Growth response of marigold (Tagetes erecta L.) to inoculation withGlomus mosseae,Trichoderma aureoviride andPythium ultimum in a peat-perlite mixture

The interactions between the mycorrhizal fungusGlomus mosseae, the plant pathogenPythium ultimum, and a pathogen-antagonistTrichoderma aureoviride in the rhizosphere ofTagetes erecta (marigold) were studied for their effects on plant growth in a peat-perlite substrate. Mycorrhizal fungus inoculation protected the plant againstP. ultimum, since both phytomass production and foliar development were higher in mycorrhizal plants.T. aureoviride had no effect on nonmycorrhizal plants in the presence or absence ofP. ultimum. However, more biomass was produced by mycorrhizal plants whenT. aureoviride was present, whether or not soil was infested withP. ultimum. ei]R Rodriguez-Kabana     

Structure and organization of the rDNA intergenic spacer region in <Emphasis Type="Italic">Pythium ultimum</Emphasis>

Nucleotide sequences of the rDNA intergenic spacer (IGS) region in Pythium ultimum were determined in 16 clones obtained from three isolates differing in production of sexual organs. Several sequences with different lengths were detected in each isolate, showing heterogeneity in the IGS region. In addition, several tandem repeat regions were detected in all the clones. The sequences, length, and number of each copy largely varied among repeat regions. Length heterogeneity arose from the complex combination of the number of copy within the repeat regions. Furthermore, the nucleotide sequence of each copy and the number of repetition varied not only between isolates but also between clones from an isolate. Based on the sequence similarity and the number of copies in repeat regions, specific patterns different between homothallic P. ultimum and the Pythium group HS (hyphal swellings) were recognized in a few regions. These results suggest that these two groups have slight genetic differences in the IGS region, although the differences in most of the repeat regions were not enough to identify each group.     

Towards a legal framework for systematic conservation: identification and development of allele-specific PCR markers for conspecific varieties of an endangered perennial herb <Emphasis Type="Italic">Primula kisoana</Emphasis> Miquel based on sequence variation of chloroplast DNA

Primula kisoana var. kisoana (Primulaceae) is a narrow endemic found only in extremely restricted areas of central Honshu Island, Japan. Although the species is included as ‘Critically Endangered (CR)’ in the latest Japanese Red List, it is not covered by legislation such as the ‘Law for the Conservation of Endangered Species of Wild Fauna and Flora, Japan’. This poor conservation status is due, largely, to the presence of another conspecific variety, var. shikokiana, which is regarded as less threatened than var. kisoana. In this study, we investigated the genetic dissimilarity between the two varieties by examining sequence variation in three noncoding regions of chloroplast DNA. Ten distinct haplotypes were detected, none of which were distributed across populations and varieties. The genetic differentiation between the two varieties revealed by an AMOVA and a minimum spanning network suggests that var. kisoana and var. shikokiana should be conserved and managed as separate units. Using the allele-specific PCR method, four primer pairs were developed at the point mutations and insertion/deletion loci that exhibited only inter-variety variation. These markers will facilitate reliable identification of var. kisoana, assisting in the implementation of restoration programs including the introduction of seedlings and construction of a legal framework for conservation.     

Chemical,physical and biological control of carrot seedling diseases

In naturally infested soil containingPythium ultimum, P. acanthicum andPhytophthora megasperma, onlyP. ultimum was associated with root rot and damped-off seedlings. Damping-off was promoted by low soil temperatures and by flooding. Seedling stands were markedly reduced when seed was pre-incubated in soil at 12°C but not at 25°C or 35°C. Dusting carrot seed with metalaxyl significantly increased seedling stands in the field at rates from 1.5–6 g kg⁻¹ seed and in both flooded and unflooded, naturally infested soil at 3.15 g kg⁻¹. In greenhouse experiments using artifically infested soil,P. ultimum andP. paroecandrum caused damping-off of carrot seedlings andRhizoctonia solani reduced root and shoot weights.R. solani caused damping-off in nutrient-enriched soil.P. acanthicum andP. megasperma were not pathogenic to seedlings, although both fungi colonized roots. Soil populations of allPythium spp., particularlyP. ultimum, increased during growth of seedlings and population growth ofP. megasperma was promoted by periodic flooding. Infestation of soil withP. acanthicum did not reduce damping-off of carrot seedlings byP. ultimum orP. paroecandrum, but significantly increased root and shoot weights and decreased root colonization byR. solani P. acanthicum has potential as a biocontrol agent againstR. solani.     

