Light Shade Research Articles

Recreating the Poetics of the Landscape of the Asya Novel by I. S. Turgenev in the Kyrgyz Language

The subject of this study is the Kyrgyz text of the translation of the Asya story and its original. The article uses the method of comparative analysis to compare the style of the Asya story by I. S. Turgenev with his translation into the Kyrgyz language, carried out by professional translator Murzabek Omurzakov, in the aspect of recreating landscape sketches. The purpose of the study is to identify stylistic deviations of the translation text from the original and evaluate the transformation of epithets and lexemes denoting natural phenomena. As a result of the study, it is determined that the artistic originality of the original is not adequately reflected in the translation, and deviations from the stylistic features of the original are identified. Frequent repetitions are indicated, which reduced the beauty and poetry of the original narrative. Also, as a result of the analysis, the attitude of the author of the translation is revealed, which led to the substitution of concepts and epithets; a number of verbs with the meaning of the attribute are weakened and are not reproduced. It was also possible to find out how to convey such aspects of the landscape in the Kyrgyz language as the reflection of light and color shades. The author of the translation, using equivalent lexemes, recreates with maximum accuracy the poetics of the landscape as an artistic form. The results obtained have practical significance in teaching Russian literature courses at schools and universities.

Optimizing textile dyeing and finishing for improved energy efficiency and sustainability in fleece knitted fabrics

In the industrial range, optimizing dyeing and finishing energy is important to control environmental pollution. In the Dyeing stage to finishing of textiles gas, electricity, steam, and water are used 260 m3/hour, 591 kWh, 1.2 pounds/hour, and 8.69 tons/hour respectively. If textile professionals do not match the desired shade and quality of fabrics with the use of minimal resources the energy cost will be multiple times higher. This study investigates the change in the shade of fleece knitted fabrics from the dyeing unload to the finish stage and assumes a dyeing recipe adjustment, focusing on the impact of optimized dyeing and finishing processes. Also, it focuses on qualitative changes in properties across various color variations. Identical dyeing recipes for light, medium, and dark shades of red, blue, and navy. Properties such as GSM (grams per square meter), width, color strength, shade (darker/lighter, red/green, blue/yellow), shrinkage, spirality, pilling, bursting strength, and color fastness were analyzed. Dyeing to post-finishing, an increase in color strength (K/S) values was observed, with examples including minimum increases from 2.9 to 3.18 for light red and maximum from 19.3 to 22.9 for dark navy shade. Darker shades (DL*) were observed after stenter 1st pass (among all variants, red: 1.2 % to 8.1 %, blue: 4.5 % to 6.7 %, navy: 1.6 % to 2 %), while lighter shades (DL*) were observed following sueding and napping (among all variants, red: 3.1 % to 19.7 %, blue: 11.8 % to 19.7 %, navy: 14.8 % to 27.6 %). Greenish (Da*) and yellowish (Db*) tones are prominent across all colors in the finishing stages. Besides, other properties shrinkage, spirality, pilling, bursting strength, and color fastness significantly changed. These findings offer valuable guidance for dyeing professionals aiming to achieve the desired adjustment of shades that match the quality standard and produce sustainable fleece fabrics. To compensate for the shade lightening that occurs during the finishing process, it is recommended to keep the fabric shade slightly darker (5.70 % to 23.10 %) at the dyeing stage.

