Publications by authors named "Takayoshi Koike"

74 Publications

Ozone disrupts the communication between plants and insects in urban and suburban areas: an updated insight on plant volatiles.

J For Res (Harbin) 2021 Jan 10:1-13. Epub 2021 Jan 10.

Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.

Plant-insect interactions are basic components of biodiversity conservation. To attain the international Sustainable Development Goals (SDGs), the interactions in urban and in suburban systems should be better understood to maintain the health of green infrastructure. The role of ground-level ozone (O) as an environmental stress disrupting interaction webs is presented. Ozone mixing ratios in suburbs are usually higher than in the center of cities and may reduce photosynthetic productivity at a relatively higher degree. Consequently, carbon-based defense capacities of plants may be suppressed by elevated O more in the suburbs. However, contrary to this expectation, grazing damages by leaf beetles have been severe in some urban centers in comparison with the suburbs. To explain differences in grazing damages between urban areas and suburbs, the disruption of atmospheric communication signals by elevated O via changes in plant-regulated biogenic volatile organic compounds and long-chain fatty acids are considered. The ecological roles of plant volatiles and the effects of O from both a chemical and a biological perspective are presented. Ozone-disrupted plant volatiles should be considered to explain herbivory phenomena in urban and suburban systems.

Supplementary Information: The online version of this article contains supplementary material available at (10.1007/s11676-020-01287-4) to authorized users.
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http://dx.doi.org/10.1007/s11676-020-01287-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7797194PMC
January 2021

Efficient detection of copy-number variations using exome data: Batch- and sex-based analyses.

Hum Mutat 2021 Jan 11;42(1):50-65. Epub 2020 Nov 11.

Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan.

Many algorithms to detect copy number variations (CNVs) using exome sequencing (ES) data have been reported and evaluated on their sensitivity and specificity, reproducibility, and precision. However, operational optimization of such algorithms for a better performance has not been fully addressed. ES of 1199 samples including 763 patients with different disease profiles was performed. ES data were analyzed to detect CNVs by both the eXome Hidden Markov Model (XHMM) and modified Nord's method. To efficiently detect rare CNVs, we aimed to decrease sequencing biases by analyzing, at the same time, the data of all unrelated samples sequenced in the same flow cell as a batch, and to eliminate sex effects of X-linked CNVs by analyzing female and male sequences separately. We also applied several filtering steps for more efficient CNV selection. The average number of CNVs detected in one sample was <5. This optimization together with targeted CNV analysis by Nord's method identified pathogenic/likely pathogenic CNVs in 34 patients (4.5%, 34/763). In particular, among 142 patients with epilepsy, the current protocol detected clinically relevant CNVs in 19 (13.4%) patients, whereas the previous protocol identified them in only 14 (9.9%) patients. Thus, this batch-based XHMM analysis efficiently selected rare pathogenic CNVs in genetic diseases.
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http://dx.doi.org/10.1002/humu.24129DOI Listing
January 2021

Characteristics of internalization of NMDA-type GluRs with antibodies to GluN1 and GluN2B.

J Neuroimmunol 2020 12 15;349:577427. Epub 2020 Oct 15.

Department of Molecular Neuroscience, Graduate Schools of Innovative Life Science and Medicine, University of Toyama, Toyama, Japan. Electronic address:

To characterize internalization of NMDA-type glutamate receptors (GluRs) by antibodies to NMDA-type GluRs, we produced rabbit antibodies to N-terminals of human GluN1 and GluN2B, and examined internalization of NMDA-type GluRs in HEK293T cells using confocal microscopy. Internalization of NMDA-type GluRs occurred from at least 10 min after incubation with antibodies to GluN1 and or GluN2B and was temperature-dependent. These findings confirm that antibodies to N-terminals of GluN1 and GluN2B present in the cerebrospinal fluid of patients with NMDAR encephalitis can mediate prompt internalization of NMDA-type GluR complexes.
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http://dx.doi.org/10.1016/j.jneuroim.2020.577427DOI Listing
December 2020

Ethylenediurea (EDU) effects on Japanese larch: an one growing season experiment with simulated regenerating communities and a four growing season application to individual saplings.

J For Res (Harbin) 2020 Sep 30:1-11. Epub 2020 Sep 30.

Division of Environment and Resources Research, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan.

Japanese larch ( (Lamb.) Carr.) and its hybrid are economically important coniferous trees widely grown in the Northern Hemisphere. Ground-level ozone (O) concentrations have increased since the pre-industrial era, and research projects showed that Japanese larch is susceptible to elevated O exposures. Therefore, methodologies are needed to (1) protect Japanese larch against O damage and (2) conduct biomonitoring of O in Japanese larch forests and, thus, monitor O risks to Japanese larch. For the first time, this study evaluates whether the synthetic chemical ethylenediurea (EDU) can protect Japanese larch against O damage, in two independent experiments. In the first experiment, seedling communities, simulating natural regeneration, were treated with EDU (0, 100, 200, and 400 mg L) and exposed to either ambient or elevated O in a growing season. In the second experiment, individually-grown saplings were treated with EDU (0, 200 and 400 mg L) and exposed to ambient O in two growing seasons and to elevated O in the succeeding two growing seasons. The two experiments revealed that EDU concentrations of 200-400 mg L could protect Japanese larch seedling communities and individual saplings against O-induced inhibition of growth and productivity. However, EDU concentrations ≤ 200 mg L did offer only partial protection when seedling communities were coping with higher level of O-induced stress, and only 400 mg EDU L fully protected communities under higher stress. Therefore, we conclude that among the concentrations tested the concentration offering maximum protection to Japanese larch plants under high competition and O-induced stress is that of 400 mg EDU L. The results of this study can provide a valuable resource of information for applied forestry in an O-polluted world.
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http://dx.doi.org/10.1007/s11676-020-01223-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7525765PMC
September 2020

Heterophyllous Shoots of Japanese Larch Trees: The Seasonal and Yearly Variation in CO Assimilation Capacity of the Canopy Top with Changing Environment.

Plants (Basel) 2020 Sep 28;9(10). Epub 2020 Sep 28.

Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.

