Shade Levels Research Articles

Production of forest seedlings using sewage sludge and automated irrigation with ozonated cattle wastewater.

The large volume of effluents generated by intensive cattle production can become an environmental problem, requiring solutions that combine treatment and disposal of reuse water. The quality of cattle wastewater (CWW) treated by ozonation, the water requirement and its effect on the growth of seedlings of Dalbergia nigra cultivated with sewage sludge were determined under different light conditions. The study was carried out in a split plot scheme with 2 shading levels (0%-C1, and 49.4% attenuation-C2) and 3 types of irrigation water (control-T1, 1 h ozonation-T2, and 2 h-T3), with 4 repetitions. Direct sowing was realized into 280 cm3 tubes which were irrigated by drip irrigation with automatic management. The height and collar diameter were measured every 21 days, and at the end of the nursery phase, and the Dickson quality index (DQI) and irrigation water productivity (WPir) were determined. In addition, seedlings were transplanted in a forest restauration area (FRA) of Atlantic Forest, with height and diameter monitoring for 200 days. With ozonation, there was an increase in pH and a reduction in electrical conductivity, total solids and turbidity in the CWW, allowing its use for irrigation of forest seedlings. The maximum volumes of water applied were 2.096 and 1.921 L plant-1, with water supply T2 and T1, respectively, and coverages C1 and C2. In these conditions, the seedlings reached DQI of 0.47 and 0.17, and WPir of 2.35 and 1.48 g L-1, respectively. The initial vegetative growth of the seedlings planted in the FRA was benefited by the nutrients provided by the CWW treated. Therefore, the use of sewage sludge and CWW treated has the potential to produce forest seedlings, reducing the release of waste and effluents into the environment.

Microclimate under the Cup of Papaya Planted in the North-South and East-West Directions

The objective of this work was to evaluate the variations of environmental factors under the canopy of papaya planted in a north-south and east-west orientation. Two areas were studied, one oriented north-south and the other east-west, both planted with a spacing of 3.20 mx 2.40 m, planted in April 2015. The distances from the papaya line (levels of shading) and a place in full sun, where it was evaluated, in the North-South direction: in the papaya planting line, at 40 cm west side, 40 cm east side and in full sun; in the East-West direction: In the papaya planting line, at 40 cm on the north side, 40 cm on the south side and in the planting line in full sun. The following atmospheric variables were determined: temperature, irradiance and relative humidity. Tukey's test was used to compare means at a confidence level of 95%. Papaya planted in the east-west direction, under the conditions studied, provided lower incident irradiation, reduced temperature and higher values ​​of relative humidity under its canopy, compared to papaya planted in the north-south direction. It is possible to intercrop papaya planted in the east-west direction with other agricultural crops, including conilon coffee.

Challenge of transition: the history of a case study involving tropical fruits polyculture stimulated by humic acids and plant-growth promoting bacteria

BackgroundInnovative technologies are required in agricultural production to eliminate the environmental risk generated by the intensive use of fertilizers and pesticides. Soil organic matter is a keystone for the transition towards sustainable production. However, it is not an easy task to increase soil organic matter in highly weathered soils without considerable resources and energy. Here, we highlighted the role of biological inputs in plant adaptation to low fertility and water scarcity. The direct use of humic acids and plant growth-promoting bacteria on plants can modify the root architecture systems, including surface area and roots length, thus allowing greater soil exploration.Material and methodsWithin a socio-historical perspective of concepts and research methods, a case study is presented on the effects of humic acids applied together with plant-growth promoting bacteria, as an efficient tool for supporting the transition to more suitable production system. We implemented this natural ecological approach onto a polyculture system with different tropical fruits (banana, passion fruit, papaya and pineapple) and evaluated crop yields.ResultsWe observed increases of around 50 and 90% in banana and papaya yield, respectively, and 25% in passion fruit productions, with significantly greater yields maintained over four production cycles. No effect was observed in ananas production probably due to the large shading level in the area.ConclusionThe biostimulant formulated with endophytic diazotrophic bacteria and humic acids represents a low-cost technology that enhances crop yields and can play an important role in promoting a transition process towards sustainable agriculture.Graphical

Productivity, Morphology and Chemical Composition of Brachiaria spp. Ecotypes, under Two Solar Illumination Intensities, in Yucatan, Mexico

