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  • 1
    Online Resource
    Online Resource
    Distinct xylem responses to acute vs prolonged drought in pine trees
    Oxford University Press (OUP) ; 2020
    In:  Tree Physiology Vol. 40, No. 5 ( 2020-05-11), p. 605-620
    Details
    In: Tree Physiology, Oxford University Press (OUP), Vol. 40, No. 5 ( 2020-05-11), p. 605-620
    Abstract: Increasing dryness challenges trees’ ability to maintain water transport to the leaves. Most plant hydraulics models use a static xylem response to water stress. Yet, in reality, lower soil moisture and warmer temperatures during growing seasons feed back onto xylem development. In turn, adjustments to water stress in the newly built xylem influence future physiological responses to droughts. In this study, we investigate the annual variation of anatomical traits in branch xylem in response to different soil and atmospheric moisture conditions and tree stress levels, as indicated by seasonal predawn leaf water potential (ΨL,pd). We used a 6-year field experiment in southwestern USA with three soil water treatments applied to Pinus edulis Engelm trees—ambient, drought (45% rain reduction) and irrigation (15–35% annual water addition). All trees were also subject to a natural 1-year acute drought (soil and atmospheric) that occurred during the experiment. The irrigated trees showed only moderate changes in anatomy-derived hydraulic traits compared with the ambient trees, suggesting a generally stable, well-balanced xylem structure under unstressed conditions. The artificial prolonged soil drought increased hydraulic efficiency but lowered xylem construction costs and decreased tracheid implosion safety ((t/b)2), suggesting that annual adjustments of xylem structure follow a safety–efficiency trade-off. The acute drought plunged hydraulic efficiency across all treatments. The combination of acute and prolonged drought resulted in vulnerable and inefficient new xylem, disrupting the stability of the anatomical trade-off observed in the rest of the years. The xylem hydraulic traits showed no consistent direct link to ΨL,pd. In the future, changes in seasonality of soil and atmospheric moisture are likely to have a critical impact on the ability of P. edulis to acclimate its xylem to warmer climate. Furthermore, the increasing frequency of acute droughts might reduce hydraulic resilience of P. edulis by repeatedly creating vulnerable and less efficient anatomical structure.
    Type of Medium: Online Resource
    ISSN: 1758-4469
    URL: Article
    DOI: 10.1093/treephys/tpz144
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2020
    detail.hit.zdb_id: 1473475-8
    SSG: 12
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  • 2
    Online Resource
    Online Resource
    Coupling between the terrestrial carbon and water cycles—a review
    IOP Publishing ; 2019
    In:  Environmental Research Letters Vol. 14, No. 8 ( 2019-08-01), p. 083003-
    Details
    In: Environmental Research Letters, IOP Publishing, Vol. 14, No. 8 ( 2019-08-01), p. 083003-
    Abstract: The terrestrial carbon and water cycles are strongly coupled. As atmospheric carbon dioxide concentration increases, climate and the coupled hydrologic cycle are modified, thus altering the terrestrial water cycle and the availability of soil moisture necessary for plants’ carbon dioxide uptake. Concomitantly, rising surface carbon dioxide concentrations also modify stomatal (small pores at the leaf surface) regulation as well as biomass, thus altering ecosystem photosynthesis and transpiration rates. Those coupled changes have profound implications for the predictions of the carbon and water cycles. This paper reviews the main mechanisms behind the coupling of the terrestrial water and carbon cycles. We especially focus on the key role of dryness (atmospheric dryness and terrestrial water availability) on carbon uptake, as well as the predicted impact of rising carbon dioxide on the water cycle. Challenges related to this coupling and the necessity to constrain it based on observations are finally discussed.
