scholarly journals Some Secrets of Argania spinosa Water Economy in a Semiarid Climate

2013 ◽  
Vol 8 (1) ◽  
pp. 1934578X1300800
Author(s):  
Mari Cruz Díaz Barradas ◽  
María Zunzunegui ◽  
Mari Paz Esquivias ◽  
Said Boutaleb ◽  
Javier Valera-Burgos ◽  
...  
Keyword(s):  
Carbon Isotope Discrimination ◽  
Stomatal Closure ◽  
Vapour Pressure Deficit ◽  
Distribution Area ◽  
Argania Spinosa ◽  
Arid Conditions ◽  
Use Efficiency ◽  
Two Populations ◽  
Morphological Variable

Argania spinosa is an example of an avoider tree growing under semi-arid conditions in Morocco. To assess what are the physiological strategies of this species, different variables were measured through an annual cycle in two populations located in the species’ main distribution area. Results show the expected decrease of leaf water potential (Ψ) with an increase of water-use efficiency (A/gs) with the onset of the dry season. In summer, leaf conductance (gs) was sensitive to vapour pressure deficit (VPD), and stomatal closure occurred over 30 mbar of VPD. Surprisingly, carbon isotope discrimination (δ13C) maintained very low values over the year, with almost no relationship with any physiological or morphological variable. Hence Argania spinosa presents a complex set of mechanisms to avoid water deficit, but δ13C cannot be used as an ecological tracer of long term WUE.

scholarly journals Rediscovery of the endangered lichen Pseudocyphellaria aurata (Lobariaceae, Ascomycota) in mainland Spain

2021 ◽  
Vol 77 (2) ◽  
pp. e099
Author(s):  
Ibai Olariaga ◽  
Graciela Paz-Bermúdez ◽  
Javier Calvo ◽  
Javier Etayo ◽  
María Prieto
Keyword(s):  
Fungal Pathogens ◽  
Deciduous Forest ◽  
Habitat Degradation ◽  
Conservation Status ◽  
Distribution Area ◽  
Herbarium Specimens ◽  
Ecological Stability ◽  
The 19Th Century ◽  
Two Populations

Lichens, as well as other organisms, should be considered important biodiversity components for the establishment of priorities in conservation biology. In this study, we report six new recent localities of the highly endangered, epiphytic macrolichen Pseudocyphellaria aurata in Spain: two in Navarra and four in A Coruña. Previous Spanish reports based on literature and herbarium specimens suggest a reduction of the distribution area of P. aurata and local extinction. Pseudocyphellaria aurata is known to be extinct in six localities, where it has not been observed since the middle of the 19th century (Cádiz, Pontevedra, Málaga). Four records reported for central Spain (Zaragoza, Salamanca, Teruel) are considered unplausible. The newly discovered populations are located in well-preserved patches of atlantic deciduous forest with strong oceanic influence, whose long-term ecological stability seems evident because of the presence of ancient trees. Nevertheless, these populations are small, fragmentary, and are threatened by habitat degradation, forestry and maybe fungal pathogens. Two populations, Intzola and Beba (Navarra and A Coruña, respectively), account for 75.7% of thalli. The localities with the highest number of trees colonized by P. aurata are Santa Leocadia and Beba in A Coruña. We reassessed the conservation status of this species concluding that conservation initiatives must be implemented to avoid its extinction in mainland Spain.

