Light Compensation Research Articles

Pathologists light level preferences using the microscope—study to guide digital pathology display use

BackgroundCurrently, there is a paucity of guidelines relating to displays used for digital pathology making procurement decisions, and optimal display configuration, challenging.Experience suggests pathologists have personal preferences for brightness when using a conventional microscope which we hypothesized could be used as a predictor for display setup. MethodsWe conducted an online survey across six NHS hospitals, totalling 108 practicing pathologists, to capture brightness adjustment habits on both microscopes and displays.A convenience subsample of respondents was then invited to take part in a practical task to determine microscope brightness and display luminance preferences, in the normal working environment. A novel adaptation for a lightmeter was developed to directly measure the light output from the microscope eyepiece. ResultsThe survey (response rate 59% n=64) indicates 81% of respondents adjust the brightness on their microscope. In comparison, only 11% report adjusting their digital display. Display adjustments were more likely to be for visual comfort and ambient light compensation rather than for tissue factors, common for microscope adjustments. Part of this discrepancy relates to lack of knowledge of how to adjust displays and lack of guidance on whether this is safe; But, 66% felt that the ability to adjust the light on the display was important.Twenty consultants took part in the practical brightness assessment. Light preferences on the microscope showed no correlation with display preferences, except where a pathologist has a markedly brighter microscope light preference. All of the preferences in this cohort were for a display luminance of <500 cd/m2, with 90% preferring 350 cd/m2 or less. There was no correlation between these preferences and the ambient lighting in the room. ConclusionsWe conclude that microscope preferences can only be used to predict display luminance requirements where the microscope is being used at very high brightness levels. A display capable of a brightness of 500 cd/m2 should be suitable for almost all pathologists with 300 cd/m2 suitable for the majority. Although display luminance is not frequently changed by users, the ability to do so was felt to be important by the majority of respondents.Further work needs to be undertaken to establish the relationship between diagnostic performance, luminance preferences, and ambient lighting levels.

Morphological, Anatomical, and Physiological Characteristics of Heteroblastic Acacia melanoxylon Grown under Weak Light.

Acacia melanoxylon is a fast-growing macrophanerophyte with strong adaptability whose leaf enables heteromorphic development. Light is one of the essential environmental factors that induces the development of the heteroblastic leaf of A. melanoxylon, but its mechanism is unclear. In this study, the seedlings of A. melanoxylon clones were treated with weak light (shading net with 40% of regular light transmittance) and normal light (control) conditions for 90 d and a follow-up observation. The results show that the seedlings' growth and biomass accumulation were inhibited under weak light. After 60 days of treatment, phyllodes were raised under the control condition while the remaining compound was raised under weak light. The balance of root, stem, and leaf biomass changed to 15:11:74 under weak light, while it was 40:15:45 under control conditions. After comparing the anatomical structures of the compound leaves and phyllode, they were shown to have their own strategies for staying hydrated, while phyllodes were more able to control water loss and adapt to intense light. The compound leaves exhibited elevated levels of K, Cu, Ca, and Mg, increased antioxidant enzyme activity and proline content, and higher concentrations of chlorophyll a, carotenoids, ABA, CTK, and GA. However, they displayed a relatively limited photosynthetic capacity. Phyllodes exhibited higher levels of Fe, cellulose, lignin, IAA content, and high photosynthetic capacity with a higher maximum net photosynthetic rate, light compensation point, dark respiration rate, and water use efficiency. The comparative analysis of compound leaves and phyllodes provides a basis for understanding the diverse survival strategies that heteroblastic plants employ to adapt to environmental changes.

Improving nitrogen content in the carboxylation and electron transfer component can boost the reproductive biomass of filmless cotton in arid areas

