Colored Shade Nets Research Articles

Influence of Colored Shade Nets and Salinity on the Development of Roselle Plants

Adequate fertilizer concentration and use of shade nets can favor the development and yield of agricultural crops. The objective of this investigation was to evaluate the growth of roselle plants with nutrient solutions of different electrical conductivities (ECns) (1.0, 2.0, 3.0, 4.0 and 5.0 dS m−1) and under different colored shade nets (red, blue, black) compared with full sun. The experiments were conducted in a controlled greenhouse environment and in full sun in the Plant Production Department of ESALQ-USP, Piracicaba, SP, Brazil. The experiments were organized using a 4 × 5 randomized block design. The results of analysis of variance and regression showed a significant impact of EC and colored shade nets on plant height, stem diameter, number of leaves, number of flowers, fresh and dry mass of shoots and fresh and dry calyxes. The data were subjected to analysis of variance and regression, which showed a quadratic effect for the variables studied, with increasing values up to 3.0 dS m−1; after this value, there was a decrease. Increasing ECns up to approximately 3.0 dS m−1 promoted increments of 2.34% in plant height, 7.21% in number of leaves, 19.76% in shoot fresh mass and 12.38% in shoot dry mass.

Effects of Shading Nets Color on the Internal Environmental Conditions, Light Spectral Distribution, and Strawberry Growth and Yield in Greenhouses.

Greenhouses are used to create the appropriate environment for plant growth. Controlling the level of lighting using shading nets is one of the most commonly used methods for making suitable environmental modifications in greenhouses. The objective of this study was to examine the impact of three colored shading nets (green, black, and beige at shading rates of 50%) on inside air temperature, relative humidity, and spectral distribution of light in a greenhouse, as well as their effect on the growth and yield of strawberry plants. Data were collected during winter (December and January) and spring (March and April) months from shaded and unshaded blocks. The green net had the highest transmittance to solar radiation (τSR) during the two periods (38% and 35%, respectively) and the highest transmittance to photosynthetically active radiation (τPAR) of 34% during spring months, while the beige net had the highest τPAR of 27% during winter months. The black net had the smallest τPAR values during the two periods (22% and 29%, respectively). The lowest total light levels per season for solar radiation (SR) and photosynthetically active radiation (PAR) (746.8 and 293.7 MJ·m-2, respectively) were obtained under the black net, compared with (906.7 and 320.8 MJ·m-2, respectively) for the beige net, and (969.6 and 337.2 MJ·m-2, respectively) for the green net. The ratio of PAR to SR (PAR:SR) was 41% and 44% outside and inside the greenhouse for the control (without shade), respectively. The black net had the highest ratio of PAR:SR (39%) among the treatment nets. The green net transmitted more light in the blue-green region (400 to 570 nm) and transmitted the highest photon flux at 480 nm, while the beige net increased the infrared radiation flux from 730 nm and above and transmitted the highest photon flux at 604 nm. The study found that the green net increased the ratio of blue to red light (B/R), while the beige and green nets reduced the red to far-red light (R/FR) ratio. The photosynthetic rate, conductance to water, and transpiration were significantly higher for strawberries grown under the beige net. These results indicate that the beige net positively influenced leaf and stem characteristics, leading to improved strawberry yields. The best yields of strawberries were obtained under the beige net and the control group (no shade), surpassing the yields achieved under the black net by 26.3% and 21.4%, respectively.

Influence of Colored Shade Nets and Media Types on the Development of Rhoeo discolor (Boat Lily)

Study was carried out Department of Floriculture and Landscaping, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha during 2018-19. The experiment was designed to determine the optimal conditions for enhancing plant growth, focusing on the effects of different colored shade nets (green, white, red and black) with open light and various media mixture combinations (soil, coco peat, and FYM). Key growth parameters such as plant height, plant spread, leaf number, leaf area, chlorophyll content, and number of suckers were measured over a specified growth period. Results indicated that boat lily grown under red shade net and pots filled with soil, FYM and cocopeat media mixture in 1:1:1 (v/v) proportion performed best in all the characters. It has significantly enhanced plant height (22.11 cm), number of leaves per plant (15.89) and leaf area (110.42 cm2), plant spread in E-W direction (28.78 cm), plant spread in N-S direction (28.78 cm) and leaf thickness (1.32 mm).