Variation characteristics of long-term water use efficiency based on tree-ring carbon isotope discrimination

2017 ◽  
Vol 37 (6) ◽  
Author(s):  
路伟伟 LU Weiwei ◽  
余新晓 YU Xinxiao ◽  
贾国栋 JIA Guodong ◽  
李瀚之 LI Hanzhi ◽  
刘自强 LIU Ziqiang
Keyword(s):  
Water Use Efficiency ◽  
Carbon Isotope ◽  
Water Use ◽  
Tree Ring ◽  
Carbon Isotope Discrimination ◽  
Isotope Discrimination ◽  
Ring Carbon ◽  
Variation Characteristics ◽  
Use Efficiency

Photosynthetic gas exchange and water use in tropical and subtropical populations of the mangrove Aegiceras corniculatum

1998 ◽  
Vol 49 (4) ◽  
pp. 329 ◽  
Author(s):  
Tarek Youssef ◽  
Peter Saenger
Keyword(s):  
Gas Exchange ◽  
Water Use ◽  
Vapour Pressure Deficit ◽  
Photosynthetic Gas Exchange ◽  
Aegiceras Corniculatum ◽  
Stomatal Behaviour ◽  
Arid Conditions ◽  
Air Temperatures ◽  
Quantum Flux ◽  
Use Efficiency

Photosynthetic gas exchange and stomatal behaviour in the tropical (Darwin: 12°25′S) and subtropical (Ballina: 28°50′S) populations of the mangrove Aegiceras corniculatum (L.) Blanco were compared at elevated air temperatures (>32°C) and leaf-to-air vapour pressure deficit (vpd >25 mbar) with a quantum flux at, or above, their light saturation capacity (>600 µmol m-2 s-1). At the lower end of the tested aridity range, the tropical population showed a less conservative water use than the subtropical population. As aridity increased, both populations showed a reduction in stomatal conductance. However, transpiration rates remained higher in the subtropical population at all times, reducing its water-use efficiency from that under less arid conditions. At extreme aridity (temperature >37°C and vpd >35 mbar), the efficiency of the evaporative cooling of fully exposed leaves was evident in the leaf-to-air temperature differential which remained minimal in the tropical population while it increased significantly in the subtropical population. Aridity tolerance was more pronounced in individuals from the tropical site than from the subtropical site, as evidenced by a tighter stomatal control on water use in the tropical population. These data suggest that the tropical and subtropical populations of A. corniculatum have different physiological responses to aridity.

Connecting Crop Nutrient Use Efficiency to Future Soil Productivity

2018 ◽  
Vol 102 (4) ◽  
pp. 8-10
Author(s):  
Fernando García ◽  
Andrés Grasso ◽  
María González Sanjuan ◽  
Adrián Correndo ◽  
Fernando Salvagiotti
Keyword(s):  
Nutrient Management ◽  
Nutrient Use Efficiency ◽  
Management Strategies ◽  
Crop Productivity ◽  
Soil Productivity ◽  
Nutrient Use ◽  
Grain Crop ◽  
Wide Scale ◽  
Use Efficiency

Trends over the past 25 years indicate that Argentina’s growth in its grain crop productivity has largely been supported by the depletion of the extensive fertility of its Pampean soils. Long-term research provides insight into sustainable nutrient management strategies ready for wide-scale adoption.

scholarly journals Overexpression of MdATG8i improves water use efficiency in transgenic apple by modulating photosynthesis, osmotic balance, and autophagic activity under moderate water deficit

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xin Jia ◽  
Ke Mao ◽  
Ping Wang ◽  
Yu Wang ◽  
Xumei Jia ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Deficit ◽  
Water Use ◽  
Photosynthetic Capacity ◽  
Critical Role ◽  
Drought Conditions ◽  
Moderate Drought ◽  
Use Efficiency ◽  
Autophagic Activity

