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101.
Ecological investigation of the distribution and composition of dung beetle species utilizing feces of wild mammals has rarely
been attempted, especially in cool-temperate forests. In this study we recorded and evaluated the community structure of dung
beetle species utilizing feces of Japanese monkeys (Macaca fuscata) by conducting a macro-scale inventory survey in the northeastern Shirakami Mountains, located in the northernmost part of
mainland Japan. Moreover, to assess the effect of human-induced forest disturbance on species assemblages in this cool-temperate
area, we also carried out field sampling using pitfall traps baited with monkey feces in primary forests, secondary forests,
and coniferous plantations, during every season except winter. Our findings were: (1) 14 dung beetle species comprising eight
dwellers and six tunnelers utilized monkey feces; (2) Aphodius eccoptus was the core species in dung beetle assemblages attracted to the feces during spring and summer; (3) the frequency of occurrence
of every species was extremely high in spring; and (4) human-induced forest disturbance did not increase species richness
or biomass in cool-temperate forests. 相似文献
102.
Kobayashi Makoto Muneto Hirobe Thomas H. DeLuca Semyon V. Bryanin Valentina F. Procopchuk Takayoshi Koike 《Journal of Soils and Sediments》2011,11(8):1317-1322
Purpose
Fire is a primary form of disturbance in boreal ecosystems. Charcoal is an important by-product of forest fire and has been reported to have the potential to influence the plant community establishing after fire. To date, however, no study has effectively tested the relationship between charcoal and plant regeneration in the actual post-fire forests. To determine the contribution of charcoal to soil properties and plant regeneration after forest fires, we conducted in situ investigations concerning the relationship between charcoal and the plant–soil system. 相似文献103.
Increasing demands for value-added salad products have triggered revolutionary changes in the production practices of vegetable salad crops in recent years. One of the pivotal changes is the adaptation of 2-m-wide beds for increased vegetable biomass per unit area. The move away from the traditional 1-m-wide raised beds in cool-season vegetable production and the associated irrigation practices potentially can have a major influence on diseases affecting cool-season vegetables. To assess the potential impacts of this shift on lettuce drop caused by Sclerotinia minor and S. sclerotiorum, the two bed widths and different irrigation frequencies within each were compared in two separate field experiments over four lettuce crops in 2 years. Treatments included 1- and 2-m bed widths with twice-weekly, weekly and biweekly drip irrigation serving as subplot treatments that were begun immediately following thinning. Incidence of lettuce drop was evaluated weekly thereafter until maturity. For S. sclerotiorum, 36 half-liter soil samples were also collected once each season and assayed for the number of sclerotia, and apothecia were counted weekly in a 10-m(2) area for each plot. Regardless of the species, the effects of bed width and irrigation frequency were both significant. Twice-weekly irrigation and 2-m bed width resulted in higher lettuce drop incidence than other treatments. For S. sclerotiorum, twice-weekly irrigation and 2-m bed width also significantly increased the number of apothecia per unit area and the accumulation of soilborne sclerotia over multiple cropping seasons. Results demonstrated that the 2-m bed width combined with the practiced frequency of irrigations can result in higher lettuce drop caused by S. minor and increased incidence of airborne infection by S. sclerotiorum in the Salinas Valley where, historically, it has not been a serious threat. Increased incidence of S. sclerotiorum infection in commercial lettuce fields in the Salinas Valley between 2001 and 2006 validates these experimental results. These relatively new crop production practices can alter the balance of the two Sclerotinia spp. that has long existed in California. 相似文献
104.
Since 2002, severe leaf spotting on parsley (Petroselinum crispum) has occurred in Monterey County, CA. Either of two different pathovars of Pseudomonas syringae sensu lato were isolated from diseased leaves from eight distinct outbreaks and once from the same outbreak. Fragment analysis of DNA amplified between repetitive sequence polymerase chain reaction; 16S rDNA sequence analysis; and biochemical, physiological, and host range tests identified the pathogens as Pseudomonas syringae pv. apii and P. syringae pv. coriandricola. Koch's postulates were completed for the isolates from parsley, and host range tests with parsley isolates and pathotype strains demonstrated that P. syringae pv. apii and P. syringae pv. coriandricola cause leaf spot diseases on parsley, celery, and coriander or cilantro. In a multilocus sequence typing (MLST) approach, four housekeeping gene fragments were sequenced from 10 strains isolated from parsley and 56 pathotype strains of P. syringae. Allele sequences were uploaded to the Plant-Associated Microbes Database and a phylogenetic tree was built based on concatenated sequences. Tree topology directly corresponded to P. syringae genomospecies and P. syringae pv. apii was allocated appropriately to genomospecies 3. This is the first demonstration that MLST can accurately allocate new pathogens directly to P. syringae sensu lato genomospecies. According to MLST, P. syringae pv. coriandricola is a member of genomospecies 9, P. cannabina. In a blind test, both P. syringae pv. coriandricola and P. syringae pv. apii isolates from parsley were correctly identified to pathovar. In both cases, MLST described diversity within each pathovar that was previously unknown. 相似文献
105.
