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Flexible hydrogel film sensors have great advantages as human–machine interfaces for conformal contact with bio‐tissues, but suffer from weakness and dehydration, compromising flexibility and performance. Here, a breathable, highly stretchable, and anti‐dehydrating ultrathin organohydrogel film as a skin‐attachable strain sensor for long‐term motion monitoring is developed. An electrospun TPU (eTPU) nanomesh with hidden strength is used as skeleton to host in situ free radical polymerization of 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) and acrylamide (AAm) to form an interpenetrating double network organohydrogel with glycerol and water as solvent. Extensive hydrogen bonding between eTPU nanomesh and P(AMPS‐co‐AAm) network yields ultrathin organohydrogel film (≈200 µm) with synergetic deformation and energy dissipation upon stretching, leading to record‐high stretchability up to 920%, fracture toughness of 20.14 MJ m−3, fracture energy of 10 000 J m−2, and robustness over 4000 notched stretching cylcles to 50% strain. The binary glycerol/water solvent imparts excellent anti‐dehydration at room temperature for 10 d, and stable sensory performance from −20 to 60 °C. With a high water vapor transmission rate of 1.3 kg m−2 d−1, the film sensor ensures comfortable skin contact for continuous knee flexion monitoring throughout the day with stable signals. These organohydrogel film strain sensors are promising for wearable and long‐term motion monitoring applications. [ABSTRACT FROM AUTHOR]

Leptochloa chinensis is a troublesome rice weed in many countries, and knowledge of its seed germination ecology varied in different reports. To reveal the range and general characteristics of L. chinensis seed germination under different drought stresses, and seedling emergence under different burial depths, we conducted a serial of germination experiments with 242 L. chinensis populations collected along ranges spanning 4° latitudes and 4° longitudes from rice fields in eastern China. We found that 1000‐seed weight ranged from 0.056 to 0.129 g, with an average of 0.088 g; the OR50 (the osmotic potentials at which the germination percentage reaches 50%) was −0.47 to −0.07 MPa, with an average of −0.28 MPa; and BR50 (the burial depth at which the emergence percentage reaches 50%) ranged from 0.07 to 0.26 cm, with an average of 0.18 cm. At −0.5 MPa, the mean germination percentage of 242 populations was 4.1%. Seed germination percentages under 0.5 and 1.5 cm quartz sand layer were both >75%, while no seedling emerged up to the surface of quartz sand. Populations collected from rice fields in northern regions leaned to be higher in 1000‐seed weights, and OR50 values. Moreover, populations collected from transplanting rice fields slightly and significantly leaned to be more adapted to drought stresses and soil burial depths. The ability to quickly germinate, together with seed germination sensitive to drought stress and seedling emergence sensitive to soil burial, facilitate L. chinensis to avoid suicide seed germination, occupy niches under suitable environments and escape chemical control practices on rice fields. [ABSTRACT FROM AUTHOR]

Flow control devices have garnered significant attention from domestic and international wind energy scholars. In an effort to capture more wind energy and boost the output power of wind turbines, this study incorporates flow control devices into the upstream area of the wind turbine. The study then assesses the impact of the spacing, tilt angle, and height of the flow control devices on the turbine's performance. The study demonstrates that the addition of flow control devices does lead to a notable enhancement in wind turbine power, with a maximum power output growth rate of 9.74%. The maximum growth rates for the average output power of the wind turbine due to the three factors (α, H, and Lw) are 4.20%, 3.76%, and 3.54%, respectively. The degree of influence of the three factors is as follows: α > H > Lw. [ABSTRACT FROM AUTHOR]

Thermochromic energy efficient windows dynamically regulate building energy exchange by changing their optical transmittance. Recently, thermochromic materials with different chromic mechanisms are developed to fulfill smart window demands. Advanced fabrication technologies for smart windows also lead to building energy efficiency optimization. In this Perspective, representative mechanisms and performances of promising thermochromic systems, including vanadium dioxide, hydrogels, perovskites, ionic liquids, and liquid crystals, are discussed. Furthermore, the emerging technology of radiative cooling is emphasized for future building energy saving. Building temperature regulation and energy saving based on smart windows will make great impacts on the global low carbon economy. [ABSTRACT FROM AUTHOR]