A Womanist Study of Biliqisu Abubakar’s The Woman In Me

Northern Nigeria is today rife with spontaneous proliferous writing(s) by women authors, arising from the honed systemic patriarchy that relegates them to obedience, social and cultural subjugation, mental and emotional redundancy as well as denies them the space to productively be at par with their talents, giftings and abilities. This problem allows these teaming writers to question the social and cultural practices of the customs, beliefs, thoughts, and value systems of the society they represent, through their writings. It is on the premise of this background that this paper, deploys Womanism into Bilqisu Abubakar's The Woman in Me, to expose this systemic patriarchal hold on the women and shade light on the Womanist strand of feminism as Africa’s perception to what Feminism is to the West. In light of the foregoing, the paper finds that the phenomenon of culture and religion (in all forms), can negatively reconfigure the livelihood of not just the Northern Nigerian woman, but the African woman at large, as well as denying her femininity the space to thrive. The paper thus, concludes by showing that contemporary female writers in Northern Nigeria are emerging and re-evaluating the nexus between them and the erstwhile systemic patriarchy with subtlety, yet firmness to air out their voices to the balanced and safe spaces Womanism, Motherism, Black feminism, African feminism, and the like offer.

Determination of Color Preferences and Trend Colors in Hotel Room Interior Design

Buildings and environmental colors create differences in perception, both psychologically and physically. Colors interact with and have an impact on the form, space components, surroundings, materials textures, space lighting, the size of the surfaces, and the function and aesthetics of the space. Color preference varies according to personality traits, age and gender, habits and experiences, fashion, and style. The research is aimed to determine the color preferences and trends in hotel interior designs. Many hotel projects are designed and completed throughout the world every year. In this context, project designs awarded in international competitions were selected. To collect the data for the study, details of award-winning hotel interior designs available through competition websites are reviewed and the Adobe Color analytical tool is employed to characterize the color schemes reflected in the designs. Adobe Color is more successful than other tools in creating color schemes, such as the color wheel, gradient extraction, and theme extraction, suitable for all color selection methods, including colorful, bright, muted, deep, and dark options. As a result of this study, based on the designs awarded in 2022, it was determined that blue, red, and green colors were most frequently used, respectively. Furthermore, the data suggest that all colors were used in pastel tones, with light shades of blue mixed with different grays being used more frequently, while red and green generally were used in darker tones. The results were significantly correlated with the theoretical research and studies on user preferences.

EFS-Former: An Efficient Network for Fruit Tree Leaf Disease Segmentation and Severity Assessment

Fruit is a major source of vitamins, minerals, and dietary fiber in people’s daily lives. Leaf diseases caused by climate change and other factors have significantly reduced fruit production. Deep learning methods for segmenting leaf diseases can effectively mitigate this issue. However, challenges such as leaf folding, jaggedness, and light shading make edge feature extraction difficult, affecting segmentation accuracy. To address these problems, this paper proposes a method based on EFS-Former. The expanded local detail (ELD) module extends the model’s receptive field by expanding the convolution, better handling fine spots and effectively reducing information loss. H-attention reduces computational redundancy by superimposing multi-layer convolutions, significantly improving feature filtering. The parallel fusion architecture effectively utilizes the different feature extraction intervals of the convolutional neural network (CNN) and Transformer encoders, achieving comprehensive feature extraction and effectively fusing detailed and semantic information in the channel and spatial dimensions within the feature fusion module (FFM). Experiments show that, compared to DeepLabV3+, this method achieves 10.78%, 9.51%, 0.72%, and 8.00% higher scores for mean intersection over union (mIoU), mean pixel accuracy (mPA), accuracy (Acc), and F_score, respectively, while having 1.78 M fewer total parameters and 0.32 G lower floating point operations per second (FLOPS). Additionally, it effectively calculates the ratio of leaf area occupied by spots. This method is also effective in calculating the disease period by analyzing the ratio of leaf area occupied by diseased spots. The method’s overall performance is evaluated using mIoU, mPA, Acc, and F_score metrics, achieving 88.60%, 93.49%, 98.60%, and 95.90%, respectively. In summary, this study offers an efficient and accurate method for fruit tree leaf spot segmentation, providing a solid foundation for the precise analysis of fruit tree leaves and spots, and supporting smart agriculture for precision pesticide spraying.

A tutorial on the physics of light and image shading.