Upper limits of temperature for growth inChlorella (Chlorophyceae)

The upper limit of temperature for growth is a species-specific character in the genusChlorella. The limits of 14Chlorella species range from 26–30°C (C. saccharophila) to 38–42°C (C. sorokiniana), withC. fusca var.vacuolata (34°C) andC. kessleri (34–36°C) assuming an intermediate position. Thus, there is no wide gap in the temperature limits between the normal (“low-temperature”) species ofChlorella and the “high-temperature” species,C. sorokiniana.     

Lecanosticta acicola, causal fungus of brown spot needle blight inPinus thunbergii, new to Japan

A needle blight disease with brown spots was found on ornamental trees ofPinus thunbergii in Shimane Prefecture, Japan. The causal fungus was identified asLecanosticta acicola, known as causal fungus of brown spot needle blight of pines recorded in the Americas, Europe, and China.Pinus thunbergii was heavily infected following inoculation with the fungus in June, but only slightly infected following inoculation in September. The mycelia of the fungus were raised and produced conidial masses on potato-dextrose and Waksman agars. They grew well at 20–25°C within the range of 5 to 35°C.     

河北坝上樟子松人工林径向生长及其对气候因素的响应

利用树木年轮学方法测定了河北坝上地区樟子松逐年树轮宽度和胸高断面积增量,建立了樟子松树轮宽度差值年表并分析其对气候因素的响应以及生态弹性,为河北坝上地区利用樟子松开展退化杨树防护林更新建设的适宜性提供理论参考。研究结果表明,河北坝上地区樟子松树龄在28 a左右,其生长阶段可划分为快速生长期(0—10 a),生长下降期(11—20 a)和生长平稳期(21—28 a);樟子松树轮宽度在1992—2000年期间为快速增长期((4.49±1.15)mm/a),在2001—2010年期间呈现下降趋势((3.62±1.39)mm/a),而在2011—2019年期间樟子松生长呈平稳特征((2.21±0.68)mm/a),约为快速增长期增长速度的一半;樟子松BAI在1992—2000年间一直呈上升趋势((5.09±2.26)cm~2/a),2001—2019年期间呈平稳特征((10.46±0.67)cm~2/a),表现出稳定且持续的生长能力。樟子松差值年表与气候因素的相关性显示：樟子松径向生长主要与上一年生长季末期(9、10月)、休眠期(12月)及当年生长季(7月)平均温度和最高温度呈显著负相关,其中...     

Conversion of crude chitosan to an anti-fungal protease by <Emphasis Type="Italic">Bacillus cereus</Emphasis>

Bacillus cereus AU004, isolated from soil samples, secreted a complex of hydrolytic enzymes into the culture broth when it was grown aerobically in a medium containing crude chitosan flakes. The presence of the AU004 culture supernatant substantially influenced the growths of the plant-pathogenic fungi Fusarium oxysporum, F. solani and Pythium ultimum in terms of dry weight. AU004 excreted a protease when cultivated in a medium that contained 4% (w/v) chitosan as the major nutritional source. The protease was purified by sequential chromatography and characterized as a novel extracellularly neutral protease. The protease had an Mr of 28.8 kDa. The optimal pH and temperature for protease activity were 7 and 50°C, respectively. Antifungal activity of the protease was observed using an assay based on the inhibition of spore germination and hyphal extension of the fungal Pythium ultimum. This investigation is the first report of the production of an anti-fungal protease from Bacillus spp.     

