Rational design of polymer structures at the molecular level promotes the iteration of high‐performance photocatalyst for sustainable photocatalytic hydrogen peroxide (H2O2) production from oxygen ...and water, which also lays the basis for revealing the reaction mechanism. Here we report a benzoxazine‐based m‐aminophenol‐formaldehyde resin (APFac) polymerized at ambient conditions, exhibiting superior H2O2 yield and long‐term stability to most polymeric photocatalysts. Benzoxazine structure was identified as the crucial photocatalytic active segment in APFac. Favorable adsorption of oxygen/intermediates on benzoxazine structure and commendable product selectivity accelerated the reaction kinetically in stepwise single‐electron oxygen reduction reaction. The proposed benzoxazine‐based phenolic resin provides the possibility of production in batches and industrial application, and sheds light on the de novo design and analysis of metal‐free polymeric photocatalysts.
A facile and exceptional benzoxazine‐based phenolic resin photocatalyst was developed for hydrogen peroxide photosynthesis. Benzoxazine structure was identified as the crucial active segment in resins, which accelerated the reaction kinetically through low energy barrier and favorable adsorption of oxygen and intermediates.
Green alga Chlorella ohadii is known for its ability to carry out photosynthesis under harsh conditions. Using cryogenic electron microscopy (cryoEM), we obtained a high-resolution structure of PSII ...at 2.72 Å. This structure revealed 64 subunits, which encompassed 386 chlorophylls, 86 carotenoids, four plastoquinones, and several structural lipids. At the luminal side of PSII, a unique subunit arrangement was observed to protect the oxygen-evolving complex. This arrangement involved PsbO (OEE1), PsbP (OEE2), PsbB, and PsbU (a homolog of plant OEE3). PsbU interacted with PsbO, PsbC, and PsbP, thereby stabilizing the shield of the oxygen-evolving complex. Significant changes were also observed at the stromal electron acceptor side. PsbY, identified as a transmembrane helix, was situated alongside PsbF and PsbE, which enclosed cytochrome b559. Supported by the adjacent C-terminal helix of Psb10, these four transmembrane helices formed a bundle that shielded cytochrome b559 from the surrounding solvent. Moreover, the bulk of Psb10 formed a protective cap, which safeguarded the quinone site and likely contributed to the stacking of PSII complexes. Based on our findings, we propose a protective mechanism that prevents Qsub.B (plastoquinone B) from becoming fully reduced. This mechanism offers insights into the regulation of electron transfer within PSII.
Physiological novelties are often studied at macro‐evolutionary scales such that their micro‐evolutionary origins remain poorly understood. Here, we test the hypothesis that key components of a ...complex trait can evolve in isolation and later be combined by gene flow. We use C4 photosynthesis as a study system, a derived physiology that increases plant productivity in warm, dry conditions. The grass Alloteropsis semialata includes C4 and non‐C4 genotypes, with some populations using laterally acquired C4‐adaptive loci, providing an outstanding system to track the spread of novel adaptive mutations. Using genome data from C4 and non‐C4 A. semialata individuals spanning the species’ range, we infer and date past migrations of different parts of the genome. Our results show that photosynthetic types initially diverged in isolated populations, where key C4 components were acquired. However, rare but recurrent subsequent gene flow allowed the spread of adaptive loci across genetic pools. Indeed, laterally acquired genes for key C4 functions were rapidly passed between populations with otherwise distinct genomic backgrounds. Thus, our intraspecific study of C4‐related genomic variation indicates that components of adaptive traits can evolve separately and later be combined through secondary gene flow, leading to the assembly and optimization of evolutionary innovations.
Gibberellins (GAs) are involved in regulation of many aspects during plant development. To investigate the impact of altered GA levels on plant growth and metabolism, transgenic tobacco (Nicotiana ...tabacum) plants have been engineered to express either a GA20-oxidase (AtGA20-ox) or a GA2-oxidase (AtGA2-ox) gene from Arabidopsis under control of the cauliflower mosaic virus 35S promoter. Resulting plants were characterized by elongated or stunted shoot growth, respectively, indicating changes in the content of bioactive GAs. In accordance with the effect on plant growth, biomass production was increased or decreased in AtGA20-ox or AtGA2-ox plants, respectively, and was found to be positively correlated with the rate of photosynthesis as determined at the whole plant level. Differences in dry matter accumulation were most likely due to changes in lignin deposition as indicated by histochemical staining and quantitative measurements. Altered lignification of transgenic plants was paralleled by up- or down-regulation of the expression of lignin biosynthetic genes. Short-term GA3 feeding of excised petioles induced lignin formation in the absence of a transcriptional activation of pathway-specific genes. Thus, short-term GA treatment mediates lignin deposition most likely by polymerization of preformed monomers, whereas long-term effects on lignification involve elevated production of precursors by transcriptional stimulation of the biosynthetic pathway. Interestingly, analysis of stem cross sections revealed a differential effect of GA on the formation of xylem and pith cells. The number of lignified vessels was increased in AtGA20-ox plants pointing to a stimulation of xylem formation while the number of pith cells declined indicating a negative regulation.
