With the deepening of marine resource development and marine science research, developing devices capable of underwater sensing and self-powering has become a significant challenge. Moreover, there is a growing demand for the environmental sustainability of the substrate materials used in the device. Herein, we have synthesized a lignin-based polyurethane foam with a high biobased content (HBLPUF) by the reaction of pentamethylene diisocyanate (PDI) with lignin polyol. The conductive polyaniline (PANI) was grown in situ on the surface of HBLPUF, serving as the substrate, and assembled with a polytetrafluoroethylene (PTFE) film to form a vertical contact-separation triboelectric nanogenerator. It was additionally encapsulated with polydimethylsiloxane (PDMS) to ensure stable performance underwater. A voltage of up to 148 V and a current output of 1.8 μA were achieved, successfully overcoming the challenge of the underwater power supply. The excellent fatigue resistance of the foam substrate allowed it to maintain stable output even after 10,000 impact tests. The sensor could detect various movements in both conventional and underwater environments, including twisting, finger bending, and wrist flexion. This study introduced a novel approach for fabricating a lignin-based underwater triboelectric nanogenerator, which holds significant implications for advancing the application of polyurethane foam and the development of underwater sensing technologies.

A high toughness, and deformation-responsive covalent adaptable lignin-based polyurethane was synthesized.

Spectral splitting is a promising strategy for wavelength-selective solar energy harvesting, offering the potential to combine photosynthesis with artificial solar technologies for higher hybrid efficiencies. Despite this potential, the photosynthetic performance and biomass production of plants under split sunlight has remained unclear. Photosynthetic organisms under full sunlight must dissipate excess absorbed light energy as heat, resulting in suboptimal photosynthetic efficiency. Here, we show that solar spectral splitting can enhance photosynthesis and yield while utilizing excess sunlight for energy polygeneration. Specifically, we observed increased electron transport rate (22 %), daily leaf photosynthetic CO2 uptake (12 %), and plant biomass productivity (up to 136 %) under the selected solar spectral bands, largely due to decreased photoinhibition and improved stomatal conductance. The theoretical limit and practical guideline for photovoltaic (PV) efficiency under complementary spectral bands were -22.5 % and -14.6 %, respectively, highlighting the substantial potential for energy production. This study provides a basis for the design and application of spectral splitting energy systems on agricultural lands, which not only encompasses the concept of sharing the land or the solar spectrum, but also presents an effective strategy for enhancing crop production.

Underwater flexible sensors are important for the exploration of and detection in underwater environments.

In this study, a novel bio-based diol containing imine dynamic bonds (Vanp2) were synthesized using vanillin and bio-based 1,5-pentanediamine. Vanp2 was then introduced into the cross-linking network of betulin-based polyurethanes to obtain betulin-based polyurethanes containing covalent adaptive networks (CANs). Imine dynamic bonds within CAN endowed these betulin-based polyurethanes with self-healing, re-processability, de-gradability, and editable shape memory functionalities. Meanwhile, the mechanical and thermal properties of these fully bio-based polyurethane materials were characterized. The maximum tensile strength reached 9.5 MPa, while the maximum strain at break was 248 % and the maximum toughness was 13.2 MJ/m3. Thermal decomposition temperature was greater than 300 degrees C. Since the imine structure could be dissociated under acidic conditions, these polyurethanes could be rapidly degraded in a mixed acid solution at 50 degrees C in 4 h. This study demonstrated a strategy for synthesizing betulin-based polyurethane elastomers containing CAN using only bio-based feedstock.