Isozyme variation in Larrea ameghinoi and Larrea nitida (Zygophyllaceae): genetic diversity and its bearing on their relationship

Electrophoretic variants for 11 isozyme systems were examined by horizontal polyacrilamide gel electrophoresis in natural populations of Larrea ameghinoi and L. nitida (section Larrea). The two taxa presented fixed alternative allelic variants at loci Adh-1, Gdh-1 and Mdh-1. Genetic variability estimates showed no statistically significant differences among populations of section Larrea (H_e: 0.097–0.167). However, these values were significantly lower than those reported for species of section Bifolium (L. divaricata, diploid L. tridentata) in a previous contribution (H_e: 0.17–0.29). Positive and highly significant Wright's fixation indices are in agreement with higher amounts of inbreeding for nitida and L. ameghinoi, as suggested on the basis of floral morphology by previous authors. Moreover, the higher levels of genetic differentiation obtained for conspecific populations of section Larrea as compared to those of section Bifolium are also consistent with these observations. Nei's genetic identity values obtained for sympatric (I=0.80) and allopatric (I=0.63–0.73) L. ameghinoi – L. nitida population pairs are concordant with those expected for different, but closely related congeneric species. This revised version was published online in July 2006 with corrections to the Cover Date.     

Isolation and characterization of microsatellite loci in the endangered tree Berchemiella wilsonii var. pubipetiolata and cross-species amplification in closely related taxa

Twenty-eight polymorphic microsatellite loci were developed and characterized for the endangered tree Berchemiella wilsonii var. pubipetiolata. The observed number of allele ranged from two to seven. The ranges of observed and expected heterozygosity were 0.039–1.000 and 0.038–0.816, respectively. In addition, this set of microsatellites produced robust cross-species amplification in other two endangered taxa: Berchemiella berchemiaefolia and Berchemiella wilsonii, suggesting these microsatellite markers should provide a useful tool for genetic and conservation studies of the globally endangered genus Berchemiella.     

Synchronized spawning ofanguilla japonica inferred from daily otolith increments in leptocephali

The exact timing ofAnguilla japonica spawning was determined from analyses of daily otolith increments in leptocephali collected near a spawning area west of the Mariana Islands on July 1–18, 1991. The birth dates of the 54 leptocephali examined (10.2 to 30.5 mm in total length) ranged from May 22 to June 24, 1991, the individuals clearly comprising two age groups, May-born fish (mode May 28) and June-born fish (mode June 21). The data showed thatA. japonica spawns intermittently during the spawning season, with fixed synchronized timing. Each group of leptocephali collected along three different north-south transects (131°, 134° and 137°E between 10° and 22°N) comprised both May-born and June-born fish. The latter were dominant along the easternmost and middle transects, whereas the May-born fish were more abundant along the westernmost transect. The modal ages of the June-born and May-born fish collected along 137°E on July 1–3 were 13 d and 35 d, respectively, while those of the two age groups collected along 134°E on July 17 and 18 were 28 d and 50 d, respectively. These data show that the interval between the sampling dates for the two transects (ca. 15 d) corresponded closely to the differences in modal ages of specimens from the two transects (15 d) for both the May- and June-born fish, and further, that the difference in modal age between the two age groups (22 d) was the same at both transects. A similar correspondence in total length was also observed between the two age groups at the above two transects. The findings clearly demonstrated parallel westward transport by the North Equatorial Current for both the May- and June-born eel leptocephali, which originated from a spawning area estimated as being between 141° and 143°E.     

Protecting evolutionary significant units for the remnant populations of <Emphasis Type="Italic">Berchemiella wilsonii</Emphasis> var. <Emphasis Type="Italic">pubipetiolata</Emphasis> (Rhamnaceae)

Berchemiella wilsonii var. pubipetiolata (Rhamnaceae) is an endangered tree in eastern China. Habitat destruction has resulted in fragmentation of remnant populations and extinction of local populations. AFLP and cpDNA markers were used to determine the population structure of remnant populations of B. wilsonii var. pubipetiolata. Moderate nuclear genomic diversity was found within each of the four remnant populations (H _S = 0.141–0.172), while the cpDNA haplotype diversity in each population ranged from 0.356 to 0.681. Six haplotypes were identified by a combined cpRFLP and cpSSR analysis in a total of 89 individuals. AMOVA revealed significantly AFLP genetic differentiation within and between regions (Φ_SC = 0.196, Φ_CT = 0.396, respectively), and a high cpDNA haplotype differentiation between regions (Φ_CT = 0.849). The results suggest low gene flow between populations of B. wilsonii var. pubipetiolata. Strong genetic divergence between two regional populations as revealed by both AFLP and cpDNA markers provided convincing evidence that two distinct evolutionary lineages existed, and should be recognized as ‘evolutionary significant units’ (ESUs) for conservation concerns.     

