Strong Light Conditions Research Articles

Enclosing gases by gas circulation to establish photosynthetic O2-supported algal-bacterial granular system in pseudo-closed sequencing batch reactors for greenhouse gas emission mitigation

Photosynthetic O2-supported algal-bacterial aerobic granular sludge (AGS) presents great potential in carbon emission mitigation and operation cost saving in wastewater treatment processes. This study used gas circulation to enclose the photosynthetic O2 and the emitted CO2 for the development of photosynthetic O2-supported algal-bacterial AGS in a pseudo-closed sequencing batch reactors (SBR), targeting greenhouse gas emission mitigation (including CO2, N2O and CH4). Results showed that photosynthetic O2-supported AGS with abundant Cyanobacteria were achieved in this pseudo-closed SBR under strong light conditions. Although gas circulation enclosed acidic CO2, excessive Chlorophyll-a (Chl-a) in biomass still led to the increase of pH, followed by the occurrence of CO2 limitation and the loss of functional strains and extracellular polymeric substances, eventually collapsing granular structure. Interestingly, gas circulation can reduce GHG emissions due to prolonged contact time between gases and microorganisms. Chl-a contents showed an inversely proportional relationship with CO2 emission factors (0.04–0.61 kg-CO2/kg-COD), but over-high algae in biomass may induce more N2O emissions (0.45 % to 5.3 %) by affecting nitrification and denitrification processes. Compared to CO2 and N2O, the emission of CH4 was negligible. It was estimated that zero non-CO2 GHG emissions could be achieved when stable granules containing Chl-a content of > 5.8 mg/g-MLVSS. This study proposed that achieving low-carbon photosynthetic O2-supported algal-bacterial AGS requires minimizing the adverse impact of existing algae on denitrification and nitrification.

GS‐Octree: Octree‐based 3D Gaussian Splatting for Robust Object‐level 3D Reconstruction Under Strong Lighting

AbstractThe 3D Gaussian Splatting technique has significantly advanced the construction of radiance fields from multi‐view images, enabling real‐time rendering. While point‐based rasterization effectively reduces computational demands for rendering, it often struggles to accurately reconstruct the geometry of the target object, especially under strong lighting conditions. Strong lighting can cause significant color variations on the object's surface when viewed from different directions, complicating the reconstruction process. To address this challenge, we introduce an approach that combines octree‐based implicit surface representations with Gaussian Splatting. Initially, it reconstructs a signed distance field (SDF) and a radiance field through volume rendering, encoding them in a low‐resolution octree. This initial SDF represents the coarse geometry of the target object. Subsequently, it introduces 3D Gaussians as additional degrees of freedom, which are guided by the initial SDF. In the third stage, the optimized Gaussians enhance the accuracy of the SDF, enabling the recovery of finer geometric details compared to the initial SDF. Finally, the refined SDF is used to further optimize the 3D Gaussians via splatting, eliminating those that contribute little to the visual appearance. Experimental results show that our method, which leverages the distribution of 3D Gaussians with SDFs, reconstructs more accurate geometry, particularly in images with specular highlights caused by strong lighting. The source code can be downloaded from https://github.com/LaoChui999/GS-Octree.

Nghiên cứu đặc điểm hình thái, giải phẫu của loài Điên điển (Sesbania sesban (L.) Merr.) ở huyện Tân Hưng, tỉnh Long An

Fabaceae is the second largest flowering plant family (after the Asteraceae) with approximately 17,500 - 18,000 species belonging to 786 genera primarily distributed in tropical regions. In Vietnam, over 450 species from 90 genera have been reported, showcasing a rich diversity in habitat and distribution. Many species in this family are valuable for their timber such as Rosewood (Dalbergia cochinchinensis Pierre), and Sua wood (Dalbergia tonkinensis Prain); they also provide medicinal ingredients and food sources like Mung beans (Vigna radiata (L.) R.Wilczek) and Black gram (Vigna mungo (L.) Hepper). This research has been conducted to identify the morphological and anatomical characteristics of Sesbania sesban (L.) Merr., a species found in Tan Hung district, Long An province. Fresh samples of the species were collected and analyzed, describing the morphological features and anatomy of the reproductive and nutrient organs. The study revealed that the stems and leaves of S. sesban exhibit adaptations to strong light conditions, with stomata mainly concentrated on the lower leaf surface, stem hairs that aid in light reflection and moisture retention, and root nodules containing Rhizobium bacteria for nitrogen fixation. The anatomical structure of the nutrient organs showed strong development of pith and wood rings, indicating the adaptation of S. sesban to windy environments near river banks and canals.

