First report of Puccinia psidii on Corymbia citriodora and Eucalyptus in Colombia

A rust disease was observed during routine disease surveys of Eucalypt species in Colombia. The cause of the disease was identified, using morphology and DNA sequence data, as the myrtle rust pathogen, Puccinia psidii. We evaluated the susceptibility of Eucalyptus grandis and the hybrid Eucalyptus urograndis to P. psidii. This is the first report of this pathogen on Corymbia citriodora and Eucalyptus species in Colombia.     

Identification of some Douglas fir mycorrhizae1

The mycorrhizal associations Pseudotsuga menziesii+Cantharellus cibarius, P. menziesii+Inocybe geophylla and P. menziesii+Piloderma byssinum were demonstrated by comparing the mycorrhizal mantle with the sporocarp stipe base mycelium, with respect to morphology, reaction to chemical reagents and autofluorescence in long-wave ultraviolet light. P. byssinum was found to be a strong inhibitor of the root rot agents Fomes annosus and Poria weirii in pure culture.     

Identification of the Armillaria root rot pathogen in Ethiopian plantations

Armillaria root rot is a well‐known disease on a wide range of plants, world‐wide. In Ethiopia, the disease has previously been reported on Pinus spp., Coffea arabica and on various native hardwoods. The causal agent of the disease has been attributed to Armillaria mellea, a species now known to represent a complex of many different taxa. The aim of this study was to determine the extent of Armillaria root rot and the identity of the Armillaria sp. in Ethiopian plantations. As part of a plantation disease survey in 2000 and 2001, samples were collected in plantations at and around Munessa Shashemene, Wondo Genet, Jima, Mizan and Bedele, in south and south‐western Ethiopia. Basidiocarps were collected and their morphology studied. Morphological identification was confirmed by sequencing the intergenic spacer (IGS‐1) region of the ribosomal rRNA operon and comparing data with published sequences of Armillaria spp. Armillaria isolates were collected from Acacia abyssinica, Pinus patula, Cedrela odorata and Cordia alliodora trees. Sporocarps were found on stumps of native Juniperus excelsa. Basidiocarp morphology and sequence data suggested that the fungus in Ethiopia is similar to that causing disease of Pinus spp. in South Africa and previously identified as A. fuscipes. This identification was confirmed for all isolates, based on sequence data. Armillaria fuscipes is known to be common in southern Africa. Its widespread occurrence in Ethiopia suggests that it is also the major cause of Armillaria root rot in that country.     

In vitro influence of phosphite on chlamydospore production and viability of Phytophthora cinnamomi

Chlamydospores of four isolates of Phytophthora cinnamomi were produced on mycelium grown on medium with or without 100 μg phosphite/ml, then tested for germination on medium containing no phosphite or 100 or 160 μg phosphite/ml. For each isolate when spores were produced on medium without phosphite, there was no effect of phosphite on germination. However, chlamydospores produced in the presence of 100 μg phosphite/ml showed significantly lower germination on media with no phosphite, 100 or 160 μg phosphite/ml than those produced in the absence of phosphite. For isolates known to be phosphite sensitive, the level of viable non‐germinated chlamydospores was higher amongst those produced on medium containing phosphite than amongst the controls, suggesting phosphite induces chlamydospore dormancy in some isolates of P. cinnamomi. Chlamydospores were produced uniformly across the radius of colonies on solid or liquid control media, but on media containing 100 μg phosphite/ml, chlamydospore production was lower in the centre of the colony and peaked at a point where mycelial morphology changed from tightly packed to sparse. This change in mycelial morphology and the peak in chlamydospore numbers did not occur when the pathogen was grown on liquid medium renewed every few days. In renewed medium, chlamydospores were evenly distributed across the radius of the colony.     

Infection of Populus alba var. hickeliana by Melampsora medusae Thüm.

The first record of infection of Populus alba var. hickeliana by the American rust, Melampsora medusae Thum. is reported. The morphology of uredospores of rust on P. alba is compared with that of other Melampsora spp. infecting white poplars. The implications of these observations for the widespread establishment in the future of white × black hybrid poplars are discussed.     

Observations on some italian provenances of Melampsora populnea

Melmpsora pinitorqua on Populus tremula from Tuscany and M. larici-tremulae on P. tremula from central Alps were artificially inoculated on the same pycnio-aecial hosts in the genera Pinus and Larix, and were compared on the grounds of their pathogenicity and of some morphological aspects. The results indicate that the two rusts can be effectively considered as two separate species as they are different both in their pathogenicity, not withstanding the partially overlapping host range, and their morphology, at least in a few characters.     