Eastern Cottontail (<Emphasis Type="Italic">Sylvilagus Floridanus)</Emphasis> as Carrier of Dermatophyte Fungi

Eastern cottontail (Sylvilagus floridanus, fam. Leporidae), introduced into Piedmont (Italy) in the 1960s, was studied as carrier of dermatophyte fungi. Of 216 hair samples collected from animals culled between September 1999 and July 2000 in the Province of Alessandria (Piedmont, Italy) during a pest control project, 57 (26.4%) yielded dermatophyte colonies. As two different species of dermatophytes grew from two samples, a total of 59 fungal isolates (26.5%) were obtained. Six dermatophyte species both geophilic (M. gypseum, M. cookei, Trichophyton ajelloi, T. terrestre) and zoophilic (M. canis, T. mentagrophytes) were identified. No sex-related differences were found but season-related differences were observed. The highest prevalence of dermatophyte-positive samples was recorded in May–September, due to the geophilic fungi whose prevalence decreased during colder and increased during warmer months ( p < 0.001). The presence of zoophilic dermatophytes, T. mentagrophytes, commonly associated with rodents, small mammals and lagomorphs and M. canis, usually correlated with domestic environment, did not change the whole year round. As Eastern cottontail has been showed to be a carrier of dermatophytes transmissible to man (M. canis, T. mentagrophytes and M. gypseum), it may represent a source of infection for gamekeepers, hunters and veterinarians.     

Flavonoids in roots of white clover: interaction of arbuscular mycorrhizal fungi and a pathogenic fungus

The effects of two arbuscular mycorrhizal fungi (AMF) (Glomus mosseae and G. claroideum) and a pathogenic fungus (Pythium ultimum) on the production of eight flavonoids in roots of two white clover (Trifolium repens L.) cultivars were evaluated. Quantification of AM and pathogenic fungi in the roots showed that the AM symbiosis significantly reduced P. ultimum biomass and in some cases prevented infection. The flavonoid productions in clover roots varied depending on the presence of beneficial and/or pathogenic fungi, fungal isolate or plant cultivar. Only plants colonized with G. claroideum showed detectable concentrations of either coumestrol or kaempferol (cultivar-dependant). In addition, inoculation with G. claroideum resulted in significantly higher concentrations of coumestrol in cv. Sonja and medicarpin in cv. Milo. A low production of coumestrol and kaempferol in mycorrhizal plants may be G. mosseae-specific. Only the concentrations of formononetin and daidzein increased in clover roots in response to infection with P. ultimum. These flavonoids are supposedly stress metabolites, synthesized or produced from glycosides in response to pathogen infection. However, the presence of one or both AMF significantly lowered the formononetin and daidzein concentrations, and overruled the inductive effect of P. ultimum. Therefore the antagonistic action of AM against the pathogen must take place through another mechanism.     

Water temperature and upstream migration of glass eels in New Zealand: implications of climate change

Glass eels migrating upstream in a New Zealand river showed a clear preference for water temperatures between 12 and 20°C, with an optimum of 16.5°C. Water temperatures <12°C and >22°C almost completely inhibited migration, which implies that warmer temperatures associated with global climate change might have a detrimental impact on glass eel recruitment in their current ranges. We established this by trapping glass eels of shortfin, Anguilla australis, and longfin, A. dieffenbachii, eels nightly from September to November. Eels caught in 2001 (50,287) outnumbered those caught in 2002 (19,954); shortfin glass eels dominated catches in both years, comprising 91–93% of the catch. Longfins were larger than shortfins, and size and pigmentation in both species increased as the seasons progressed. Temperatures within the migratory season in 2001 showed ∼14-day intervals between maxima that appeared to be associated with the new and full moons.     