This paper provides an overview of the many different ways that light interacts with surfaces in the natural environment to provide useful information for visual perception. It begins with a discussion of how the concept of light has evolved over the course of human history. It then considers a wide variety of optical phenomena including Lambert's laws of illumination, the effects of microscopic surface structure on patterns of reflection, the bidirectional reflectance distribution function, the refraction of transmitted light, chromatic dispersion, thin film interference, sub-surface scattering, the Fresnel effects, indirect illumination from multiple reflections, caustics, and the structure of the light field. The primary goal of this discussion is to provide the necessary background information to help students and young researchers more easily understand the scientific literature on the perception of 3D shape and material properties from patterns of image shading.

Observations of phosphorus-bearing molecules in the interstellar medium

The chemistry of phosphorus (31P) in space is particularly significant due to the key role it plays in biochemistry on Earth. Utilising radio and infrared spectroscopic observations, several key phosphorus-containing molecules have been detected in interstellar clouds, circumstellar shells, and even extragalactic sources. Among these, phosphorus nitride (PN) was the first P-bearing molecule detected in space, and still is the species detected in the largest number of sources. Phosphorus oxide (PO) and phosphine (PH3) were also crucial species due to their role both in chemical networks and in forming biogenic compounds. The still limited high-angular resolution observations performed so far are shading light on the geometrical distribution of these molecules, which represent crucial insights on their formation processes. Observations have also highlighted the challenges and complexities associated with detecting and understanding phosphorus chemistry in space, owing to the low elemental abundance of P relative to other elements. This review article provides a state-of-art picture of the observational results obtained so far on phosphorus compounds in the interstellar medium. Special attention is given to star-forming regions, and to their implications for our understanding of prebiotic chemistry and the potential for life beyond Earth. Our knowledge of the dominant formation and destruction pathways of the most abundant species has improved, but critical questions remain open, among which: what is (are) the main phosphorus carrier(s) in space? Upcoming new facilities are expected to contribute significantly to this field, offering opportunities to both detect new phosphorus-bearing molecules and enlarge the number of sources in which the chemistry of P can be studied. The synergy between observations, theoretical models, laboratory experiments, and computational chemistry is mandatory to significantly progress in our comprehension of the chemistry of this important but poorly studied chemical element.

Milk Tea–Colored Perovskite Solar Cells Fabricated Through a Multilayer Film Design

This study presents the fabrication of perovskite thin-film solar cells (PTSCs) with adjustable colors, achieved through a multilayer film design. The multilayer film, comprising Au and indium-tin-oxide (ITO), functions as an adjusted color reflectance (ACR) multilayer film. When the ITO thickness is varied from 100 to 150 nm, the color of the PTSCs can be adjusted from lighter shades that resemble fresh milk tea to darker tones akin to caramel. The color changes that the ACR multilayer film induces correlate well with its reflectance response. Compared with traditional black-colored PTSCs, the milk tea–colored PTSCs maintain a power conversion efficiency of >12%. This achievement suggests the potential for fabricating PTSCs in various colors and patterns that are suitable for use in furnishings, accessories, and other applications.

Performance enhancement of reactive foam dyeing for cotton fabric through different foaming agents and stabilizers

Purpose In the textile dyeing industry, the foam dyeing has been recognized as a significantly sustainable alternative for the cotton fabrics. However, this efficient technology undergoes the many issues related to the foam generation, foam optimization and the required performance of the resultant fabrics. The purpose of this paper is to address these issues through the development and optimization of the novel reactive foam dyeing recipes for the cotton fabrics. Design/methodology/approach The foam dyeing recipes were generated and optimized using the different stabilizers, foaming agents and three primary colors of reactive dyes. The different recipes were applied onto the cotton fabric using laboratory scale foam coating machine. The performance of the foam coated and padded fabrics was evaluated using different criteria including the shade depth, rubbing fastness, air permeability, washing fastness, perspiration fastness, light fastness and tear strength. Then, a complex decision-making approach, namely, analytic hierarchy process (AHP), was applied for the ranking of the key recipes based on the main criteria. Findings The newly optimized foam dyeing recipes were found very competitive with the conventional pad dyeing process with respect to the shade-depth and the other performance properties. The optimization of foaming parameters and addition of stabilizers have advanced the foam dyeing process, which would accelerate the implementation of foam dyeing methods in the textile industry. Furthermore, significant water and energy savings would be achieved as compared to the conventional foam dyeing. AHP model offered a comprehensive and rational way to identify the most important recipes amongst the selected recipes. Originality/value In this research, novel foam dyeing recipes have been developed for the cotton fabrics through the optimization of the different stabilizers, foaming agents and the three primary colors of reactive dyes. Until now, the exiting literature has not reported the combination of these stabilizers with the different foaming agents and three primary reactive dyes for the improvement of sustainable foam cotton dyeing process.