Phelps CJ Koike C Vaught TD Boone J Wells KD Chen SH Ball S Specht SM Polejaeva IA Monahan JA Jobst PM Sharma SB Lamborn AE Garst AS Moore M Demetris AJ Rudert WA Bottino R Bertera S Trucco M Starzl TE Dai Y Ayares DL 《Science (New York, N.Y.)》2003,299(5605):411-414
The enzyme alpha1,3-galactosyltransferase (alpha1,3GT or GGTA1) synthesizes alpha1,3-galactose (alpha1,3Gal) epitopes (Galalpha1,3Galbeta1,4GlcNAc-R), which are the major xenoantigens causing hyperacute rejection in pig-to-human xenotransplantation. Complete removal of alpha1,3Gal from pig organs is the critical step toward the success of xenotransplantation. We reported earlier the targeted disruption of one allele of the alpha1,3GT gene in cloned pigs. A selection procedure based on a bacterial toxin was used to select for cells in which the second allele of the gene was knocked out. Sequencing analysis demonstrated that knockout of the second allele of the alpha1,3GT gene was caused by a T-to-G single point mutation at the second base of exon 9, which resulted in inactivation of the alpha1,3GT protein. Four healthy alpha1,3GT double-knockout female piglets were produced by three consecutive rounds of cloning. The piglets carrying a point mutation in the alpha1,3GT gene hold significant value, as they would allow production of alpha1,3Gal-deficient pigs free of antibiotic-resistance genes and thus have the potential to make a safer product for human use. 相似文献
106.
The use of forest biomass as a renewable energy source has received much attention as a response to climate change and the
increasing global demands for energy. Local availability and conversion into secondary energy carriers with a lower capital
investment shows more weights on its interests. The substitution of fossil fuel by biomass fuel can have a strong effect on
the mitigation of climate change through reducing greenhouse gases, which can be an important consideration for CDM projects
in Bangladesh. This study uses literature review to analyse the legal framework of carbon trading under CDM, CDM additionality,
CDM and bioenergy promotion, land availability and technology for biomass production, and sustainability of CDM projects in
Bangladesh. The barriers to CDM projects in Bangladesh are explained as well as measures for promoting biomass production.
Biomass and bioenergy-based CDM projects can be attractive and support sustainable development in Bangladesh. The study suggests
capacity building and policy changes needed in order to comply with CDM modalities. The study can be useful to the climate
change mitigation and development policy makers in Bangladesh. 相似文献
107.
During the past 4 years, significant damage occurred to commercially grown celery (Apium graveolens), an important vegetable crop grown in coastal areas of California. Symptoms consisted of dry, brown to tan lesions on the lower portions of plant petioles. Designated as celery petiole lesion (CPL), this problem only occurred during the summer and autumn growing periods and could cause mature plants to be unmarketable. Extensive isolations for pathogens failed to find an agent associated with the problem, and field trials involving fertilizers failed to reproduce CPL symptoms. However, experiments with pesticides indicated that the insecticide naled was associated with CPL. Greenhouse and field trials successfully reproduced symptoms identical to those found in commercial celery fields. Surveys in 1994 and 1995 indicated that all confirmed CPL cases in commercial fields were associated with the application of naled. In 1996, with the cancellation of the celery label for naled, no CPL was found in any celery field. Celery petiole lesion therefore should be identified as phytotoxicity due to ground applications of naled. 相似文献
108.