Japanese larch ( = ) is often characterized by its high growth rate with heterophyllous shoots, but the functional differences of heterophyllous shoots still remain unclear. Recently, abrupt high temperature and drought during spring induced high photosynthetic rate via change in leaf morphology of the deciduous habit. In order to reveal the photosynthetic characteristics of both short and long-shoot needles of sunny canopy of the larch trees using a canopy tower, we calculated the seasonal change of gas exchange characters and leaf mass per area (LMA) and foliar nitrogen content (N) of heterophyllous needles: short and long-shoot needles over 3 years. No marked difference in light-saturated photosynthetic rates (P) was observed between short and long shoots after leaf maturation to yellowing, although the difference was obvious in a specific year, which only shows that seasonal change in temperature and soil moisture determines the in situ photosynthetic capacity of needles. The large annual and seasonal variations in P in both shoots were found to be mainly determined by climatic variations, while shoot types determined the strategy of their photosynthetic N utilization as well as the stomatal regulation.
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http://dx.doi.org/10.3390/plants9101278DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7601333PMC
September 2020

Pyridoxal in the Cerebrospinal Fluid May Be a Better Indicator of Vitamin B6-dependent Epilepsy Than Pyridoxal 5'-Phosphate.

Pediatr Neurol 2020 12 2;113:33-41. Epub 2020 Sep 2.

Department of Child Neurology, Okayama University Hospital, Okayama, Japan; Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.

Background: We aimed to demonstrate the biochemical characteristics of vitamin B6-dependent epilepsy, with a particular focus on pyridoxal 5'-phosphate and pyridoxal in the cerebrospinal fluid.

Methods: Using our laboratory database, we identified patients with vitamin B6-dependent epilepsy and extracted their data on the concentrations of pyridoxal 5'-phosphate, pyridoxal, pipecolic acid, α-aminoadipic semialdehyde, and monoamine neurotransmitters. We compared the biochemical characteristics of these patients with those of other epilepsy patients with low pyridoxal 5'-phosphate concentrations.

Results: We identified seven patients with pyridoxine-dependent epilepsy caused by an ALDH7A1 gene abnormality, two patients with pyridoxal 5'-phosphate homeostasis protein deficiency, and 28 patients with other epilepsies with low cerebrospinal fluid pyridoxal 5'-phosphate concentrations. Cerebrospinal fluid pyridoxal and pyridoxal 5'-phosphate concentrations were low in patients with vitamin B6-dependent epilepsy but cerebrospinal fluid pyridoxal concentrations were not reduced in most patients with other epilepsies with low cerebrospinal fluid pyridoxal 5'-phosphate concentrations. Increase in 3-O-methyldopa and 5-hydroxytryptophan was demonstrated in some patients with vitamin B6-dependent epilepsy, suggestive of pyridoxal 5'-phosphate deficiency in the brain.

Conclusions: Low cerebrospinal fluid pyridoxal concentrations may be a better indicator of pyridoxal 5'-phosphate deficiency in the brain in vitamin B6-dependent epilepsy than low cerebrospinal fluid pyridoxal 5'-phosphate concentrations. This finding is especially helpful in individuals with suspected pyridoxal 5'-phosphate homeostasis protein deficiency, which does not have known biomarkers.
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http://dx.doi.org/10.1016/j.pediatrneurol.2020.08.020DOI Listing
December 2020

Interactive effect of leaf age and ozone on mesophyll conductance in Siebold's beech.

Physiol Plant 2020 Oct 31;170(2):172-186. Epub 2020 May 31.

Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8689, Japan.

Mesophyll conductance (G ) is one of the most important factors determining photosynthesis. Tropospheric ozone (O ) is known to accelerate leaf senescence and causes a decline of photosynthetic activity in leaves. However, the effects of age-related variation of O on G have not been well investigated, and we, therefore, analysed leaf gas exchange data in a free-air O exposure experiment on Siebold's beech with two levels (ambient and elevated O : 28 and 62 nmol mol as daylight average, respectively). In addition, we examined whether O -induced changes on leaf morphology (leaf mass per area, leaf density and leaf thickness) may affect CO diffusion inside leaves. We found that O damaged the photosynthetic biochemistry progressively during the growing season. The G was associated with a reduced photosynthesis in O -fumigated Siebold's beech in August. The O -induced reduction of G was negatively correlated with leaf density, which was increased by elevated O , suggesting that the reduction of G was accompanied by changes in the physical structure of mesophyll cells. On the other hand, in October, the O -induced decrease of G was diminished because G decreased due to leaf senescence regardless of O treatment. The reduction of photosynthesis in senescent leaves after O exposure was mainly due to a decrease of maximum carboxylation rate (V ) and/or maximum electron transport rate (J ) rather than diffusive limitations to CO transport such as G . A leaf age×O interaction of photosynthetic response will be a key for modelling photosynthesis in O -polluted environments.
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http://dx.doi.org/10.1111/ppl.13121DOI Listing
October 2020

Methylprednisolone pulse therapy in 31 patients with refractory epilepsy: A single-center retrospective analysis.

Epilepsy Behav 2020 08 6;109:107116. Epub 2020 May 6.

National Epilepsy Center, NHO, Shizuoka Institute of Epilepsy and Neurological Disorders, Japan.

Purpose: We investigated the efficacy of methylprednisolone pulse therapy (MP) and responder characteristics in patients with refractory epilepsy.

Methods: We reviewed medical records of our center to identify patients with refractory epilepsy treated with MP other than continuous spikes and waves during slow sleep (CSWS), Landau-Kleffner syndrome (LKS), or Rasmussen's syndrome (RS) between 2004 and 2015. A course of MP consisted of intravenous methylprednisolone (30 mg/kg/day) on three consecutive days. Patients received multiple courses at intervals of four weeks. We examined seizure outcome, developmental outcome, antibodies to N-methyl-d-aspartate (NMDA)-type glutamate receptors (GluRs), cerebral spinal fluid (CSF)-albumin/serum-albumin ratio, and interictal electroencephalograms (EEGs). Responder to MP was defined as maintaining seizure reduction rate (SRR) ≥50% for three months after the first course of MP.