Ultra-low-defect homoepitaxial micro-LEDs with enhanced efficiency and monochromaticity for high-PPI AR/MR displays

The issue of brightness in strong ambient light conditions is one of the critical obstacles restricting the application of augmented reality (AR) and mixed reality (MR). Gallium nitride (GaN)-based micro-LEDs, renowned for their exceptional brightness and stability, are considered the foremost contenders for AR applications. Nevertheless, conventional heteroepitaxial growth micro-LED devices confront formidable challenges, including substantial wavelength shifts and efficiency droop. In this paper, we firstly demonstrated the high-quality homoepitaxial GaN-on-GaN micro-LEDs micro-display, and thoroughly analyzed the possible benefits for free-standing GaN substrate from the material-level characterization to device optoelectronic properties and micro-display application compared with sapphire substrate. The GaN-on-GaN structure exhibits a superior crystal quality with ultra-low threading dislocation densities (TDDs) of ~ 105 cm−2, which is three orders of magnitude lower than that of GaN-on-Sapphire. Through an in-depth size-dependent optoelectronic analysis of blue/green emission GaN-on-GaN/ Sapphire micro-LEDs from 100 × 100 shrink to 3 × 3 μm2, real that a lower forward voltage and series resistance, a consistent emission wavelength (1.21 nm for blue and 4.79 nm for green @ 500 A/cm2), coupled with a notable reduction in efficiency droop ratios (15.6% for blue and 28.5% for green @ 500 A/cm2) and expanded color gamut (103.57% over Rec. 2020) within GaN-on-GaN 10 μm micro-LEDs. Last but not least, the GaN-on-GaN micro-display with 3000 pixels per inch (PPI) showcased enhanced display uniformity and higher luminance in comparison to its GaN-on-Sapphire counterpart, demonstrating significant potentials for high-brightness AR/MR applications under strong ambient light.

Synergistic Antioxidant Effects of Cysteine Derivative and Sm-Cluster for Food Applications.

The incorporation of antioxidants in food products is essential to prevent or delay deterioration, thereby addressing food spoilage. Thiol compounds, recognized for their natural antioxidant properties, are widely used in various foods; however, their antioxidant capacity is often limited. This study investigates the potential enhancement of thiol antioxidant capacity through the addition of a soluble, low-toxic inorganic Sm-cluster. Our findings demonstrate that the Sm-cluster significantly bolsters the antioxidant efficacy of thiol compounds. We explored, for the first time, the in vitro antioxidant activities of an Sm-oxo/hydroxy cluster combined with a cysteine derivative for potential food applications. The composition exhibited a robust inhibition of aromatic aldehyde flavor compound oxidation and displayed strong, dose-dependent DPPH (2,2-diphenyl-1-picrylhydrazine) radical scavenging activity. Notably, the antioxidant activity of the Sm-cluster/cysteine derivative was further enhanced under strong visible light conditions, which typically increased the likelihood of oxidation. These results suggest that the combination of inorganic cluster and thiol compounds presents a promising natural alternative to traditional antioxidants in the food industry.