Combined metabolome and transcriptome analyses reveal that growing under Red shade affects secondary metabolite content in Huangjinya green tea.

Shading treatments impact the tea (Camellia sinensis L.) quality. The sunlight sensitive varieties can be grown under shading nets for better growth and secondary metabolite content. Here, we studied the responses of a sunlight sensitive green tea variety "Huangjinya" by growing under colored shading nets (red, yellow, blue, and black (75% and 95%) shading rates) to find out the most suitable color of the shading net. Red shading was the most promising treatment as it positively affected the weight and length of 100 one-bud-three leaves and reduced the degree and rate of new shoots burn compared to control (natural sunlight). We then explored the comparative metabolomic changes in response to red shading by using UPLC-ESI-MS/MS system. The amino acids and derivatives, flavonoids, and alkaloids were downaccumulated whereas lipids, organic acids, and lignans were upaccumulated in Red shade grown tea samples. The red shading nets caused a decreased catechin, epicatechin, dopamine, and L-tyramine contents but increased caffeine content. We then employed transcriptome sequencing to find key changes in expressions of related genes and pathways. Notably, key genes associated with the phenylpropanoid and flavonoid biosynthesis pathways exhibited complex regulation. These expression changes suggested a potential trend of polymerization or condensation of simple molecules like catechin or pelargonidin into larger molecules like glucoside or proanthocyanidins. Here, Red shading net triggered higher expression of genes enriched in lipid biosynthesis and jasmonic acid biosynthesis, suggesting an interplay of fatty acids and JA in improving tea performance. These findings contribute to the metabolic responses of Huangjinya tea to red shading nets which might have implications for flavor and health benefits. Our data provide a foundation for further exploration and optimization of cultivation practices for this unique tea variety.

Production and quality of ornamental peppers cultivated under colored shade nets

The cultivation of ornamental peppers in places with high temperature and incidence of solar radiation limits the production and quality of plants and fruits. The colored shade nets were introduced and adopted, because they reduce the temperature and intensity of solar radiation, as well as, low cost and simple to handle. The aimed was to evaluate the production and quality of C. chinense and C. frutescens cultivated under colored shade nets. The experiment was developed in the Floriculture Sector of the Agronomy Department of the Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil from February to August 2021 in entirely randomized design. C. chinense and C. frutescens were cultivated under red, pearl and aluminet nets with 35% shading and without net. At 150 days, production variables were quantified. The red net reduced the maximum temperature by at 4.1ºC and the pearl and aluminet nets reduced the minimum temperature by 3ºC. The maximum and minimum relative humidity was increased by 2.6 and 8.5%, respectively, by the red net. The pearl net obtained the lowest percentage of solar radiation incidence. Plant height was greater in the red and pearl nets, and C. frutescens. The diameter and stem fresh matter did not differ statistically between treatments. Root length was greater in the red and aluminet nets. The longitudinal and transverse canopy ratio was higher in C. chinense cultivated under the aluminet net. The number of leaves and leaves fresh matter was higher in pearl and aluminet net, and in C. frutescens, but leaves dry matter was higher in C. chinense. The number of flower buds and flowers, and flower buds dry matter was higher in C. chinense. The root fresh matter and dry matter was greater in C. chinese. The use of colored shade nets during the cultivation period effectively reduced temperature and light intensity. The aluminet net in association with C. chinense are recommended considering the compactness of height, pot coverage, greater number, shape and arrangement of fruits.