Results: Thirty-one consecutive patients treated with MP at our center were studied. Seizure types were focal onset impaired awareness seizure (FIAS) only (n = 23), FIAS with epileptic spasms (ES) (n = 7), and ES only (n = 1). Responder rate was 32.2% (10/31 patients), and seizure-free rate was 9.7% (3/31). Responders constituted 43.5% of patients without ES. No patient with ES was responder. Behavior and cognition also improved in 6 of 10 responders. History of seizure aggravation after inactivated vaccine before MP was found significantly higher rate in responder patients, comparing with nonresponder patients (p = 0.01).

Conclusion: Methylprednisolone pulse therapy may be considered for possible treatment in patients with focal epilepsy with drug-resistant seizures without ES, and it may improve cognitive function and behavioral comorbidities.
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http://dx.doi.org/10.1016/j.yebeh.2020.107116DOI Listing
August 2020

Identification of new biomarkers of pyridoxine-dependent epilepsy by GC/MS-based urine metabolomics.

Anal Biochem 2020 09 24;604:113739. Epub 2020 Apr 24.

Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, 10595, USA.

α-Aminoadipic semialdehyde and its cyclic form (Δ-piperideine-6-carboxylate) accumulate in patients with α-aminoadipic semialdehyde dehydrogenase (AASADH; antiquitin; ALDH7A1) deficiency. Δ-Piperideine-6-carboxylate is known to react with pyridoxal 5'-phosphate (PLP) to form a Knoevenagel condensation product, resulting in pyridoxine-dependent epilepsy. Despite dramatic clinical improvement following pyridoxine supplementation, many patients still suffer some degree of intellectual disability due to delayed diagnosis. In order to expedite the diagnosis of patients with suspected AASADH deficiency and minimize the delay in treatment, we used gas chromatography-mass spectrometry-based metabolomics to search for potentially diagnostic biomarkers in urine from four patients with ALDH7A1 mutations, and identified Δ-piperideine-6-carboxylate, 6-oxopipecolate, and pipecolate as candidate biomarkers. In a patient at postnatal day six, but before pyridoxine treatment, Δ-piperideine-6-carboxylate and pipecolate were present at very high concentrations, indicating that these compounds may be good biomarkers for untreated AASADH deficiency patients. On the other hand, following pyridoxine/PLP treatment, 6-oxopipecolate was shown to be greatly elevated. We suggest that noninvasive urine metabolomics screening for Δ-piperideine-6-carboxylate, 6-oxopipecolate, and pipecolate will be useful for prompt and reliable diagnosis of AASADH deficiency in patients within any age group. The most appropriate combination among Δ-piperideine-6-carboxylate, 6-oxopipecolate, and pipecolate as biomarkers for AASADH deficiency patients appears to depend on the age of the patient and whether pyridoxine/PLP supplementation has been implemented. We anticipate that the present bioanalytical information will also be useful to researchers studying glutamate, proline, lysine and ornithine metabolism in mammals and other organisms.
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http://dx.doi.org/10.1016/j.ab.2020.113739DOI Listing
September 2020

Leaf defense capacity of Japanese elm (Ulmus davidiana var. japonica) seedlings subjected to a nitrogen loading and insect herbivore dynamics in a free air ozone-enriched environment.

Environ Sci Pollut Res Int 2020 Jan 16;27(3):3350-3360. Epub 2019 Dec 16.

Silviculture and Forest Ecological Studies, Hokkaido University, Sapporo, 060-8589, Japan.

Japanese elm (Ulmus davidiana var. japonica) is a native species in cool-temperate forests in Japan. We investigated growth, physiological reactions, and leaf defense capacity of Japanese elm seedlings under nitrogen (N) loading (45.3 kg N ha year) and seasonal insect dynamics in a free-air ozone (O)-enriched environment (about 54.5 nmol O mol) over a growing season. Higher leaf N content and lower condensed tannin content in the presence of N loading and lower condensed tannin content in elevated O were observed, suggesting that both N loading and elevated O decreased the leaf defense capacity and that N loading further enhanced the leaf quality as food resource of insect herbivores. Two major herbivores were observed on the plants, elm leaf beetle (Pyrrhalta maculicollis) and elm sawfly (Arge captiva). The peak number of observed insects was decreased by N loading. Visible foliar injury caused by N loading might directly induce the reduction of number of the observed elm sawfly individuals. While elevated O slightly suppressed the chemical defense capacity, significantly lower number of elm leaf beetle was observed in elevated O. We conclude that N loading and elevated O can alter not only the leaf defense capacity of Japanese elm seedlings but also the dynamics of elm leaf beetle and sawfly herbivores.
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http://dx.doi.org/10.1007/s11356-019-06918-wDOI Listing
January 2020

A quantitative assessment of hormetic responses of plants to ozone.

Environ Res 2019 09 7;176:108527. Epub 2019 Jun 7.

Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA.

Evaluations of ozone effects on vegetation across the globe over the last seven decades have mostly incorporated exposure levels that were multi-fold the preindustrial concentrations. As such, global risk assessments and derivation of critical levels for protecting plants and food supplies were based on extrapolation from high to low exposure levels. These were developed in an era when it was thought that stress biology is framed around a linear dose-response. However, it has recently emerged that stress biology commonly displays non-linear, hormetic processes. The current biological understanding highlights that the strategy of extrapolating from high to low exposure levels may lead to biased estimates. Here, we analyzed a diverse sample of published empirical data of approximately 500 stimulatory, hormetic-like dose-responses induced by ozone in plants. The median value of the maximum stimulatory responses induced by elevated ozone was 124%, and commonly <150%, of the background response (control), independently of species and response variable. The maximum stimulatory response to ozone was similar among types of response variables and major plant species. It was also similar among clades, between herbaceous and woody plants, between deciduous and evergreen trees, and between annual and perennial herbaceous plants. There were modest differences in the stimulatory response between genera and between families which may reflect different experimental designs and conditions among studies. The responses varied significantly upon type of exposure system, with open-top chambers (OTCs) underestimating the maximum stimulatory response compared to free-air ozone-concentration enrichment (FACE) systems. These findings suggest that plants show a generalized hormetic stimulation by ozone which is constrained within certain limits of biological plasticity, being highly generalizable, evolutionarily based, and maintained over ecological scales. They further highlight that non-linear responses should be taken into account when assessing the ozone effects on plants.
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http://dx.doi.org/10.1016/j.envres.2019.108527DOI Listing
September 2019

Effects of ozone and ammonium sulfate on cauliflower: Emphasis on the interaction between plants and insect herbivores.