Enhanced Real-Time Target Detection for Picking Robots Using Lightweight CenterNet in Complex Orchard Environments

The rapid development of artificial intelligence and remote sensing technologies is indispensable for modern agriculture. In orchard environments, challenges such as varying light conditions and shading complicate the tasks of intelligent picking robots. To enhance the recognition accuracy and efficiency of apple-picking robots, this study aimed to achieve high detection accuracy in complex orchard environments while reducing model computation and time consumption. This study utilized the CenterNet neural network as the detection framework, introducing gray-centered RGB color space vertical decomposition maps and employing grouped convolutions and depth-separable convolutions to design a lightweight feature extraction network, Light-Weight Net, comprising eight bottleneck structures. Based on the recognition results, the 3D coordinates of the picking point were determined within the camera coordinate system by using the transformation relationship between the image’s physical coordinate system and the camera coordinate system, along with depth map distance information of the depth map. Experimental results obtained using a testbed with an orchard-picking robot indicated that the proposed model achieved an average precision (AP) of 96.80% on the test set, with real-time performance of 18.91 frames per second (FPS) and a model size of only 17.56 MB. In addition, the root-mean-square error of positioning accuracy in the orchard test was 4.405 mm, satisfying the high-precision positioning requirements of the picking robot vision system in complex orchard environments.

The Application of IoT Technology and Deep Learning in Automated Intelligent Control Systems

In order to accurately monitor the environmental information of agricultural greenhouses, achieve remote automatic control, and improve crop yield, the author proposes an application method of Internet of Things technology in automatic intelligent control systems. This method utilizes IoT technologies such as WSN, Android, and cloud platforms to design an intelligent agricultural greenhouse monitoring system, taking sensors such as soil moisture, lighting, temperature and humidity as examples, and using shading, water spraying, fans, and fill lights as control devices. Design from aspects such as system architecture, perception control system, cloud database, and mobile terminal management system to achieve automatic monitoring of agricultural greenhouse environmental information.Experimental results show that: The data collected by the sensor is compared with the actual monitoring data of the instrument, taking temperature as an example, the errors are all within ±0.5◦C of multiple measurements. Conclusion: The system has the advantages of good scalability, convenient networking, and high cost performance, which makes up for the difficulties in wiring and inconvenient use of the traditional agricultural greenhouse monitoring system, and has high practical value.

Doctrinal, Educational and Behavioral Foundations for Dealing with Hypocrites in The Expression of Caution in Surat Al-Tawbah

In this research, the researcher dealt with the word caution in Surat Al-Tawbah in verse: 64, by studying it, which is repeated in the same verse at its beginning and end. The researcher shaded light on the doctrinal, educational and behavioral bases for this warning in this place, which reveals what is going on in the secrets of the hypocrites fearing that their matter will be exposed and what It is woven in their chests. and they are keen to conceal it, so the study was divided into several demands in which explaining the concept of research vocabulary in language and terminology, which are (belief, education, behavior, caution), and the sensory miracle of the Prophet - may God bless him and grant him peace - in the word “you warn” and its educational and behavioral impact, the doctrinal, educational and behavioral side in the manifestation of the attributes of hearing, sight and knowledge to God Almighty in the word “you warn”. In addition, the doctrinal, behavioral and educational aspects in a statement that mocking the Messenger of God and the believers is a mockery of God Almighty, and the educational and behavioral aspects in purifying the heart from hypocrisy in the word “you warn”. And the divine support and victory for the believers in the word “You warn” and the threat and the intimidation and their educational and behavioral effects in the word “You warn” and then the conclusion in which explained that this word in this place carries doctrinal, educational and behavioral warnings to the believers and lays the foundations for dealing with the category of hypocrites.