Eye-tracking as a tool for researching user behavior

This article discusses eye-tracking technology, one of the critical technologies in analyzing user behavior when interacting with computer systems, and has a wide range of practical applications. The current capabilities and limitations of existing methods and equipment for eye tracking were reviewed and analyzed, and problems and promising areas for further research were identified. The central hardware systems were studied, such as desktop trackers, mobile glasses for eye-tracking, systems for immersive environments, and systems based on embedded cameras. This research also includes analyzing and classifying eye localization methods: eye shape-based, feature-based, and appearance-based. Also were investigated modern gaze-tracking methods, which are crucial to analyzing eye movement and determining the user's point of view. Feature-based methods provide accuracy but have limitations in strong lighting conditions. Model-based methods require high image resolution and calibration to measure gaze direction using facial characteristics. Cross-ratio-based methods do not require calibration but require additional lighting. Appearance-based methods are effective with low-quality images but have limitations concerning head position. The study indicates significant potential for improving gaze-tracking technologies to enhance user interfaces and increase accessibility. It emphasizes the need to develop adaptive methods that function in different environmental conditions and hardware limitations.

Pose estimation algorithm based on point pair features using PointNet + +

This study proposes an innovative deep learning algorithm for pose estimation based on point clouds, aimed at addressing the challenges of pose estimation for objects affected by the environment. Previous research on using deep learning for pose estimation has primarily been conducted using RGB-D data. This paper introduces an algorithm that utilizes point cloud data for deep learning-based pose computation. The algorithm builds upon previous work by integrating PointNet + + technology and the classical Point Pair Features algorithm, achieving accurate pose estimation for objects across different scene scales. Additionally, an adaptive parameter-density clustering method suitable for point clouds is introduced, effectively segmenting clusters in varying point cloud density environments. This resolves the complex issue of parameter determination for density clustering in different point cloud environments and enhances the robustness of clustering. Furthermore, the LineMod dataset is transformed into a point cloud dataset, and experiments are conducted on the transformed dataset to achieve promising results with our algorithm. Finally, experiments under both strong and weak lighting conditions demonstrate the algorithm's robustness.

Increased secretion of bacterial pyomelanin caused by light accelerates corrosion of low alloy steel

Microorganisms in the waterline zone can secrete pigments to avoid damage caused by ultraviolet radiation, some of which have corrosive effects. In this work, we found that the secretion of pyomelanin by P3 strain of Pseudoalteromonas lipolytica significantly increases under strong lighting conditions, accelerating the corrosion of the material. Molecular mechanisms indicate that strong light, as a stressful environmental factor, enhances the expression of melanin secretion-related genes to prevent bacteria from being damaged by ultraviolet radiation. Therefore, this work proposes a new corrosion mechanism in the waterline zone, pigment-producing microorganisms are also involved in the waterline corrosion process.

Effects of light on the quality of honeysuckle during storage based on physico–chemical indicators and chemical composition

Honeysuckle, as a medicinal and edible substance, has been widely used for thousands of years. However, its quality is easy to change during storage by strong light, high temperature, high humidity and other inappropriate conditions. In this study, taking light as an example, the quality changes of honeysuckle during storage were explored by simulated accelerated test. The results showed that after 18 days of storage under light (6000 ± 10 Lx), the color changed from green-white to yellow-white, and the color parameter showed that a* value increased from 0.522 to 4.061, and L* value increased from 68.51 to 75.05. The contents of chlorophyll a, chlorophyll b, and carotenoid decreased by 90%, 78.67, and 75.69%, respectively. Total phenol content decreased from 18.200 to 13.087 GAE mg·g−1, although total flavonoid and antioxidant activities fluctuated without significant difference. Except quercetin, chlorogenic acid and other nine bio-active compounds contents fluctuated and increased, resulting in higher contents after storage than before storage, which indicated that the honeysuckle still had good utilization value after discoloration. Combined with metabolomics technology, 22 different metabolites related to these changes were screened and identified, such as pheophorbide a, astilbin, and succinic acid. KEGG enrichment analysis showed that the oxidative decomposition of phenolic compounds and pigment components such as chlorophylls and carotenoid caused the chlorosis of honeysuckle. In summary, although the light caused the chlorosis of honeysuckle, it didn’t affect the utilization value. Meanwhile, this also systematically explains why the Chinese pharmacopoeia describes the character of honeysuckle as “green-white or yellow-white”.