Sci Total Environ 2019 Apr 28;659:995-1007. Epub 2018 Dec 28.

Research Faculty of Agriculture, Hokkaido University, Kita ku Kita 9 Nishi 9, Sapporo, Hokkaido 060-8589, Japan.

Ammonium sulfate [(NH)SO] deposition and elevated ozone (O) concentrations may negatively affect plants and trophic interactions. This study aimed to evaluate for the first time the interactive effects of high (NH)SO load and elevated O levels on cauliflower (Brassica oleracea L.) under field conditions. Cauliflower seedlings were treated with 0 (AS0) or 50 (AS50) kg ha (NH)SO and exposed to ambient (AOZ, ≈20 ppb) or elevated (EOZ, ≈55 ppb) O for about one month, in a Free Air O Concentration Enrichment (FACE) system. The oligophagous diamondback moth (Plutella xylostella Linnaeus, 1758) showed a clear preference towards the seedlings treated with AS50, which intensively grazed. Plant-herbivore interactions were driven by (NH)SO availability, rather than O, via increased nitrogen content in the leaves. Further laboratory bioassays were followed to confirm the validity of these observations using polyphagous Eri silkmoth larvae (Samia ricini) as a biological model in a standardized experimental setup. Choice assays, where larvae could select leaves among leaf samples from the different experimental conditions, and no-choice assays, where larvae could graze leaves from just one experimental condition, were conducted. In the choice assay, the larvae preferred AS50-treated leaves, in agreement with the field observations with diamondback moth. In the no-choice assay, larval body mass growth was inhibited when fed with leaves treated with EOZ and/or AS50. Larvae fed with AS50-treated leaves displayed increased mortality. These observations coincide with higher NO and Zn content in AS50-treated leaves. This study shows that plant-herbivore interactions can be driven by (NH)SO availability, independently of O, and suggests that high N deposition may have severe health implications in animals consuming such plant tissues. Key message: Plant-herbivore interactions are driven by high (NH)SO availability, independently of O.
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http://dx.doi.org/10.1016/j.scitotenv.2018.12.388DOI Listing
April 2019

Nitrogen loading increases the ozone sensitivity of larch seedlings with higher sensitivity to nitrogen loading.

Sci Total Environ 2019 May 24;663:587-595. Epub 2019 Jan 24.

Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8689, Japan.

Larch (Larix sp.) tree is a critical species for the future afforestation in Northeast Asia. The impacts of elevated concentrations of ground-level ozone (O) and nitrogen (N) deposition are raising concerns. However, knowledge of the combined effects of elevated O and N loading are still limited. We investigated whether nitrogen loading mitigates the negative impacts of ozone on two larch species: the Japanese larch (L. kaempferi) and its hybrid larch F (L. gmelinii var. japonica × L. kaempferi) or not. We used open-top cambers and compared responses of the larch seedlings. Results showed the N loading mitigated the negative effects of O on Japanese larch. However, in hybrid larch F, N loading did not mitigate O-induced inhibition of growth and photosynthetic capacity. Mitigation effect of N loading on negative O impacts may vary between the two Larix spp., Hybrid larch F could be more affected by the combined effects of O and N loading due to its higher growth response to N loading. Elevated O also reduced leaf nitrogen/phosphorus (N/P) ratio by elevated O, with significant effects in hybrid larch F, particularly under N loading. In the present study, leaf N/P ratio was utilized to validate the hypothesis that a positive effect of N loading may be observed if O does not induce P limitation in Larix spp. We demonstrated a potential leaf N/P ratio function, which could reflect responses to O and N loading in hybrid larch F.
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http://dx.doi.org/10.1016/j.scitotenv.2019.01.292DOI Listing
May 2019

Commentary: EPA's proposed expansion of dose-response analysis is a positive step towards improving its ecological risk assessment.

Environ Pollut 2019 Mar 18;246:566-570. Epub 2018 Dec 18.

Department of Environmental Health Sciences, Morrill I, N344, University of Massachusetts, Amherst, MA, 01003, USA.

The United States Environmental Protection Agency (US EPA) has recently proposed changes to strengthen the transparency of its pivotal regulatory science policy and procedures. In this context, the US EPA aims to enhance the transparency of dose-response data and models, proposing to consider for the first time non-linear biphasic dose-response models. While the proposed changes have the potential to lead to markedly improved ecological risk assessment compared to past and current approaches, we believe there remain open issues for improving the quality of ecological risk assessment, such as the consideration of adaptive, dynamic and interactive effects. Improved risk assessment including adaptive and dynamic non-linear models (beyond classic threshold models) can enhance the quality of regulatory decisions and the protection of ecological health. We suggest that other countries consider adopting a similar scientific-regulatory posture with respect to dose-response modeling via the inclusion of non-linear biphasic models, that incorporate the dynamic potential of biological systems to adapt (i.e., enhancing positive biological endpoints) or maladapt to low levels of stressor agents.
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http://dx.doi.org/10.1016/j.envpol.2018.12.046DOI Listing
March 2019

Chronic dysfunction of blood-brain barrier in patients with post-encephalitic/encephalopathic epilepsy.

Seizure 2018 Dec 13;63:85-90. Epub 2018 Nov 13.

Department of Pediatrics, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, NHO, Shizuoka, Japan.

Purpose: This study aimed to elucidate the characteristics and effects of chronic blood-brain barrier (BBB) dysfunction in patients with post-encephalitic/encephalopathic epilepsy (PEE), using brain images and the cerebral spinal fluid (CSF)/serum albumin ratio (albumin quotient, QAlb) as a marker of BBB function.