Polymodality of perception and its reflection in fiction text: Сognitive and semiotic perspectives

The issues related to the polymodality of perception and various forms of intermediality are widely discussed in linguistics whereas the aspect of their interrelation is seldom considered. This research is aimed at tracing the participation of various modes of perception in the process of interaction with the world, the reflection of this process in our consciousness and memory in the form of various images up to the manifestation of those images in the intermedial relations in fiction text. The study draws on cognitive semiotics, text linguistics, polymodality and intermediality. The theoretical analysis sugessts that the polymodality of perception results in the formation of synesthetic mental images represented in the phenomenon of intermediality. The empirical material of the research includes text fragments from the works by Virginia Woolf, James Joyce, Joyce Cary and Adam Thorpe containing samples of linguа-artistic and linguа-musical techniques of writing as forms of intermediality. The intermedial analysis of the empirical material shows how the polymodality of perception determines the specificity of the authors’ creative thinking represented in the choice of language means that activate musical and visual images in the readers’ minds. As a result, such fiction texts are constituted as related to a specific art whose forms and devices are used in it. The analysis has also revealed that in the process of verbal representation of musical or artistic images language exploits all forms of its semiotic signs: symbols (for naming colours, shades of light, sounds of music), indices (allusions to works of art or their authors) and icons (the use of forms and devices characteristic of other arts). The study confirms the productivity of exploring intermedial interaction in the cognitive and semiotic perspectives to demonstrate the relations between perception, conceptualization and the embodiment of the results in fiction text.

Interactive Effect of Fertilization and Biochar on the Growth of Juniperus scopulorum under Various Shading and Irrigation Conditions

The global demand for landscape trees has been amplified with the increasing anthropogenic activity. South Korea has also witnessed a surge in demand for landscape plants, among others, Juniperus scopulorum gaining popularity for its ecological, economic, adaptability, and management attributes. However, the optimum management practice for high-quality Juniperus seedling production in South Korea remains unknown. This research was conducted on the one-to-two-years-old two cultivars of J. scopulorum, namely Blue Angel and Blue Heaven seedlings, to investigate the combined impacts of varying fertilizer concentrations (0 ppm, 150 ppm, 300 ppm) and biochar content (0% and 20%) under contrasting shading intensities (0%, 35%, 55%) and irrigation levels (200 ml, 400 ml, 800 ml). The study revealed that biochar and fertilizer amendment significantly (p < 0.01 and p < 0.05) enhanced the height and root collar diameter growth in Blue Angel and Blue Heaven in light shade intensity (0–35%) and higher irrigation (400–800 ml) conditions. Similarly, seedlings planted in 20% biochar and 300 ppm fertilizer yielded higher foliar, stem, and root biomass in low shade and higher irrigation conditions. The amount of shade and irrigation and their interactions significantly affected the morphological growth of seedlings for both cultivars, causing positive interaction with soil amendment (biochar and fertilizer application). These findings suggest that efficient seedling production of J. scopulorum management should focus primarily on light shading and moderate irrigation under biochar and higher fertilizer application. The research contributes valuable insights toward optimizing management practices and reducing costs associated with J. scopulorum seedling production in the region. Keywords: biochar, fertilizer, irrigation, Juniperus scopulorum, shading