There are mixed reports about the advantages and disadvantages of the presence of shade produced by trees over the understory-growing grasses; thus, it is urgent to test grass species and cultivars with potential to develop in shaded conditions associated with trees that occur in silvopastoral systems. The objective of the present study was to identify Brachiaria spp. ecotypes adapted for cultivation under tree shade, typical of silvopastoral systems. The study was conducted at Kampepen ranch, located 14 km south of Merida, Yucatan, Mexico. A factorial 6 (ecotypes) x 2 (sunlight intensities) treatment structure was used, arranged in split-plot design; with sunlight intensity levels being the plots and ecotypes the subplots, with three replications. The ecotypes were T1: Brachiaria hybrid cv. Mulato II, T2: Brachiaria hybrid cv. Cayman Blend, T3: Brachiaria hybrid cv. Talisman (BR05/1467), T4: Brachiaria hybrid cv. Camello Blend, T5: Brachiaria brizantha cv. Marandu and T6 (the control): M. maximus cv. Mombasa, while the two sunlight intensity levels were higher and lower sunlight reductions with respect to full sunlight (25% and 50% light transmission with respect to full sunlight, respectively). Variables were plant height, forage yield and chemical composition; leaf, stem and dead material fractions and leaf:stem ratio; plant canopy cover, plant maturity, and growth rate. Significant (p < 0.050) ecotype x sunlight intensity interactions were recorded for most of the studied variables. Independent of the shading levels, ecotype Talisman showed superior performance compared with the other assessed ecotypes, yielding up to 20 ton ha−1 under the highest light intensity, means across light intensities for crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) of 11.8%, 59.7%, and 34.7%, respectively, and more than 90% plant canopy cover. It is concluded that Talisman has promising characteristics for cultivation under silvopastoral systems, where tree shading is common, in the dry tropics of Yucatan, Mexico.

Growth and Total Flavonoid of Three Celery (Apium graveolens L.) Varieties in Shaded Environments in The Tropical Lowland

Celery is an introduced species of family Apiaceae from the subtropical areas. Celery leaves and stalks contain vitamins, phenolic compounds, essential oils, and other nutrients that have been used in the foods, cosmetics, and herbal industries. Shading can create a better environment for varieties adapted to the highlands to succeed to grown in the lowlands. However, the changes in the growing environment including light and temperatures might affect the flavonoid production. This study aimed to determine the growth and production of flavonoids of the highland celery varieties in the lowlands when treated with various level of shades, i.e. without shade/control, 50% shade, and 70% shade. The study used “Aroma”, a celery variety adapted to the highland, and “Summer Green”, a variety adapted to the lowland. Increases in the shade levels decrease air temperature, increases air humidity, and significantly improved the growth and production of the three celery varieties in terms of plant height, leaflets number except for the “Aroma” variety; increased leaf area, stem diameter, tiller number, crown diameter, total wet weight, total dry weight, chlorophyll a, chlorophyll b, total chlorophyll, anthocyanins, plant N (Nitrogen), P (Phosphor), K (Potassium), and total flavonoids. “Amigo” exposed to 50% shade had significantly higher flavonoids than “Aroma”. Providing shades to “Summer Green” resulted in the lower levels of flavonoids compared to without shading.

Effects of Shading on Anatomical Aspects and Chlorophyll and Carotenoid Contents in Paricá

Paricá (Schizolobium parahyba variety amazonicum) is an important species for reforestation programs in the Amazon; nevertheless, the anatomical and physiological parameters of the seedlings of this species under shading are not yet fully understood. This study evaluated the chlorophyll and carotenoid contents, the stomatal structure, and the stomatal position in the leaf epidermis under shading of paricá seedlings. The experiment comprised a randomized block design in a subdivided plot scheme, with two sources (Belterra and Urupá) and different shading levels (full sun, 30%, 50%, and 70%). At 100 days after sowing, we performed the analyses of photosynthetic pigment concentration and leaf anatomy. We found that the leaf is hypoestomatic with paracitic stomata and unicellular filiform trichomes on both sides. Higher levels of shading increased the contents of chlorophyll a and b and reduced the stomata density and carotenoid contents in the leaves of young paricá, showing that paricá has phenotypic plasticity to shading.

