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In recent years, the frequency and intensity of exposure to heat stress have increased gradually, seriously hampering the production of maize. This paper presents a study designed to analyze how the development, physiology and dispersal of pollen from the heat‐resistant maize variety Zhengdan958 and the heat‐sensitive maize variety Xianyu335 are affected by exposure to heat stress during the tasselling stage. Our results showed That exposure to heat stress significantly increased the antioxidant enzyme activity in pollen. Upon visual inspection of the pollen, we found that the lower water content had given rise to wrinkles in the pollen surface, sunken germination pores, and morphological deformations. In addition, the anther dehiscence process was hindered, resulting in a reduced amount of pollen being dispersed. We also found elevated levels of abscisic acid (ABA), jasmonic acid (JA) and its derivatives, indole acetic acid (IAA) and gibberellin‐3 (GA3) in heat‐pollens, as well as elevated ratios of IAA to ABA and ABA to GA3. Ultimately impaired pollen fertility. Summarizing, our experiment revealed that reduced pollen quantity and quality are significant contributors to fertility losses in summer maize exposed to heat stress at anthesis, and we hope that our analysis of the physiological mechanisms involved can contribute to the development of crop management measures aimed at countering the increasingly detrimental effects of heat stress on the production of summer maize. [ABSTRACT FROM AUTHOR]

Dielectric elastomers (DEs) are typical electro‐active polymers that can achieve an electro‐actuated deformation under an applied electric field. However, obtaining a large low‐field‐actuated strain of DEs is still a key challenge, which is critical to their practical application range. Herein, a typical CaCu3Ti4O12@TiO2 (CCTO@TiO2) core–shell‐structured nanowires were synthesized by the micro‐emulsion method. Additionally, a series of polydimethylsiloxane (PDMS)‐based DE composites combining variable proportions of CCTO@TiO2 were prepared. The CCTO@TiO2 nanowires with the design of both decreasing dielectric constant from core to shell and a high aspect ratio can provide larger heterogeneous interfaces for the DE composites, leading to a promoted interfacial polarization. The maximum electro‐actuated strain of 37.66% is achieved from the DE composite incorporated with 20 wt% CCTO@TiO2 when subjected to a relatively low electric field of 40 V/μm, which is 14 times higher than that of pure PDMS (strain ~2.5%). Moreover, the composite exhibits the largest electro‐actuated strain (45.83%) under the electric field approaching its breakdown strength of 43.57 V/μm. The results demonstrate that the one‐dimensional core–shell nanowires have a positive effect on improving the low‐field‐actuated strain of DE composites. This research reveals an effective and feasible method to prepare the DE composites exhibiting enhanced low‐field electro‐actuated characteristics. [ABSTRACT FROM AUTHOR]

Efficient ultraviolet (UV) electroluminescent materials remain a great challenge, since short peak wavelength <400 nm and narrow full width at half maximum (FWHM) <50 nm are simultaneously required. In this sense, multi‐resonance (MR) thermally activated delayed fluorescence (TADF) emitters featuring narrow‐band emissions hold the promise for UV applications. Herein, a novel MR‐TADF skeleton featuring carbazole‐phosphine oxide (P=O) fused aromatics is developed to construct the first two UV MR emitters named CzP2PO and tBCzP2PO. In addition to synergistic resonance effects of P=O and N atom, sp3‐hybrid P atom renders the curved polycyclic planes of CzP2PO and tBCzP2PO, giving rise to their narrowband UV emissions with peak wavelengths <390 nm and FWHM<35 nm. Besides configuration quasi‐planarization for radiation enhancement and quenching suppression, P=O moiety further enhances singlet‐triplet coupling to facilitate reverse intersystem crossing, resulting in the state‐of‐the‐art photoluminescence quantum yield of 62 % in tBCzP2PO doped films. As consequence, tBCzP2PO endowed its UV organic light‐emitting diodes with the peak at 382 nm and FWHM of 32 nm, and especially the record‐high external quantum efficiency (EQE) of 15.1 % among all kinds of UV devices. Our results demonstrate great potential of P=O based MR emitters in practical applications including optoelectronics, biology and medicine science. [ABSTRACT FROM AUTHOR]