Explore the vast range of titles available.

A photon avalanche (PA) effect that occurs in lanthanide-doped solids gives rise to a giant nonlinear response in the luminescence intensity to the excitation light intensity. As a result, much weaker lasers are needed to evoke such PAs than for other nonlinear optical processes. Photon avalanches are mostly restricted to bulk materials and conventionally rely on sophisticated excitation schemes, specific for each individual system. Here we show a universal strategy, based on a migrating photon avalanche (MPA) mechanism, to generate huge optical nonlinearities from various lanthanide emitters located in multilayer core/shell nanostructrues. The core of the MPA nanoparticle, composed of Yb 3+ and Pr 3+ ions, activates avalanche looping cycles, where PAs are synchronously achieved for both Yb 3+ and Pr 3+ ions under 852 nm laser excitation. These nanocrystals exhibit a 26th-order nonlinearity and a clear pumping threshold of 60 kW cm −2 . In addition, we demonstrate that the avalanching Yb 3+ ions can migrate their optical nonlinear response to other emitters (for example, Ho 3+ and Tm 3+ ) located in the outer shell layer, resulting in an even higher-order nonlinearity (up to the 46th for Tm 3+ ) due to further cascading multiplicative effects. Our strategy therefore provides a facile route to achieve giant optical nonlinearity in different emitters. Finally, we also demonstrate applicability of MPA emitters to bioimaging, achieving a lateral resolution of ~62 nm using one low-power 852 nm continuous-wave laser beam. A general mechanism, migrating photon avalanche, can generate large optical nonlinearity from various lanthanides emitters at the nanoscale.

To increase rice yields and feed billions of people, it is essential to enhance genetic gains. However, the development of new varieties is hindered by longer generation times and seasonal constraints. To address these limitations, a speed breeding facility has been established and a robust speed breeding protocol, SpeedFlower is developed that allows growing 4–5 generations of indica and/or japonica rice in a year. Our findings reveal that a high red‐to‐blue (2R > 1B) spectrum ratio, followed by green, yellow and far‐red (FR) light, along with a 24‐h long day (LD) photoperiod for the initial 15 days of the vegetative phase, facilitated early flowering. This is further enhanced by 10‐h short day (SD) photoperiod in the later stage and day and night temperatures of 32/30 °C, along with 65% humidity facilitated early flowering ranging from 52 to 60 days at high light intensity (800 μmol m −2  s −1 ). Additionally, the use of prematurely harvested seeds and gibberellic acid treatment reduced the maturity duration by 50%. Further, SpeedFlower was validated on a diverse subset of 198 rice accessions from 3K RGP panel encompassing all 12 distinct groups of Oryza sativa L. classes. Our results confirmed that using SpeedFlower one generation can be achieved within 58–71 days resulting in 5.1–6.3 generations per year across the 12 sub‐groups. This breakthrough enables us to enhance genetic gain, which could feed half of the world's population dependent on rice. We've developed a robust SpeedFlower protocol for rapid rice breeding, enabling 4–5 generations of indica and/or japonica rice annually. The SpeedFlower protocol was validated on 198 diverse rice accessions, representing all 12 sub‐groups of Oryza sativa L . With a timeframe of 58–71 days per generation, we achieved 5.1–6.3 generations per year. Therefore, SpeedFlower has shown a transformative potential in enhancing genetic gain with the pace of climate change.