The impacts of tropical agriculture on biodiversity: A meta‐analysis

Abstract Biodiversity underpins all food production and strengthens agricultural resilience to crop failure. However, agricultural expansion is the primary driver of biodiversity loss, particularly in the tropics where crop production is increasing and intensifying rapidly to meet a growing global food demand. It is therefore crucial to ask, how do different crops and crop production systems impact biodiversity? We first use the FAO database of harvested crop area to explore temporal changes in crop area and intensification across the entire tropical realm. We show that the harvested area of tropical crops has more than doubled since 1961, with ever‐increasing intensification. The harvested area in 2019 was 7.21 million km2, equivalent to 5.5% of global ice‐free land area, or 11.5% of land area in the tropics. Second, we conducted a meta‐analysis of 194 studies and 1364 pairwise comparisons to assess the impact of tropical agriculture on biodiversity, comparing biodiversity values in food crop sites versus natural reference habitats. Our meta‐analysis shows that crop type, rotation time and level of shading are important determinants of biodiversity assemblages. Perennial tropical crops that are grown in shaded plantations or agroforests (e.g. banana and coffee) support higher biodiversity, while crops cultivated in unshaded and often homogeneous croplands (e.g. maize, sugarcane and oil palm), and particularly annual crops, have impoverished biodiversity communities. Policy implications. Our findings highlight the increasing agricultural expansion and intensification over the last 60 years and inform our understanding of how different crops and crop production systems impact biodiversity. Furthermore, they provide insight into the long‐term sustainability of tropical food production and may serve as a warning sign for agricultural systems that rely on the ecosystem services provided by biodiversity.

Estimating soil water evaporation as influenced by “dry-and green-mulch” cover beneath maize canopy

Soil evaporation reduction can improve rainfed crop production in semi-arid climates. The purpose of this study was to develop empirical models to estimate cumulative soil evaporation (∑Es) from a maize field across the basin and runoff area (BA and RA) of the in-field rainwater harvesting (IRWH) technique as influenced by different levels of stover mulch ("dry-mulch") and canopy shading ("green-mulch"). Soil water evaporation (Es) was measured with micro-lysimeters 300 mm deep and 71 mm in diameter in the BA and RA sections for three consecutive drying cycles. Four different runoff strip lengths, RSL (RSL-1, 1.5, 2 and 3m) and three mulching levels (ML) of bare, 39%, and 96% were used to estimate the Es. The coefficient crop cover (Kcover) values for full and partial canopy shade (FC and PC) on the RA were in the range of 0.46–0.97 and 0.43–0.94, respectively, while in the BA the Kcover values ranged between 0.33 and 0.92. Under IRWH, the ∑Es values from a basin area beneath a maize canopy averaged 42% of the seasonal rainfall. ∑Es proportion of seasonal rainfall is about 62, 64, and 66 percent for bare soil, but as low as 28, 30 and 32 percent for FC, PC, and unshaded canopy (UC), respectively. In conclusion, the microclimate of the cropping system changes according to surface treatments, which greatly affect the Es losses for the IRWH technique and contributes to ET partitioning. Hence, reducing unproductive water losses in dryland crop production improves water use efficiency by storing more water in the root zone for transpiration.

Partial shading detection and hotspot prediction in photovoltaic systems based on numerical differentiation and integration of the P − V curves

Hotspot phenomenon is an expected consequence of long-term partial shading condition (PSC), which results in early degradation and permanent damage of the shaded cells in the photovoltaic (PV) systems. Hence, partial shading detection and estimation of its intensity is a significant factor to predict the possibility of hotspotting process and its occurrence time for PV system protection. In this paper, two partial shading detection indices are introduced based on the extracted power-voltage ( P − V $P - V$ ) curves. The first P − V $P - V$ characteristic is related to the real shaded PV system and the second P − V $P - V$ curve is numerically obtained from the equivalent single-diode circuit model. The proposed PSC detection indices are established according to the difference between the numerical differentiation and integration of the P − V $P - V$ curves from the real PV system and the virtual reference model. These techniques have the advantages to distinguish between temporary and permanent PSC. Moreover, it is possible to estimate the intensity of the shading level and predict the hotspot occurrence time, accordingly. The performance of these methods are confirmed using some simulations and an experimental setup. The results verify the capabilities of the methods for partial shading detection without the requirement of an extra physical cell/module as a reference model.