Variation in leaf morphology of Quercus crispula and Quercus dentata assemblages among contact zones: a method for detection of probable hybridization

I describe variation in leaf morphology of Quercus crispula and Quercus dentata assemblages within and among their contact zones. Such relationships provide a relatively fast and accurate method for detecting hybridization. Using discriminant function (DF) analysis based on leaf characteristics, I was able to differentiate between these two species in pure zones. In three of five contact zones, the DF scores showed broad, continuous distributions with three or more peaks. The trees showing intermediate leaf morphology are considered to be hybrids. In the other two contact zones, the DF scores showed distinct bimodal distributions, suggesting that Q. crispula and Q. dentata rarely hybridize in these sites. Thus, the method described in this study should be effective for detecting probable hybridization between these two species in contact zones, and the relative frequency of hybridization among contact zones. However, there was likely to be intraspecific variation of Q. crispula between geographic ranges, restricting interpretations to patterns occurring within sites or limited geographic ranges.     

Effects of Light Intensity and Regeneration Mode on Stem Form and Growth of Cunninghamia lanceolata Saplings

ABSTRACT

Regeneration plays an essential role in the restructuring of plant communities, with seedlings and sprouts representing two different regeneration strategies. As an important timber species, Cunninghamia lanceolata is widely distributed throughout southern and eastern China. However, the morphology and growth of its sprouts and seedlings under natural environments have not been examined in detail. Our study quantified the morphology and growth of Cunninghamia lanceolata during its early regeneration phase. We selected a secondary mixed coniferous forest in the Huangshan region of China as the research location, and examined sapling height, basal stem diameter, lateral branch length, as well as the relationships between main stem and lateral branch elongation, and between sapling basal stem diameter and height. The results showed that high light intensity promoted the extension growth of main stems and the elongation of lateral branches of seedlings. Meanwhile, sprouts generally had shorter height growth than seedlings with the same basal stem diameter, and the growth allocation of seedlings was generally more dependent on light intensity. Our findings suggest that the morphology and growth of C. lanceolata might vary depending on the interaction of regeneration mode (plants originating from sprouts or seedlings) and light intensity.     

First report of Exobasidium gracile causing hypertrophied leaves of Camellia sasanqua in South Korea

This study presents the first report of Exobasidium gracile in South Korea. In 2012, a Camellia sasanqua tree with typical Exobasidium disease symptoms was observed for the first time in South Korea. The causal fungus was determined as E. gracile. The identification was based on host range, symptomatology, morphology and two‐gene sequence analyses.     

Effects of site preparation on soil properties and on morphology of Pinus sylvestris and Picea abies seedlings sown at different dates

The aims of the study are to find out the effects of site preparation on soil properties and on the morphology of three-year-old Pinus sylvestris L. and Picea abies (L.) Karst. seedlings sown at different dates along a slope with variation in soil texture, water, and fertility. Based on the hypothesis that soil texture affects soil water content, water retention capacity, and nutrient content, we studied site preparation of varying intensities: exposed C horizon, mounds (broken O/E/B horizons piled over undisturbed ground), and exposed E/B horizon. Though the growing time difference between sowings was about one month, after three growing seasons, spring-sown seedlings were larger than summer-sown seedlings. P. sylvestris seedlings were largest with mounds and smallest with exposed C horizon, but site preparation did not affect the morphology of P. abies seedlings.     

Pollen development and floral morphology of Populus pseudo-simonii

Pollen development and floral morphology of Populus pseudo-simonii were investigated by stain-squashing and anatomical techniques. It took approximately 16 days for the pollen to develop from pollen mother cells to mature pollen in the greenhouse. Meiosis of pollen mother cells was regularly applied and completed by a process of simultaneous cytokinesis. Pollen development was considerably asynchronous. The meiotic division was initiated at the bulgy middle position of the flower bud and proceeded towards the tip and base of the bud. The number and size of the nucleoli varied during pollen development and at most eight nucleoli formed in each daughter nucleus at the meiotic telophase, suggesting a paleopolyploid origin of the genus Populus. An association between floral morphology and pollen development was found and the ratio of width to length of flower buds or catkins presented an S-shaped curve related to pollen development as a function of time. The investigation on the pollen development and floral morphology of P. pseudo-simonii is important for further cross breeding programs of the section Tacamahaca.     

Dieback of cork oak (Quercus suber) in Catalonia (NE Spain) caused by Botryosphaeria stevensii

Botryosphaeria stevensii Shoemaker (anamorph: Diplodia mutila Fr. apud Mont.) is reported as the cause of canker and dieback of cork oak (Quercus suber L.) in Catalonia (NE Spain). It also causes wilting of trees after cork is removed for industrial purposes. Symptomatology and details of morphology for both anamorph and teleomorph are given.     

核桃褐斑病病原菌的分离鉴定和发病规律的调查

[目的]为了明确四川核桃褐斑病的病原菌及其发病规律。[方法]采用组织分离法,对四川中江核桃果园自然发病的核桃病原菌进行分离,并回接检测分离物的致病性;结合孢子形态学、ITS序列和gdp序列分析对病原菌进行鉴定;同时对核桃褐斑病的发病规律进行了调查。[结果]分离得到6种真菌,回接只有菌株ZJ5能使核桃发病;孢子形态和多序列比较分析将菌株ZJ5鉴定为链格孢菌;调查明确了核桃褐斑病的发病规律。[结论]本文首次报道了四川核桃褐斑病病原菌为链格孢菌,并揭示了该病原菌的发病规律。     

Studies of microconidia of Marssonina brunnea and apothecia of Drepanopeziza tremulae

Microconidia of M. brunnea were induced in the laboratory on 15 % V8 juice agar and poplar leaf discs. Apothecia of Drepanopeziza tremulae and stromata containing conidia were formed on naturally infected leaves and leaf-discs. The influence of temperature on apothecial development was investigated. The morphology of apothecia and stromata is described.     