At the dawn of the 21st century, the rapid expansion of manufacturing plants and the widespread destruction of natural habitats significantly contributed to accelerating global warming. This ...phenomenon has led to severe droughts, irreversible agricultural damage, and substantial challenges in securing food supplies for the burgeoning global population. The alarming surge in atmospheric carbon dioxide concentrations underscores the urgent need to embrace clean energy technologies. To date, the primary goal of mankind is to develop innovative approaches to return Earth's ecology to its pre-industrial condition, as a century ago. The special issue (SI) in the International Journal of Hydrogen Energy presents a collection of papers on photosynthetic and biomimetic hydrogen (H2) production, presented at the 'Photosynthesis and Hydrogen Energy Research for Sustainability - 2023' conference, held in Istanbul, Turkey, from 3-9 July 2023 (https://phrs-conference.com). The event was supported by the International Society of Photosynthesis Research (ISPR) and the International Association for Hydrogen Energy (IAHE). SI aims to deliver the latest insights into sustainable energy, with a particular emphasis on Biohydrogen and Artificial Photosynthesis. At the conference, nine promising young investigators were honoured with awards. Included herein are photographs capturing the conference's congenial atmosphere. We cordially invite you to the 12th International Meeting of 'Photosynthesis and Hydrogen Energy Research for Sustainability - 2024', honouring esteemed researchers John Allen (UK), Eva-Mari Aro (Finland), Ibrahim Dincer (Canada), Kazunari Domen (Japan), Elizabeth Gantt (USA), Andrey Rubin (Russia), and scheduled to take place in Turkey (13-19 October 2024).
Maximize your almond dormancy period Industry Voice by Wilbur Ellis
Western Farm Press,
11/2021
Magazine Article, Journal Article, Trade Publication Article
The industry responded and now uses chill portions as the standard measurement to better calculate the effects of temperature fluctuations. Extreme hot and extreme cold alike shock almond trees out ...of their “REM sleep” state of dormancy. With unpredictable weather, what can growers do to increase yield? A product such as Diffusion reflects light and protects almond trees from heat without interfering with photosynthesis.
Decoupled Artificial Photosynthesis Zhang, Linlin; Wang, Yaobing
Angewandte Chemie International Edition,
June 5, 2023, Volume:
62, Issue:
23
Journal Article
Peer reviewed
Natural photosynthesis (NP) generates oxygen and carbohydrates from water and CO2 utilizing solar energy to nourish lives and balance CO2 levels. Following nature, artificial photosynthesis (AP), ...typically, overall water or CO2 splitting, produces fuels and chemicals from renewable energy. However, hydrogen evolution or CO2 reduction is inherently coupled with kinetically sluggish water oxidation, lowering efficiencies and raising safety concerns. Decoupled systems have thus emerged. In this review, we elaborate how decoupled artificial photosynthesis (DAP) evolves from NP and AP and unveil their distinct photoelectrochemical mechanisms in energy capture, transduction and conversion. Advances of AP and DAP are summarized in terms of photochemical (PC), photoelectrochemical (PEC), and photovoltaic‐electrochemical (PV‐EC) catalysis based on material and device design. The energy transduction process of DAP is emphasized. Challenges and perspectives on future researches are also presented.
Decoupled artificial photosynthesis (DAP) strides one step closer to natural photosynthesis (NP) thanks to a photoelectrochemical energy transduction process. In this review, we elaborate how DAP evolves from NP and traditional artificial photosynthesis (AP), summarize recent advances of AP and DAP, and discuss current challenges and future developments of DAP.