We describe a smart hybrid system that integrates a temperature-sensitive polymer and photothermal material. The system enables algae to produce hydrogen under both low and high light intensities (100–2000 μmol photons·m–2·s–1).Algae-based hydrogen production, which relies only on sunlight and water, offers a green alternative that provides clean, low-carbon energy for sustainable development.High light intensity typically damages algae and halts hydrogen production. Our system dynamically regulates light exposure, protecting algal cells and sustaining hydrogen generation for 25 days.This self-regulating, energy-efficient system works without external power and reduces carbon emissions, paving the way for scalable outdoor biohydrogen production. Cleaner, lower carbon energy is needed for more sustainable development. Algal production of hydrogen directly from water and sunlight is a promising route toward such sustainable energy. However, algae can only produce hydrogen continuously in weak light. We developed a hybrid system using a designed thermosensitive material, poly(N-isopropylacrylamide)-co-poly(butyl acrylate) (PNIPAM-BA), and a photothermal material, graphene oxide (GO), to dynamically sense light intensity. This system regulates the entry of incident light to protect the activity of algal hydrogenase, which enables algae to efficiently produce hydrogen through photosynthesis across a range of light intensities (100–2000 μmol photons·m–2·s–1). Even under the standard maximum solar intensity of 2000 μmol photons·m–2·s–1, we achieved continuous hydrogen production over 25 days with an average hydrogen production rate of 17.53 μmol H2 (mg chlorophyll)–1 h–1. Thus, this study addresses the challenge of continuous hydrogen production by algae under high light intensity, greatly advancing prospects for large-scale outdoor hydrogen production. [Display omitted] The proposed algae/polymer hybrid system demonstrates significant technological advances in photosynthetic hydrogen production under high light intensities. While laboratory-scale results showcase sustained hydrogen production over 25 days with high efficiency, several challenges must be addressed for large-scale implementation. These include ensuring uniform light distribution in larger photobioreactors, preventing oxygen accumulation that can inhibit hydrogenase activity, and maintaining consistent environmental conditions across diverse reactor regions. To overcome these barriers, innovative reactor designs, real-time automation for oxygen and temperature control, and efficient gas exchange systems will be crucial. In addition, the scalability of the light-regulating capability of the hybrid system and its long-term stability require further validation. While these discussions involve some level of speculation, they are grounded in the experimental outcomes outlined in this study, which underscore the potential for a low-carbon transition enabled by scalable, algae-based hydrogen production systems. We developed a smart algae/polymer hybrid system that enabled sustained photosynthetic hydrogen production under high light intensities (100–2000 μmol photons·m-2·s-1), overcame photoinhibition and oxygen-related challenges, and advances outdoor large-scale green hydrogen production.

The decreased quality of leafy vegetables and tipburn caused by inappropriate light intensity are serious problems faced in plant factories, greatly reducing the economic benefits. The purpose of this study was to comprehensively understand the impact of light intensity on the growth and quality of different crops and to develop precise lighting schemes for specific cultivars. Two lettuce (Lactuca sativa L.) cultivars—Crunchy and Deangelia—and one spinach (Spinacia oleracea L.) cultivar—Shawen—were grown in a plant factory using a light-emitting diode (LED) under intensities of 300, 240, 180, and 120 μmol m−2 s−1, respectively. Cultivation in a solar greenhouse using only natural light (NL) served as the control. The plant height, number of leaves, and leaf width exhibited the highest values under a light intensity of 300 μmol m−2 s−1 for Crunchy. The plant width and leaf length of Deangelia exhibited the smallest values under a light intensity of 300 μmol m−2 s−1. The fresh weight of shoot and root, soluble sugar, soluble protein, and ascorbic acid contents in the three cultivars increased with the increasing light intensity. However, tipburn was observed in Crunchy under 300 μmol m−2 s−1 light intensity, and in Deangelia under both 300 and 240 μmol m−2 s−1 light intensities. Shawen spinach exhibited leaf curling under all four light intensities. The light intensities of 240 and 180 μmol m−2 s−1 were observed to be the most optimum for Crunchy and Deangelia (semi-heading lettuce variety), respectively, which would exhibit relative balance growth and morphogenesis. The lack of healthy leaves in Shawen spinach under all light intensities indicated the need to comprehensively optimize cultivation for Shawen in plant factories to achieve successful cultivation. The results indicated that light intensity is an important factor and should be optimized for specific crop species and cultivars to achieve healthy growth in plant factories.

Aurantiochytrium is a promising source of docosahexaenoic acid (DHA) and carotenoids, but their synthesis is influenced by environmental stress factors. In this study, the effect of different light intensities on the fermentation of DHA oil and carotenoids using Aurantiochytrium sp. TZ209 was investigated. The results showed that dark culture and low light intensity conditions did not affect the normal growth of cells, but were not conducive to the accumulation of carotenoids. High light intensity promoted the synthesis of DHA and carotenoids, but caused cell damage, resulting in a decrease of oil yield. To solve this issue, a light intensity gradient strategy was developed, which markedly improved the DHA and carotenoid content without reducing the oil yield. This strategy produced 30.16 g/L of microalgal oil with 15.11 g/L DHA, 221 µg/g astaxanthin, and 386 µg/g β-carotene. This work demonstrates that strain TZ209 is a promising DHA producer and provides an efficient strategy for the co-production of DHA oil together with carotenoids.