In this study, we successfully synthesized lignin-based covalent adaptable polyurethane networks containing lignin-graphite nanosheet composite particles with a light controllable positive temperature coefficient (LPTC) effect. The use of lignin facilitated the direct exfoliation of graphite, thus overcoming the challenge of achieving a uniform dispersion of conductive fillers in the polymer matrix. The exfoliated graphite had a thickness of approximately 3.0 nm, which was equivalent to three to five layers of graphene. By preparing lignin-based covalent adaptable polyurethane without graphite composite particles (LPU) and lignin-based covalent adaptable polyurethane with graphite composite particles (LPU-G), we achieved remoldable properties and a high LPTC intensity for LPU-G. LPU-60G (60 represents the mass fraction of lignin-graphite nanosheets in polyols) exhibited an excellent LPTC effect, with sharp increases in resistance under light, particularly under near-infrared light (NIR), enabling the control of the current in circuits. Additionally, both LPU and LPU-G demonstrated degradability by slowly degrading in a PBS solution while rapidly degrading in an alkaline solution. Overall, the LPU-G synthesized in this study displayed superior stability in the LPTC effect and possessed degradability, providing a promising avenue for the future development of smart materials.

Thermoset polymer materials are widely used in various fields due to their excellent performance brought by their permanently cross -linked structures. However, their inability to be recycled also leads to a serious waste of resources. The emergence of covalent adaptable networks (CANs) has solved the problem perfectly that thermoset materials are difficult to recycle. Meanwhile, with the increasing concern for resources and the environment, bio-based materials have sparked a research boom. Itaconic acid is a biomass feedstock with great prospects for development. In this study, itaconic acid, 1,6-hexanediol, 6-mercapto-1-hexanol, isocyanate, and 4,4 '-dithiodiphenylamine were used as raw materials. Itaconic acid -based polyols were first synthesized by thiolene click reaction, and a series of itaconic acid -based polyurethane (PU) materials containing dynamic covalent networks were synthesized by varying the ratios between the amino and hydroxyl groups. The obtained material has good mechanical properties with a maximum tensile strength of 31.5 MPa and a modulus of 717 MPa. The presence of disulfide bonds allows the material to be recycled by remodeling, and the recovery efficiency of tensile strength after three remodeling cycles is 85.1 %. The material also has excellent solvent resistance and UV -blocking resistance. In conclusion, this work provides possible ideas for the high -value utilization of itaconic acid in polyurethanes.

In this work, high-performance, light-stimulation healable, and closed-loop recyclable covalent adaptable networks are successfully synthesized from natural lignin-based polyurethane (LPU) Zn2+ coordination structures (LPUxZy). Using an optimized LPU (LPU-20 with a tensile strength of 28.4 ± 3.5 MPa) as the matrix for Zn2+ coordination, LPUs with covalent adaptable coordination networks are obtained that have different amounts of Zn. When the feed amount of ZnCl2 is 9 wt%, the strength of LPU-20Z9 reaches 37.3 ± 3.1 MPa with a toughness of 175.4 ± 4.6 MJ m-3 , which is 1.7 times of that of LPU-20. In addition, Zn2+ has a crucial catalytic effect on "dissociation mechanism" in the exchange reaction of LPU. Moreover, the Zn2+ -based coordination bonds significantly enhance the photothermal conversion capability of lignin. The maximum surface temperature of LPU-20Z9 reaches 118 °C under the near-infrared illumination of 0.8 W m-2 . This allows the LPU-20Z9 to self-heal within 10 min. Due to the catalytic effect of Zn2+ , LPU-20Z9 can be degraded and recovered in ethanol completely. Through the investigation of the mechanisms for exchange reaction and the design of the closed-loop recycling method, this work is expected to provide insight into the development of novel LPUs with high-performance, light-stimulated heal ability, and closed-loop recyclability; which can be applied toward the expanded development of intelligent elastomers.

