The antagonistic interaction between iron (Fe) and phosphorus (P) has been noted in the area of plant nutrition. To understand the physiology and molecular mechanisms of this interaction, we studied the growth performance, nutrient concentration, and gene expression profiles of root and shoot segments derived from 10-d-old rice (Oryza sativa) seedlings under four different nutrient conditions: (1) full strength of Fe and P (+Fe+P); (2) full strength of P and no Fe (2Fe+P); (3) full strength of Fe and no P (+Fe2P); and (4) without both Fe and P (2Fe2P). While removal of Fe in the growth medium resulted in very low shoot and root Fe concentrations, the chlorotic symptoms and retarded seedling growth were only observed on seedlings grown in the presence of P. Microarray data showed that in roots, 7,628 transcripts were significantly changed in abundance in the absence of Fe alone. Interestingly, many of these changes were reversed if P was also absent (2Fe2P), with only approximately 15% overlapping with -Fe alone (-Fe+P). Analysis of the soluble Fe concentration in rice seedling shoots showed that P deficiency resulted in significantly increased Fe availability within the plants. The soluble Fe concentration under -Fe-P conditions was similar to that under +Fe+P conditions. These results provide evidence that the presence of P can affect Fe availability and in turn can influence the regulation of Fe-responsive genes.

A stable composite photocatalyst, that is, MAPbI3 decorated with Ni3C, is synthesized by a facile surface charge-promoted self-assembly approach and is demonstrated to be a high-efficiency, stable visible-light photocatalyst for H2 evolution in aqueous MAPbI3-saturated HI solution with H3PO2 as a stabilizer. The optimal 15% Ni3C/MAPbI3 suspension under visible illumination displays the hydrogen evolution reaction (HER) rate of 2362 μmol g–1 h–1, which is approximately 55-fold higher than that of MAPbI3 (43 μmol g–1 h–1) and far superior to that of Pt/MAPbI3 (534 μmol g–1 h–1). In particular, the Ni3C/MAPbI3 photocatalyst is ultrastable, showing no obvious decrease of HER activity in a given HER process, that is, 10 runs, one-month storage, and another 10 runs. The origin of the superior performance is proven to be predominantly attributed to the improved capabilities of charge carrier transfer and separation as well as the massive reactive centers on the surface of MAPbI3 by Ni3C decoration, together with the high stability of the composite in HI solution during the photoreaction.

New‐era soft microrobots for biomedical applications need to mimic the essential structures and collective functions of creatures from nature. Biocompatible interfaces, intelligent functionalities, and precise locomotion control in a collective manner are the key parameters to design soft microrobots for the complex bio‐environment. In this work, a biomimetic magnetic microrobot (BMM) inspired by magnetotactic bacteria (MTB) with speedy motion response and accurate positioning is developed for targeted thrombolysis. Similar to the magnetosome structure in MTB, the BMM is composed of aligned iron oxide nanoparticle (MNP) chains embedded in a non‐swelling microgel shell. Linear chains in BMMs are achieved due to the interparticle dipolar interactions of MNPs under a static magnetic field. Simulation results show that, the degree and speed of assembly is proportional to the field strength. The BMM achieves the maximum speed of 161.7 µm s−1 and accurate positioning control under a rotating magnetic field with less than 4% deviation. Importantly, the locomotion analyses of BMMs demonstrate the frequency‐dependent synchronization under 8 Hz and asynchronization at higher frequencies due to the increased drag torque. The BMMs can deliver and release thrombolytic drugs via magneto‐collective control, which is promising for ultra‐minimal invasive thrombolysis.

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Plants employ two distinct strategies to obtain iron (Fe) from the soil. In Strategy I but not Strategy II plants, Fe limitation invokes ethylene production which regulates Fe deficiency responses. Oryza sativa (rice) is the only graminaceous plant described that possesses a Strategy I-like system for iron uptake as well as the classic Strategy II system. Ethylene production of rice roots was significantly increased when grown under Fe-depleted conditions. Moreover, 1-aminocyclopropane-1-carboxylic acid (ACC) treatment, a precursor of ethylene, conferred tolerance to Fe deficiency in rice by increasing internal Fe availability. Gene expression analysis of rice iron-regulated bHLH transcription factor OsIRO2, nicotianamine synthases 1 and 2 (NAS1 and NAS2), yellow-stripe like transporter 15 (YSL15) and iron-regulated transporter (IRT1) indicated that ethylene caused an increase in transcript abundance of both Fe (II) and Fe (III)-phytosiderophore uptake systems. RNA interference of OsIRO2 in transgenic rice showed that ethylene acted via this transcription factor to induce the expression of OsNAS1, OsNAS2, OsYSL15, and OsIRT1. By contrast, in Hordeum vulgare L. (barley), no ethylene production or ethylene-mediated effects of Fe response could be detected. In conclusion, Fe-limiting conditions increased ethylene production and signalling in rice, which is novel in Strategy II plant species.

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