AbstractDeep drip irrigation combined with high‐density planting is one of the most economical and effective ways to address residual film pollution. This study aimed to explore the photosynthetic potential of and achieve water‐saving and high‐yielding filmless cotton (Gossypium hirsutum L.) by optimizing the irrigation amount. We analyzed the effect of source leaf activity on leaf nitrogen allocation and photosynthetic nitrogen utilization efficiency (PNUE) under different irrigation amounts (mm, 375 (W5), 348 (W4), 320 (W3), 293 (W2), and 265 (W1)) in a 2‐year field experiment under this planting mode. The photosynthetic pigment content, leaf mass per area, and light compensation point all decreased with increasing amounts of irrigation, while the apparent quantum yield of photosynthesis, light saturation point, maximum carboxylation rate (Vcmax), maximum electron transport rate (Jmax), triose phosphate utilization rate (VTPU), nitrogen content in the electron transfer component (NB), and nitrogen content in the carboxylation component (NC) showed opposite trends. At the later full boll stage, the W3 and W4 treatments increased the leaf area of a whole plant (LA) by 10.4% and 19.4%, respectively, compared to that in the W1 treatment, while the PNUE increased by 20.2% and 20.8%, respectively, compared to that in the W5 treatment. In addition, principal component analysis found that the factor variables total nitrogen content in the photosynthetic apparatus (NT), net photosynthetic rate (Pn), stomatal conductance (Gs), light‐saturated net photosynthetic rate (Amax), NC, and Vcmax had higher loadings and were all positively correlated with PNUE; LA had a higher loading and was positively correlated with reproductive organ biomass. Therefore, we recommend using an irrigation rate of 320 mm in this cultivation system to increase nitrogen in carboxylation and electron transport components, enhance photosynthetic capacity, and thereby improve PNUE to increase reproductive organ biomass and reduce the irrigation amount in arid areas.

Acyl-homoserine lactones regulate the photosynthesis of Chlorella sorokiniana to promote biomass and lipid

In the phycosphere, quorum sensing molecules (QSMs) might mediate an intricate interaction between microalgae and specified bacteria, yet little research had been reported in this area. In this study, the impacts of QSMs excreted by microalgae growth-promotion bacteria (MGPB) on Chlorellla sorokiniana were analyzed from phenotype and genes expression. In the control, the biomass and lipid content of C. sorokiniana were 93.06 mg/L and 37.58% after 15 days of cultivation. By adding 50 nmol L−1 of N-Octanoyl-dl-homoserine lactone (C8-HSL) and N-Tetradecanoyl-dl-homoserine lactone (C14-HSL) to the microalgae cultivation medium respectively, the biomass was raised by 7.42% and 13.86%, and the lipid contents were raised by 11.31% and 21.87%. The C8-HSL and C14-HSL could also enhance the photosynthesis of C. sorokiniana. After treated by 50 nmol L−1 of C8-HSL and C14-HSL, the maximum photosynthetic rates (Pm) were 17.80% and 28.81% higher than the control (the Pm was 2.36 μmol O2 mg−1 Chla min−1), and the light compensation points (Ic) were 1.88- and 1.67-fold increases compared to the control (the Ic was 27.23 μmol m−2 s−1). Furthermore, a total of 753 genes showed significant difference in expression, and the analysis of gene related to photosystem, chlorophyll synthesis and electron transport chains verified that acyl-homoserine lactones mediated the expression of photosynthesis-related genes. This study revealed the signaling communication mechanism between microalgae and bacteria, thereby guiding the regulation depending on QSMs.

3D facial animation generation technology based on 2D image

In order to improve the modeling efficiency and ensure the authenticity of the model, this paper proposes a 3D facial animation generation method based on front and side images. First, the feature point information reflecting the shape characteristics of the face is extracted from the front and side photos of a given face, and then these feature point information is used to modify the general face model to obtain a specific face model. Then, the face texture information in the front and side photos is used to texture map the specific face model, and finally a realistic virtual 3D face animation is obtained. In the aspect of feature extraction, this paper uses an improved color Snake model to accurately locate contour lines. The experimental results show that the system still has good processing performance, and the average processing time is less than 0.1s. On the set V, the light source angle is greater than 78 °, the illumination is seriously uneven, and the recognition rate is very low, which indicates that the texture features are not well extracted. But even in this case, the recognition rate after light compensation has doubled, which proves that the two-dimensional image can realize the three-dimensional facial animation generation technology.

Face orientation recognition based on Kinectv2 and an improved ELM model

Abstract Face orientation recognition is a crucial component of human behavior analysis. Challenges such as face occlusion and varying lighting conditions frequently degrade recognition accuracy. This study introduces an innovative approach using the Kinect sensor’s skeleton tracking technology to capture face orientation images across different lighting scenarios. To enhance image quality, techniques such as light attenuation and compensation are applied. Furthermore, multiple feature vectors based on face orientation are extracted and fused, followed by the optimization of the Extreme Learning Machine (ELM) model through the Archimedean Optimization Algorithm (AOA). The developed AOA-ELM model for face orientation recognition is compared with traditional models, including Back Propagation (BP), Radial Basis Function (RBF), standard ELM, and Genetic Algorithm enhanced ELM (GA-ELM). The AOA-ELM model exhibits superior performance in estimating face orientation amidst lighting disturbances, achieving an accuracy exceeding 95% in varied lighting conditions, thereby outperforming other classification models.