Methods: We examined the albumin levels in CSF and serum samples from 312 patients with refractory epilepsy in our center between 2004 and 2015. Sixty samples from patients with PEE and 97 samples from age- and sex-matched disease controls (DC) were evaluated. We classified PEE patients into a widespread lesion group and a focal lesion group by severity on brain magnetic resonance images in the chronic phase after acute encephalitis/encephalopathy.

Results: Median QAlb was higher in PEE than in DC [median (range) ×10: PEE 3.6 (1.0-10.3) versus DC 2.7 (1.0-6.7), p = 0.007]. In a linear regression analysis of the relationship between QAlb and patient's age at CSF examination or duration of epilepsy, the slope of the regression line was greater in PEE than in DC. Furthermore, in patients under ten years of age, linear regression analysis of QAlb versus seizure frequency showed a weak but positive correlation. Among PEE patients, seizure frequency was higher in the widespread lesion group than in the focal lesion group [300 (4-3000) versus 30 (1-1500) seizures/month, p <  0.001].

Conclusion: Our study suggests that patients with PEE have more severe BBB dysfunction, and that the BBB dysfunction is associated with refractory epilepsy.
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http://dx.doi.org/10.1016/j.seizure.2018.11.005DOI Listing
December 2018

Preface.

J Plant Res 2018 Nov;131(6):895-896

Silviculture and Forest Ecological Studies, Hokkaido University, Sapporo, 060-8689, Japan.

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http://dx.doi.org/10.1007/s10265-018-1072-3DOI Listing
November 2018

Enzyme activity modification in adult beetles (Agelastica coerulea) inhabiting birch trees in an ozone-enriched atmosphere.

Environ Sci Pollut Res Int 2018 Nov 22;25(32):32675-32683. Epub 2018 Sep 22.

Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-85889, Japan.

Tropospheric ozone (O) is a naturally occurring gas in the atmosphere. However, the concentration of O increased in the twentieth century. Although the effects of O on vegetation have been extensively studied since the 1950s, limited information exists regarding the effects of O on insect herbivores. In particular, evidence is lacking regarding the effects of O on the biology of insect herbivores. Agelastica coerulea Baly (1874) is a coleopteran species that grazes on Betulaceae plants. In this study, to investigate the effects of O on A. coerulea biology for the first time, female adult insects were collected from Japanese white birch trees grown in a Free Air Controlled Exposure System (FACE) in Sapporo, Japan. These beetles inhabited trees exposed either to ambient or to elevated O for 23 days. After collection, the enzyme activities in the beetles were measured. Elevated O led to a greater total antioxidant activity and lower α- and β-esterase activities, a phenomenon that may suggest an increased resistance of the beetles to stress. Our results are further discussed with regard to biological and toxicological aspects. Collectively, our findings indicate that total antioxidants and α- and β-esterase activities can serve as effective O biomarker systems in this beetle species. This adaptive response of the beetle, which was induced by moderate O exposure, should be further tested across generations and for its protection against greater exposure.
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http://dx.doi.org/10.1007/s11356-018-3243-0DOI Listing
November 2018

Photosynthetic activity in relation to a gradient of leaf nitrogen content within a canopy of Siebold's beech and Japanese oak saplings under elevated ozone.

Sci Total Environ 2018 Sep 5;636:1455-1462. Epub 2018 May 5.

Silviculture and Forest Ecological Studies, Hokkaido University, Sapporo, Hokkaido 0608589, Japan. Electronic address:

The primary objective of this study was to describe parameters related to the leaf biochemical assimilation capacity of photosynthesis, such as the maximum rates of carboxylation (V) and electron transport (J), as a function of the leaf nitrogen content throughout a canopy of Siebold's beech and Japanese oak grown under elevated ozone (O) conditions during a growing season. To this end, we investigated the relationship between photosynthetic traits and leaf nitrogen content in various canopy positions of two tree species under free-air O exposure (60 nmol mol, during daylight hours) in June, August, and October 2012. We observed O-induced reduction in V and J without reduction of leaf nitrogen content in both tree species. In Siebold's beech, V and J in leaves with higher N were largely decreased by O from August, while little effect of O was observed in leaves with lower N. On the other hand, there was no difference in the extent of O-induced reduction in V and J across the range of N in leaves of Japanese oak. Reduction of leaf nitrogen content under elevated O conditions was observed only in Siebold's beech in October. These results indicated that the decrease in the efficiency of photosynthetic nitrogen use is in an earlier step in O-induced decline of photosynthesis in Siebold's beech and Japanese oak. Based on these results, we emphasize the importance of integration of O effects into the conventional estimation of V and J from leaf nitrogen content for evaluating canopy photosynthesis under current and future elevated O conditions.
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http://dx.doi.org/10.1016/j.scitotenv.2018.04.423DOI Listing
September 2018

Effects of ozone (O) and ethylenediurea (EDU) on the ecological stoichiometry of a willow grown in a free-air exposure system.

Environ Pollut 2018 Jul 2;238:663-676. Epub 2018 Apr 2.

Research Faculty of Agriculture, Hokkaido University, Kita ku Kita 9 Nishi 9, Sapporo, Hokkaido, 060-8589, Japan.

Ground-level ozone (O) concentrations have been elevating in the last century. While there has been a notable progress in understanding O effects on vegetation, O effects on ecological stoichiometry remain unclear, especially early in the oxidative stress. Ethyelenediurea (EDU) is a chemical compound widely applied in research projects as protectant of plants against O injury, however its mode of action remains unclear. To investigate O and EDU effects early in the stress, we sprayed willow (Salix sachalinensis) plants with 0, 200 or 400 mg EDU L, and exposed them to either low ambient O (AOZ) or elevated O (EOZ) levels during the daytime, for about one month, in a free air O controlled exposure (FACE); EDU treatment was repeated every nine days. We collected samples for analyses from basal, top, and shed leaves, before leaves develop visible O symptoms. We found that O altered the ecological stoichiometry, including impacts in nutrient resorption efficiency, early in the stress. The relation between P content and Fe content seemed to have a critical role in maintaining homeostasis in an effort to prevent O-induced damage. Photosynthetic pigments and P content appeared to play an important role in EDU mode of action. This study provides novel insights on the stress biology which are of ecological and toxicological importance.
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http://dx.doi.org/10.1016/j.envpol.2018.03.061DOI Listing
July 2018

Growth and nutrition of Agelastica coerulea (Coleoptera: Chrysomelidae) larvae changed when fed with leaves obtained from an O-enriched atmosphere.