Influence of Different Colored Shade Nets on Micro Environmental Parameters and Pest Incidence of Various Ornamental Plants

A field experiment was carried out at Floriculture and Landscaping Block, College of Horticulture, Anantharajupeta during 2022 and 2023. to study the Influence of different colored shade nets on microenvironmental parameters of various ornamental plants. The experiment consists of 25 treatments with three replications which were laid out in FRBD. The treatments were formed with two factors viz. Factor I (Colour shade nets, Green (C1), White (C2), Black (C3), Red nets (C4) and Open (C5) condition and Factor II plants (Pandanus veitchii (P1), Epipremnum aureum (P2), Sansevieria trifasciata (P3), Aglaonema commutatum var. Redgold (P4), Rhoeo spathacea (P5) were taken. The results shown that the maximum temperature was under black net (32.43, 34.10 0C in first and second year respectively), maximum RH was under black net (88.09, 83.11 % in first and second year respectively), lowest canopy temperature was under shade nets than open. Maximum light intensity (653.21, 669.4 lux in first and second year respectively), average PAR values were maximum under white net (718.05 µmol m-2 s-1) in both years. Mealy bug incidence was maximum under black net in both years during the period of study

Production of American lettuce cultivars under different colored shade nets

Shading nets are used to reduce the amount of radiant energy reaching crops. The objective of the work was to compare the influence of black and red shading nets on the production of nine American lettuce cultivars in the Autumn period under the conditions of the Central Department of Paraguay. The experiment was carried out in the Experimental Field of the Departmental Agronomic Center (CAD) in the Municipality of Julián Augusto Saldívar. The treatments consisted of the combination of two types of shading netting (red with 35% shade and black with 35% shade) and nine cultivars of American lettuce (Julia, Dora, Angelina, Tainá, Sun Valley, Betty, Lucy Brown, Mara, and Serena) totaling 18 treatments. The experiment consisted in a complete randomized block design, arranged in split blocks 2×9 (the color of shading netting was considered the main plot, and the lettuce cultivars as the secondary plot) with four repetitions. Each experimental unit consisted of four crop rows with seven plants. Plant diameter, plant height, head diameter and height, commercial number of leaves per plant, fresh mass, and commercial productivity were evaluated. The data were subjected to analysis of variance, and when differences were found, the means were compared by the Scott-Knott test at 5% probability. The results indicate that using the red netting with the Serena and Dora cultivars provides greater fresh mass and commercial production.

Differential performance of Dianella tasmanica and Pleomele reflexa under coloured shade nets

Cut greens are emerging as an important constituent of the floricultural industry as they add freshness and colour to floral designs. An experiment was conducted to evaluate the effect of different coloured shade nets (black, blue, green, red, white and no shade) at 50% shade intensity on growth and quality parameters of Dianella tasmanica and Pleomele reflexa. Both species significantly responded to the change in colour of shade nets. In D. tasmanica, maximum plant height (85.66 cm), stem diameter (8.63 mm) and leaf length (68.33 cm) were recorded under red shade net, while, plant spread (63.03 cm) and leaf breadth (4.06 cm) under black shade net, however, leaf thickness (0.57 cm) and vase life (24.33 days) under white shade net. In P. reflexa, maximum plant height (63.66 cm), stem diameter (9.76 mm), leaf length (17.50 cm), leaf thickness (0.93 cm) and SPAD index (60.10) were recorded under red shade net, whereas, plant spread (36.34 cm) and leaf breadth (3.00 cm) under black shade net, and vase life (25.66 days) under white shade net. Thus, red coloured shade nets could be preferred commercially for better performance of D. tasmanica and P. reflexa.

