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Michiyasu Yasaka Mika Takiya Ichiro Watanabe Yasuyuki Oono Norio Mizui 《Journal of Forest Research》2008,13(2):83-88
Seed production is the most problematic part of tree regeneration and is the least amenable to control by silvicultural management.
Understanding variability in seed production among years and among trees will allow better planning of seed collection for
seedling production and natural regeneration. We estimated the extent of variability in seed production among years and within
years among individual trees. Specifically, we measured individual annual seed production in 11 woody species in Hokkaido,
northern Japan. We analyzed the coefficient of variation (CV) of seed production among years and among individual trees. We
used population- and individual-based CVs (CVpt and
) to estimate the variability in seed production among individual trees. Alnus hirsuta, in which these CVs among trees were maximal, will require further analyses of the spatial patterns of seed production among
individual trees. Additionally, we used population- and individual-based CVs (CVpy and ) to estimate the variability in seed production among years. The was statistically higher than in 2 of the 11 species: Betula maximowicziana and Sorbus alnifolia. Activities for the regeneration of these species should regard the annual variation in seed production as more important
than individual variation. For the nine species in which was similar to even if seed production by specific trees was not sufficient for regeneration in a particular year, other trees or stands
often had high seed production in that year. We discuss the relative importance of annual and individual variability in determining
efficient methods for artificial and natural regeneration of these woody plant species. 相似文献
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Mika Takiya Hiromasa Koyama Kiyoshi Umeki Michiyasu Yasaka Yasuyuki Ohno Ichiro Watanabe Kazuhiko Terazawa 《Journal of Forest Research》2010,15(3):149-160
We examined the effect of early and intense pruning on light intensity under the canopy, individual growth, diameter–height
relationships, and epicormic shoot dynamics in young hybrid larch (Larix gmelinii var. japonica × L. kaempferi) to establish a new effective management method for hybrid larch plantations. The objective is to produce high-quality wood
while reducing silviculture costs using a combination of low-density planting and early and intense pruning. In a young hybrid
larch plantation, we pruned branches to two different heights (2 and 4 m above ground level) using a no-pruning treatment
as a control. Although the growth rates were lower in the heavy pruning treatment (4 m above the ground level) than in other
treatments in the year following pruning, when measured 4 years later, growth did not differ between treatments. The number
of epicormic shoots increased in the year following pruning, as did the relative photosynthetic photon flux density (rPPFD).
The number of epicormic shoots was also dependent on the size of individual trees. However, survival of epicormic shoots was
not sufficiently high to be problematic for high-quality timber production. If branches are pruned carefully such that the
rPPFD does not rise above 20%, the emergence of epicormic shoots can also be controlled. Our results indicate that early and
intense pruning is an effective component of a new management system for hybrid larch plantations. 相似文献
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Yasaka Yurie Binh Phan Trong Hayami Yuki Tanaka Ryusuke Uchida Katsuhisa Taoka Yousuke 《Fisheries Science》2023,89(1):41-51
We focused on developing an epidemic prevention method for circulating masu salmon aquaculture using the probiotic Lactococcus lactis strain K-C2. This study aimed to evaluate the antibacterial activities of strain K-C2 against pathogens isolated from dead Yamame and masu salmon. First, we identified pathogenic bacteria that were isolated from dead masu salmon based on phylogenetic analysis of the 16S rRNA gene sequence and biological and biochemical characterization. The antibacterial activity of strain K-C2 against seven pathogenic strains isolated from dead masu salmon in this study and two strains of Aeromonas salmonicida previously isolated from dead Yamame was tested using a double agar plate method. The results of a BLAST search using 16S rRNA partial sequence data (1200–1300 bp) revealed that six of the former strains and one of the latter strains showed high similarity to Vibrio anguillarum and Tenacibaculum maritimum, respectively. Strain K-C2 showed antibacterial activity against all pathogenic bacteria. In this study, pathogenic bacteria were newly isolated from dead seawater-acclimated masu salmon, and strain K-C2 was found to have antibacterial effects against these pathogens.
相似文献5.