Colour Perception in Camper Van Interior Design Using Virtual Reality Technology

Virtual reality (VR) technology has been developing progressively and rapidly in the past decades. VR technology is used to create 3D models of rooms and spaces, which can be used to create more accurate and detailed designs. Colours used in interior design have the ability to create specific moods, create harmony, and change the perception of how large or small a space may look or feel. The purpose of this study is to explore the application of virtual reality technology in the interior design of a camper van considering the role of colour perception. We aim to determine the effect of colour on the interior design creating professional-looking 3D camper van layout. The results show that any non-professional in 3D design can design a functional and comfortable living space in the camper van using Vanspace 3D software. It was found that light colours and shades create the feeling of space, light, comfort and cosiness. When choosing colours for the interior design of a small limited space, as is the case with a camper van, it is advisable to combine warm earth colours, white and beige colours.

Encapsulation of Cu-modified SnO2 yolk-shell in V2O5-amalgamated wrinkled g-C3N4 lamella for boosting antibiotic photodegradation

The remarkable application of tin oxide in various domains is indebted to its photoelectronic merits. However, significant efforts to discover its photocatalytic potential were restricted through arduous challenges, which were the amelioration of light-harvesting and -utilizing. In fact, the uncommon light absorption energy has drawn veil over the brilliance of astounding oxidation potential, which is much more than that of TiO2. Herein, our attention was focused on the taking advantages of self-template structure for simultaneously enjoying the two sides of photoelectronic justification as well as the S-step system for eminent charge dissociation. In this regard, the optimized Cu-modified SnO2 yolk-shell ((5)YS-CuSnO) spheres were engineered through the copper modulation into glycerate-assisted metal-organic structure. As a result, the exceptional light-harvesting was achieved through desirable defects and oxygen vacancy resulted from Cu-doping, and also efficient light-utilization was obtained by the multi-scattering/reflection effect resulted from multi-shell configuration. After the effectual incorporation (40 wt⁒) of (5)YS-CuSnO was encapsulated into the V2O5-decorated wrinkled g-C3N4 lamella (VO–WCN), the dual S-step VO-WCN@(5)YS-CuSnO introduced unprecedented levofloxacin (LFC) decontamination performance, which was kinetically 5.2 and 30.2-times greater than of the (5)YS-CuSnO and bare SnO2 yolk-shell. The conspicuous fulfillment of nanocomposite was manifested in the LFC mineralization, pharmaceutical effluent treatment within 360 min, and successive cycling reactions. The fusion of the extraordinary architecture of YS-CuSnO with S-Step system not only initiates the facile and practical photocatalytic exploitation, but shade light on some undeveloped side of tin oxide.

Investigating and Improving Pedestrian Safety in an Urban Environment of a Low- or Middle-Income Country: A Case Study of Yaoundé, Cameroon

In Yaoundé, Cameroon, where walking dominates transport modes, pedestrian safety remains an issue as pedestrians account for a fair share of road traffic casualties, partly due to the lack of walking policies and pedestrian facilities safety data, hindering targeted intervention. This study used a pedestrian safety index (PSI) and the Global Walkability Index (GWI) to investigate 12 road segments frequented by diverse pedestrian groups. Indexes were graded from E—lowest to A—highest and analyzed using description and rank correlation. Main safety issues included lack of adequate and accessible sidewalks, bollards, pedestrian crossings, signage, shade, and street lighting. Only one segment (R7) achieved grade C, while the remainder scored D or E, indicating poor pedestrian safety conditions and an unpleasant walking experience. The correlation coefficient (0.69) between the PSI and GWI at a 99% significance level validated the safety assessment, providing confidence in the results. A seven-year (2024–2030) safety strategy is proposed to improve all roads to grade B. This strategy contains several interventions, including engineering improvement, which have been proven effective. This study offers evidence for city officials to improve pedestrian safety and informs walking policies and the implementation of upcoming projects. Future research should quantify the recommendations’ benefits and validate indexes with crash or conflict data.