Environ Sci Pollut Res Int 2018 May 10;25(13):13186-13194. Epub 2018 Mar 10.

Research Faculty of Agriculture, School of Agriculture, Hokkaido University, Kita 9 Nishi 9, Sapporo, 060-85889, Japan.

A series of laboratory no-choice assays were performed to test changes in the feeding, growth, and nutrition of leaf beetle (Agelastica coerulea) larval instars on O-treated leaves of Japanese white birch (Betula platyphylla var. japonica). Larvae fed with O-treated leaves grew and developed significantly faster throughout their developmental cycle than the corresponding controls. The growth rate (GR) and consumption index (CI) were mostly decreased with age for both control and O-treated leaves. Efficiency of conversion of both ingested and digested food (ECI, ECD) showed an increase from the 2nd to the 4th instar, after which they decreased significantly and reached the lowest value in the last larval instars (7th). GR, CI, ECI, and ECD were greater and approximate digestibility (AD) was lower in larvae fed with O-treated leaves than those fed with control leaves. This indicated that the greater rate of growth on fumigated leaves was due primarily to a greater rate of consumption (i.e., O increased the "acceptability" of the host more than "suitability") and efficiency in converting food into body mass. Overall, larval performance seemed to have improved when fed with O-treated leaves in these assays. This study suggests that insects may be more injurious to O-treated plants and warrants further investigations on birch-beetle interactions under field conditions.
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http://dx.doi.org/10.1007/s11356-018-1683-1DOI Listing
May 2018

Climate change accelerates growth of urban trees in metropolises worldwide.

Sci Rep 2017 11 13;7(1):15403. Epub 2017 Nov 13.

Department of Earth and Atmospheric Sciences, University of Houston, 4800 Calhoun Road, 312 Science & Research Bldg 1, Houston, TX, 77204-5007, USA.

Despite the importance of urban trees, their growth reaction to climate change and to the urban heat island effect has not yet been investigated with an international scope. While we are well informed about forest growth under recent conditions, it is unclear if this knowledge can be simply transferred to urban environments. Based on tree ring analyses in ten metropolises worldwide, we show that, in general, urban trees have undergone accelerated growth since the 1960s. In addition, urban trees tend to grow more quickly than their counterparts in the rural surroundings. However, our analysis shows that climate change seems to enhance the growth of rural trees more than that of urban trees. The benefits of growing in an urban environment seem to outweigh known negative effects, however, accelerated growth may also mean more rapid ageing and shortened lifetime. Thus, city planners should adapt to the changed dynamics in order to secure the ecosystem services provided by urban trees.
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http://dx.doi.org/10.1038/s41598-017-14831-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5684322PMC
November 2017

Effects of simulated nitrogen deposition on ectomycorrhizae community structure in hybrid larch and its parents grown in volcanic ash soil: The role of phosphorous.

Sci Total Environ 2018 Mar 18;618:905-915. Epub 2017 Oct 18.

Research Faculty of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan. Electronic address:

With the rapid industrial development and modern agricultural practices, increasing nitrogen (N) deposition can cause nutrient imbalance in immature volcanic ash soil commonly found in Japan. Larch species, widely distributed in northeast Eurasia, are associated with ectomycorrhizal (ECM) fungi which play a critical role in nutrient acquisition for their hosts. In this study, we investigated species richness and diversity of ECM fungi associated with a hybrid larch (F) and its parents, Dahurian larch (Larix gmelinii var. japonica) and Japanese larch (L. kaempferi), under simulated N deposition (0 and 100kghayr) with/without phosphorous (P) (0 and 50kghayr). Seedlings planted in immature volcanic ash with low nutrient availability were subjected to the N and P treatments for fifteen months. We found that response of ECM community structure to the increased nutrient availability depended on host genotypes. Nutrient addition significantly affected ECM structure in Japanese larch, but no such significant effect was found for Dahurian larch. Effects of the nutrient addition to ECM fungal community in F were intermediate. F was tolerant to high N loading, which was due to consistent, relatively high association with Suillus sp. and Hebeloma sp. F showed heterosis in relative biomass, which was most apparent under high N treatments. This co-variation of ECM fungal community structure and F biomass in response to N loading suggest that ECM community structure might play an important role in host growth. The present findings indicate effects of N deposition on ECM fungal community structure can depend on larch species, thus it is challenging to predict general trends.
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http://dx.doi.org/10.1016/j.scitotenv.2017.08.283DOI Listing
March 2018

High doses of ethylenediurea (EDU) as soil drenches did not increase leaf N content or cause phytotoxicity in willow grown in fertile soil.

Ecotoxicol Environ Saf 2018 Jan 15;147:574-584. Epub 2017 Sep 15.

Silviculture & Forest Ecological Studies, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan. Electronic address:

Ground-level ozone (O) levels are nowadays elevated in wide regions of the Earth, causing significant effects on plants that finally lead to suppressed productivity and yield losses. Ethylenediurea (EDU) is a chemical compound which is widely used in research projects as phytoprotectant against O injury. The EDU mode of action remains still unclear, while there are indications that EDU may contribute to plants with nitrogen (N) when the soil is poor in N and the plants have relatively small leaf area. To reveal whether the N content of EDU acts as a fertilizer to plants when the soil is not poor in N and the plants have relatively large total plant leaf area, willow plants (Salix sachalinensis Fr. Schm) were exposed to low ambient O levels and treated ten times (9-day interval) with 200mL soil drench containing 0, 800 or 1600mg EDU L. Fertilizer was added to a nutrient-poor soil, and the plants had an average plant leaf area of 9.1m at the beginning of EDU treatments. Indications for EDU-induced hormesis in maximum electron transport rate (J) and ratio of intercellular to ambient CO concentration (C:C) were observed at the end of the experiment. No other EDU-induced effects on leaf greenness and N content, maximum quantum yield of photosystem II (F/F), gas exchange, growth and matter production suggest that EDU did not act as N fertilizer and did not cause toxicity under these experimental conditions.
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http://dx.doi.org/10.1016/j.ecoenv.2017.09.017DOI Listing
January 2018

Ozone alters the feeding behavior of the leaf beetle Agelastica coerulea (Coleoptera: Chrysomelidae) into leaves of Japanese white birch (Betula platyphylla var. japonica).

