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81.
ANTTI KILPELÄINEN ASHRAFUL ALAM HARRI STRANDMAN SEPPO KELLOMÄKI 《Global Change Biology Bioenergy》2011,3(6):461-471
The study describes an integrated impact assessment tool for the net carbon dioxide (CO2) exchange in forest production. The components of the net carbon exchange include the uptake of carbon into biomass, the decomposition of litter and humus, emissions from forest management operations and carbon released from the combustion of biomass and degradation of wood‐based products. The tool enables the allocation of the total carbon emissions to the timber and energy biomass and to the energy produced on the basis of biomass. In example computations, ecosystem model simulations were utilized as an input to the tool. We present results for traditional timber production (pulpwood and saw logs) and integrated timber and bioenergy production (logging residues, stumps and roots) for Norway spruce, in boreal conditions in Finland, with two climate scenarios over one rotation period. The results showed that the magnitude of management related emissions on net carbon exchange was smaller when compared with the total ecosystem fluxes; decomposition being the largest emission contributor. In addition, the effects of management and climate were higher on the decomposition of new humus compared with old humus. The results also showed that probable increased biomass growth, obtained under the changing climate (CC), could not compensate for decomposition and biomass combustion related carbon loss in southern Finland. In our examples, the emissions allocated for the energy from biomass in southern Finland were 172 and 188 kg CO2 MW h?1 in the current climate and in a CC, respectively, and 199 and 157 kg CO2 MW h?1 in northern Finland. This study concludes that the tool is suitable for estimating the net carbon exchange of forest production. The tool also enables the allocation of direct and indirect carbon emissions, related to forest production over its life cycle, in different environmental conditions and for alternative time periods and land uses. Simulations of forest management regimes together with the CC give new insights into ecologically sustainable forest bioenergy and timber production, as well as climate change mitigation options in boreal forests. 相似文献
82.
JOONG KI CHOI D. WAYNE COATS DAVID C. BROWNLEE EUGENE B. SMALL 《The Journal of eukaryotic microbiology》1992,39(1):80-92
ABSTRACT. The infraciliatures of three Chesapeake Bay species of Eutintinnus conforming in lorica morphology to E. angustatus, E. pectinis , and E. tenuis were compared following Protargol silver impregnation. The kinetome of these species had a number of shared attributes including: 1) a right and left field that were of similar length and kinetal spacing; 2) two, rarely three, long dorsal kineties composed of monokinetids; 3) a ventral kinety; and 4) the absence of a true posterior kinety. Nonetheless, the specific organization of infraciliary components varied considerably among species. For example, the organization of the ventral kinety and several kineties along the border of the left field was different in all three species. In addition, the dorsal kineties of E. angustatus differed positionally from those of E. pectinis and E. tenuis . Some divergence in oral infraciliature was also noted, with the arrangement of infundibular oral polykinetids in E. pectinis and E. tenuis being distinct from that of E. angustatus . The amount of variation in the infraciliature of Eutintinnus spp. was much greater than previously noted for congeneric species of tintinnines and supports the separation E. angustatus, E. pectinis , and E. tenuis at the generic or subgeneric level. 相似文献
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84.
Syouhei Nishihama Akira Haraguchi Tomonori Kawano Keisuke Michiki Kohji Nakazawa Takuya Suzuki Kazuya Uezu Kazuharu Yoshizuka 《Limnology》2008,9(1):35-45
The total viable count, population density of Escherichia coli and coliform bacteria, and nitrogen in the microbiomass (microbiomass-N) in sediments were monitored monthly at 12 points
in the Ongagawa River basin from June 2002 to May 2006. The measurement of the sediment microbiomass-N was used for evaluation
of the sediment’s microbial population in the river ecosystem. An extraordinarily high population of E. coli was observed during the season when there was stagnant water in the basin, with a high population and an insufficient drain
diffusion system, and, thus hydrological water control is indispensable to prevent rapid E. coli growth. Microbiomass-N in sediments showed a negative correlation or independent fluctuation in relation to the bacterial
population in the water column of the river. Seasonal changes in extracted nitrogen (N) in river sediments did not show correspondence
with microbiomass-N in sediments. The microbiomass-N in sediments changed independently of the bacterial population in the
river water, indicating that the high population of bacteria in the water does not lead to a high microbial population in
river sediments. Ordination of the microbial parameters by canonical correspondence analysis (CCA) showed that microbiomass-N
in sediments was quite different from other parameters. Relatively higher H+ (lower pH), PO4
3− concentration and dissolved oxygen (DO) were the determinant parameters of higher microbiomass-N in sediments. A relative
microbial abundance between the water column and sediments as well as each of the microbial populations in the water column
and sediments could be a quantitative parameter for evaluating the biochemical processes of stream water. 相似文献
85.
