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161.
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Evapotranspiration and water yield of a pine‐broadleaf forest are not altered by long‐term atmospheric [CO2] enrichment under native or enhanced soil fertility 下载免费PDF全文
Eric J. Ward Ram Oren Hyun Seok Kim Dohyoung Kim Pantana Tor‐ngern Brent E. Ewers Heather R. McCarthy Andrew Christopher Oishi Diane E. Pataki Sari Palmroth Nathan G. Phillips Karina V. R. Schäfer 《Global Change Biology》2018,24(10):4841-4856
Changes in evapotranspiration (ET) from terrestrial ecosystems affect their water yield (WY), with considerable ecological and economic consequences. Increases in surface runoff observed over the past century have been attributed to increasing atmospheric CO2 concentrations resulting in reduced ET by terrestrial ecosystems. Here, we evaluate the water balance of a Pinus taeda (L.) forest with a broadleaf component that was exposed to atmospheric [CO2] enrichment (ECO2; +200 ppm) for over 17 years and fertilization for 6 years, monitored with hundreds of environmental and sap flux sensors on a half‐hourly basis. These measurements were synthesized using a one‐dimensional Richard's equation model to evaluate treatment differences in transpiration (T), evaporation (E), ET, and WY. We found that ECO2 did not create significant differences in stand T, ET, or WY under either native or enhanced soil fertility, despite a 20% and 13% increase in leaf area index, respectively. While T, ET, and WY responded to fertilization, this response was weak (<3% of mean annual precipitation). Likewise, while E responded to ECO2 in the first 7 years of the study, this effect was of negligible magnitude (<1% mean annual precipitation). Given the global range of conifers similar to P. taeda, our results imply that recent observations of increased global streamflow cannot be attributed to decreases in ET across all ecosystems, demonstrating a great need for model–data synthesis activities to incorporate our current understanding of terrestrial vegetation in global water cycle models. 相似文献
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Elizabeth A. Bray Amybeth Cohen Áine L. Plant Meena S. Moses Ryozo Imai Allen Griffiths 《Acta Physiologiae Plantarum》1997,19(4):405-418
In response to water deficit, endogenous abscisic acid (ABA) accumulates in plants. This ABA serves as a signal for a multitude
of processes, including regulation of gene expression. ABA accumulated in response to water deficit signals cellular as well
as whole plant responses playing a role in the pattern of gene expression throughout the plant. Although the function of genes
regulated by ABA during stress are currently poorly understood, a number of these genes may permit the plant to adapt to environmental
stress. 相似文献
166.
Acute myocardial ischemia was induced by occluding the LAD in Clawn miniature pigs. Eight pigs (group 1) were subjected to 6 h ischemia and nine pigs (group 2) were subjected to 20 min ischemia, followed by reperfusion for 340 min. Three animals of the group 1 died due to ventricular fibrillation after occlusion and in group 2, four animals died due to the arrhythmia after reperfusion. Though the ischemic area of group 2 (15.6% of the ventricle) was narrower than that of group 1 (21.7%), the survival rate was lower. We supposed that ischemia-reperfusion injuries were strongly connected with the hemodynamics of group 2. Clawn miniature pigs are useful experimental animals for myocardial ischemic researches. 相似文献
167.
Toshio Itoh T. Tanaka Ryozo Nagai Tetsuro Kamiya Toshitami Sawayama Toshio Nakayama Hitonobu Tomoike Harumizu Sakurada Yoshio Yazaki Yusuke Nakamura 《Human genetics》1998,102(4):435-439
Familial long QT syndrome (LQTS) is characterized by prolonged ventricular repolarization. Clinical symptoms include recurrent
syncopal attacks, and sudden death may occur as a result of ventricular tachyarrhythmias. Three genes responsible for this
syndrome (KVLQT1, HERG, and SCN5A) have been identified so far, and mutations have been reported on the basis of partially characterized genomic organization.