Improved capacity for the repair of photosystem II via reinforcement of the translational and antioxidation systems in Synechocystis sp. PCC 6803.

In the cyanobacterium Synechocystis sp. PCC 6803, translation factor EF-Tu is inactivated by reactive oxygen species (ROS) via oxidation of Cys82 and the oxidation of EF-Tu enhances the inhibition of the repair of photosystem II (PSII) by suppressing protein synthesis. In our present study, we generated transformants of Synechocystis that overexpressed a mutated form of EF-Tu, designated EF-Tu (C82S), in which Cys82 had been replaced by a Ser residue, and ROS-scavenging enzymes individually or together. Expression of EF-Tu (C82S) alone in Synechocystis enhanced the repair of PSII under strong light, with the resultant mitigation of PSII photoinhibition, but it stimulated the production of ROS. However, overexpression of superoxide dismutase and catalase, together with the expression of EF-Tu (C82S), lowered intracellular levels of ROS and enhanced the repair of PSII more significantly under strong light, via facilitation of the synthesis de novo of the D1 protein. By contrast, the activity of photosystem I was hardly affected in wild-type cells and in all the lines of transformed cells under the same strong-light conditions. Furthermore, transformed cells that overexpressed EF-Tu (C82S), superoxide dismutase, and catalase were able to survive longer under stronger light than wild-type cells. Thus, the reinforced capacity for both protein synthesis and ROS scavenging allowed both photosynthesis and cell proliferation to tolerate strong light.

Time-resolved study on signaling pathway of photoactivated adenylate cyclase and its nonlinear optical response

Photoactivated adenylate cyclases (PACs) are multidomain BLUF proteins that regulate the cellular levels of cAMP in a light-dependent manner. The signaling route and dynamics of PAC from Oscillatoria acuminata (OaPAC), which consists of a light sensor BLUF domain, an adenylate cyclase domain, and a connector helix (α3-helix), were studied by detecting conformational changes in the protein moiety. Although circular dichroism and small-angle X-ray scattering measurements did not show significant changes upon light illumination, the transient grating method successfully detected light-induced changes in the diffusion coefficient (diffusion-sensitive conformational change (DSCC)) of full-length OaPAC and the BLUF domain with the α3-helix. DSCC of full-length OaPAC was observed only when both protomers in a dimer were photoconverted. This light intensity dependence suggests that OaPAC is a cyclase with a nonlinear light intensity response. The enzymatic activity indeed nonlinearly depends on light intensity, that is, OaPAC is activated under strong light conditions. It was also found that both DSCC and enzymatic activity were suppressed by a mutation in the W90 residue, indicating the importance of the highly conserved Trp in many BLUF domains for the function. Based on these findings, a reaction scheme was proposed together with the reaction dynamics.

Fusion of RetinaFace and improved FaceNet for individual cow identification in natural scenes

Cows’ posture change is the fatal influencing factor for accurate identification of individual cows. To achieve non-contact, high-precision detection and identification of individual cows in farm environment, a cow individual identification method by the fusion of RetinaFace and improved FaceNet was proposed. MobileNet-enhanced RetinaFace was applied to ameliorate the impact of output channel quantity and convolution kernel dynamics using depthwise convolution combined with pointwise convolution. Regression predictions of bovine facial features and keypoints were generated under varying distances, scales and sizes. FaceNet's core feature network was enhanced through MobileNet integration, and the loss function was jointly optimized with Cross Entropy Loss and Triplet Loss to achieve a quicker and more stable convergence curve. The distances between the generated embedding vectors of cow facial features were corresponding to the similarity between cow faces, enabling accurate matching. RetinaFace exhibited detection false negative rates of 2.67%, 0.66%, 2.67%, and 3.33% under conditions of occlusion, no occlusion, low light, and bright light for cow facial detection. For cow facial pattern detection, the false negative rates for black and white patterns, pure black and pure white were 1.33%, 6.00% and 8.00%, respectively. Regarding cow facial posture changes, the false negative rates for face upward, bowing down, profile, and normal posture were 1.33%, 1.33%, 4.00% and 0.66%, respectively. Improved FaceNet model achieved an accuray of 99.50% on training set and 83.60% on test set. In comparison to YOLOX, the recognition model presented in this research demonstrated increased accuracy in cow facial detection under occlusion, no occlusion and strong lighting conditions by 2.67%, 0.40%, and 0.40%, respectively. Moreover, the accuracy for patterns with pure black and pure white tones surpassed that of YOLOX by 1.06% and 5.71%, correspondingly. Additionally, the accuracy rates for face upward, bowing down, profile and normal posture were higher than YOLOX by 2.00%, 3.34%, 2.66% and 0.40%, respectively. The proposed model demonstrates the proficiency in accurately identifying individual cows in natural scenes.