Colored Shading Nets Differentially Affect the Phytochemical Profile, Antioxidant Capacity, and Fruit Quality of Piquin Peppers (Capsicum annuum L. var. glabriusculum)

Piquin pepper fruits, a semi-domesticated wild pepper species highly valued in Mexico, currently face the threat of unsustainable harvesting practices that endanger the species. For this reason, it is necessary to establish sustainable agricultural practices for the cultivation of these peppers. Solar radiation, a critical determinant in crop production, plays a crucial role in plant development, influencing a spectrum of physiological and morphological processes, including the synthesis of phytochemicals. Our study evaluated the effect of light manipulation through colored shading nets on the phytochemical profile, antioxidant capacity, and fruit quality of semi-domesticated piquin peppers at two maturation stages: immature and mature (green and red fruits). Our hypothesis posits that these shading treatments may induce changes in these fruits’ phytochemical composition and antioxidant properties, as well as quality. Our results indicate that the shading treatments and maturity stage have significant on capsaicinoid and carotenoid levels, with the highest levels observed in mature fruits. Notably, red fruits grown under black shading treatments resulted in the highest capsaicinoid levels. Carotenoid levels were higher in the black shading treatment during the first cycle, while in the second cycle, the blue shading treatment showed elevated carotenoid levels, suggesting that high irradiance conditions could reduce carotenoid contents. Although no significant differences were observed among the treatments in green fruits, in red fruits, both black and blue treatments exhibited the highest total phenolic compounds in both production cycles. Furthermore, the antioxidant capacity revealed that red fruits exhibited higher antioxidant levels than green fruits. Color analysis showed that red fruits had higher chroma and hue angle values, indicating their brighter and more intense red color than green fruits. The morphological changes in fruit width, length, and weight can be attributed to shading treatments and maturation stages. These results indicate the potential of piquin peppers to act as rich sources of bioactive compounds, emphasizing the benefits of shading as an effective strategy to improve the quality and quantity of phytochemical compounds in piquin peppers. Our findings provide substantial insights into the intricate relationship between maturation, shading treatments, and phytochemical composition, offering a path to improve the nutritional value and quality of piquin peppers.

Shade Nets Reduced Growth, Nutrition, and Sugars of Hydroponic Lettuce and Basil

Colored shade nets are known to alter the light quality and quantity and thus can influence plant growth and nutritional quality of crops. Lettuce (‘Lollo Antonet’ and ‘Green Forest’) and basil (‘Aroma-2’ and ‘Genovese’) were grown in ebb-and-flow hydroponic tables for 4 weeks. Colored shade nets of aluminet, black, pearl, and red with 50% shading intensity along with a control (no-shade) were used in this experiment. Data for plant growth and leaf quality attributes were collected at harvest time. The no-shade treatment showed increased shoot fresh and dry weight, sugar, and relative chlorophyll content in both lettuce and basil cultivars, whereas plant height and net photosynthesis rates were increased under aluminet, pearl, and red nets. In basil, calcium and sulfur were greatest under no-shade, whereas zinc and copper were greatest under aluminet. Zinc, iron, calcium, magnesium, and manganese concentrations were greatest under no-shade in lettuce. The pearl-colored net increased leaf soluble solids content. No-shade produced the greatest starch values in basil, whereas pearl shade net produced the greatest starch in ‘Lollo Antonet’ in the fall. Light spectra varied with shade net resulting in 90%, 65%, 50%, 30%, and 70% of incident light occurring between 400 and 700 nm for no-shade, pearl, aluminet, black, and red shade nets, respectively. Overall, lettuce and basil plants under no-shade (daily light integral of 20 to 24 mol·m−2·d−1 and temperature of 26 to 30 °C) had increased plant growth and leaf quality in late spring and fall, compared with colored shade nets.