Quantitative analysis of the effect of illumination variations on image processing in machine vision inspection

Abstract When unavoidable light, age, expression, and gesture changes occur, the machine vision detection accuracy will be greatly reduced, especially the light change impact on image processing. Combining the reflection equation and frequency domain analysis to construct a light change model based on spherical harmonic function and process the image from four directions, namely, digital image conversion, median filtering, sharpening processing, and image global segmentation. Aiming at the shortcomings of traditional image processing algorithms, the light compensation based on the improved pulse-coupled neural network model is proposed, and the model is used to analyze the impact of light changes on image processing. Despite the changes in light conditions, this algorithm maintains above 0.95 in each subset and has the best overall performance, as shown by the results. When the light intensity is less than 41.88kLux, using the optimal threshold for background segmentation of adult green peppers with respect to a fixed threshold T=0.3 results in a significant reduction of the background segmentation error. When the light intensity is greater than 41.88kLux, the superiority of the optimal threshold is not obvious. The results of this research not only have a significant role in promoting the development of the field of computer vision but also can provide people with convenient and efficient services in all aspects of social life.

Non-photochemical quenching may contribute to the dominance of the pale mat-forming lichen Cladonia stellaris over the sympatric melanic Cetraria islandica.

The mat-forming fruticose lichens Cladonia stellaris and Cetraria islandica frequently co-occur on soils in sun-exposed boreal, subarctic, and alpine ecosystems. While the dominant reindeer lichen Cladonia lacks a cortex but produces the light-reflecting pale pigment usnic acid on its surface, the common but patchier Cetraria has a firm cortex sealed by the light-absorbing pigment melanin. By measuring reflectance spectra, high-light tolerance, photosynthetic responses, and chlorophyll fluorescence in sympatric populations of these lichens differing in fungal pigments, we aimed to study how they cope with high light while hydrated. Specimens of the two species tolerated high light equally well but with different protective mechanisms. The mycobiont of the melanic species efficiently absorbed excess light, consistent with a lower need for its photobiont to protect itself by non-photochemical quenching (NPQ). By contrast, usnic acid screened light at 450-700nm by reflectance and absorbed shorter wavelengths. The ecorticate usnic species with less efficient fungal light screening exhibited a consistently lower light compensation point and higher CO2 uptake rates than the melanic lichen. In both species, steady state NPQ rapidly increased at increasing light with no signs of light saturation. To compensate for less internal shading causing light fluctuations with a larger amplitude, the usnic lichen photobiont adjusted to changing light by faster induction and faster relaxation of NPQ rapidly transforming excess excitation energy to less damaging heat. The high and flexible NPQ tracking fluctuations in solar radiation probably contributes to the strong dominance of the usnic mat-forming Cladonia in open lichen-dominated heaths.

Integrative Physiological, Transcriptome, and Proteome Analyses Provide Insights into the Photosynthetic Changes in Maize in a Maize-Peanut Intercropping System.

Intercropping is a traditional and sustainable planting method that can make rational use of natural resources such as light, temperature, fertilizer, water, and CO2. Due to its efficient resource utilization, intercropping, in particular, maize and legume intercropping, is widespread around the world. However, the molecular details of these pathways remain largely unknown. In this study, physiological, transcriptome, and proteome analyses were compared between maize monocropping and maize-peanut intercropping. The results show that an intercropping system enhanced the ability of carbon fixation and carboxylation of maize leaves. Apparent quantum yield (AQY), the light-saturated net photosynthetic rate (LSPn), the light saturation point (LSP), and the light compensation point (LCP) were increased by 11.6%, 9.4%, 8.9%, and 32.1% in the intercropping system, respectively; carboxylation efficiency (CE), the CO2 saturation point (Cisat), the Rubisco maximum carboxylation rate (Vcmax), the maximum electron transfer rate (Jmax), and the triose phosphate utilization rate (TPU) were increased by 28.5%, 7.3%, 18.7%, 29.2%, and 17.0%, respectively; meanwhile, the CO2 compensation point (Γ) decreased by 22.6%. Moreover, the transcriptome analysis confirmed the presence of 588 differentially expressed genes (DEGs), and the numbers of up-regulated and down-regulated genes were 383 and 205, respectively. The DEGs were primarily concerned with ribosomes, plant hormone signal transduction, and photosynthesis. Furthermore, 549 differentially expressed proteins (DEPs) were identified in the maize leaves in both the maize monocropping and maize-peanut intercropping systems. Bioinformatics analysis revealed that 186 DEPs were related to 37 specific KEGG pathways in each of the two treatment groups. Based on the physiological, transcriptome, and proteome analyses, it was demonstrated that the photosynthetic characteristics in maize leaves can be improved by maize-peanut intercropping. This may be related to PS I, PS II, cytochrome b6f complex, ATP synthase, and photosynthetic CO2 fixation, which is caused by the improved CO2 carboxylation efficiency. Our results provide a more in-depth understanding of the high yield and high-efficiency mechanism in maize and peanut intercropping.