Masayuki Onishi Nolan Ko Ryuichi Nishihama John R. Pringle 《The Journal of cell biology》2013,202(2):311-329
In yeast and animal cytokinesis, the small guanosine triphosphatase (GTPase) Rho1/RhoA has an established role in formation of the contractile actomyosin ring, but its role, if any, during cleavage-furrow ingression and abscission is poorly understood. Through genetic screens in yeast, we found that either activation of Rho1 or inactivation of another small GTPase, Cdc42, promoted secondary septum (SS) formation, which appeared to be responsible for abscission. Consistent with this hypothesis, a dominant-negative Rho1 inhibited SS formation but not cleavage-furrow ingression or the concomitant actomyosin ring constriction. Moreover, Rho1 is temporarily inactivated during cleavage-furrow ingression; this inactivation requires the protein Cyk3, which binds Rho1-guanosine diphosphate via its catalytically inactive transglutaminase-like domain. Thus, unlike the active transglutaminases that activate RhoA, the multidomain protein Cyk3 appears to inhibit activation of Rho1 (and thus SS formation), while simultaneously promoting cleavage-furrow ingression through primary septum formation. This work suggests a general role for the catalytically inactive transglutaminases of fungi and animals, some of which have previously been implicated in cytokinesis. 相似文献
86.
Yuuki Sakai Takumi Higaki Kimitsune Ishizaki Ryuichi Nishihama Takayuki Kohchi Seiichiro Hasezawa 《Plant Biotechnology》2022,39(1):5
The development of the plant body starts with spore germination in bryophytes. In many cases, the first division of the spore occurs after germination and cell elongation of the spore. In Marchantia polymorpha, asymmetric division occurs upon spore germination to generate two daughter cells: the larger one retains the ability to divide and develops into the thallus via sporeling or protonema, while the smaller one maintains tip growth and differentiates into the first rhizoid, providing a scaffold for initial development. Although spore germination of M. polymorpha was described in the 19th century, the intracellular processes of the first asymmetric division of the spore have not been well characterized. In this study, we used live-cell imaging analyses to elucidate microtubule dynamics during the first asymmetric division concomitantly with germination. In particular, we demonstrated that the preprophase band was not formed in the spore and that the bipolar prospindle, which is a microtubule structure surrounding the nucleus during prophase, migrated from the center to the periphery in the spore, suggesting that it was the earliest visible sign of cell polarity. We also showed that the occurrence of asymmetric division depended on actin filaments. Our findings regarding the first division of the spore in M. polymorpha will lead to a better model for cell-autonomous asymmetric division in plants. 相似文献
87.
E.-M. LUOMALA K. LAITINEN S. KELLOMÄKI & E. VAPAAVUORI 《Plant, cell & environment》2003,26(5):645-660
In this experiment, the photosynthetic acclimation of successive needle cohorts of Scots pine were studied during 3 years of growth at elevated CO2 and temperature. Naturally regenerated Scots pine (Pinus sylvestris L.) trees were subjected to elevated CO2 concentration (+CO2, 700 p.p.m), elevated temperature (+T, ambient +2 to +6 °C) and to a combination of elevated CO2 and temperature (+CO2 + T) in closed‐top chambers, starting in August 1996. Trees growing in chambers with ambient CO2 and ambient temperature served as controls (AmbC). Elevated CO2 influenced the dark reactions more than the light reactions of photosynthesis, as in the 1996 and 1997 cohorts the carboxylation capacity of Rubisco was reduced in the first and second year of exposure, but there was no consistent change in chlorophyll fluorescence. Net photosynthesis measured at growth concentration of CO2 was higher at +CO2 than at AmbC on only one measuring occasion, was generally lower at +T and was not changed at +CO2 + T. However, trees grown at +T tended to invest more nitrogen (N) in Rubisco, as Rubisco/chlorophyll and the proportion of the total needle N bound to Rubisco occasionally increased. The interaction of +CO2 and +T on Rubisco was mostly negative; consequently, in the second and third year of the experiment the carboxylation capacity decreased at +CO2 + T. In the 1996, 1997 and 1998 cohorts, the structural N concentration of needles was lower at +CO2 than at AmbC. Elevated CO2 and elevated temperature generally had a positive interaction on N concentration; consequently, N concentration in needles decreased less at +CO2 + T than at +CO2. At +CO2 + T, the acclimation response of needles varied between years and was more pronounced in the 1‐year‐old needles of the 1997 cohort than in those of the 1998 cohort. Thus, acclimation was not always greater in 1‐year‐old needles than in current‐year needles. In the +CO2 + T treatment, elevated temperature had a greater effect on acclimation of needles than elevated CO2. 相似文献
88.
89.
90.
The frost hardiness of 20 to 25-year-old Scots pine (Pinus sylvestris L.) saplings was followed for 2 years in an experiment that attempted to simulate the predicted climatic conditions of the future, i.e. increased atmospheric CO2 concentration and/or elevated air temperature. Frost hardiness was determined by an electrolyte leakage method and visual damage scoring on needles. Elevated temperatures caused needles to harden later and deharden earlier than the controls. In the first year, elevated CO2 enhanced hardening at elevated temperatures, but this effect disappeared the next year. Dehardening was hastened by elevating CO2 in both springs. The frost hardiness was high (40 °C), even at elevated temperatures, in midwinter, at which time the electrolyte leakage method underestimated the frost hardiness compared with the visual scoring. In addition to the significant differences between treatments, there was also significant variation between trees in frost hardiness within treatments. These results suggest that the risks of frost damage are marked in the predicted climatic conditions in Finland, and, more specifically, they depend on how the occurrence of the frost episodes changes with respect to climatic warming during the annual cycle, especially in the autumn and spring. We also conclude that the conditions in midwinter are not critical for frost injury to trees in the future. 相似文献