Natural biotissues like muscles, ligaments, and nerves have highly aligned structures, which play critical roles in directional signal transport, sensing, and actuation. Inspired by anisotropic biotissues, composite hydrogels with outstanding mechanical properties and conductivity are developed by compositing thermo‐responsive poly (N‐isopropylacrylamide) (PNIPAM) hydrogels with highly aligned carbon fibers (CFs). The anisotropic hydrogels show superior tensile strength (3.0 ± 0.3), modulus (74 ± 7.0 MPa), excellent electrical conductivity (≈670 S m−1), and ultra‐high sensitivity (gauge factor up to 647) along CFs, with an anisotropic ratio (AR) up to 740 over those in perpendicular direction. The extremely high AR in conductivity (more than 400) produces high‐level output in parallel direction and low‐level output in perpendicular direction with a direct current (DC) power supply, which is used to fabricate AND and OR gates. Moreover, the composite hydrogels are converted into thermo‐responsive actuators with CFs twisted before compositing with PNIPAM/clay network. The pre‐twisted CF helices impart internal stress that drives reversible actuation of hydrogel helices upon thermo‐stimulating. The actuation is self‐sensed due to the extremely high sensitivity of the composite hydrogels. Such biomimetic anisotropic self‐sensing hydrogel actuators resemble natural biotissues with both actuation and sensing capabilities, and have promise applications for artificial robotics. [ABSTRACT FROM AUTHOR]

Effective accumulated temperature (EAT) is a basic index to predict plant growing and development, while EATs for key stages during Echinochloa crus‐galli seed‐setting are still unclear. We collected three E. crus‐galli populations (Nanling [NL], Feidong [FD], and Sihong [SH]) from different rice fields in eastern China and conducted four sets of pot experiments in a greenhouse. Plants of the three populations sown on May 9–12, averagely reproduced 484–671 mature seeds per plant; showed a duration of 67–76 days from sowing to heading, with an average EAT of 1,156–1,274°C; showed a duration of 90–94 days from sowing to seeds starting maturation in plant individuals with average EATs about 1,571–1,647°C; and showed a maturation stage lasting for 14–36 days. Significant negative correlations (p <.01) were found between the period of collecting day after seed maturation and the number or 1,000‐seed weight of mature seeds collected on the day, in each set of experiment. Compared with NL individuals sown on May 9, NL individuals sown on April 10 needed significantly higher EATs for periods from sowing to seed maturation, and from heading to seed maturation. According to logistic regressions, duration days needed for 50% of seeds to mature were 93–122 days after sowing, with EATs of 1,625–1893°C for these E. crus‐galli populations. This study revealed EATs for E. crus‐galli seed‐setting, which suggested time windows for panicle‐removing control of E. crus‐galli in rice fields. [ABSTRACT FROM AUTHOR]

Angiosperms are believed to have emerged initially in the tropics and expanded their distribution range poleward through diverse mechanisms, for example polyploidization‐driven cold tolerance evolution. Reversed expansion from temperate to pan‐tropic climates through a polyploidization‐driven shift in heat tolerance remains largely unknown. Here, we found autopolyploidy in relation to the global expansion of Solidago canadensis from its temperate‐climate native range in North American to hot‐summer climate in an introduced range. Our cytogeographical study of 2,062 accessions from 471 locations worldwide demonstrates that ploidy levels correlate negatively with latitude and positively with average temperature. An isotherm‐dependent shift of the climate niches at the threshold of 20°–24°C between geo‐cytotypes can be attributed mainly to autopolyploidy‐driven differentiation of heat tolerance; only polyploids and not diploids are able to complete sexual reproduction, germinate, and grow in the hot‐summer climate of low latitudes. Ploidy‐dependent fertility appears to play a key role in the hot‐summer introduced range in the northern hemisphere through both pre‐adaptation and rapid post‐introduction adaptive evolution of delayed flowering and improved heat tolerance during embryo development. The MaxEnt model predicts continued expansion of this plant species under global change. These results provide new insights into the mechanisms governing autopolyploidy‐driven backward range expansion of plant species from temperate origins. [ABSTRACT FROM AUTHOR]

I Solidago canadensis i L., a native wildflower in temperate North America, has been widely introduced as a cut flower and has become a global invasive weed. (A) Pollen germination; (B) pollen tube growth; (C) penetration of pollen tubes into an ovary. Pollen germination and pollen tube growth on a stigma. [Extracted from the article]