Crop yield is determined by potential harvest organ size, source organ photosynthesis and carbohydrate partitioning. Filling the harvest organ efficiently remains a challenge. Here, we developed a kinetic model of rice grain filling, which scales from the primary biochemical and biophysical processes of photosynthesis to whole-plant carbon and nitrogen dynamics. The model reproduces the rice yield formation process under different environmental and genetic perturbations. In silico screening identified a range of post-anthesis targets-both established and novel-that can be manipulated to enhance rice yield. Remarkably, we pinpointed the stability of grain-filling rate from flowering to harvest as a critical factor for maximizing grain yield. This finding was further validated in two independent super-high-yielding rice cultivars, each yielding approximately 21 t ha-1 of rough rice at 14% moisture content. Furthermore, we revealed that stabilizing the grain-filling rate could lead to a potential yield increase of 30-40% in an elite rice cultivar. Notably, the instantaneous grain-filling rates around 15- and 38-day post-flowering significantly influence grain yield; and we introduced an innovative in situ approach using ear respiratory rates for precise quantification of these rates. We finally derived an equation to predict the maximum dried brown rice yield (Y, t ha-1) of a cultivar based on its potential gross photosynthetic accumulation from flowering to harvest (Apc, t CO2 ha-1): Y = 0.74 x Apc + 1.9. Overall, this work establishes a framework for quantitatively dissecting crop physiology and designing high-yielding ideotypes.

Maintaining proper metabolite levels in a complex metabolic network is crucial for maintaining a high flux through the network. In this paper, we discuss major regulatory mechanisms over the Calvin Benson Cycle (CBC) with regard to their roles in conferring homeostasis of metabolite levels in CBC. These include: 1) Redox regulation of enzymes in the CBC on one hand ensures that metabolite levels stay above certain lower bounds under low light while on the other hand increases the flux through the CBC under high light. 2) Metabolite regulations, especially allosteric regulations of major regulatory enzymes, ensure the rapid up-regulation of fluxes to ensure sufficient amount of triose phosphate is available for end product synthesis and concurrently avoid phosphate limitation. 3) A balanced activities of enzymes in the CBC help maintain balanced flux through CBC; some innate product feedback mechanisms, in particular the ADP feedback regulation of GAPDH and F6P feedback regulation of FBPase, exist in CBC to achieve such a balanced enzyme activities and hence flux distribution in the CBC for greater photosynthetic efficiency. Transcriptional regulation and natural variations of enzymes controlling CBC metabolite homeostasis should be further explored to maximize the potential of engineering CBC for greater efficiency.

Superwettability can affect the performance of oil separation from water during the treatment of oily wastewater. Among various types of materials developed for cleaning oil pollution, foam is a popular choice due to its attractive lightweight properties and adjustable porosities. Foams with superwetting surfaces (superhydrophilic/ superoleophobic underwater) are ideal for oil/water separations. In this study, lignin-based polyurethane foams (LPUFs) were synthesized first, and then polydopamine particles were deposited on the surface of the foam by in situ polymerization under weak alkaline conditions to increase its surface roughness. Afterwards, phytic acid was used to modify the foam to achieve surface superhydrophilicity and underwater superoleophobicity. Successful loading of polydopamine (PDA) particles and coating of phytic acid (PA) onto the foam was demonstrated by SEM, EDS, FTIR, XPS, and thermogravimetric analysis measurements. It was shown in the cyclic compression tests that LPUFs had good mechanical properties. Under 75 % compression strain, the maximum stress in the first cycle of LPUF/PDA/PA was 105.92 kPa. After 30 cyclic compression tests, the maximum stress of LPUF/PDA/PA under 75 % compression strain was 105.63 kPa, demonstrating a high mechanical stability. The contact angle of the foam modified by PDA and PA was 0 degrees for water, 166.7 degrees for chloroform, and 158.4 degrees for hexane, which also demonstrated excellent underwater anti-oil adhesion performances. Oil-water separation tests by using PDA and PA modified lignin-based foam with mixtures of water and n-hexane, cyclohexane, toluene, and pump oil indicated a separation efficiency of over 99 % for the types of mixtures tested together with excellent repeat-ability. In addition, the PDA and PA modified lignin-based foams were able to adsorb 67.1 mg/g of methylene blue, 96.1 mg/g of rhodamine B, and 98.2 mg/g of copper sulfate. The lignin-based foam could completely degrade under weak alkaline conditions after usage. This study highlighted a novel strategy for synthesizing environmentally friendly high-performance adsorbents to efficiently treat polluted wastewater using lignin as a raw material.