Improved method for positioning crane grab boom corner points using Hough transform and k‐means clustering

AbstractIn the process of automatic grabbing of bridge segment beams, it is crucial to accurately locate and align the corner points of the crane's boom with the beam's lifting holes. This requires the utilization of image processing techniques to precisely detect and locate the corner points of the crane's boom. Existing feature matching methods face challenges such as low detection accuracy and unsuitability for this specific scenario. This article proposes a novel approach for corner point localization by using the intersection points of lines, facilitating the matching of feature points between left and right images. The method consists of three steps: first, a grayscale difference map is constructed by utilizing the R and G channels of the RGB color space. This enhances the bimodal characteristics of the grayscale histograms between the foreground and background, which facilitates the subsequent binarization process. Additionally, opening and closing operations are employed to remove small artifacts from the Canny edge detection results, effectively reducing noise. Second, an adaptive thresholding method based on the mean and variance of Hough transform voting scores is proposed. This method filters out interference lines from the clustering results by selecting appropriate voting scores. Furthermore, an improved centroid calculation method is introduced, which utilizes weighted formulas based on different proportions of voting scores. These weighted formulas replace the original clustering centroids as the basis for line fitting. Finally, the corner coordinates of the crane's boom are computed based on the line fitting results, and the recognition accuracy is compared under different lighting conditions. Experimental results demonstrate that the proposed algorithm exhibits smaller detection errors and higher robustness compared to other corner detection algorithms, particularly when there are numerous interference edge points in the edge detection results. The computed corner coordinates achieve pixel‐level accuracy. The algorithm performs optimally under strong supplementary lighting conditions, with an average detection error percentage of 97.1% within 0–2 pixels and a recognition accuracy of 98.6%. The recognition success rates under different lighting conditions are all above 92.9%. This method is superior to traditional corner detection methods, meets the requirements for automatic grabbing of the boom, and holds practical engineering value. It provides a basis for addressing the accuracy and robustness challenges of crane algorithms influenced by multiple environmental factors.

Application of optical switching technology inalunar laser ranging system based on a superconducting detector.

The TianQin laser ranging station has successfully obtained the effective echo signals of the all five corner-cube reflectors on the lunar surface by using a 1064nm Nd:YAG laser with 100Hz repetition frequency and a 2×2 array of superconducting nanowire single-photon detectors (SNSPDs). The application of the SNSPD in the lunar laser ranging system (LLRS) has demonstrated its detection ability, but it loses its superconducting state and cannot work under strong stray light conditions. In this paper, a high-speed optical switch experimental device based on 100Hz is developed to solve the application problem of the SNSPD in the LLRS, and its main technical parameters are tested. The results show that the maximum running distance of the switch is 200µm; the switching time is better than 2ms; and the extinction ratio is better than 57dB. Moreover, the application of the high-speed optical switch experimental device in the lunar laser ranging system is designed, and the effective detection time between two laser pulses (10ms) is determined to be 6.1ms.