We used chlorophyll fluorescence to examine photosynthetic responses to excess Mn accumulation in leaves of four tree species differing in successional traits. Betula ermanii Cham. (Be) and Alnus hirsuta Turcz. (Ah) were studied as representatives of early-successional species. Ulmus davidiana Planch. var. japonica (Rehder) Nakai (Ud) was selected as a mid-successional species, and Acer mono Maxim. var. glabrum (Lév. et Van't.) Hara (Am) was chosen as a late-successional species. In Be, Ah and Am, high foliar concentrations of Mn had little effect on maximum photochemical efficiency of photosystem II (PSII), as indicated by the values of dark-adapted F(v)/F(m), whereas a significant decrease was observed in Ud. Photochemical quenching (qP) and the excitation capture efficiency of open PSII (F'(v)/F'(m)) decreased with increasing leaf Mn concentration at photosynthetic steady state after a 15-min exposure to 430 &mgr;mol m(-2) s(-1) PPFD. Compared with early-successional species, these decreases were greater in mid- and late-successional species leading to lower effective quantum efficiencies of PSII (DeltaF/F'(m) = qP x F'(v)/F'(m) = (F'(m) - F)/F'(m)). To determine the extent of photoinhibition, F(v)/F(m) of the illuminated leaves was remeasured after a 15-min dark period. Compared with the dark-adapted F(v)/F(m), we observed a significant decrease in F(v)/F(m) in Am leaves containing high concentrations of Mn. These chlorophyll fluorescence studies indicate that the early-successional species Be and Ah have a higher tolerance to excessive accumulations of Mn in leaves than the mid- and late-successional species Ud and Am. 相似文献
109.
Joni Kujansuu Koh Yasue Takayoshi Koike Anatoly P. Abaimov Takuya Kajimoto Takashi Takeda Morihiko Tokumoto Yojiro Matsuura 《Journal of Wood Science》2007,53(2):87-93
An analysis was performed on the climatic responses of the radial growth of Larix gmelinii (Rupr.) Rupr. on contrasting north-facing and south-facing slopes in Tura, central Siberia. We developed chronologies of
tree-ring width for four plots, designated as north-upper, northlower, south-upper, and south-lower. Both residual and standard
chronologies of tree-ring widths exhibited a significant positive correlation with temperature from the end of May until early
June in all four plots. The chronologies of ring width did not reveal any major difference in the response to temperature
among the four plots. The standard chronologies of ring widths on the north-facing slope were negatively correlated with precipitation
during the winter (October–April) and in early and mid-May, whereas the residual chronologies did not reveal clear relationships
with precipitation during the winter and May. The significant correlation between ring width and temperature from the end
of May until early June indicates that temperatures in springtime play a significant role in the radial growth of L. gmelinii. The negative correlations between standard chronologies of tree-ring width and precipitation in the winter and in May on
the north-facing slope indicate that lowfrequency fluctuations in snowfall have negative effects on the radial growth. However,
these effects vary and depend on the microscale topography.
Part of this report was presented at the 55th Annual Meeting of the Japan Wood Society, March 2005, Kyoto 相似文献
110.
Effects of elevated CO2 concentration on growth, annual ring structure and photosynthesis in Larix kaempferi seedlings 总被引:2,自引:0,他引:2
Yazaki K Ishida S Kawagishi T Fukatsu E Maruyama Y Kitao M Tobita H Koike T Funada R 《Tree physiology》2004,24(9):951-959
We evaluated the effects of elevated carbon dioxide concentration ([CO2]) and two nutrient regimes on stem growth rate, annual ring structure and temporal variations in photosynthetic characteristics of seedlings of Japanese larch (Larix kaempferi (Lamb.) Carr.). Seedlings were grown in phytotron chambers in an ambient (360 ppm) or an elevated (720 ppm) [CO2] in two nutrient regimes for one growing season. Elevated [CO2] reduced stem height and increased stem basal diameter compared with ambient [CO2]. The effect of elevated [CO2] on growth tended to be greater at high-nutrient supply than at low-nutrient supply. Elevated [CO2] had no significant effect on ring width or the number of tracheids per radial file. There was no obvious difference in cell wall thickness or the relative area of the cell wall between seedlings grown in ambient or elevated [CO2]. Although growth in elevated [CO2] resulted in a slight increase in cell diameter, the increase had a relatively minor effect on the relative area of the cell wall. Net assimilation rate increased in response to elevated [CO2]; however, the increase in whole-crown photosynthetic rate (Total Agrowth) in seedlings in the elevated [CO2] treatment was minimal because of the smaller specific needle area and acclimation of the photosynthetic characteristics of the needles to the growth [CO2]. In conclusion, we observed no obvious enhancement in the capacity for carbon fixation in Japanese larch seedlings grown in the presence of elevated [CO2] that might be attributable to changes in stem growth. However, elevated [CO2] caused changes in the temporal pattern of stem growth and in some anatomical features of the tracheids. 相似文献