Growth and production of cucumber plants as affected by colored shade nets and soil covering under Sharm El-Sheikh conditions

Growth and production of cucumber plants as affected by colored shade nets and soil covering under Sharm El-Sheikh conditions

Colored Shade Nets Affect Growth but Not Flowering of Four Greenhouse-grown Potted Ornamental Species

The color of horticultural shade nets is known to influence crop growth and quality because of variations in the amount and quality of light. Four ornamental plant species (celosia, begonia, gerbera, and fountain grass) were grown under aluminet, pearl, and red shade nets plus black as the control at 50% shade intensity for 8 weeks. Black had the least transmittance (∼10% to 30% of ambient) within the red spectrum (620–750 nm), whereas red had the greatest at ∼70% to 80%. Aluminet and pearl resulted in a similar reduction in photosynthetic photon flux at ∼50% to 55% and ∼55% to 65% of ambient, respectively. Aluminet increased the shoot dry weight for begonia and celosia, whereas no differences among shade nets were seen for gerbera or fountain grass. The chlorophyll concentration was greatest under aluminet for each species except begonia. Shade net color did not affect flower number.

Economic Assessment of Coloured Shade Net Improve Growth and Yield in Mango CV. Keitt

Colored shade net is an effective tool for sustainable agricultural production. Shade nets of five colors (white, yellow, red, blue, and black), in comparison to open field conditions, were studied in mango cv. Keitt. The aim of the study was to explore the profitability of different colored shade nets (white, yellow, red, blue, black, and control) on the yield of ‘Keitt’ mango during the period of 2016-2020. The results showed that the use of white colored shade net increased the yield 2000·m-2. The average yield of the trees under white colored shade net was about 7.3 kg·tree-1, compared to about 6.3, 5.8, 5.1, 4.3, 4.3 kg·tree-1 for yellow, red, blue and black colored shade nets and control, respectively. The black colored shade net had the lowest economical profit. Thus, growing mango under a white colored shade net is useful to increase marketable and exportable yield, as well as to improve the quality of mangoes compared to other treatments.

Colored shade nets and different harvest times alter the growth, antioxidant status, and quantitative attributes of glandular trichomes and essential oil of Thymus vulgaris L.

Its popularity in Mediterranean cuisine and gastronomy in general, as well as its medicinal and aromatic value, contributes to the high demand for Thymus vulgaris L. (thyme). Light is the source of energy, a signaling agent for growth, and a modulator of physiological responses in plants. The objective of this study was to evaluate the effects of cultivating T. vulgaris in tropical conditions under differently colored shade nets on vegetative growth, photosynthetic pigments, antioxidant activity, and quantitative and qualitative characteristics of its essential oil (EO) in two seasons. The treatments were cultivation in sunlight and under blue, black, and red nets in tropical conditions in the fall and spring seasons. The plants were harvested 100 days after transplanting. Leaf, stem, root, and total dry weight were evaluated; photosynthetic pigments and nonenzymatic antioxidant activities were quantified; and parameters related to the production of EO were determined. With the exception of chlorophyll a, carotenoids, and some EO chemical compounds, the cultivation of thyme in the spring brought significant gains to the plants regardless of the light conditions. The cultivation of T. vulgaris under sunlight produced an increase of up to 82.2 % in dry weight and 639 % in EO yield compared to cultivation under nets. It also supported the highest antioxidant activity, regardless of the growing season. On the other hand, cultivation under sunlight provided the lowest chlorophyll a and b and thymol contents. Thus, cultivation in the warmer seasons and under full-sun conditions are the best options for cultivating T. vulgaris in a region with a tropical temperate rainy climate (mesothermal).