Environ Sci Pollut Res Int 2017 Jul 8;24(21):17577-17583. Epub 2017 Jun 8.

Research Faculty of Agriculture, School of Agriculture, Hokkaido University, Sapporo, 060-85889, Japan.

High mixing ratios of ground-level O threaten trophic interactions. In the present study, we conducted laboratory assays, where insect larvae and adults were not directly exposed to O, to test the feeding behavior and attraction of the coleopteran leaf beetle Agelastica coerulea to early and late leaves of Japanese white birch (Betula platyphylla var. japonica) treated with ambient or elevated O levels. We found that overwintered adults were not deterred from grazing elevated O-treated leaves, but rather preferred them than ambient O-treated ones. We also found that the feeding behavior of 2nd instar larvae fed on early or late leaves was not influenced by the O treatment of the leaves when larvae could choose leaves. These observations of the adults and larvae feeding preferences contradict prior observations in the field conditions where the insects avoided leaves in O-enriched atmosphere. Since adults preferred elevated O-exposed leaves in the present laboratory assays, it is worthy of further investigations whether adults change their grazing preference so as to ensure the leaf palatability as a feeding source for their larvae. Hence, new direction towards detailed ovipositional behavior surveys under field conditions is encouraged.
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http://dx.doi.org/10.1007/s11356-017-9369-7DOI Listing
July 2017

Stem and crown growth of Japanese larch and its hybrid F grown in two soils and exposed to two free-air O regimes.

Environ Sci Pollut Res Int 2017 Mar 12;24(7):6634-6647. Epub 2017 Jan 12.

School of Agriculture, Hokkaido University, Sapporo, Hokkaido, 060-8589, Japan.

Ozone (O) pollution and soil infertility may negatively affect boreal forests across the Northern Hemisphere. Impacts to economically and ecologically important larches (Larix sp., Pinacaeae) are particularly concerning. Using a free air O enrichment (FACE) system, we investigated the effect of 2-year elevated O exposure (≈66 nmol mol) on Japanese larch (L. kaempferi) and its hybrid larch F (L. gmelinii var. japonica × L. kaempferi) planted directly into either fertile brown forest soil (BF) or BF mixed with infertile volcanic ash soil (VA). Overall, photosynthetic pigmentation and the growth performance of the stem and crown were reduced in both taxa exposed to elevated O. Furthermore, hybrid larch, in both O treatments, performed better than Japanese larch. This finding contradicts findings of prior experiments with potential experimental artifacts of O exposure facilities and root restrictions. Elevated O also disproportionately inhibited stem diameter growth and caused an imbalance in chlorophylls a/b and chlorophyll/carotenoid ratios. Hybrid and Japanese larches grown in BF and VA had a significantly lower drop of stem diameter over the run of stem height (from base to top) when exposed to elevated O, compared to ambient O. This finding indicates altered stem shape under elevated O. Among 11 response variables, there were no significant interactions between O treatment and taxa. There was also no significant interaction of soil condition and taxa, suggesting that the two larches shared a similar response to O and soil type. Understanding the performance of hybrid larch in relation to its parent species has ramifications for breeding success in a soil-degraded and O-polluted environment.
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http://dx.doi.org/10.1007/s11356-017-8401-2DOI Listing
March 2017

A case of early onset epileptic encephalopathy with de novo mutation in SLC35A2: Clinical features and treatment for epilepsy.

Brain Dev 2017 Mar 12;39(3):256-260. Epub 2016 Oct 12.

Department of Pediatrics, National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, NHO, Japan.

Introduction: Mutations of SLC35A2 that encodes Golgi-localized Uridine diphosphate (UDP)-galactose transporter at Xp11.23 lead to congenital disorders of glycosylation (CDG). Although patients with CDG generally have diverse systemic symptoms, patients with a SLC35A2 mutation manifest predominantly disorders of the central nervous system (CNS).

Case Report: A female infant aged 12months was referred to our center because of intractable seizures. The patient was born with birth weight of 3228g after 40weeks of unremarkable gestation. At the age of 2months, she had partial seizures evolving to epileptic spasms. Her electroencephalogram showed hypsarrhythmia. Her seizures were refractory to antiepileptic drugs. At referral to our center at 12months, she had developmental delay (no head control), widely spaced inverted nipples, external strabismus, and bilateral heterochromia of irises. Blood examinations were normal. Brain magnetic resonance imaging findings included cerebral and cerebellar atrophy, thinning of the corpus callosum, and arachnoid pouch. Whole-exome sequencing detected a de novo frameshift mutation c.950delG (p.Gly317Alafs*32) at exon 4 in SLC35A2. Seizures subsided after the second adrenocorticotropic hormones (ACTH) therapy at 18months. At the age of 36months, although she had intellectual disability with no meaningful words, she was seizure-free and was able to sit without support and showed smiling face a lot.

Conclusion: This report reviewed the clinical features of patients with a SLC35A2 mutation. ACTH therapy may be effective for refractory epilepsy in these patients.
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http://dx.doi.org/10.1016/j.braindev.2016.09.009DOI Listing
March 2017

Impacts of ethylenediurea (EDU) soil drench and foliar spray in Salix sachalinensis protection against O-induced injury.

Sci Total Environ 2016 Dec 6;573:1053-1062. Epub 2016 Sep 6.

Silviculture and Forest Ecological Studies, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan.