Artificial neural networks prediction and optimization based on four light regions for light utilization from Synechocystis sp. PCC 6803

Light is crucial in microalgae growth. However, dividing the microalgae growth region into light and dark regions has limitations. In this study, the light response of Synechocystis sp. PCC 6803 was investigated to define four light regions (FLRs): light compensation region, light limitation region, light saturation region, and photoinhibition region. The proportions of cells’ residence time in the FLRs and the number of times cells (NTC) passed through the FLRs in photobioreactors were calculated by using MATLAB. Based on the FLRs and NTC passed through the FLRs, a growth model was established by using artificial neural network (ANN).The ANN model had a validation R2 value of 0.97, which was 76.36% higher than the model based on light-dark regions. The high accuracy of the ANN model was further verified through dynamic adjustment of light intensity experiments.This study confirmed the importance of the FLRs for studying microalgae growth dynamics.

Nonuniform salinity regulate leaf characteristics and improve photosynthesis of cherry tomatoes under high salinity

Cherry tomato (Lycopersicon esculentum var. cerasiforme) is a relatively salt-tolerant fruit and vegetable widely planted worldwide. In this study, the growth and physiological responses and the different regulatory of cherry tomatoes under high, low salinity, and partial root zone salinity conditions were investigated. Cherry tomatoes grown under nonuniform salinity (0/20, 0/100 mM NaCl) conditions in a split-root pot were compared with seedlings grown under uniform salinity (20, 100 mM NaCl) conditions, and their growth and physiological parameters were determined. Our results showed that the growth was not hindered under a low salinity (20 mM NaCl), and the fruit quality was improved without a yield reduction; this was caused by promoted root growth and better leaf function maintenance. The relief effects under the higher salt stress (100 mM NaCl) conditions were more significant than those under a lower salt stress condition (20 mM NaCl). Compared with uniform high salinity conditions, nonuniform salinity conditions could improve photosynthetic characteristics and maintain better leaf function. The apparent quantum efficiency (AQE), carboxylation efficiency (CE) and light saturation irradiance (LSP) increased, while the light compensation point (LCP) and CO2 compensation point (CCP) decreased; this enhanced the light energy and CO2 utilization. Chlorophyll content (Chl), including Chl a and b and the carotenoids (Car), and the chlorophyll fluorescence parameters, including the maximum quantum efficiency of photosystem II (PSII) reaction centers (Fv/Fm), the quantum efficiency of PSII (Y(II)) and electron transport rate through PSII (ETR), were increased; this significantly promoted the net photosynthetic rate (Pn) and water use efficiency (WUE). Compared with a uniform high salt stress treatment, the leaf relative water content (RWC) and water potential (Ψ) increased by 22.57% and 13.71%, respectively, the electrolyte leakage rate decreased by 36.13%, and the final yield increased by 2.89 times under a nonuniform high salinity treatment. These results indicated that nonuniform salinity conditions regulated the leaf water relations and the antioxidant system and maintained better anatomical structure to improve photosynthesis in cherry tomato under a high salinity environment. Finally, our results can aid in the improvement of tomato productivity from salt-affected lands.