A new mechanistic model of the photosynthesis–light response is developed based on photosynthetic electron transport via photosystem II (PSII) to specifically describe light-harvesting characteristics and associated biophysical parameters of photosynthetic pigment molecules. This model parameterizes ‘core’ characteristics not only of the light response but also of difficult to measure physical parameters of photosynthetic pigment molecules in plants. Application of the model to two C3 and two C4 species grown under the same conditions demonstrated that the model reproduced extremely well (r 2 > 0.992) the light response trends of both electron transport and CO2 uptake. In all cases, the effective absorption cross-section of photosynthetic pigment molecules decreased with increasing light intensity, demonstrating novel operation of a key mechanism for plants to avoid high light damage. In parameterizing these previously difficult to measure characteristics of light harvesting in higher plants, the model provides a new means to understand the mechanistic processes underpinning variability of CO2 uptake, for example, photosynthetic down-regulation or reversible photoinhibition induced by high light and photoprotection. However, an important next step is validating this parameterization, possibly through application to less structurally complex organisms such as single-celled algae.

Cigar tobacco stands as a pivotal economic crop, with its leaf growth and development profoundly influenced by light intensity. Present study specifically aimed to investigate how leaf morphology and anticlinal growth responds to varying light intensities, including normal light intensity (NL–300 µmol m − 2 s − 1 ) and lower light intensity (LL–100 µmol m − 2 s − 1 ). The research elucidates significant morphological shifts in cigar tobacco leaves under LL, revealing significant alterations in leaf area, leaf length, and leaf width. Early reductions in leaf dimensions, ranging from 30 to 48%, were succeeded by a substantial enhancement in expansion rates from day 9 to day 26, contributing to expanded leaf surfaces at later stages. Upper epidermis thickness declined by 29 − 19%, with a notably slower expansion rate in the initial 20 days. Palisade cell length consistently decreased by 52 − 17%, corresponding with upper epidermis trends. Spongy tissue thickness was reduced by 31 − 12%, with a slower expansion rate in LL for the initial 14 days, and leaf thickness dropped by 34 − 11%. LL resulted in slower leaf anticlinal expansion, leading to reduced leaf thickness (LT). LL significantly influenced phytohormones in cigar tobacco leaves. Gibberellic acid (41–16%) and auxin (20–35%) levels were found in higher amounts, while cytokinin levels (19–5%) were lowered compared to NL, indicating the intricate regulatory role of light in hormonal dynamics. The observed increase in LT and different cell layers at specific time points (day 8, day 12, day 24, and day 28) under LL, although lower than NL, may be attributed to elevated expression of genes related to cell expansion, including Nt GRF1 , Nt XTH , and Nt SAUR19 at those time points. This comprehensive understanding elucidates the intricate mechanisms by which light intensity orchestrates the multifaceted processes governing leaf anatomy and anticlinal expansion in cigar tobacco plants.

Sedentary behavior is associated with health risks in adults. The potential benefits of reducing sedentary time may be dependent not only on decrease per se, but also on the type of activity it replaces. Few longitudinal studies have investigated the effects on mortality when replacing objectively assessed sedentary time with another physical activity (PA) behavior. To investigate the effects of replacing objectively assessed sedentary time with time in light-intensity PA or moderate-vigorous PA (MVPA) on all-cause mortality, cardiovascular disease (CVD) mortality or cancer mortality in a cohort with 15 years follow-up time. In total, 851 women and men from the population-based Sweden Attitude Behaviour and Change study were included. Time spent sedentary, in light-intensity PA and in MVPA were assessed using an Actigraph 7164 accelerometer. Mortality data were obtained from Swedish registers. Cox proportional hazards models estimated hazard ratios (HR) of mortality with 95% confidence intervals (CI) and isotemporal substitution models were used to estimate the effect of replacing sedentary behavior with PA for the same amount of time. Over a follow-up of 14.2 years (SD 1.9) with 12,117 person-years at risk, 79 deaths occurred, 24 deaths from CVD, 27 from cancer, and 28 from other causes. Replacing 30 minutes/day of sedentary time with light-intensity PA was associated with significant reduction in all-cause mortality risk (HR: 0.89, 95% CI: 0.81-0.98) and CVD mortality risk (HR: 0.76, 95% CI: 0.63-0.92). Replacing 10 minutes of sedentary time with MVPA was associated with reduction in CVD mortality risk (HR: 0.62, 95% CI: 0.42-0.91). No statistically significant reductions were found for cancer mortality. This statistical modelling study suggests that replacing sedentary time with light-intensity PA could have beneficial effect on both all-cause mortality and CVD mortality. Replacing sedentary time with MVPA could reduce CVD mortality.