It is widely accepted that elevated levels of surface ozone (O) negatively affect plants. Ethylenediurea (EDU) is a synthetic substance which effectively protects plants against O-caused phytotoxicity. Among other questions, the one still open is: which EDU application method is more appropriate for treating fast-growing tree species. The main aims of this study were: (i) to test if chronic exposure of Salix sachalinensis plants to 200-400mgEDUL, the usually applied range for protection against O phytotoxicity, is beneficial to plants; (ii) to evaluate the effects of chronic exposure to elevated O on S. sachalinensis; (iii) to assess the efficacy of two methods (i.e. soil drench and foliar spray) of EDU application to plants; (iv) to investigate the appropriate concentration of EDU to protect against elevated O-induced damage in S. sachalinensis; and (v) to compare the two methods of EDU application in terms of effectiveness and EDU consumption. Current-year cuttings grown in infertile soil free from organic matter were exposed either to low ambient O (AOZ, 10-h≈28.3nmolmol) or to elevated O (EOZ, 10-h≈65.8nmolmol) levels during daylight hours. Over the growing season, plants were treated every nine days with 200mL soil drench of 0, 200 or 400mgEDUL or with foliar spray of 0, 200 or 400mgEDUL (in two separate experiments). We found that EDU per se had no effects on plants exposed to AOZ. EOZ practically significantly injured S. sachalinensis plants, and the impact was indifferent between the experiments. EDU did not protect plants against EOZ impact when applied as soil drench but it did protect them when applied as 200-400mgL foliar spray. We conclude that EDU may be more effective against O phytotoxicity to fast-growing species when applied as a spray than when applied as a drench. Keymessage: Soil-drenched EDU was ineffective in protecting willow plants against O-induced injury, whereas foliar-sprayed EDU was effective even at the concentration of 200mgL.
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http://dx.doi.org/10.1016/j.scitotenv.2016.08.183DOI Listing
December 2016

Increased phytotoxic O3 dose accelerates autumn senescence in an O3-sensitive beech forest even under the present-level O3.

Sci Rep 2016 09 7;6:32549. Epub 2016 Sep 7.

Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.

Ground-level ozone (O3) concentrations are expected to increase over the 21(st) century, especially in East Asia. However, the impact of O3 has not been directly assessed at the forest level in this region. We performed O3 flux-based risk assessments of carbon sequestration capacity in an old cool temperate deciduous forest, consisting of O3-sensitive Japanese beech (Fagus crenata), and in a warm temperate deciduous and evergreen forest dominated by O3-tolerant Konara oak (Quercus serrata) based on long-term CO2 flux observations. On the basis of a practical approach for a continuous estimation of canopy-level stomatal conductance (Gs), higher phytotoxic ozone dose above a threshold of 0 uptake (POD0) with higher Gs was observed in the beech forest than that in the oak forest. Light-saturated gross primary production, as a measure of carbon sequestration capacity of forest ecosystem, declined earlier in the late growth season with increasing POD0, suggesting an earlier autumn senescence, especially in the O3-sensitive beech forest, but not in the O3-tolerant oak forest.
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http://dx.doi.org/10.1038/srep32549DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5013268PMC
September 2016

A meta-analysis of leaf nitrogen distribution within plant canopies.

Ann Bot 2016 08 13;118(2):239-47. Epub 2016 Jun 13.

National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan Japan Agency for Marine-Earth Science and Technology, Yokohama 236-0001, Japan.

Background And Aims: Leaf nitrogen distribution in the plant canopy is an important determinant for canopy photosynthesis. Although the gradient of leaf nitrogen is formed along light gradients in the canopy, its quantitative variations among species and environmental responses remain unknown. Here, we conducted a global meta-analysis of leaf nitrogen distribution in plant canopies.

Methods: We collected data on the nitrogen distribution and environmental variables from 393 plant canopies (100, 241 and 52 canopies for wheat, other herbaceous and woody species, respectively).

Key Results: The trends were clearly different between wheat and other species; the photosynthetic nitrogen distribution coefficient (Kb) was mainly determined by leaf area index (LAI) in wheat, whereas it was correlated with the light extinction coefficient (KL) and LAI in other species. Some other variables were also found to influence Kb We present the best equations for Kb as a function of environmental variables and canopy characteristics. As a more simple function, Kb = 0·5KL can be used for canopies of species other than wheat. Sensitivity analyses using a terrestrial carbon flux model showed that gross primary production tended to be more sensitive to the Kb value especially when nitrogen content of the uppermost leaf was fixed.

Conclusion: Our results reveal that nitrogen distribution is mainly driven by the vertical light gradient but other factors such as LAI also have significant effects. Our equations contribute to an improvement in the projection of plant productivity and cycling of carbon and nitrogen in terrestrial ecosystems.
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http://dx.doi.org/10.1093/aob/mcw099DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4970363PMC
August 2016

High doses of ethylene diurea (EDU) are not toxic to willow and act as nitrogen fertilizer.

Sci Total Environ 2016 Oct 31;566-567:841-850. Epub 2016 May 31.

Silviculture & Forest Ecological Studies, Hokkaido University, Sapporo, Hokkaido 060-8589, Japan. Electronic address:

Unlabelled: Ethylene diurea (EDU) is synthetic chemical which protects plants against damage caused by ground level O3 and is used experimentally as a biomonitoring tool at doses usually ranging from 200 to 400mgL(-1) a.i. Although several studies have investigated the protective action of EDU, this mechanism remains unclear. Important uncertainties in EDU action are whether EDU acts as a source of nitrogen (N) to plants and whether high doses are phytotoxic. In order to answer these questions, we conducted an open-field experiment where potted willow (Salix sachalinensis Fr. Schm) plants were exposed to ambient O3 conditions and treated with 0, 800 or 1600mgL(-1) EDU as a soil drench, every nine days, for about 2.5months. We examined approximately 50 response variables. Based on N content in different plant organs, we found that (a) all EDU was transferred to the leaves and (b) high doses of EDU increased the leaf N content. However, EDU did not affect the C content and distribution within the plant body. Still, even at the highest dose, EDU was not toxic to this fast-growing species (however such a high dose should not be applied in uncontrolled environments); and there was no EDU persistence in the soil, as indicated by soil N content. Notably, our soil was free from organic matter and N-poor.

Key Message: EDU per se does not cause toxicity to willow plants when applied as drench to a soil with no organic matter, rather, high EDU doses may act as nitrogen fertilizer in a nitrogen-poor soil.
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http://dx.doi.org/10.1016/j.scitotenv.2016.05.122DOI Listing
October 2016