In recent years, the problem of crop yield reduction caused by drought has become increasingly serious in countries around the world. China, in particular, is facing a pressing issue of water ...resource scarcity that is limiting agricultural production and food security. To address this, studying the drought resistance of plants is crucial to understanding the limitations of cultivated plants in dealing with drought. It can also contribute to an improvement in plant drought resistance theory and provide a theoretical foundation for sustainable agricultural development. In this study, we used Pugionium corntum (L.) Gaertn. as the experimental material and analyzed the transcriptome data of P. corntum under drought stress using high-throughput Illumina sequencing technology. Under the simulated drought environment, we compared P. corntum with the control and observed that the number of differentially expressed genes involved in the carbon fixation pathway in photosynthetic organisms was 14 and 30 under moderate and severe drought stress, respectively. Our findings revealed the presence of genes related to the Csub.4 cycle pathway in P. corntum, which effectively explains its adaptation mechanism to arid desert environments. This adaptation mechanism alleviates the negative impact of drought on photosynthesis in seedlings.
Citrus nursery trees in California must be grown in insect exclusion facilities to protect them against Huanglongbing (HLB), a deadly disease caused by Candidatus liberibacter spp. and spread by the ...Asian citrus psyllid (Diaphorina citri). Faster year-round propagation is critical for citrus nurseries to offset their investment in new exclusion facilities, but nurseries currently face serious problems in terms of poor bud push and slow scion growth in fall-budded, container-grown trees. The purpose of this study was to explore the effect of supplemental LED lighting techniques on the photosynthesis and total non-structural carbohydrate (TNC) partitioning within citrus trees that is responsible for growth cessation during the fall. A total of 72 trees of Carrizo citrange rootstock with and without Clementine Mandarin scions, were placed in growth chambers during four photoperiods: T1, 10 h LED + 4 h extension of day length (EoD, 10 μmol·m−2·s−1); T2, 10 h LED with 1 h supplemental night interruption (NI); T3, 10 h LED with 10 h supplemental far-red (FR) lighting; and T4, controls (10 h LED). The LED light spectrum was adjusted to 90 red and 10 blue ratios. The trees were grown in the growth chambers at 21/13°C day/night temperatures and 80% RH for 12 weeks. Trees were harvested and separated into leaves, stems, and roots at the end of the experiment. Different tissues were oven dried, ground and analyzed for TNC. The results showed that NI and EoD resulted in significantly higher plant growth. Both NI and EoD allowed trees to accumulate lower levels of carbohydrates in the root system, thereby decreasing the root: shoot ratio. NI and EoD trees had lower root: shoot ratios for TNC than control and FR trees in both budded and unbudded trees, suggesting the storage of reserves in roots can be enhanced during shorter day length. Results also showed that NI and EoD photoperiods triggered phytochrome with low light intensity, which in turn induced a long day effect and further translocation of reserves from roots to aboveground parts to improve vegetative growth.
“Least‐cost theory” posits that C3 plants should balance rates of photosynthetic water loss and carboxylation in relation to the relative acquisition and maintenance costs of resources required for ...these activities. Here we investigated the dependency of photosynthetic traits on climate and soil properties using a new Australia‐wide trait dataset spanning 528 species from 67 sites. We tested the hypotheses that plants on relatively cold or dry sites, or on relatively more fertile sites, would typically operate at greater CO2 drawdown (lower ratio of leaf internal to ambient CO2, Ci:Ca) during light‐saturated photosynthesis, and at higher leaf N per area (Narea) and higher carboxylation capacity (Vcmax 25) for a given rate of stomatal conductance to water vapour, gsw. These results would be indicative of plants having relatively higher water costs than nutrient costs. In general, our hypotheses were supported. Soil total phosphorus (P) concentration and (more weakly) soil pH exerted positive effects on the Narea–gsw and Vcmax 25–gsw slopes, and negative effects on Ci:Ca. The P effect strengthened when the effect of climate was removed via partial regression. We observed similar trends with increasing soil cation exchange capacity and clay content, which affect soil nutrient availability, and found that soil properties explained similar amounts of variation in the focal traits as climate did. Although climate typically explained more trait variation than soil did, together they explained up to 52% of variation in the slope relationships and soil properties explained up to 30% of the variation in individual traits. Soils influenced photosynthetic traits as well as their coordination. In particular, the influence of soil P likely reflects the Australia's geologically ancient low‐relief landscapes with highly leached soils. Least‐cost theory provides a valuable framework for understanding trade‐offs between resource costs and use in plants, including limiting soil nutrients.
Using an Australia‐wide photosynthetic trait dataset, we tested predictions from least‐cost optimality theory, which posits that plants balance nutrient use and water loss to optimize photosynthesis. We found that leaf nitrogen and rates of water loss co‐vary with one another in response to climate and to a lesser extent, soils. While much attention has been paid to the role of climate in driving photosynthesis, fewer studies have investigated soil effects, despite the important role of soil in limiting plant growth and in shaping the distributions of vegetation communities.
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