A high throughput array microhabitat platform reveals how light and nitrogen colimit the growth of algal cells

A mechanistic understanding of algal growth is essential for maintaining a sustainable environment in an era of climate change and population expansion. It is known that algal growth is tightly controlled by complex interactive physical and chemical conditions. Many mathematical models have been proposed to describe the relation of algal growth and environmental parameters, but experimental verification has been difficult due to the lack of tools to measure cell growth under precise physical and chemical conditions. As such, current models depend on the specific testing systems, and the fitted growth kinetic constants vary widely for the same organisms in the existing literature. Here, we present a microfluidic platform where both light intensity and nutrient gradients can be well controlled for algal cell growth studies. In particular, light shading is avoided, a common problem in macroscale assays. Our results revealed that light and nitrogen colimit the growth of algal cells, with each contributing a Monod growth kinetic term in a multiplicative model. We argue that the microfluidic platform can lead towards a general culture system independent algal growth model with systematic screening of many environmental parameters. Our work advances technology for algal cell growth studies and provides essential information for future bioreactor designs and ecological predictions.

Fusion of Mask RCNN and multi-augmentation for rice recognition

In the real world, the appearance of similar rice varieties depends on various factors such as resolution, angle, lighting conditions, and perspective. Additionally, complex environmental factors and characteristics of each rice type, such as enhanced light intensity, cross-polarization, and shading, rice background color, and image similarity, play a role. This indicates that the data augmentation process may enhance the accuracy of crop identification, particularly in the context of self-supervised machine learning. The aim of this research is to develop a precise rice segmentation method based on the improved Mask R-CNN (Region-based Convolutional Neural Network) with multitask data augmentation. The Mask R-CNN model is enhanced by incorporating multitask input to improve feature extraction for rice. Experimental results demonstrate that the improved Mask R-CNN model can accurately segment various rice types under different conditions, such as different background colors and varying sizes of rice grains. The achieved precision, recall, F1 score, and segmentation mean Average Precision (mAP) are 95.5%, 96.3%, 95.9%, and 0.924, respectively. The average runtime on the test set is 0.35 seconds per image. Our method outperforms two comparative approaches, showcasing its ability to accurately segment rice in the market deployment phase with near real-time performance. This study establishes the foundation for the accurate detection of valuable agricultural products.

Control of overgrowth of Potamogeton crispus in shallow lakes by light shading and artificial introductions

Potamogeton crispus is a common submersed aquatic plant in shallow lakes in China, and its overgrowth and rapid decomposing have become an important environmental problem affecting the water quality of lakes every summer. Introducing other submersed plants to substitute Potamogeton crispus can improve the structure of the aquatic plant community and to reduce the growth of Potamogeton crispus to some degree, but the effect is poor and short-lived. Considering the fact that Potamogeton crispus is sensitive to changes in light intensity, the two methods of shading the water surface and introduction of other submerged plants were used synergistically. In a large simulated experimental pool, light intensity was reduced by placing black polyethylene floating spheres on the water surface and planting three species of submerged plants, namely, Vallisneria natans, Hydrilla verticillata and Potamogeton wrightii. Changes in the physico-chemical properties of the experimental pool water and the physiological and biochemical characteristics (morphology, chlorophyll, biomass, antioxidant enzymes and malondialdehyde) of the submerged plants during the period of 0–40 d were analyzed. The results showed that: (1) After the light intensity was reduced by 85%, Potamogeton crispus seedlings showed a significant decrease in biomass and chlorophyll content and died in large numbers within 20–30 days. (2) Catalase is the main tool for Potamogeton crispus to cope with low light stress. The activities of various antioxidant enzymes and the malondialdehyde content of Potamogeton crispus showed a decreasing trend under shade conditions, but the catalase activity increased dramatically. (3) Vallisneria natans is more tolerant of low light conditions than the other two submersed plant species. Therefore, we tried to reduce the biomass of Potamogeton crispus by combing introduction of other submersed plants and shading treatment. (4) The water quality objectives remained stable over the period of the trial, indicating that short-term shading does not have a negative impact on the quality of the water quality.