    Type of Medium: Online Resource
    ISSN: 1748-9326
    URL: Article
    DOI: 10.1088/1748-9326/ab22d6
    Language: Unknown
    Publisher: IOP Publishing
    Publication Date: 2019
    detail.hit.zdb_id: 2255379-4
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  • 3
    Online Resource
    Online Resource
    Measuring Tree Properties and Responses Using Low-Cost Accelerometers
    MDPI AG ; 2017
    In:  Sensors Vol. 17, No. 5 ( 2017-05-11), p. 1098-
    Details
    In: Sensors, MDPI AG, Vol. 17, No. 5 ( 2017-05-11), p. 1098-
    Type of Medium: Online Resource
    ISSN: 1424-8220
    URL: Article
    DOI: 10.3390/s17051098
    Language: English
    Publisher: MDPI AG
    Publication Date: 2017
    detail.hit.zdb_id: 2052857-7
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  • 4
    Online Resource
    Online Resource
    An allometry‐based model of the survival strategies of hydraulic failure and carbon starvation
    Wiley ; 2016
    In:  Ecohydrology Vol. 9, No. 3 ( 2016-04), p. 529-546
    Details
    In: Ecohydrology, Wiley, Vol. 9, No. 3 ( 2016-04), p. 529-546
    Abstract: A simplified soil–plant–atmosphere–continuum model of carbon starvation and hydraulic failure is developed and tested against observations from a drought‐manipulation experiment in a woodland dominated by piñon pine ( Pinus edulis ) and juniper ( Juniperus monosperma ) in New Mexico. The number of model parameters is reduced using allometric relationships. The model can represent more isohydric (piñon) and more anisohydric (juniper) responses. Analysis of the parameter space suggests four main controls on hydraulic failure and carbon starvation: xylem vulnerability curve, root:shoot area ratio, rooting depth and water use efficiency. For piñon, an intermediate optimal (1.5–2 m 2  m −2 ) tree leaf area index reduces the risk of hydraulic failure. For both piñons and junipers, hydraulic failure was relatively insensitive to root:shoot ratio across a range of tree LAI. Higher root:shoot ratios however strongly decreased the time to carbon starvation. The hydraulic safety margin of piñons is strongly diminished by large diurnal variations in xylem/leaf water potential. Diurnal drops of water potential are mitigated by high maximum hydraulic conductivity, high root:shoot ratio and stomatal regulation (more isohydric). The safety margin of junipers is not very sensitive to diurnal drops in water potential so that there is little benefit in stomatal regulation (more anisohydric). Narrower tracheid diameter and a narrower distribution of tracheid diameters reduce the risk of hydraulic failure and carbon starvation by reducing diurnal xylem water potential drop. Simulated tree diameter‐dependent mortality varies between these two species, with piñon mortality decreasing with increasing tree size, whereas juniper mortality increases with tree size. Juvenile piñons might thus be overimpacted by water stress. Copyright © 2015 John Wiley & Sons, Ltd.
    Type of Medium: Online Resource
    ISSN: 1936-0584 , 1936-0592
    URL: Issue
    URL: Article
    DOI: 10.1002/eco.v9.3
    DOI: 10.1002/eco.1654
    Language: English
    Publisher: Wiley
    Publication Date: 2016
    detail.hit.zdb_id: 2418105-5
    SSG: 12
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  • 5
    Online Resource
    Online Resource
    Interannual variations in needle and sapwood traits of Pinus edulis branches under an experimental drought
    Wiley ; 2018
    In:  Ecology and Evolution Vol. 8, No. 3 ( 2018-02), p. 1655-1672
    Details
    In: Ecology and Evolution, Wiley, Vol. 8, No. 3 ( 2018-02), p. 1655-1672
    Abstract: In the southwestern USA , recent large‐scale die‐offs of conifers raise the question of their resilience and mortality under droughts. To date, little is known about the interannual structural response to droughts. We hypothesized that piñon pines ( Pinus edulis ) respond to drought by reducing the drop of leaf water potential in branches from year to year through needle morphological adjustments. We tested our hypothesis using a 7‐year experiment in central New Mexico with three watering treatments (irrigated, normal, and rain exclusion). We analyzed how variation in “evaporative structure” (needle length, stomatal diameter, stomatal density, stomatal conductance) responded to watering treatment and interannual climate variability. We further analyzed annual functional adjustments by comparing yearly addition of needle area ( LA ) with yearly addition of sapwood area ( SA ) and distance to tip ( d ), defining the yearly ratios SA : LA and SA : LA / d . Needle length ( l ) increased with increasing winter and monsoon water supply, and showed more interannual variability when the soil was drier. Stomatal density increased with dryness, while stomatal diameter was reduced. As a result, anatomical maximal stomatal conductance was relatively invariant across treatments. SA : LA and SA : LA / d showed significant differences across treatments and contrary to our expectation were lower with reduced water input. Within average precipitation ranges, the response of these ratios to soil moisture was similar across treatments. However, when extreme soil drought was combined with high VPD , needle length, SA : LA and SA : LA / d became highly nonlinear, emphasizing the existence of a response threshold of combined high VPD and dry soil conditions. In new branch tissues, the response of annual functional ratios to water stress was immediate (same year) and does not attempt to reduce the drop of water potential. We suggest that unfavorable evaporative structural response to drought is compensated by dynamic stomatal control to maximize photosynthesis rates.