AbstractWater deficit is one of the major limiting factors for apple (Malus domestica) production on the Loess Plateau, a major apple cultivation area in China. The identification of genes related to the regulation of water use efficiency (WUE) is a crucial aspect of crop breeding programs. As a conserved degradation and recycling mechanism in eukaryotes, autophagy has been reported to participate in various stress responses. However, the relationship between autophagy and WUE regulation has not been explored. We have shown that a crucial autophagy protein in apple, MdATG8i, plays a role in improving salt tolerance. Here, we explored its biological function in response to long-term moderate drought stress. The results showed that MdATG8i-overexpressing (MdATG8i-OE) apple plants exhibited higher WUE than wild-type (WT) plants under long-term moderate drought conditions. Plant WUE can be increased by improving photosynthetic efficiency. Osmoregulation plays a critical role in plant stress resistance and adaptation. Under long-term drought conditions, the photosynthetic capacity and accumulation of sugar and amino acids were higher in MdATG8i-OE plants than in WT plants. The increased photosynthetic capacity in the OE plants could be attributed to their ability to maintain optimal stomatal aperture, organized chloroplasts, and strong antioxidant activity. MdATG8i overexpression also promoted autophagic activity, which was likely related to the changes described above. In summary, our results demonstrate that MdATG8i-OE apple lines exhibited higher WUE than WT under long-term moderate drought conditions because they maintained robust photosynthesis, effective osmotic adjustment processes, and strong autophagic activity.

Evaluation of the CERES-Rice Model for Precision Nitrogen Management for Rice in Northeast China

2017 ◽  
Vol 8 (2) ◽  
pp. 328-332
Author(s):  
J. Zhang ◽  
Y. Miao ◽  
W.D. Batchelor
Keyword(s):  
Northeast China ◽  
Weather Data ◽  
Cool Season ◽  
Use Efficiency ◽  
Optimum N Rate ◽  
Management Recommendations ◽  
N Management ◽  
N Rates ◽  
N Use

Over-application of nitrogen (N) in rice (Oryza sativaL.) production in China is common, leading to low N use efficiency (NUE) and high environmental risks. The objective of this work was to evaluate the ability of the CERES-Rice crop growth model to simulate N response in the cool climate of Northeast China, with the long term goal of using the model to develop optimum N management recommendations. Nitrogen experiments were conducted from 2011–2015 in Jiansanjiang, Heilongjiang Province in Northeast China. The CERES-Rice model was calibrated for 2014 and 2015 and evaluated for 2011 and 2013 experiments. Overall, the model gave good estimations of yield across N rates for the calibration years (R2=0.89) and evaluation years (R2=0.73). The calibrated model was then run using weather data from 2001–2015 for 20 different N rates to determine the N rate that maximized the long term marginal net return (MNR) for different N prices. The model results indicated that the optimum mean N rate was 120–130 kg N ha–1, but that the simulated optimum N rate varied each year, ranging from 100 to 200 kg N ha–1. Results of this study indicated that the CERES-Rice model was able to simulate cool season rice growth and provide estimates of optimum regional N rates that were consistent with field observations for the area.

scholarly journals Transcriptome and chromatin landscape of iNKT cells are shaped by subset differentiation and antigen exposure

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mallory Paynich Murray ◽  
Isaac Engel ◽  
Grégory Seumois ◽  
Sara Herrera-De la Mata ◽  
Sandy Lucette Rosales ◽  
...  
Keyword(s):  
T Cells ◽  
Inkt Cells ◽  
Phenotypic Analysis ◽  
Follicular Helper ◽  
Transcriptional Changes ◽  
Innate Lymphocytes ◽  
Killer T Cells ◽  
Invariant Natural Killer ◽  
Two Populations

AbstractInvariant natural killer T cells (iNKT cells) differentiate into thymic and peripheral NKT1, NKT2 and NKT17 subsets. Here we use RNA-seq and ATAC-seq analyses and show iNKT subsets are similar, regardless of tissue location. Lung iNKT cell subsets possess the most distinct location-specific features, shared with other innate lymphocytes in the lung, possibly consistent with increased activation. Following antigenic stimulation, iNKT cells undergo chromatin and transcriptional changes delineating two populations: one similar to follicular helper T cells and the other NK or effector like. Phenotypic analysis indicates these changes are observed long-term, suggesting that iNKT cells gene programs are not fixed, but they are capable of chromatin remodeling after antigen to give rise to additional subsets.

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