Sowing depth and light intensity in the emergence and development of monocotyledonous weeds

This study aimed to evaluate the effects of different sowing depths and light intensities on the emergence and development of the monocot weed species, Urochloa decumbens and Cenchrus echinatus, under field conditions. Each species constituted an experiment, and the experimental design was completely randomized with four replicates. The treatments were arranged in a 6 x 4 factorial scheme, with six sowing depths (0.5, 1.0, 2.0, 4.0, 8.0, and 12.0 cm) associated with four solar radiation intensities (100%, 70%, 50%, and 30%) obtained through the use of shading screens. Seedling emergence capacity was evaluated daily to obtain the emergence percentage and speed index. Plant height, floral induction time, and plant dry matter at flowering were measured. Even when subjected to different solar radiation intensities, U. decumbens and C. echinatus seedlings emerged at all the sowing depths. Sowing between 2.0- and 4.0-cm depths favored the emergence of seedlings of U. decumbens and C. echinatus. However, sowing at 12-cm depth reduced the emergence of both species regardless of the solar radiation intensity. Urichloa decumbens plants grown under conditions of greater shading showed the lowest values of height and dry matter accumulation during flowering. High levels of shading facilitated only the etiolation of C. echinatus plants. Increased shading flowering time in both species compared to full sunlight.

Growth Effects of Corn Plants (Zea mays) on Agronomic Aspects of Oil Palm Tree Stands

The study aimed to determine the agronomic study of the tolerance of corn plants to conditions shaded by oil palm trees. This research was conducted from July to October 2022. At the Oil Palm Plantation of the Community of Bunut Seberang Village, Asahan Regency, North Sumatra. This study used a factorial randomized block design with two factors and three replications. The first treatment consisted of a shading level (P) with 4 treatment levels namely (P0) without shading, (P1) 35% shading, (P2) 70% shading. The second treatment consisted of a variety of corn (J) with 6 varieties, namely Exsotic Pertiwi (V1), Paragon (V2), Bonanza F1 (V3), Bisi 2 (V4) varieties. The best plant height parameter in the shade level treatment showed 35% shade (P1) resulted in the highest plant height of 113.98 cm, while in the Variety (V4) Bisi-2 variety treatment showed the highest plant, namely 112.83 when compared to other varieties. The effect of various varieties on leaf area showed a significant effect at the age of 6 and 8 WAP. The degree of shade and differences in varieties show the similarity in the quality of the green leaves. The level of shade showed a significant effect on chlorophyll-a and total chlorophyll-a and b where the highest amount of chlorophyll-a was found in the treatment without shade, which was not significantly different from the level of 70% shade, while varieties had a significant effect in producing net photosynthesis formed

Shading Reduces Water Deficits in Strawberry (Fragaria X Ananassa) Plants during Vegetative Growth

ABSTRACT The strawberry (Fragaria × ananassa Duch.) is a commercially important crop with high water requirements, making strategies that mitigate the influence of water deficits on plant growth necessary. This study aimed to evaluate the effects of shading on the vegetative growth of strawberry cv. Sweet Ann under a water deficit. The treatments consisted of the combination of two levels of shading (light intensity reduced by 47% vs. non-shaded plants) and two levels of water availability (water deficit vs. well-watered plants). The water deficit reduced the leaf water potential from −1.52 to −2.21 MPa, and diminished stomatal conductance, net photosynthetic rate (from 9.13 to 2.5 µmol m−2 s−1), maximum quantum efficiency of PSII photochemistry (from 0.79 to 0.67), and biomass accumulation, but increased the electrolyte leakage. The shading allowed the water-deficient plants to maintain water potential (−1.58 MPa) and photosystem II efficiency (0.79) and to increase water use efficiency (from 14.80 to 86.90 µmol CO2/mmol H2O), net photosynthetic rate (from 2.40 to 9.40 µmol m−2 s−1) and biomass of leaves, crowns, and roots, as compared to the non-shaded plants without a water limitation. These results suggest, for the first time in strawberry, that a reduction in incident light intensity attenuates the effects of stomatic and non-stomatic limitations caused by a water deficit during vegetative growth in strawberry.

A review of the vascular plant flora of the Cairngorms Connect project area, Scotland, and some possible implications of forest expansion to the natural tree line

Cairngorms Connect, a partnership of four adjoining land owners, is committed to a 200-year vision to enhance and restore habitats, species and ecological processes across a 592 km2 area within the Cairngorms National Park. This will be achieved by, inter alia, expanding woodland to its natural altitudinal limit, including high altitude sub-alpine scrub. All or parts of six native Caledonian pinewoods occur here, c.26% of the national total. Ancient, semi-natural woodland within the Cairngorms Connect area is 43% of the National Park total. