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1. Resolving the contrasting leaf hydraulic adaptation of C₃ and C₄ grasses

   https://doi.org/10.1111/nph.20341  

   Baird, Alec_S; Taylor, Samuel_H; Pasquet‐Kok, Jessica; Vuong, Christine; Zhang, Yu; Watcharamongkol, Teera; Cochard, Hervé; Scoffoni, Christine; Edwards, Erika_J; Osborne, Colin_P; et al (January 2025, New Phytologist)

   Summary Grasses are exceptionally productive, yet their hydraulic adaptation is paradoxical. Among C₃grasses, a high photosynthetic rate (A_area) may depend on higher vein density (D_v) and hydraulic conductance (K_leaf). However, the higherD_vof C₄grasses suggests a hydraulic surplus, given their reduced need for highK_leafresulting from lower stomatal conductance (g_s).Combining hydraulic and photosynthetic physiological data for diverse common garden C₃and C₄species with data for 332 species from the published literature, and mechanistic modeling, we validated a framework for linkages of photosynthesis with hydraulic transport, anatomy, and adaptation to aridity.C₃and C₄grasses had similarK_leafin our common garden, but C₄grasses had higherK_leafthan C₃species in our meta‐analysis. Variation inK_leafdepended on outside‐xylem pathways. C₄grasses have highK_leaf : g_s, which modeling shows is essential to achieve their photosynthetic advantage.Across C₃grasses, higherA_areawas associated with higherK_leaf, and adaptation to aridity, whereas for C₄species, adaptation to aridity was associated with higherK_leaf : g_s. These associations are consistent with adaptation for stress avoidance.Hydraulic traits are a critical element of evolutionary and ecological success in C₃and C₄grasses and are crucial avenues for crop design and ecological forecasting. 

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2. Identification of a prismatic P3N3 molecule formed from electron irradiated phosphine-nitrogen ices

   https://doi.org/10.1038/s41467-021-25775-1  

   Zhu, Cheng; Eckhardt, André K.; Chandra, Sankhabrata; Turner, Andrew M.; Schreiner, Peter R.; Kaiser, Ralf I. (September 2021, Nature Communications)

   Abstract Polyhedral nitrogen containing molecules such as prismatic P₃N₃- a hitherto elusive isovalent species of prismane (C₆H₆) - have attracted particular attention from the theoretical, physical, and synthetic chemistry communities. Here we report on the preparation of prismatic P₃N₃[1,2,3-triaza-4,5,6-triphosphatetracyclo[2.2.0.0^2,6.0^3,5]hexane] by exposing phosphine (PH₃) and nitrogen (N₂) ice mixtures to energetic electrons. Prismatic P₃N₃was detected in the gas phase and discriminated from its isomers utilizing isomer selective, tunable soft photoionization reflectron time-of-flight mass spectrometry during sublimation of the ices along with an isomer-selective photochemical processing converting prismatic P₃N₃to 1,2,4-triaza-3,5,6-triphosphabicyclo[2.2.0]hexa-2,5-diene (P₃N₃). In prismatic P₃N₃, the P–P, P–N, and N–N bonds are lengthened compared to those in, e.g., diphosphine (P₂H₄), di-anthracene stabilized phosphorus mononitride (PN), and hydrazine (N₂H₄), by typically 0.03–0.10 Å.  These findings advance our fundamental understanding of the chemical bonding of poly-nitrogen and poly-phosphorus systems and reveal a versatile pathway to produce exotic, ring-strained cage molecules. 

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3. Immobilized phosphate‐binding protein can effectively discriminate against arsenate during phosphate adsorption and recovery

   https://doi.org/10.1002/wer.1498  

   Venkiteshwaran, Kaushik; Wells, Erin; Mayer, Brooke K. (December 2020, Water Environment Research)

   Abstract There is a strong impetus to establish a circular phosphorus economy by securing internally renewable phosphate (P_i) resources for use as agricultural fertilizers. Reversible P_iadsorption technologies such as ion exchange can remove and recover P_ifrom water/wastewater for reuse. However, existing reversible adsorbents cannot effectively discriminate against arsenate (As(V)) due to the similarity between As(V) and P_ichemical structure. If As(V) is co‐recovered with P_i, the value of the recovered products for agricultural reuse is low. The objective of this study was to construct an immobilized phosphate‐binding protein (PBP)‐based P_iremoval and recovery system and analyze its selectivity for P_iadsorption in the presence of As(V). A range of conditions was tested, including independent, sequential, and simultaneous exposure of the two oxyanions to immobilized PBP (PBP resin). The purity of the recovered P_iproduct was assessed after inducing controlled desorption of the adsorbed oxyanions at high pH (pH 12.5). P_iconstituted more than 97% of the adsorbed oxyanions in the recovered product, even when As(V) was initially present at twofold higher concentrations than P_i. Therefore, PBP resin has potential to selectively remove P_i, as well as release high‐purity P_ifree of As(V) contamination suitable for subsequent agricultural reuse. Practitioner pointsExisting reversible phosphate (P_i) adsorbents cannot effectively discriminate against arsenate (As(V)) due to the similarity in their chemical structure.Co‐recovery of As(V) with P_ican reduce the recovered product's reuse as a fertilizer.An immobilized phosphate‐binding protein (PBP)‐based system can be highly selective for P_ieven in the presence of As(V).P_iconstituted more than 97% of the recovered product, even when As(V) was present at 2‐fold higher concentrations than P_i.Immobilized PBP offers advantages over existing P_iadsorbents by providing high‐purity P_iproducts free of As(V) contamination for reuse. 

