Desert dust outbreak in the Canary Islands (February 2020): assessment and impacts

World Weather Research Programme (WWRP 2021–1

Could fruits modify leaf soluble sugars and determine water-carbon relations in plants?

2 páginas.- 2 referencias.- Poster presentado en el BP2021: XXIV Reunión de la Sociedad Española de Biología de Plantas y XVII Congreso Hispano-Luso de Biología de Plantas, 7 y 8 de julio de 2021. onlineWater seareity is one of the main restrietions to aehieve food security for a growing population. Thus, new defieit irrigation strategies are being developed based on plant physiology but surprisingly, little is known on fruit physiology. The reeent results on the importanee on non-struetural earbohydrates (NSC) to faeilitate osmotie adjustment (Blum, 2017) and their differential transport depending on the water stress level (Gersony et al., 2020) eould be useful to explain the effeet of fruil loading on plant water relations but it has not been studied yet. The aim of this work is to study the effeet of the fruit presenee or absenee on the leaves water relations mediated by their effeet on leaf soluble sugar dynamies and thus, on leaf osmotie potential analyzing (i) the regulation of stomatal eonduetanee (gs), net photosynthesis (AN) and leafwater potential ('I'lcar) produeed by fruits and (ii) determine leaf osmotie potential (lt) and NSC dynamies depending on the presenee or absenee of fruits and water stress. The experiment was earried out between July and November 2018 on twelve olive trees. Six of them were well-watered (WW) trees and the rest were water-stressed (WS). In eaeh of these treatments, half had the presenee of fruits (+) and the other half had absenee of fruils (-) (n = 3). AN, gs, 'l'le,r, were measured weekly and lt and NSC eontent were measured in four speeifie moments in eaeh tree. The results showed that WW+ presented higher AN and gs values, lower leaf NSC and lt less negative than WW-, indieating that earbohydrates were being exported to the fruit. Assuming that fruits behave as a earbon sink organ, we also observe that WS+ presented more negative 'l'le,r values than WS-. This response would be modulated by the hydrie treatments, beeause the effeet of AN and gs was not as prominent in WS nor that of the hydrie potential in WW. In eonclusion, our results suggested that fruits can modulate leaf NSC and maintain the earbon and water relations under water stress.This researeh was supported by Spanish Ministry of Seienee, Innovation and Universities (researeh projeet AGL2015-71585-R). A. Montero and A. Perez-Martin helped us with field measurements and osmotie potential analysis. A.P-A was the recipienl of a eontraet form FPI-CSIC program (Spain). We thank to Internacional Olivarera, S.A. U (Interoliva), for allowing us 10 make the experimenls at Sanabria orehardPeer reviewe

Dual effect of the presence of fruits on leaf gas exchange and water relations of olive trees

11 páginas..- 6 figuras.- 64 referencias.- Supplementary data for this article are available at Tree Physiology Online https://academic.oup.com/treephys/advance-article/doi/10.1093/treephys/tpac123/6764541#supplementary-dataThe presence of fruits provokes significant modifications in plant water relations and leaf gas exchange. The underlying processes driving these modifications are still uncertain and likely depend on the water deficit level. Our objective was to explain and track the modification of leaf-water relations by the presence of fruits and water deficit. With this aim, net photosynthesis rate (A(N)), stomatal conductance (g(s)), leaf osmotic potential (psi(pi)), leaf soluble sugars and daily changes in a variable related to leaf turgor (leaf patch pressure) were measured in olive trees with and without fruits at the same time, under well-watered (WW) and water stress (WS) conditions. Leaf gas exchange was increased by the presence of fruits, this effect being observed mainly in WW trees, likely because under severe water stress, the dominant process is the response of the plant to the water stress and the presence of fruits has less impact on the leaf gas exchange. psi(pi) was also higher for WW trees with fruits than for WW trees without fruits. Moreover, leaves from trees without fruits presented higher concentrations of soluble sugars and starch than leaves from trees with fruits for both WW and WS, these differences matching those found in psi(pi). Thus, the sugar accumulation would have had a dual effect because on one hand, it decreased psi(pi), and on the other hand, it would have downregulated A(N), and finally g(s) in WW trees. Interestingly, the modification of psi(pi) by the presence of fruits affected turgor in WW trees, the change in which can be identified with leaf turgor sensors. We conclude that plant water relationships and leaf gas exchange are modified by the presence of fruits through their effect on the export of sugars from leaves to fruits. The possibility of automatically identifying the onset of sugar demand by the fruit through the use of sensors, in addition to the water stress produced by soil water deficit and atmosphere drought, could be of great help for fruit orchard management in the future.Spanish Ministry of Science, Innovation and Universities (research project AGL2015–71585-R).Peer reviewe

Preservation Factors during Cretaceous Oceanic Anoxic Events in the Espírito Santo Basin, Southeast Brazil

The oceanic anoxic events (OAEs) are characterized by enhanced accumulation of organic matter in marine sediments. However, there is still an ongoing debate regarding the interplay between production and preservation during these events. Moreover, few studies provide quantitative estimations of primary productivity and/or the amount of carbon preserved during the OAEs. Here, we used geochemical data from multiple wells located at the Espírito Santo Basin that cover the intervals of events OAE1d and OAE2 to provide quantitative estimates of preservation factors. Our results show enhanced preservation during OAEs compared to modern conditions and a stronger preservation during OAE1d compared to OAE2 in the Espírito Santo Basin. The amount of preserved carbon could reach up to 8.6% during OAE1d, depending on the productivity of the system. In addition, we show that such improvement in preservation is linked to the bottom water with low-O2 concentrations and not due to fast burial caused by high sedimentation rates. Our findings are extremally relevant for organic carbon and source rock modelling studies since model simulations need quantitative estimations