避光对麻竹笋苦涩味及单宁含量、形态与分布的影响

[目的]探讨不同避光处理对麻竹笋苦涩味强度及单宁含量、形态与分布影响的机理。[方法]运用感官评定、光学显微镜、电子显微镜透射技术和磷钨酸-钨酸钠比色法,采用覆土(EP)、双层不透光套袋(CLPB)和自然生长(CK)3种不同处理,对麻竹鲜笋的口感品质进行感官评定,分析测定麻竹笋笋体单宁物质含量、形态和分布。[结果](1)不同处理的麻竹鲜笋的口感不仅均呈苦涩味,且苦涩味强度均表现为由麻竹笋的基部到笋尖逐渐增强的趋势,其苦涩味强度整体大小顺序为:CKCLPBEP。(2)麻竹竹笋壁中含有单宁物质的细胞(CWT)可被2%氯化亚铁溶液染成黑色,与不含单宁物质的细胞区别明显。(3)单宁大量分布在薄壁细胞内,少量在纤维细胞内,维管束中的筛管和导管细胞中无单宁分布。(4)单宁在薄壁细胞中主要分布于细胞质内,少量分布在液泡中,电镜下CWT中积累的单宁可分为絮状、颗粒状和块状3种类型。(5)不同处理的麻竹笋单宁含量为CK:1.15 2.67 mg·g~(-1),CLPB:1.03 1.43 mg·g~(-1),EP:0.36 1.13 mg·g~(-1),其相应的CWT密度大小顺序为:CKCLPBEP,3种处理不同部位的单宁含量与CWT密度大小均为笋尖中部基部。[结论]避光显著降低麻竹竹笋壁的苦涩味强度及单宁含量,自然光照下生长的麻竹笋苦涩味强度及单宁含量显著高于避光处理;光与竹笋中单宁物质分布和形态相关不显著,单宁形态仅与竹笋部位密切相关。覆土、套袋等避光措施可显著降低笋体单宁物质的含量,降低苦涩味,改善竹笋的口感品质,为培育低苦涩味麻竹笋提供科学的理论依据。     

The pupal morphology of <Emphasis Type="Italic">Cameraria ohridella</Emphasis> compared with that of the genus <Emphasis Type="Italic">Phyllonorycter</Emphasis> (Lepidoptera: Gracillariidae)

The pupal morphology of the pest species Cameraria ohridella is described and compared with that of the genus Phyllonorycter. The most striking differences are the longer antennal appendages, the absence of a cremaster, the presence of strong lateral thorns on abdominal segments 1–5 and an area without small spines on the same abdominal segments in Cameraria.     

Morphological and cultural variation of Seiridium spp. from cankered Cupressaceae hosts in New Zealand

Studies of Seiridium. spp. isolated from cankered cypresses and related hosts in New Zealand indicate that only 2 species are present, namely, 5. unicorne and 5. cardinale, following sdtton, and not 3 species as proposed by boesewinkel. Apart from a difference in the presence/absence of conidial appendages, the two pathogens are similar in many biological characteristics. Isolates of S. unicorne showed a continuum of variation in conidial size and cultural morphology making it difficult to justify splitting of the species.     

Studies of Marssonina castagnei in Australasia

Comparative studies of conidium morphology and host range and pathogenicity tests of Australian and New Zealand isolates of Marssonina castagnei in the laboratory established their equivalence which was indicative of a common origin. It is speculated that trans-Tasman dispersal is responsible for the introduction of M. castagnei into New Zealand and its widespread distribution. This is based on the prior recording of M. castagnei in Australia, the potential of M. castagnei conidia for long distance transport and the proven records of trans-Tasman dispersal of other pathogens. Laboratory inoculations and field observations showed P. alba cv. Silver poplar and its hybrids to be highly susceptible to M. castagnei. Populus alba X P. glandulosa hybrids and Italian selections of P. alba showed high field resistance.     

Morphology and molecular phylogeny of Erysiphe japonica var. japonica found on Quercus aliena in Korea

In October 2022, Erysiphe powdery mildew from the section Typhulochaeta was found on Quercus aliena for the first time in Korea. Based on morphological characteristics and molecular-phylogenetic analysis of the internal transcribed spacer region (ITS) and large subunit (LSU) gene sequences of the rDNA, the fungus was identified as Erysiphe japonica var. japonica. This is the first report of E. japonica var. japonica in Korea and the third report of this mildew on Q. aliena, with this current fungus-host association spreading to China and Japan. Based on Korean samples, this study provides detailed morphology and molecular phylogeny of E. japonica var. japonica.