Canopy photosynthesis is the sum of photosynthesis of all above-ground photosynthetic tissues. Quantitative roles of nonfoliar tissues in canopy photosynthesis remain elusive due to methodology limitations. Here, we develop the first complete canopy photosynthesis model incorporating all above-ground photosynthetic tissues and validate this model on wheat with state-of-the-art gas exchange measurement facilities. The new model precisely predicts wheat canopy gas exchange rates at different growth stages, weather conditions, and canopy architectural perturbations. Using the model, we systematically study (1) the contribution of both foliar and nonfoliar tissues to wheat canopy photosynthesis and (2) the responses of wheat canopy photosynthesis to plant physiological and architectural changes. We found that (1) at tillering, heading, and milking stages, nonfoliar tissues can contribute ~4, ~32, and ~50% of daily gross canopy photosynthesis (Acgross; ~2, ~15, and ~-13% of daily net canopy photosynthesis, Acnet) and absorb ~6, ~42, and ~60% of total light, respectively; (2) under favorable condition, increasing spike photosynthetic activity, rather than enlarging spike size or awn size, can enhance canopy photosynthesis; (3) covariation in tissue respiratory rate and photosynthetic rate may be a major factor responsible for less than expected increase in daily Acnet; and (4) in general, erect leaves, lower spike position, shorter plant height, and proper plant densities can benefit daily Acnet. Overall, the model, together with the facilities for quantifying plant architecture and tissue gas exchange, provides an integrated platform to study canopy photosynthesis and support rational design of photosynthetically efficient wheat crops.

Abstract Compared to the large number of studies focused on the factors controlling C3 photosynthesis efficiency, there are relatively fewer studies of the factors controlling photosynthetic efficiency in C4 leaves. Here, we used a dynamic systems model of C4 photosynthesis based on maize (Zea mays) to identify features associated with high photosynthetic efficiency in NADP-malic enzyme (NADP-ME) type C4 photosynthesis. We found that two additional factors related to coordination between C4 shuttle metabolism and C3 metabolism are required for efficient C4 photosynthesis: (1) accumulating a high concentration of phosphoenolpyruvate through maintaining a large PGA concentration in the mesophyll cell chloroplast and (2) maintaining a suitable oxidized status in bundle sheath cell chloroplasts. These identified mechanisms are in line with the current cellular location of enzymes/proteins involved in the starch synthesis, the Calvin–Benson cycle and photosystem II of NADP-ME type C4 photosynthesis. These findings suggested potential strategies for improving C4 photosynthesis and engineering C4 rice.

Improving canopy photosynthetic light use efficiency and energy conversion efficiency (εc) is a major option to increase crop yield potential. However, so far, the diurnal and seasonal variations of canopy light use efficiency (LUE) and εc are largely unknown due to the lack of an efficient method to estimate εc in a high temporal resolution. Here we quantified the dynamic changes of crop canopy LUE and εc during a day and a growing season with the canopy gas exchange method. A response curve of whole-plant carbon dioxide (CO2) flux to incident photosynthetically active radiation (PAR) was further used to calculate εc and LUE at a high temporal resolution. Results show that the LUE of two wheat cultivars with different canopy architectures at five stages varies between 0.01 to about 0.05 mol CO2 mol–1 photon, with the LUE being higher under medium PAR. Throughout the growing season, the εc varies from 0.5 to 3.7% (11–80% of the maximal εc for C3 plants) with incident PAR identified as a major factor controlling variation of εc. The estimated average εc from tillering to grain filling stages was about 2.17%, i.e., 47.2% of the theoretical maximal. The estimated season-averaged radiation use efficiency (RUE) was 1.5–1.7 g MJ–1, which was similar to the estimated RUE based on biomass harvesting. The large variations of LUE and εc imply a great opportunity to improve canopy photosynthesis for greater wheat biomass and yield potential.