Effect of mycorrhization on growth and physiology performance of Quercus species

The development of mycorrhiza could contribute to strengthening the resilience of forest ecosystems to climate change. Several mycorrhizal fungi are known for their valuable effect in increasing plant performances and adaptation to stressful environmental conditions. Thereby, this research aims to investigate how Terfezia boudieri (Chatin) mycorrhizal fungi affects the growth (primary root length, above-ground plant weight) and the physiological behaviour (net photosynthesis, responses to intercellular [CO2] and the intensity of photosyntically active radiation) of Quercus subsp. coccifera and Q. suber L. Inoculated and non-inoculated seedlings of the two Quercus species were grown in one-liter pots in the greenhouse, with a temperature that ranged from 25 to 30 °C, natural lighting and an irrigation applied twice a week with top water. Results revealed that primary root length and the above-ground biomass increased with mycorrhization. In addition, mycorrhization promoted net photosynthesis (at 400 ppm and at saturation point), the apparent quantum yield, the water use efficiency, and the photosynthetic pigments contents. However, inoculation decreased the light compensation point for both species. Effectiveness of T. boudieri inoculation on Quercus sp. performance, highlights the potential of the mycorrhization process to improve forest management and resilience to climate change.

Optimizing Light Use Efficiency and Quality of Indoor Organically Grown Leafy Greens by Using Different Lighting Strategies

Vertical farming is experiencing significant growth, and the optimization of artificial lighting is essential for enhancing the sustainability of this growing system. Therefore, the aim of this study was to examine how light segmentation, the incorporation of a low-intensity lighting phase known as the light compensation point (LCP) instead of the traditional dark phase, and variations in the light spectrum impact the agricultural outcomes of organically cultivated leafy greens. In controlled growth chamber environments, a variety of leafy plant species (Spinacia oleracea L., Ocimum basilicum, Beta vulgaris L., Lactuca sativa L. cv. ‘Garrison’ and ‘Blade’, Brassica rapa cv. ‘Japonica’ and ‘Chinensis’, Brassica juncea cv. ‘Scarlet Frills’ and ‘Wasabina’, Eruca sativa and Perilla frutescens L.) were subjected to four light treatments with varying intensities and durations of lighting, while in a second experiment, five different spectral growing conditions were compared. Irrespective of the plant species, shortening the length of the diel cycle by extending the cumulative daily lighting to 20–24 h per day (5L/1N [5 h at 261 µmol m−2 s−1 + 1 h darkness for a total of 20 h of light per day] and 5L/1LCP [5 h at 256 µmol m−2 s−1 + 1 h LCP at 20 µmol m−2 s−1 for a total of 24 h of light per day]) led to an average increase of +12% in height, fresh weight (+16%), dry weight (+23%), and specific leaf weight (+11%), compared to the control plants (18L/6N; 18 h at 289 µmol m−2 s−1 + 6 h darkness) and 6L/6LCP plants (6 h at 418 µmol m−2 s−1 + 6 h LCP at 20 µmol m−2 s−1 for a total of 24 h of light per day) during the first harvest. This also resulted in better light utilization, expressed as increased fresh (+16%) and dry (+24%) biomass per mol of light received. Conversely, the studied light spectral treatments had no effect on the growth parameters of the four selected species. In conclusion, our study showed that reducing light intensity while extending the photoperiod could potentially represent a cost-effective LED strategy for the indoor cultivation of organically or conventionally grown leafy greens.

Method for selecting ornamental species for different shading intensity in urban green spaces.

In urban areas, ornamental plants face different constraints, such as the shading of buildings and trees. Therefore, the selection of suitable species and their integration or combination with pre-existing plants is very important. Trees, shrubs, and herbaceous plant species must be distributed according to plant light requirements and shading intensity. Ornamental plants are classified into two groups based on their light intensity or shade tolerance: sun and shade species. To properly position the plants, especially in the immediate vicinity of buildings, it is necessary to study the projection of shadows during the year and the most critical periods, such as July and August. The position of ornamental species with different shading tolerances can be obtained by characterizing the leaf gas exchange for each species. Among the physiological parameters, the most important is the light compensation point, which is the light intensity corresponding to a net photosynthesis equal to zero. This means that the assimilation of carbon dioxide through photosynthesis is equal to the carbon dioxide emitted by respiration. This steady state represents the most critical condition for plants to endure the summer. The distribution of species inside a green area should be determined by considering the minimum light intensity that allows sufficient photosynthesis to compensate for the respiration rate. In this context, non-destructive leaf gas exchange, chlorophyll a fluorescence, and chlorophyll content can be useful tools for selecting suitable ornamental plants under diverse shading conditions.