Naofumi Yasaka Keisuke Suzuki Yasuhiro Kishioka Jun‐ichi Wakamatsu Takanori Nishimura 《Animal Science Journal》2013,84(9):663-668
Myostatin is a growth and differentiation factor and acts as a negative regulator of skeletal muscle mass. Although the mechanism whereby myostatin controls muscle cell growth is mostly clarified, the regulation of myostatin activity after its secretion into the extracellular matrix (ECM) is still unclear. In the present study, we investigated the interaction between laminin and myostatin and the effect of laminin on myostatin signaling in vitro. The surface plasmon resonance assay showed that laminin bound to mature myostatin and activin receptor type IIB (ActRIIB), but did not bind to latency‐associated protein, which remains non‐covalently linked to mature myostatin. Furthermore, kinetic analysis demonstrated that the affinity of mature myostatin for laminin was similar to that for ActRIIB. Next, we examined the action of laminin on the myostatin signaling pathway using a conventional reporter assay. The luciferase activity of myostatin‐treated cells was repressed significantly (P < 0.05) by coincubation of laminin. These results suggest that laminin has a potential to regulate myostatin activity through binding to mature myostatin and/or its receptor ActRIIB. 相似文献
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In this study, a weeding-duration model for Larix kaempferi plantations was developed that employs a generalized linear model. The number of years that weeding is necessary is the response
variable, and elevation, slope, maximum snow depth, annual precipitation, geological type, soil type, site index, slope aspect,
and vegetation type are explanatory variables. Among the explanatory variables, geological type, soil type, slope aspect,
and vegetation type are categorical data. We assumed a Poisson distribution for the response variable. The link function was
log. Among the models that could be developed from these variables, we chose the model with the smallest Akaike’s information
criterion (AIC). The weeding-duration model can be written as follows: years that weeding is necessary = Exp (−0.0172833 × site
index + 0.0014053 × maximum snow depth (cm) + 1.7417731). The results of this study imply that weeding of Larix kaempferi plantations is needed for more years as the maximum snow depth increases and fewer years as the site index increases. This
model is useful for cost–benefit analyses of afforestation or reforestation with Larix kaempferi. 相似文献
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Yasuyuki Ohno Kiyoshi Umeki Kazuhiko Terazawa Michiyasu Yasaka Ichiro Watanabe Mika Takiya 《Journal of Forest Research》2010,15(3):161-168
We analyzed the probability that Betula maximowicziana Regel (monarch birch) would suffer crown dieback (crown-dieback probability) and the basal area growth rate (GB), which was
found to be a predisposing stress factor making birch trees susceptible to crown dieback. First, we analyzed the relationship
between the probability that birch trees would suffer from crown dieback in 1999 and GB from a period prior to the occurrence
of crown dieback (1985–1987), using a data set of repeated measurements on 217 trees. Logistic regression analysis revealed
that monarch birch had a larger crown-dieback probability when GB was low in the preceding period. Hence, there were predisposing
stress factors that reduced GB and continued to affect trees for at least a decade. Next, we analyzed GB in the same period
in relation to symmetrical and asymmetrical competition between trees and found that GB was reduced by symmetrical competition,
suggesting that this was one of the predisposing factors for crown dieback. Based on these results, we used selected models
for crown-dieback probability and GB to calculate crown-dieback probabilities for individuals with different initial basal
areas and experiencing different intensities of symmetrical competition. The predicted crown-dieback probability decreased
with decreasing symmetrical competition between trees. We discuss a possible process of crown dieback to death for monarch
birch and the use of thinning as a method to reduce the risk of crown dieback. 相似文献
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Basal area growth and mortality of Betula maximowicziana affected by crown dieback in a secondary forest in Hokkaido, northern Japan 总被引：1，自引：0，他引：1
Yasuyuki Ohno Kiyoshi Umeki Ichiro Watanabe Mika Takiya Kazuhiko Terazawa Michiyasu Yasaka Sawako Matsuki 《Journal of Forest Research》2009,14(1):37-43
Since the late 1990s, decline of B. maximowicziana Regel has been observed in mature secondary forests in various parts of Hokkaido, northern Japan. To develop a method of
thinning for large-timber production of B. maximowicziana, we measured basal area growth and the mortality of 217 trees during a four-year period (1999–2003) in a 90-year-old secondary
forest with serious tree damage. We analyzed growth and mortality in relation to the degree of crown dieback (DC), symmetric
and asymmetric competition from neighbors, and initial tree size. Individual basal area growth decreased with increasing DC,
with increasing symmetric (two-sided) competition, and with decreasing initial tree size. During the four-year period, 4.1%
of the observed trees died. Logistic regression analysis revealed that mortality rate increased with increasing DC and with
increasing symmetric competition. These results suggest that both growth and mortality rates were affected by the same factors
(i.e., DC and symmetric competition). We concluded that the resource for which individuals were competing at the study site
was underground, most likely water. Modeled growth and mortality rates can be used to improve the management of damaged forests.
A management plan for the damaged study site is proposed. 相似文献
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