Honglong Zhao is a postdoctoral researcher at the Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences. There, he studies plant systems biology and works on the mathematical model construction of primary metabolism in C3 photosynthetic leaves. He received a PhD in Botany in 2020 working with Prof. Xinguang Zhu.

Agrivoltaic combines crop planting and electricity generation on the same land, it is considered as an opportunity to resolve the competition for land use between food and energy production. In addition to growing crops, farmers can gain electricity with the installation of agrivoltaic systems on their farmland. They can use this clean energy for agricultural production or sell it for extra income. The Chinese government considers it an important strategy for “Targeted Poverty Alleviation”. However, current methods of agrivoltaic provide uneven and low irradiance for crops, which usually results in reduced yield and low quality. In this study, an improved agrivoltaic system with a grooved glass plate has been designed, manufactured, and investigated, called Even-lighting Agrivoltaic System (EAS). Two experiments were conducted to test the effectiveness of the improvement. We measured the crops’ light environment, the crop growth process, the crop yield and quality, the electricity generation, and calculated the Land Equivalent Ratio (LER) as well as the comprehensive economic benefits on the farmland per hectare. Under the EAS, crops grew fast and the yield was similar or better than that under the natural state. By adding supplementary LED lamps into the EAS, the soluble sugar content of lettuce increased by 72.14% and the nitrate content of lettuce decreased by 21.51%. The average LER of the EAS for common vegetables was 1.64 as demonstrated in this work. Comprehensive economic benefits outperform the installation and maintenance costs, thus, the EAS can increase farmers’ income by an average of 5.14 times. The EAS provides new ideas and directions for the future development of agrivoltaic.

Overexpressing Calvin–Benson cycle (CBC) enzyme shown to limit the flow of CO2 through the cycle is a major approach to improve photosynthesis. Though control coefficients of CBC enzymes vary under different environmental and developmental conditions, it is usually implicitly assumed that enzymes in the CBC have a monotonic impact on the CBC fluxes. Here, with a dynamic systems model of the photosynthetic carbon metabolism, we show that, for glycerate-3-phosphate kinase (PGAK), fructose-1,6-bisphosphatase (FBPase), fructose-1,6-bisphosphate aldolase (FBA) and transketolase (TKa), individually increasing activity of these CBC enzymes theoretically leads to an initial increase then decrease in the fluxes through the CBC. Also, the inhibition constants of adenosine diphosphate (ADP) for PGAK and of fructose-6-phosphate (F6P) for FBPase influence the CBC flux in a biphasic manner. These predicted enzymes showing a biphasic manner are always located in different subcycles of the CBC, which consume the shared substrates in the early steps in the CBC and produce intermediates used as substrates for enzymes in the later reactions. We show that the excessive increase in activities of enzymes in one subcycle consuming the shared metabolite could cause low concentrations of metabolites in the other subcycles, which results in low reaction rates of the later reactions and hence lowers overall CBC flux. This study provides a model to explain the underlying reasons that overexpression of enzymes in the CBC sometimes can negatively impact photosynthesis. We find that balanced activities of enzymes in the subcycles of the CBC are required to gain a higher efficiency of the CBC.