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4. Responses of stomatal features and photosynthesis to porewater N enrichment and elevated atmospheric CO ₂ in Phragmites australis , the common reed

   https://doi.org/10.1002/ajb2.1638  

   Garrison, Julian R.; Caplan, Joshua S.; Douhovnikoff, Vladimir; Mozdzer, Thomas J.; Logan, Barry A. (April 2021, American Journal of Botany)

   PREMISEBiological invasions increasingly threaten native biodiversity and ecosystem services. One notable example is the common reed,Phragmites australis, which aggressively invades North American salt marshes. Elevated atmospheric CO₂and nitrogen pollution enhance its growth and facilitate invasion becauseP. australisresponds more strongly to these enrichments than do native species. We investigated how modifications to stomatal features contribute to strong photosynthetic responses to CO₂and nitrogen enrichment inP. australisby evaluating stomatal shifts under experimental conditions and relating them to maximal stomatal conductance (g_wmax) and photosynthetic rates. METHODSPlants were grownin situin open‐top chambers under ambient and elevated atmospheric CO₂(eCO₂) and porewater nitrogen (N_enr) in a Chesapeake Bay tidal marsh. We measured light‐saturated carbon assimilation rates (A_sat) and stomatal characteristics, from which we calculatedg_wmaxand determined whether CO₂and N_enraltered the relationship betweeng_wmaxandA_sat. RESULTSeCO₂and N_enrenhanced bothg_wmaxandA_sat, but to differing degrees;g_wmaxwas more strongly influenced by N_enrthrough increases in stomatal density whileA_satwas more strongly stimulated by eCO₂. There was a positive relationship betweeng_wmaxandA_satthat was not modified by eCO₂or N_enr, individually or in combination. CONCLUSIONSChanges in stomatal features co‐occur with previously described responses ofP. australisto eCO₂and N_enr. Complementary responses of stomatal length and density to these global change factors may facilitate greater stomatal conductance and carbon gain, contributing to the invasiveness of the introduced lineage. 

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5. Variability and Controls on δ ¹⁸ O, d‐excess, and ∆′ ¹⁷ O in Southern Peruvian Precipitation

   https://doi.org/10.1029/2020JD034009  

   Aron, Phoebe G.; Poulsen, Christopher J.; Fiorella, Richard P.; Levin, Naomi E.; Acosta, Rene P.; Yanites, Brian J.; Cassel, Elizabeth J. (December 2021, Journal of Geophysical Research: Atmospheres)

   Abstract The isotopic composition of precipitation is used to trace water cycling and climate change, but interpretations of the environmental information recorded in central Andean precipitation isotope ratios are hindered by a lack of multi‐year records, poor spatial distribution of observations, and a predominant focus on Rayleigh distillation. To better understand isotopic variability in central Andean precipitation, we present a three‐year record of semimonthly δ¹⁸O_pand δ²H_pvalues from 15 stations in southern Peru and triple oxygen isotope data, expressed as ∆′¹⁷O_p, from 32 precipitation samples. Consistent with previous work, we find that elevation correlates negatively with δ¹⁸O_pand that seasonal δ¹⁸O_pvariations are related to upstream rainout and local convection. Spatial δ¹⁸O_pvariations and atmospheric back trajectories show that both eastern‐ and western‐derived air masses bring precipitation to southern Peru. Seasonal d‐excess_pcycles record moisture recycling and relative humidity at remote moisture sources, and both d‐excess_pand ∆′¹⁷O_pclearly differentiate evaporated and non‐evaporated samples. These results begin to establish the natural range of unevaporated ∆′¹⁷O_pvalues in the central Andes and set the foundation for future paleoclimate and paleoaltimetry studies in the region. This study highlights the hydrologic understanding that comes from a combination of δ¹⁸O_p, d‐excess_p, and ∆′¹⁷O_pdata and helps identify the evaporation, recycling, and rainout processes that drive water cycling in the central Andes. 

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