Analysis of Environmental Factors Affecting the Quality of Neopyropia yezoensis Cultivated in the Yellow Sea

To investigate the potential influences of nutrients and solar irradiance of the sea area on the laver industry, Neopyropia yezoensis samples and the corresponding surface water were collected at different sites in Haizhou Bay and the Jimo aquafarm, and the solar irradiance was recorded on-site. Then the cellular compositions and the nutrients of seawater were determined. A comparative experiment was also designed to investigate the effect of strong light on the cellular composition of N. yezoensis. Gray correlation analysis showed that the seawater nutrient levels and solar irradiance had a similar correlation degree of 0.6 to 0.8, which indicated similar effects on algal cellular composition. Compared with those samples collected from Haizhou Bay, the algae cultivated at the Jimo aquafarm had higher contents of total protein and hydrolyzable polysaccharides. In addition, the content of chlorophyll a was relatively lower and that of β-carotene higher in the early-stage samples. The results of the comparative experiment showed that the decrease in light intensity on algae promoted the synthesis of chlorophyll a and R-phycoerythrin. It is speculated that the nutrient deficiency in the seawater and the resulting high transparency of the water make the algae more exposed to strong light conditions. This may be the reason for the poor glossiness and hardness of the laver products made from the cultivated algae in the north Yellow Sea. Thus, it puts forward specific requirements for the modification of N. yezoensis cultivation techniques in the north Yellow Sea.

Environmental drivers of the leaf nitrogen and phosphorus stoichiometry characteristics of critically endangered Acer catalpifolium.

Acer catalpifolium is a perennial deciduous broad-leaved woody plant, listed in the second-class protection program in China mainly distributed on the northwest edge of Chengdu plain. However, extensive anthropogenic disturbances and pollutants emissions (such as SO2, NH3 and NOX) in this area have created a heterogeneous habitat for this species and its impacts have not been systematically studied. In this study, we investigated the leaf nitrogen (N) and phosphorus (P) content of A. catalpifolium in the natural distribution areas, and a series of simulation experiments (e.g., various water and light supply regimes, different acid and N deposition levels, reintroduction management) were conducted to analyze responses of N and P stoichiometric characteristics to environmental changes. The results showed that leaf nitrogen content (LNC) was 14.49 ~ 25.44 mg g-1, leaf phosphorus content (LPC) was 1.29~3.81 mg g-1 and the N/P ratio of the leaf (L-N/P) was 4.87~13.93. As per the simulation experiments, LNC of A. catalpifolium is found to be relatively high at strong light conditions (80% of full light), high N deposition (100 and 150kg N ha-1), low acidity rainwater, reintroduction to understory area or N fertilizer applications. A high level of LPC was found when applied with 80% of full light and moderate N deposition (100kg N ha-1). L-N/P was high under severe shade (8% of full light), severe N deposition (200kg N ha-1), and reintroduction to gap and undergrowth habitat; however, low L-N/P was observed at low acidity rainwater or P fertilizer application. The nutrient supply facilitates corresponding elements uptake, shade tends to induce P limitation and soil acidification shows N limitation. Our results provide theoretical guidance for field management and nutrient supply regimes for future protection, population rejuvenation of this species and provide guidelines for conservation and nutrient management strategies for the endangered species.

Design and Experimental Verification of the YOLOV5 Model Implanted with a Transformer Module for Target-Oriented Spraying in Cabbage Farming

Due to large line spacing and planting distances, the adoption of continuous and uniform pesticide spraying in vegetable farming can lead to pesticide waste, thus increasing cost and environmental pollution. In this paper, by applying deep learning and online identification methods, control technology for target-oriented spraying is studied with cabbages as the research object. To overcome motion blur and low average precision under strong light conditions during the operation of sprayers, an innovative YOLOV5 model implanted with a transformer module is utilized to achieve accurate online identification for cabbage fields under complex environments. Based on this concept, a new target-oriented spray system is built on an NVIDIA Jetson Xavier NX. Indoor test results show that the average precision is 96.14% and the image processing time is 51.07 ms. When motion blur occurs, the average precision for the target is 90.31%. Then, in a field experiment, when the light intensity is within the range of 3.76–12.34 wlx, the advance opening distance is less than 3.51 cm, the delay closing distance is less than 2.05 cm, and the average identification error for the cabbage diameter is less than 1.45 cm. The experimental results indicate that changes in light intensity have no significant impact on the identification effect. The average precision is 98.65%, and the savings rate reaches 54.04%. In general, the target-oriented spray system designed in this study achieves the expected experimental results and can provide technical support for field target spraying.