Background Global climate change significantly affects photosynthesis in spring wheat. However, the successive dynamic effects of multiple environmental interactions on photosynthesis in spring wheat have been inadequately investigated. This study conducted pot control experiments to determine photosynthesis characteristics, namely light and CO 2 response curves, in spring wheat under progressive drought stress. Results Progressive drought stress caused all parameters of the light response curve to decrease logistically and all parameters of the CO 2 response curve to change exponentially. There were noticeable thresholds for these parameter changes. The ability of spring wheat to utilize light was weakened by progressive drought stress. Under all drought levels, the reduction in photosynthetic capacity was greater under strong light than under weak light. The effects on CO 2 utilization and the corresponding photosynthetic capacity depended on the drought level and CO 2 concentration. The optimal light intensity (I opt ) for spring wheat showed a logistic decreasing trend under progressive drought stress. Unexpectedly, the optimal atmospheric CO 2 concentration (CO 2opt ) remained at 800 µmol·mol − 1 under drought stress, which was less severe than extreme drought. Conclusions Our results showed that progressive drought stress, combined with different environmental factors, had distinct impacts on the photosynthetic efficiency and carbon assimilation capacity of spring wheat, providing a basis for rational carbon and water resource utilization in spring wheat under climate change.

Light intensity ( I ) is the most dynamic and significant environmental variable affecting photosynthesis ( A n), stomatal conductance ( g s), transpiration ( T r), and water-use efficiency (WUE). Currently, studies characterizing leaf-scale WUE– I responses are rare and key questions have not been answered. In particular, (1) What shape does the response function take? (2) Are there maximum intrinsic (WUEi; WUEi–max) and instantaneous WUE (WUEinst; WUEinst–max) at the corresponding saturation irradiances ( I i–sat and I inst–sat)? This study developed WUEi– I and WUEinst– I models sharing the same non-asymptotic function with previously published A n– I and g s– I models. Observation-modeling intercomparison was conducted for field-grown plants of soybean (C3) and grain amaranth (C4) to assess the robustness of our models versus the non-rectangular hyperbola models (NH models). Both types of models can reproduce WUE– I curves well over light-limited range. However, at light-saturated range, NH models overestimated WUEi–max and WUEinst–max and cannot return I i–sat and I inst–sat due to its asymptotic function. Moreover, NH models cannot describe the down-regulation of WUE induced by high light, on which our models described well. The results showed that WUEi and WUEinst increased rapidly within low range of I , driven by uncoupled photosynthesis and stomatal responsiveness. Initial response rapidity of WUEi was higher than WUEinst because the greatest increase of A n and T r occurred at low g s. C4 species showed higher WUEi–max and WUEinst–max than C3 species—at similar I i–sat and I inst–sat. Our intercomparison highlighted larger discrepancy between WUEi– I and WUEinst– I responses in C3 than C4 species, quantitatively characterizing an important advantage of C4 photosynthetic pathway—higher A n gain but lower T r cost per unit of g s change. Our models can accurately return the wealth of key quantities defining species-specific WUE– I responses—besides A n– I and g s– I responses. The key advantage is its robustness in characterizing these entangled responses over a wide I range from light-limited to light-inhibitory light intensities, through adopting the same analytical framework and the explicit and consistent definitions on these responses. Our models are of significance for physiologists and modelers—and also for breeders screening for genotypes concurrently achieving maximized photosynthesis and optimized WUE.