Abstract: BACKGROUND: Alopecurus japonicus is a serious grass weed species in wheat fields in eastern Asia, and has evolved strong resistance to acetyl‐CoA carboxylase (ACCase)‐inhibiting herbicides. Although target‐site resistance (TSR) to ACCase inhibitors in A. japonicus has been reported, non‐target site resistance (NTSR) has not. This study investigated both TSR and NTSR in a fenoxaprop‐P‐ethyl‐resistant A. japonicus population (AHFD‐3), which was collected in Feidong County, Anhui Province, China. RESULTS: We found that AHFD‐3 exhibited high resistance to fenoxaprop‐P‐ethyl and low resistance to flucarbazone‐sodium. The sensitivity of AHFD‐3 to fenoxaprop‐P‐ethyl increased significantly after treatment with cytochrome P450 (P450) inhibitors; however, such synergies between P450 inhibitors and fenoxaprop‐P‐ethyl were not found in two control populations. Sequences of the entire carboxyltransferase domain of A. japonicus ACCase were obtained, and AHFD‐3 plants showed an Asp‐2078‐Gly substitution in the ACCase. With the derived cleaved amplified polymorphic sequence (dCAPS) method, we found that 85.4% of the plants of AHFD‐3 carried this mutation. The P450 content in AHFD‐3 plants was significantly higher than those of the two control populations after treatment with fenoxaprop‐P‐ethyl. Ten partial sequences of P450 genes in A. japonicus were cloned. Three P450 genes were up‐regulated 12 h after fenoxaprop‐P‐ethyl treatment, which were all from the P450 subfamily CYP72A. Moreover, a P450 gene from the P450 family CYP81 was up‐regulated after fenoxaprop‐P‐ethyl treatment in all populations studied. CONCLUSION: Fenoxaprop‐P‐ethyl resistance in AHFD‐3 plants was conferred by up‐regulation of cytochrome P450s in the CYP72A subfamily and target site mutation of the ACCase gene. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Echinochloa crus-galli is a serious weed worldwide. Microsatellite markers (simple sequence repeats, SSRs) are important molecular markers that are used widely for studying genetic diversity in plants. However, a limited number of SSRs is available for E. crus-galli. The restriction site-associated DNA ( RAD) sequencing approach was combined with Illumina DNA sequencing for the rapid and mass detection of SSRs in E. crus-galli. The RAD tags were generated from the genomic DNA of E. crus-galli and were sequenced in order to produce 6921.6 Mb of high-quality sequences with 45.1% guanine-cytosine content. In total, 3081 putative SSRs were detected, of which 82.2% were dinucleotide motif-repeats. AT was the most frequent motif, accounting for 35.0% of the SSRs. In order to test the validity of the SSRs that were developed here, eight SSRs that were selected from putative SSRs were used to study the genetic diversity and structures of 20 E. crus-galli populations that had been collected from rice fields in eastern China. Ninety-seven alleles were amplified from the eight microsatellite loci among the 20 E. crus-galli populations. These populations showed low genetic diversity and were classified on the basis of their genetic structures into three distinct groups that corresponded to the three regions of population sampling. The SSRs that were identified in this study represent a valuable resource for studying the genetic diversity, population biology and evolution of E. crus-galli. [ABSTRACT FROM AUTHOR]

Barnyardgrass ( Echinochloa crus-galli) proliferation seriously threatens rice production worldwide. Whole-plant bioassays were conducted in order to test the sensitivity to penoxsulam of 52 barnyardgrass populations and the resistance of six penoxsulam-resistant populations to 12 other herbicides that are commonly used in rice fields. Among the 48 populations that had escaped penoxsulam control in the rice fields, 8.3% showed a very high level of resistance, 58.3% showed a high level of resistance and 10.4% showed a moderate level of resistance. Multiple resistance was confirmed in all six penoxsulam-resistant populations that were tested further. They exhibited at least a moderate level of resistance; that is, to 6-10 of the total of 13 herbicides that was tested. Most of the six penoxsulam-resistant populations showed at least a moderate level of resistance to bispyribac-sodium, quinclorac, metamifop, cyhalofop-butyl and oxadiazon, three populations held at least a moderate level of resistance to oxyfluorfen and pretilachlor, two populations also held at least a moderate level of resistance to pyrazosulfuron-ethyl, pyribenzoxim and fenoxaprop-P-ethyl, but the resistance indices of the six populations to pendimethalin were all low. This study has confirmed resistance to pretilachlor and oxadiazon in weeds for the first time. [ABSTRACT FROM AUTHOR]