Preservation Factors during Cretaceous Oceanic Anoxic Events in the Espírito Santo Basin, Southeast Brazil

The oceanic anoxic events (OAEs) are characterized by enhanced accumulation of organic matter in marine sediments. However, there is still an ongoing debate regarding the interplay between production and preservation during these events. Moreover, few studies provide quantitative estimations of primary productivity and/or the amount of carbon preserved during the OAEs. Here, we used geochemical data from multiple wells located at the Espírito Santo Basin that cover the intervals of events OAE1d and OAE2 to provide quantitative estimates of preservation factors. Our results show enhanced preservation during OAEs compared to modern conditions and a stronger preservation during OAE1d compared to OAE2 in the Espírito Santo Basin. The amount of preserved carbon could reach up to 8.6% during OAE1d, depending on the productivity of the system. In addition, we show that such improvement in preservation is linked to the bottom water with low-O2 concentrations and not due to fast burial caused by high sedimentation rates. Our findings are extremally relevant for organic carbon and source rock modelling studies since model simulations need quantitative estimations

Benthic stable oxygen and carbon isotope records; XRF scanner S and EDP XRF S, and foraminiferal assemblages of sediment core M125-95-3

Negative excursions in the stable carbon isotopic composition (δ¹³C) at Atlantic intermediate to mid-depths are common features of millennial-scale events named Heinrich Stadials (HS). The mechanisms behind these excursions are not yet fully understood, but most hypotheses agree on the central role played by the weakening of the Atlantic meridional overturning circulation. Marine records registering millennial-scale negative δ¹³C excursions in the Atlantic are mostly restricted to the HS of the last deglacial, while the HS of the last glacial are poorly studied. Here we constrain changes in bottom water ventilation in the western tropical South Atlantic mid-depth during HS of the last glacial and deglacial by investigating marine core M125-95-3. The concurrent decreases in benthic foraminifera δ¹³C and increases in bulk sediment sulfur indicates an increased Northern Component Water (NCW) residence time in the western tropical South Atlantic mid-depth during HS. Furthermore, a coherent meridional pattern emerges from the comparison of our new data to previously published mid-depth records from the western South Atlantic. While our record shows the largest negative δ¹³C excursions during almost all HS, the western equatorial Atlantic showed medium and the subtropical South Atlantic showed the smallest negative excursions. This meridional pattern supports the notion that during HS a reduction in the NCW δ¹³C source signal together with the accumulation of respired carbon at NCW depths drove the negative δ¹³C excursions. We suggest that the negative δ¹³C excursions progressively increase along the NCW southwards pathway until the signal dissipates/dilutes by mixing with Southern Component Water

MiR-SNPs as markers of toxicity and clinical outcome in Hodgkin Lymphoma patients

Background: In recent years, microRNA (miRNA) pathways have emerged as a crucial system for the regulation of tumorogenesis. miR-SNPs are a novel class of single nucleotide polymorphisms that can affect miRNA pathways. Design and Methods: We analyzed eight miR-SNPs by allelic discrimination in 141 patients with Hodgkin lymphoma and correlated the results with treatment-related toxicity, response, disease-free survival (DFS) and overall survival (OS). Results: The KRT81 (rs3660) GG genotype was associated with an increased risk of neurological toxicity (P=0.016), while patients with XPO5 (rs11077) AA or CC genotypes had a higher rate of bleomycin-associated pulmonary toxicity (P=0.048). Both miR-SNPs emerged as independent factors in the multivariate analysis. The XPO5 AA and CC genotypes were also associated with a lower response rate (P=0.036). XPO5 (P=0.039) and TRBP (rs784567) (P=0.022) genotypes emerged as prognostic markers for DFS, and XPO5 was also associated with OS (P=0.033). In the multivariate analysis, only XPO5 emerged as an independent prognostic factor for DFS (HR: 2.622; 95%CI 1.039-6.620; P=0.041). Given the influence of XPO5 and TRBP as individual markers, we then investigated the combined effect of these miR-SNPs. Patients with both the XPO5 AA/CC and TRBP TT/TC genotypes had the shortest DFS (P=0.008) and OS (P=0.008). Conclusion: miR-SNPs can add useful prognostic information on treatment-related toxicity and clinical outcome in Hodgkin lymphoma and can be used to identify patients likely to be chemoresistant or to relapse

Late Cretaceous cyclostratigraphy for the subtropical western South Atlantic, Espírito Santo Basin

Well-log data was acquired in a Late Cretaceous section of the Espírito Santo basin (western South Atlantic). Cyclostratigraphic techniques were used to explore the eventual pacing of orbital cycles in the deposition of sequences. The frequency ratio method was used to interpret the orbital cycles and based on this a long-eccentricity signal was interpreted and extracted to create a floating time-scale. Using a seismic horizon associated Cretaceous-Paleogene transition, a strong shift in the natural gamma-ray data was anchored to an age of 66.0 Ma producing an anchored astronomical time-scale placed between late Albian and early Ypresian