Functional trait divergence associated with heteromorphic leaves in a climbing fig.

Plants that display heteroblasty possess conspicuous variations in leaf morphology between their juvenile and adult phases, with certain species retaining juvenile-like leaves even in adulthood. Nevertheless, the ecological advantages of maintaining two or more distinct leaf types in heteroblastic plants at the adult stage remain unclear. The aim of this study is to examine the adaptive significance of heteroblastic leaves sampled from branches with divergent functions (sterile and fertile branches) of mature Ficus pumila individuals by comparing their morphological, anatomical, and physiological characteristics. Leaves on sterile branches (LSs) exhibited a significantly larger specific leaf area, thinner palisade and spongy tissues, lower chlorophyll contents, and lower light saturation points than leaves on fertile branches (LFs). These results demonstrate that LSs are better adapted to low light environments, while LFs are well equipped to take advantages of high light conditions. However, both LFs and LSs have a low light compensation point with no significant difference between them, indicating that they start to accumulate photosynthetic products under similar light conditions. Interestingly, significant higher net photosynthetic rate was detected in LFs, showing they have higher photosynthetic capacity. Furthermore, LFs produced significant more nutrients compared to LSs, which may associate to their ability of accumulating more photosynthetic products under full light conditions and higher photosynthetic capacity. Overall, we observed a pattern of divergence in morphological features of leaves on two functional branches. Anatomical and physiological features indicate that LFs have an advantage in varied light conditions, providing amounts of photosynthetic products to support the sexual reproduction, while LSs adapt to low light environments. Our findings provide evidence that heteroblasty facilitates F. pumila to utilize varying light environments, likely associated with its growth form as a climbing plant. This strategy allows the plant to allocate resources more effectively and optimize its overall fitness.

Ecotype effects on photosynthesis performance using A/PFFD among Pinus nigra Arn.

This study aimed to provide insights on intraspecific variability of photosynthesis performance of 19 provenances of black pine planted in a common garden. The experiment was conducted in an experimental trial located at Souiniet (the southern limit of its range) Photosynthetic capacity char­acterized by light-saturated net photosynthetic rates, associated light compensation points and apparent quantum yield was monitored by measuring the response of leaf gas exchange to light levels. Amax was the highest in provenances Puget Theniers (nigra ssp), Saint-Guilhem (salzmanni ssp), Marghese and les barres (laricio ssp). The lowest value was recorded in Olette of the subspecies salzmanni. Needles from two provenances Crimea (pallasiana ssp) and Les Barres (ssp laricio) revealed the highest apparent quantum yield (ɸ), followed by Brougatlès Ales (salzmanni ssp), Trenta Coste (ssp laricio), Les barres and Puget Theniers (nigra ssp). The lowest apparent quantum Yield was recorded in Laricio subspecies (Cosenza; Les barres and Bois frerot). The highest value of dark respiration (Rd) was shown in provenance Les barres (laricio ssp), while Grancia and Tavola of the laricio subspecies reported the lowest one. Provenances Tavola (laricio ssp) and Puget Theniers (nigra ssp) exhibited the highest LCP. The provenance Crimée (pallasiana ssp) and Aspromonto (laricio ssp) recorded the lowest values. The maximum values of photosynthesis are positively correlated with the total chlorophyll contents and Leaf Mass area. Our study illustrates that Photosynthesis performance showed a difference between 19 provenances of black pine; it seems that black pine photosynthetic performance is eco-typical independent.

Straw Mulching Combined with Phosphorus Fertilizer Increases Fertile Florets of Wheat by Enhancing Leaf Photosynthesis and Assimilate Utilization

Lack of soil moisture and phosphorus deficiency limits wheat grain yield in dryland areas. However, the moisture-conserving effect of straw mulching combined with phosphor fertilization on fertile florets per spike (FFS) and grain yield remains unclear. During the 2020–2021 and 2021–2022 growing seasons, we investigated the combined effects of straw mulching (0 and 8000 kg ha−1) and phosphorus fertilization (0, 75, and 120 kg P2O5 ha−1) on spike development, assimilates’ availability, and the photosynthetic properties of flag leaves by conducting a field experiment. Compared with no straw mulch control, straw mulching increased fertile spike, grain number per spike (15.6%), and grain yield (22.6%), and grain number per spike was the most important contribution to increasing wheat grain yield (46%). An increase in grain number per spike is associated with FFS. Compared with no straw mulch control, straw mulching increased FFS by 19.5%, and it increased with increasing phosphorus fertilization levels. Moreover, straw mulching combined with phosphorus fertilization promoted the light compensation point (LCP), light saturation point (LSP), net photosynthetic rate (Pn), Chl b, and the maximal photochemical efficiency of photosystem II (Fv/Fm) of flag leaves to produce carbohydrates. Our study has shown that the primary factor for the divergence in FFS under straw mulching and phosphorus application was the efficiency of assimilate utilization in the spike, which ultimately led to increased grain number per spike and grain yield.

