Soil salinity is one of several major abiotic stresses that constrain maize productivity worldwide. An improved understanding of salt-tolerance mechanisms will thus enhance the breeding of salt-tolerant maize and boost productivity. Previous studies have indicated that the maintenance of leaf Na concentration is essential for maize salt tolerance, and the difference in leaf Na exclusion has previously been associated with variation in salt tolerance between maize varieties. Here, we report the identification and functional characterization of a maize salt-tolerance quantitative trait locus (QTL), Zea mays Na Content1 (ZmNC1), which encodes an HKT-type transporter (designated as ZmHKT1). We show that a natural ZmHKT1 loss-of-function allele containing a retrotransposon insertion confers increased accumulation of Na in leaves, and salt hypersensitivity. We next show that ZmHKT1 encodes a plasma membrane-localized Na -selective transporter, and is preferentially expressed in root stele (including the parenchyma cells surrounding the xylem vessels). We also show that loss of ZmHKT1 function increases xylem sap Na concentration and causes increased root-to-shoot Na delivery, indicating that ZmHKT1 promotes leaf Na exclusion and salt tolerance by withdrawing Na from the xylem sap. We conclude that ZmHKT1 is a major salt-tolerance QTL and identifies an important new gene target in breeding for improved maize salt tolerance.

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The most widespread cooling techniques based on gas compression/expansion encounter environmental problems. Thus, tremendous effort has been dedicated to develop alternative cooling technique and search for solid state materials that show large caloric effects. An application of pressure to a material can cause a change in temperature, which is called the barocaloric effect. Here we report the giant barocaloric effect in a hexagonal Ni2In-type MnCoGe0.99In0.01 compound involving magnetostructural transformation, Tmstr, which is accompanied with a big difference in the internal energy due to a great negative lattice expansion(ΔV/V ~ 3.9%). High resolution neutron diffraction experiments reveal that the hydrostatic pressure can push the Tmstr to a lower temperature at a rate of 7.7 K/kbar, resulting in a giant barocaloric effect. The entropy change under a moderate pressure of 3 kbar reaches 52 Jkg−1K−1, which exceeds that of most materials, including the reported giant magnetocaloric effect driven by 5 T magnetic field that is available only by superconducting magnets.

The intensity of galactic cosmic rays (GCRs) is modulated by solar activity on various timescales. In this study, we performed comprehensive numerical modeling of the solar rotational recurrent variation in GCRs caused by a corotation interaction region (CIR). A recently developed magnetohydrodynamic numerical model is adapted to simulate the background solar wind plasma with a CIR structure present in the inner heliosphere. As for the outer heliospheric plasma background, from 27 to 80 au, the Parker interplanetary magnetic field model is utilized. The output of these plasma and magnetic field models is incorporated into a comprehensive Parker-type transport model for GCRs. The local interstellar spectrum for galactic protons is transported to 80 au, specifying the outer boundary condition. The obtained solutions of this hybrid model, for studying the CIR effect, are as follows: (1) the onset of the decrease in the GCR intensity inside the CIR coincides with the increase of the solar wind speed with the intensity depression accompanied by a magnetic field and plasma density enhancement. Additionally, the CIR effect weakens with increasing heliocentric radial distance. (2) This decrease in GCR intensity also appears at different heliolatitudes and varies with changing latitude; the amplitude of the GCR depression exhibits a maximum in the low-latitude region. (3) The CIR affects GCR transport at different energy levels as well. Careful analysis has revealed a specific energy dependence of the amplitude of the recurrent GCR variation in the range of 30–2000 MeV.

Magnetic cooling is a highly efficient refrigeration technique with the potential of replacing expensive and rare helium-3 in the field of ultra-low temperature cooling. However, the visualization of a cryogen at an extremely low temperature and in a strong magnetic field is challenging, but it is crucial for the precise positioning and in situ thermal probe measurements in potential practical applications. Here, the activation of a red-emissive Mn(ii) ion using 3d/4f chemistry produces a luminescent molecule cooler, [Gd5Mn2(LOMe)2(OH)4(Ac)6(MeOH)10Cl2]Cl3·2MeOH (1), with the core of an Mn(ii)-anchored heptanuclear [GdIII5MnII2] pyramid. The photoluminescence (PL) of the Mn2+ emission, with a large Stokes shift (λem ∼ 690 nm) from 4T1(4G) → 6A1(6S), shows not only a sensitive temperature sensing property but also reversible mechanoluminescence (ML). More attractively, these findings reveal a considerable magnetocaloric effect (MCE) coupled with a tunable emission window, opening up new opportunities in the multifunctional applications of PL, ML, and the MCE involving red-light sources, thermometers, and stress imaging. In particular, this provides a novel resolution to design visualized PL coolers.