Height Control of Greenhouse-grown Pansy Using Colored Shade Nets

Pansy (Viola ×wittrockiana) is a greenhouse crop commonly grown under black shade net; it often requires the use of chemical plant growth regulators to maintain a compact growth habit. Nonchemical efforts to alter plant morphology, such as height, would provide a more sustainable solution than chemical application. The objective of these studies was to evaluate the effects of different colors of shade nets on controlling growth and flowering of pansy. In Expt. 1, ‘Clear Yellow’, ‘Buttered Popcorn’, and ‘Deep Orange’ pansy plugs were placed under 30% blue or black shade net or, as a control group, where grown with no shade net. In Expt. 2, the same three cultivars of pansy were grown under 50% black, red, pearl, or aluminized shade net. Data were collected on plant height, plant width, flower number, plant survival, soil plant analysis development chlorophyll meter (SPAD) readings, and light quality. In Expt. 1, the blue shade net reduced height to flower and height to leaves, but also decreased flower number and plant survival as compared with black shade net. All plants under no shade died. In Expt. 2, SPAD, an indicator of plant quality by estimating leaf greenness, was found to be lower under black shade net, whereas pearl shade net led to a decrease in plant height and no effect on the number of flowers. Light quality, including red-to-far-red ratio, varied among shade treatments, whereas light intensity was reduced under aluminized, black (50%), and red shade nets compared with other shade treatments. Blue and pearl shade nets both reduced plant height, but blue shade net also reduced plant survival and flowering.

ECONOMICAL EVALUATION OF MANGO (CV. KEITT) TREES UNDER COLOURED SHADE NETS

This study explored the economical viability of five different coloured shade nets (White, yellow, red, blue and black) on mango production (Mangifera indica L. cv. Keitt). This study investigated the climatic parameters in terms of light intensity, minimum and maximum air temperature, relative humidity and plant growth across 2019 and 2020 seasons. When compared to open field conditions, coloured shade nets resulted in higher maximum temperatures and relative humidity. The black net cover and open field treatments gave the lowest mango yield compared to all greenhouse net cover. When compared to the other treatments, the use of white or yellow nets resulted in a considerable increase in the number of fruits and total yield per plant. According to prevailed conditions, it could be concluded that optimum microclimate for growing mango in similar conditions could be obtained under white and yellow nets compared to the other net covers. Black greenhouse net cover gave the lowest productivity during the experimental duration. Production costs, total revenue, net return and ratio of total revenue to cost for Keitt mango in Egypt are presented in this study. The result shows that the net return for white net reached 15777 Egyptian pound (LE) and LE 15270 per m2 in 2019 and 2020 respectively, which was 2.63 times those grown in the open field (LE 5980 and LE 5081 per 2000 m2) in 2019 and 2020 respectively. However, Revenue to cost ratio was found higher in white net in both seasons which were 1.9 and 1.8 respectively.

Influence of Coloured Shade Nets On Growth And Biochemical Constituents In Four Species of Ocimum

Effects of different coloured shade nets (red, green, black, green, white net) and control (without net) on the biochemical and growth responses in four Ocimum spp. namely O. tenuiflorum L., O. sanctum L., O. basilicum L. and O. gratissimum L. were investigated. Results showed that plants kept under red net consistently outperformed other treatments recording significantly higher growth and biochemical characteristics for all selected Ocimum spp. after 120 days of transplantation. Parameters like shoot length (128.77 ± 4.00 cm), root length (81.48 ± 0.75 cm), leaf number (319.10 ± 3.38), total fresh biomass (158.17 ± 12.82 g/plant) and total dry biomass (63.88 ± 1.37 g/plant) witnessed a 3.38, 2.95, 2.76, 4.17 and 5.16% increase, respectively under red net over control. Plants under red net also recorded a significant increase of 9.68, 14.10 and 28.18% for total phenols (127.50 ± 2.95 mg/g DW), flavonoids (18.33 ± 2.71 mg/g DW) and alkaloids (32.31 ± 2.87 mg/g DW), respectively. Bangladesh J. Bot. 51(3): 547-554, 2022 (September)

Effects of irrigation intervals and foliar application of amino acids and humic acid on the physiological traits of strawberries under colored shading nets