    Type of Medium: Online Resource
    ISSN: 2045-7758 , 2045-7758
    URL: Issue
    URL: Article
    DOI: 10.1002/ece3.2018.8.issue-3
    DOI: 10.1002/ece3.3743
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 2635675-2
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  • 6
    Online Resource
    Online Resource
    Tree Sway Time Series of 7 Amazon Tree Species (July 2015–May 2016)
    Frontiers Media SA ; 2018
    In:  Frontiers in Earth Science Vol. 6 ( 2018-12-7)
    Details
    In: Frontiers in Earth Science, Frontiers Media SA, Vol. 6 ( 2018-12-7)
    Type of Medium: Online Resource
    ISSN: 2296-6463
    URL: Article
    DOI: 10.3389/feart.2018.00221
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2018
    detail.hit.zdb_id: 2741235-0
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  • 7
    Online Resource
    Online Resource
    Growth and physiology of a dominant understory shrub, Hamamelis virginiana , following canopy disturbance in a temperate hardwood forest
    Canadian Science Publishing ; 2017
    In:  Canadian Journal of Forest Research Vol. 47, No. 2 ( 2017-02), p. 193-202
    Details
    In: Canadian Journal of Forest Research, Canadian Science Publishing, Vol. 47, No. 2 ( 2017-02), p. 193-202
    Abstract: As global climatic changes increase plant susceptibility to large-scale disturbances such as drought and pathogens, understory responses to these disturbances will become increasingly important to long-term forest dynamics. To better understand understory responses to canopy disturbance, we measured changes in the growth and physiology of the dominant understory shrub, American witch-hazel (Hamamelis virginiana L.), in response to girdling of canopy oaks in a temperate hardwood forest of the northeastern United States. Changes in the growth and physiology of H. virginiana may be important to the regeneration of northeastern temperate forests, as this common shrub largely shapes the microenvironment for seedlings on the forest floor where it occurs. Canopy disturbance by girdling resulted in significant increases in light and soil nitrogen availability. In response to these environmental changes, basal-area growth of H. virginiana increased by an average 334%. This growth increase corresponded to significant increases in foliar nitrogen, respiration, and leaf chlorophyll and carotenoid concentrations. These findings indicate improved environmental conditions and increased growth for this understory shrub following the loss of dominant canopy trees. This study suggests that following large-scale canopy disturbance, H. virginiana and shrubs like it may play an important role in competing for soil N and shading seedlings of regenerating canopy species.
    Type of Medium: Online Resource
    ISSN: 0045-5067 , 1208-6037
    URL: Article
    DOI: 10.1139/cjfr-2016-0208
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2017
    detail.hit.zdb_id: 1473096-0
    SSG: 23
    SSG: 12
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  • 8
    Online Resource
    Online Resource
    Mutational profile and benefit of gemtuzumab ozogamicin in acute myeloid leukemia
    American Society of Hematology ; 2020
    In:  Blood Vol. 135, No. 8 ( 2020-02-20), p. 542-546
    Details
    In: Blood, American Society of Hematology, Vol. 135, No. 8 ( 2020-02-20), p. 542-546
    Abstract: Acute myeloid leukemia (AML) is a highly heterogeneous disease both in terms of genetic background and response to chemotherapy. Although molecular aberrations are routinely used to stratify AML patients into prognostic subgroups when receiving standard chemotherapy, the predictive value of the genetic background and co-occurring mutations remains to be assessed when using newly approved antileukemic drugs. In the present study, we retrospectively addressed the question of the predictive value of molecular events on the benefit of the addition of gemtuzumab ozogamicin (GO) to standard front-line chemotherapy. Using the more recent European LeukemiaNet (ELN) 2017 risk classification, we confirmed that the benefit of GO was restricted to the favorable (hazard ratio [HR], 0.54, 95% confidence interval [CI] , 0.30-0.98) and intermediate (HR, 0.57; 95% CI, 0.33-1.00) risk categories, whereas it did not influence the outcome of patients within the adverse risk subgroup (HR, 0.93; 95% CI, 0.61-1.43). Interestingly, the benefit of GO was significant for patients with activating signaling mutations (HR, 0.43; 95% CI, 0.28-0.65), which correlated with higher CD33 expression levels. These results suggest that molecular aberrations could be critical for future differentially tailored treatments based on integrated genetic profiles that are able to predict the benefit of GO on outcome.
    Type of Medium: Online Resource
    ISSN: 0006-4971 , 1528-0020
    URL: Article
    DOI: 10.1182/blood.2019003471
    RVK:
    XA 33000
    RVK:
    XA 10000
    Language: English
    Publisher: American Society of Hematology
    Publication Date: 2020
    detail.hit.zdb_id: 1468538-3
    detail.hit.zdb_id: 80069-7
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