Assessing Water Relations and Carbon Dynamics of Pinus taeda Branches Undergoing Shade-Induced Mortality

Light acts as a complex signal, influencing various plant physiological, phenological and morphogenetic traits. Although previous studies have explored the effects of varying light levels on branch growth and survival, the underlying mechanisms of branch mortality under shade conditions remain poorly understood, hindering our understanding of canopy dynamics. In this study, contrasting shade conditions were imposed on Pinus taeda branches, and the changes in their water relations and carbon dynamics were evaluated. Monthly measurements of the photosynthetic light–response curve (LRC), sap flow and water potential of the branches were conducted. Furthermore, the conditions that led to the deaths of lower branches were investigated, and principal component analysis (PCA) was used to classify branches according to their mortality status. Significant shade treatment effects were observed for all photosynthetic parameters. The assimilation at light saturation (Amax), dark respiration rate (Rd), apparent quantum yield (AQY), light compensation point (LCP) and light saturation point (LSP) all decreased from full light to deepest shade, whereas the opposite was the case for the convexity term (θ). All water relations traits also decreased from full light to deepest shade; however, although significant shade effect was observed in stomatal conductance (gs) and sap flow, the differences in the pre-dawn (Ψpre-dawn) and mid-day (Ψmid-day) water potentials among treatments were not statistically significant. The PCA classification results showed that it could be used as a reliable method to screen for branch mortality as early as four months before mortality becomes evident. Our results shed more light on branch physiology and mortality under shade and have the potential to help improve the prediction of tree crown size, ultimately improving process-based forest growth models.

Application of improved CNN-based face detection technology in public administration

In public management, intelligent face recognition detection technology plays a very crucial role, which can greatly improve the efficiency of public management and reduce the workload of staff. To address the shortcomings of traditional face detection algorithms such as low detection efficiency and easy overfitting, a face detection model based on convolutional neural network (CNN) was proposed in this study, and the structure of CNN was optimized to enhance the accuracy and efficiency of the proposed face detection model. To solve the face detection errors caused by illumination differences, a light compensation strategy was proposed to pre-process the data; meanwhile, a Gaussian curvature filtering algorithm was used to enhance the face image and improve the subsequent detection accuracy. On this basis, a face detection model based on improved CNN was designed in this study. Experiments showed that the accuracy of the model reached 99.86% with high accuracy and efficiency, indicating that such method can improve the efficiency of public management and has good application prospects in access control and check-in systems.

Lanthanum vacancy induced luminescence enhancement of Mn4+-activated LaMg2/3Nb1/3O3: A thermally stable deep-red phosphor for purple perilla cultivation

Deep-red luminescent materials have kept booming due to the distinct photophysical properties and broad application prospect in plant cultivation. Here, a series of La1-xMg2/3Nb1/3O3-δ:Mn4+ deep-red phosphors with the emission range of 660–730 nm were developed and lanthanum vacancy was introduced into the matrix via decreasing lanthanum content. The defect induced structure variation of the samples were analyzed detailedly and high structural adjustability of this perovskite was confirmed via X ray diffraction and transmission electron microscopy. By creating lanthanum vacancy into the matrix both the emission intensity and thermal stability of the phosphors were greatly improved. The emission intensity of the optimized La0.6Mg2/3Nb1/3O3-δ:Mn4+ at 423 K was improved almost 16 times than the initial sample at 423 K and kept 83.6% of that at 298 K. Furthermore, deep-red LED device was fabricated by coating this deep-red phosphor onto the near ultraviolet chip and applied to the cultivation of purple perilla. The purple perilla with additional deep-red light compensation in the night grew faster than that without light compensation. This modification strategy investigated here opens a new insight to improve the luminescence property of the phosphors for solid state lighting.