BACKGROUND: The strawberry is an important commercial crop, the improvement of its yield and quality is an imperative task. OBJECTIVE: The present research aimed to study the effect of colored netting and foliar application of amino acids on the physiological characteristics of strawberries subjected to different irrigation intervals. METHODS: The study was carried out as a factorial experiment based on a randomized complete block design with three factors including colored net at 4 levels (no netting, green, red, and yellow netting), organic acids at 4 levels (control, humic acid, glutamine, and arginine), and three levels of irrigation intervals (2, 4, and 6 days) in the greenhouse of Lahijan Agricultural Research Station, Iran. RESULTS: The results showed that the highest leaf number, shoot weight, chlorophyll and carotenoid content were related to yellow netting. The highest fruit yield, anthocyanins, and flavonoids were observed in the treatments of no-netting, green netting, and red netting, respectively. Data for the effect of organic acids showed that the glutamine-treated plants exhibited the highest yield, the humic acid-treated plants displayed the highest anthocyanin and carotenoid content, and the arginine-treated plants demonstrated the highest vitamin C content. The irrigation interval of 6 days caused to the lowest leaf number, flower and fruit number, shoot weight, fruit yield, and carotenoid content. Data for the trilateral effect of ‘netting×organic acid×irrigation’ showed that the highest flower number and fruit yield were obtained from ‘green netting×glutamine×4 days’, the highest anthocyanin content was obtained from ‘green netting×humic acid×2 days’, and the highest chlorophyll content was obtained from ‘green netting×control×6 days’. The treatment of ‘yellow netting×control×2 days’ was related to the highest flavonoid content. CONCLUSIONS: The application of colored nets provides the strawberry with more optimal vegetative and reproductive growth.

Colored Shade Nets Can Relieve Abnormal Fruit Softening and Premature Leaf Senescence of "Jumeigui" Grapes during Ripening under Greenhouse Conditions.

High temperature causes premature grape leaf senescence, abnormal berry softening, and shortening of the fruiting period. Furthermore, the fruit quality and yield are severely affected. Here, the “Jumeigui” grape quality and leaf senescence were evaluated under shading; green, blue, black, and gray nets were used for shading, and their spectra were measured. At the same density, the shade-net color significantly affected cooling and shading efficiencies, with gray nets showing the best light transmission and cooling effect. Shading significantly alleviated abnormal heat-induced grape softness. The total soluble solids (TSS) content and grape coloration were affected under gray, blue, and green shade nets. Nonetheless, TSS exceeded 18 °Brix under gray, blue, and green nets, as required of first-class high-quality fruit. The peel color was not significantly affected under gray or blue shade nets, whereas unshaded grapes showed clear heat-stress damage, especially on the edges of unshaded bottom leaves, in which the net photosynthesis rate was significantly lower than that under shading, indicating that high light intensity and heat caused premature leaf senescence. Colored shade nets reduced greenhouse temperature and light intensity, thereby alleviating the premature senescence of grape plants. Grape quality under black shade nets was poor, whereas superior quality was achieved using gray or blue shade nets.

Effect of Colored Shading Nets on the Growth and Water Use Efficiency of Sweet Pepper Grown under Semi-arid Conditions

Colored shading nets have been increasingly studied in semi-arid crop production systems, primarily because of their ability to reduce solar radiation with the attendant reductions in air, plant, and soil temperatures. However, there is a paucity of research concerning the impact of colored shading nets on various crops grown under semi-arid environments, particularly the sweet pepper (Capsicum annum) production system. This study aimed to investigate the effects of three colored shading net treatments (i.e., white, green, and black shading nets with 50% shading intensity and control with unshaded conditions) on the growth and instantaneous water use efficiency (WUE) of sweet pepper. The results showed that all colored shading nets exhibited significantly lower daytime air temperatures and light intensity (22 to 28 °C and 9992 lx, respectively) compared with the control (32 to 37 °C and 24,973 lx, respectively). There were significant differences in sweet pepper growth performance among treatments, including plant height, shoot dry weight, leaf area, leaf chlorophyll content, and vitamin C in ripened fruit. The enhanced photosynthetic rates were observed in sweet pepper plants under the colored shading nets compared with control plants. WUE increased among the colored shading net treatments in the following order: control ≤ white < black < green. Overall, the application of green and black shading nets to sweet pepper production systems under semi-arid environments significantly enhanced plant growth responses and WUE.