Involvement of G-alpha protein GNA3 in production of cell wall-degrading enzymes by Trichoderma reesei (Hypocrea jecorina) during mycoparasitism against Pythium ultimum

The involvement of the G-alpha protein GNA3 in the production of cell wall-degrading enzymes (CWDEs) by Trichoderma reesei during antagonism against Pythium ultimum was investigated. cAMP content was 2.8-fold higher in the T. reesei mutant gna3QL than in the parental TU-6. The gna3QL, like TU-6, inhibited the growth of P. ultimum in dual culture assays. Scanning electron microscopy showed that the gna3QL promoted more morphological alterations of P. ultimum cell wall than TU-6. In general, gna3QL produced higher activities of CWDEs than TU-6. We therefore suggest that CWDEs production during mycoparasitism by T. reesei against P. ultimum may be associated with the level of GNA3 activity.     

Materials for the fungus flora of Japan (56)Mariannaea camptospora andM. elegans var.punicea from Japan

One additional species and a variety ofMariannaea, M. camptospora andM. elegans var.punicea, were recorded for the first time in Japan.Mariannaea camptospora formed two types of conidiophores. One type was characterized by simple verticillate phialides sometimes with punctuate walls at the base, producing long oblique conidial chains, and symmetrical spindle-shaped conidia. The other type was characterized by more crowded and shorter phialides with small conidial droplets and hemispherical to concave smaller conidia.Mariannaea elegans var.punicea was characterized by distinct red purple pigmentation in agar media. (55): Udagawa, S. and Uchiyama, S., Mycoscience41: 263–267, 2000.     

Effects of temperature and salinity on the growth of Gracilaria verrucosa and G. chorda, with the Potential for mariculture in Korea

Effects of temperature and salinity on the growth of the two agarophytes, Gracilaria verrucosa (Hudson) Papenfuss and Gracilaria chorda Holmes were examined in Korea. Both species grew over a wide range of temperatures (10–30 ^∘C) and salinities (5–35‰), and grew well at 17–30 ^∘C and a salinity of 15–30‰. In culture, G. verrucosa grew faster than G. chorda and their maximum growth rates were 4.95% day⁻¹ (30 ^∘C, 25‰) and 4.47% day⁻¹ (at 25 ^∘C, 25‰), respectively. In the field population the maximum growth and fertility of G. chorda were observed in summer. The growth rate of G. verrucosa was slightly higher than that of G. chorda for 2 weeks on the cultivation rope and in culture but it was much lower after being contaminated with epiphytes. The biomass of the epiphytes was 0.82 g dry wt. per host plant in G. verrucosa and 0.001 g in G. chorda. G. chorda exhibited resistance to epiphytism and grew 7 times in length and the dry weight increased 15 times after 55 days. In conclusion, G. chorda appears to be a good agarophyte with a fast growth rate and resistance to epiphytesm, and compared with G. verrucosa, has good potential for commercial cultivation.     

Development and characterization of polymorphic microsatellite loci in endangered fern Adiantum reniforme var. sinense

Fourteen polymorphic microsatellite loci in the endangered fern Adiantum reniforme var. sinense were developed and characterized using the Fast Isolation by AFLP of Sequences Containing repeats (FIASCO) protocol. Polymorphism of each locus was assessed in a bulked sample of 30 individuals from 8 natural populations. The number of alleles per locus varied from 2 to 11, with an average value of 6.2. The ranges of observed and expected heterozygosity were 0.000–0.895 and 0.226–0.868, respectively. These microsatellite markers provide useful tools for the ongoing conservation genetic studies of Adiantum reniforme var. sinense.     

Application of a rapid glucose-6-phosphate isomerase assay in white cabbage breeding

In the studied conditions of cellulose acetate electrophoresis only glucose-6-phosphate isomerase (PGI, EC 5.3.1.9) appeared to be a polymorphic isozyme. The PGI analysis of 23 cabbage (Brassica oleracea var. capitata) inbred lines, carried out in two years, allowed detecting off-type individuals in four lines. Seed contamination caused by sib-pollination was detected in 10 out of 19 F₁ hybrids. In five of them the contamination did not exceed 5 %, and in the remaining five, ranged from 27–52 %. Also homozygosity of 67 plants obtained through anther culture in vitro was confirmed. The results indicate that PGI electrophoresis in cellulose acetate matrix is very fast and can be useful in the assessment of genetic purity in cabbage breeding materials.