Deacylation of galactolipids decomposes photosystem II dimers to enhance degradation of damaged D1 protein.

Photosystem II (PSII) contains many lipid molecules that are essential for the function and maintenance of PSII. Under strong light conditions, PSII complexes are dynamically modified during the repair process; however, the molecular mechanism of the dynamic changes in the PSII structure is still unclear. In the present study, we investigated the role of a lipase in the repair of PSII in Synechocystis sp. PCC 6803. We identified a protein encoded by the sll1969 gene, previously named lipase A (lipA), in the Synechocystis sp. PCC 6803 genome as a candidate for the lipase involved in PSII repair. Recombinant protein expressed in Escherichia coli cells hydrolyzed fatty acids at the sn-1 position of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol as well as triacylglycerol esterified with stearic acids. PSII repair in a disrupted mutant of the lipA gene was suppressed by the slow degradation of damaged D1 protein under strong light. The level of the PSII dimer remained higher in lipA mutant cells than wild-type (WT) cells under strong light. LipA protein was associated with the PSII dimer in vivo, and recombinant LipA protein decomposed PSII dimers purified from WT cells to monomers by reducing MGDG content in the PSII complex. These results indicate that LipA reacts with PSII dimers, dissociates them into monomers by digesting MGDG, and enhances D1 degradation during PSII repair.

GUN4 Affects the Circadian Clock and Seedlings Adaptation to Changing Light Conditions.

The chloroplast is a key organelle for photosynthesis and perceiving environmental information. GENOME UNCOUPLED 4 (GUN4) has been shown to be required for the regulation of both chlorophyll synthesis, reactive oxygen species (ROS) homeostasis and plastid retrograde signaling. In this study, we found that growth of the gun4 mutant was significantly improved under medium strong light (200 μmol photons m−2s−1) compared to normal light (100 μmol photons m−2s−1), in marked contrast to wild-type (WT). Further analysis revealed that GUN4 interacts with SIGNAL RECOGNITION PARTICLE 54 KDA SUBUNIT (SRP43) and SRP54. RNA-seq analysis indicated that the expression of genes for light signaling and the circadian clock is altered in gun4 compared with (WT). qPCR analysis confirmed that the expression of the clock genes CLOCK-RELATED 1 (CCA1), LATE ELONGATION HYPOCOTYL (LHY), TIMING OF CAB EXPRESSION 1 (TOC1) and PSEUDO RESPONSE REGULATOR 7 (PRR7) is significantly changed in the gun4 and srp54 mutants under normal and medium strong light conditions. These results suggest that GUN4 may coordinate the adaptation of plants to changing light conditions by regulating the biological clock, although it is not clear whether the effect is direct or indirect.

Effects of Colored Shade Nets on Grapes and Leaves of Shine Muscat Grown under Greenhouse Conditions

Greenhouse grapes are often ripened at very high temperatures in the south of China, however, high temperatures are detrimental to their ripening. To moderate the strong light and high temperature conditions of the growing environment, different colored shade nets (green, blue, and black) were used to cover Shine Muscat (<i>Vitis labruscana</i> L.H. Bailey × <i>Vitis vinifera</i> L.) grapes during the ripening period. Differences in the cooling effect, fruit appearance and taste, and leaf photosynthetic performance were analyzed. It was found that the shading treatment exerted a significant cooling effect, and the light transmittance of blue and green shade nets was significantly higher than that of the black shade net. Shine Muscat grapes grown under shading treatment conditions were found to have more consistent total soluble solids content and coloring. Shading was found to affect the aroma of grapes, but the effect of the green shade net treatment was lower. The shading treatments slightly alleviated the senescence of old leaves. The shading treatments were found to improve the consistency of Shine Muscat grape berries. Of the shading treatments, the green and blue shade nets were found to be most effective and can be used to cultivate high quality grapes.