苗木叶绿素含量较对照增加5.82%～36.92%、净光合速率提高120.2%～217.03%,叶片推迟10.3～25h出现萎蔫,临界致死时间推迟13.8～38.2h。(3)接种菌种厚环乳牛肝菌和点柄乳牛肝菌的苗木菌根侵染率、苗木生长量、干旱胁迫下各项生理指标均显著优于其他菌种和对照。研究表明,樟子松实生苗菌根化对苗木生长有明显的促进作用,能够提高苗木对干旱胁迫的抵御能力;厚环乳牛肝菌和点柄乳牛肝菌是有潜在研究和应用价值的优良菌株,这两个菌株的固体菌剂可用于樟子松菌苗生产。     

A new variety ofMyxotrichum ochraceum from Japanese soil

Myxotrichum ochraceum var.frigidum, a new variety ofMyxotrichum, is described and illustrated from the material from Japanese soil. It is morphologically characterized by dull green to black ascomata with a yellow-orange centrum, peridium consisting of a fragile hyphal network, peridial hyphae with internal coiled branches and short spine-like appendages, pale yellow fusiform striate ascospores, and the absence of an anamorph. The new variety primarily differs from the type variety in the absence of elongate appendages. A key to all accepted species of the genus is revised.     

Non-albicans Candida species isolated from plastic devices

In this work we point out an occurrence of non-albicans Candida species isolated from catheters, cannulas and drains. We detected eight non-albicans Candida species in 49 examined samples: C. parapsilosis (n = 26), C. tropicalis (n = 12), C. krusei (n = 4), C. claussenii, C. mesenterica (n = 2 for each), C. guilliermondii, C. kefyr and C. lusitaniae (n = 1 for each). Material examined from children hospitalized in intensive care units was the most frequent. Eight samples were from the oncology department, seven from the surgery department, six from the anaesthesiology department, four from the dialysis unit, two from the hematology department, one from the internal medicine department and one from the stomatology department. We examined cannula scraping 26 times (53%), catheter scraping 14 times (28.6%) and drain scraping nine times (18.4%). This revised version was published online in June 2006 with corrections to the Cover Date.     

A new species of Cladophialophora (hyphomycetes) from boreal and montane bryophytes

During a survey of bryophilous fungi from boreal and montane habitats in central Alberta, a hitherto undescribed species of Cladophialophora was recovered from Polytrichum juniperinum, Aulacomnium palustre, and Sphagnum fuscum. On potato dextrose agar (PDA) colonies grew slowly, attaining a diameter of 25 mm after 30 d, were dark grey, velvety, radially sulcate, and convolute and cracked at the centre. Micronematous conidiophores gave rise to branched chains of small (1–2 × 8–22 μm), cylindrical to fusiform conidia with truncate, swollen scars at each end. Phylogenies built on the ITS and ribosomal SSU regions indicate the isolates form a monophyletic clade within the family Herpotrichiellaceae (Chaetothyriales) that is composed of two geographically based groups, each with 99 % within-group sequence similarity and 97–98 % between-group sequence similarity. A teleomorph has not been found but would likely be similar to species of Capronia. In vitro inoculation of the isolates onto axenically grown P. juniperinum produced no discernible host symptoms, and host penetration could not be detected using light microscopy. The production of polyphenol oxidases by the fungus and the role of other Cladophialophora species as latent endophytes and saprobes suggest that a potential role for the fungus is the degradation of the polyphenol-rich cell walls of mosses. A dichotomous key to species of the genus Cladophialophora is provided.     

Decomposition of Japanese beech wood by diverse fungi isolated from a cool temperate deciduous forest

We assessed 62 fungal strains in 31 species of wood decay fungi in the ability to decompose wood blocks of Japanese beech (Fagus crenata) under a pure culture condition. Fungi were collected in a cool temperate beech forest in Japan and isolated from the inside of beech logs and from sporocarps fruiting on logs and snags of beech that were different in diameter and decay class. Fungi in Holobasidiomycetidae showed marked decomposition of lignin and carbohydrate. These fungi were divided into three groups according to the pattern of lignin and carbohydrate utilization. Phanerochaete filamentosa decomposed lignin selectively. Lampteromyces japonicus, Steccherinum rhois, Trichaptum biforme, Stereum ostrea, Mycena haematopoda, Antrodiella albocinnamomea, Daedalea dickinsii, Daedaleopsis tricolor, Ganoderma tsunodae, and Trametes versicolor decomposed lignin and carbohydrates simultaneously. Psathyrella candolleana, Lenzites betulinus, and Trametes hirsuta decomposed carbohydrates selectively. Species in the Phragmobasidiomycetidae and in the Ascomycota caused low mass loss of wood.     

Nutrient acquisition from different soil depths by pedunculate oak

Eight oak trees (Quercus robur L.) received ³²P at a soil depth of 50 cm and ³³P at a soil depth of 15 cm at the end of June 2002 through plastic tubes inserted into the mineral soil. The phosphorus uptake from different soil depths was estimated by analysing the concentration of ³²P and ³³P in the foliage of oak growing in a mixed stand in southern Sweden. ³²P and ³³P were recovered in the leaves/needles after 21 and 39 days. The recovery of labelled P in oak was higher from 15 cm soil depth than from 50 cm, however, more than 4% of the total amount of labelled P was taken up from 50 cm. This indicates that oak can utilize deep soil layers for nutrient uptake. A study on the uptake of Cs (as an analogue to K) and ¹⁵N into the leaves was performed on the same trees and detectable amounts of ¹⁵N and Cs were recovered in leaves and buds. This indicates that ¹⁵N and Cs can be used to study nutrient uptake of mature trees from the mineral soil.