41 Improving photosynthesis is considered a major and feasible option to 42 dramatically increase crop yield potential. Increased atmospheric CO2 concentration 43 often stimulates both photosynthesis and crop yield, but decreases protein content in 44 the main C3 cereal crops. This decreased protein content in crops constrains the 45 benefits of elevated CO2 on crop yield and affects their nutritional value for humans. 46 To support studies of photosynthetic nitrogen assimilation and its complex interaction 47 with photosynthetic carbon metabolism for crop improvement, we developed a 48 dynamic systems model of plant primary metabolism, which includes the 49 Calvin-Benson cycle (CBC), the photorespiration pathway (PRP), starch synthesis, 50 glycolysis-gluconeogenesis, the tricarboxylic acid (TCA) cycle, and chloroplastic 51 nitrogen assimilation. This model successfully captures responses of net 52 photosynthetic CO2 uptake rate (A), respiration rate, and nitrogen assimilation rate to 53 different irradiance and CO2 levels. We then used this model to predict inhibition of 54 nitrogen assimilation under elevated CO2. The potential mechanisms underlying 55 inhibited nitrogen assimilation under elevated CO2 were further explored with this 56 model. Simulations suggest that enhancing the supply of α-ketoglutarate (2-OG) is a 57 potential strategy to maintain high rates of nitrogen assimilation under elevated CO2. 58 This model can be used as a heuristic tool to support research on interactions between 59 photosynthesis, respiration, and nitrogen assimilation. It also provides a basic 60 framework to support the design and engineering of C3 plant primary metabolism for 61 D ow naded rom http/academ ic.p.com /plphys/advance-ar.1093/plphys/kiab345/6330766 by gest on 31 uly 2021

Abstract Improving photosynthesis is considered a major and feasible option to dramatically increase crop yield potential. Increased atmospheric CO2 concentration often stimulates both photosynthesis and crop yield, but decreases protein content in the main C3 cereal crops. This decreased protein content in crops constrains the benefits of elevated CO2 on crop yield and affects their nutritional value for humans. To support studies of photosynthetic nitrogen assimilation and its complex interaction with photosynthetic carbon metabolism for crop improvement, we developed a dynamic systems model of plant primary metabolism, which includes the Calvin–Benson cycle, the photorespiration pathway, starch synthesis, glycolysis–gluconeogenesis, the tricarboxylic acid cycle, and chloroplastic nitrogen assimilation. This model successfully captures responses of net photosynthetic CO2 uptake rate (A), respiration rate, and nitrogen assimilation rate to different irradiance and CO2 levels. We then used this model to predict inhibition of nitrogen assimilation under elevated CO2. The potential mechanisms underlying inhibited nitrogen assimilation under elevated CO2 were further explored with this model. Simulations suggest that enhancing the supply of α-ketoglutarate is a potential strategy to maintain high rates of nitrogen assimilation under elevated CO2. This model can be used as a heuristic tool to support research on interactions between photosynthesis, respiration, and nitrogen assimilation. It also provides a basic framework to support the design and engineering of C3 plant primary metabolism for enhanced photosynthetic efficiency and nitrogen assimilation in the coming high-CO2 world.

Huanghuazhan (HHZ) and 9,311 are two elite rice cultivars in China. They have achieved high yield through quite different mechanisms. One of the major features that gives high yield capacity to 9,311 is its strong early vigor, i.e., faster establishment of its seedling as well as its better growth in its early stages. To understand the mechanistic basis of early vigor in 9,311, as compared to HHZ the cultivar, we have examined, under controlled environmental conditions, different morphological and physiological traits that may contribute to its early vigor. Our results show that the fresh weight of the seeds, at germination, not only determined the seedling biomass at 10 days after germination (DAG), but was also responsible for ~ 80% of variations in plant biomass between the two cultivars even up to 30 DAG. Furthermore, the 9,311 cultivar had a larger root system, which led to its higher nitrogen uptake capacity. Other noteworthy observations about 9,311 being a better cultivar than HHZ are: (i) Ten out of 15 genes involved in nitrogen metabolism were much more highly expressed in its roots; (ii) it had a higher water uptake rate, promoting better root-to-shoot nitrogen transfer; and (iii) consistent with the above, it had higher leaf photosynthetic rate and stomatal conductance. All of the above identified features explain, to a large extent, why the 9,311, as compared to HHZ, exhibits much more vigorous early growth.