To optimize the search for HERG mutations, we have determined the genomic structure of HERG and investigated mutations in LQTS families. Human genomic clones containing the HERG gene were isolated from a human genomic library by using reverse-transcribed polymerase chain reaction (RT-PCR) products
from this gene as probes. We determined exon/intron boundaries and flanking intronic sequences by using primers synthesized
on the basis of the HERG cDNA sequence available in the DNA database. HERG was shown to consist of 15 exons spanning approximately 19 kb on chromosome 7q35. Subsequently, we synthesized oligonucleotide
primers to cover the entire coding region and searched for mutations in 36 Japanese LQTS families. When genomic DNA from each
proband was examined by the PCR/single-strand conformation polymorphism technique followed by direct DNA sequencing, five
novel mutations were detected. Each mutation was present in affected relatives of the respective proband. This work should
increase the efficiency of screening mutations associated with HERG.
Received: 4 November 1997 / Accepted: 5 January 1998 相似文献
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Kimberly A. Novick A. Christopher Oishi Chelcy Ford Miniat 《Global Change Biology》2016,22(12):4014-4027
In mountainous areas, cold air drainage from high to low elevations has pronounced effects on local temperature, which is a critical driver of many ecosystem processes, including carbon uptake and storage. Here, we leverage new approaches for interpreting ecosystem carbon flux observations in complex terrain to quantify the links between macro‐climate condition, drainage flows, local microclimate, and ecosystem carbon cycling in a southern Appalachian valley. Data from multiple long‐running climate stations and multiple eddy covariance flux towers are combined with simple models for ecosystem carbon fluxes. We show that cold air drainage into the valley suppresses local temperature by several degrees at night and for several hours before and after sunset, leading to reductions in growing season respiration on the order of ~8%. As a result, we estimate that drainage flows increase growing season and annual net carbon uptake in the valley by >10% and >15%, respectively, via effects on microclimate that are not be adequately represented in regional‐ and global‐scale terrestrial ecosystem models. Analyses driven by chamber‐based estimates of soil and plant respiration reveal cold air drainage effects on ecosystem respiration are dominated by reductions to the respiration of aboveground biomass. We further show that cold air drainage proceeds more readily when cloud cover and humidity are low, resulting in the greatest enhancements to net carbon uptake in the valley under clear, cloud‐free (i.e., drought‐like) conditions. This is a counterintuitive result that is neither observed nor predicted outside of the valley, where nocturnal temperature and respiration increase during dry periods. This result should motivate efforts to explore how topographic flows may buffer eco‐physiological processes from macroscale climate change. 相似文献
170.
Elizabeth A. Bray Tung-Yuan Shih Meena S. Moses Amybeth Cohen Ryozo Imai Áine L. Plant 《Plant Growth Regulation》1999,29(1-2):35-46
Many genes are induced by periods of water deficit, and a subset of these are dependent on elevated ABA content for expression. A number of drought-induced genes are not induced in leaves of the ABA-deficient mutant flacca from tomato (Lycopersicon esculentum) but are induced in detached, wilted wild-type leaves and ABA-treated leaves of both genotypes. The nucleotide sequence of the cDNA and corresponding genomic DNA fragment of one of these genes, his1-s (formerly called le20), encodes an amino acid sequence that is rich in Lys, Ala, and Ser. The predicted protein contains the tripartite structure of H1 histone and is similar to other H1 histones, especially in the globular domain. Since, his1-s is more closely related to a stress-induced gene from Lycopersicon pennellii than to another H1 histone in the tomato genome it is considered a stress-induced variant of H1 histone. his1-s mRNA accumulated in vegetative plants in response to other abiotic stress treatments, including application of polyethylene glycol, and salt. The mRNA preferentially accumulated in leaves as compared to roots. his1-s mRNA accumulation was controlled during development; the level was higher in developing seeds of mature green fruit than in detached wilted leaves. H1 histones have been implicated in the general repression of gene expression and in the regulation of specific genes. The rapid accumulation of his1-s mRNA during stress may indicate that this unique, stress-induced H1 histone is involved in controlling gene expression during plant stress. 相似文献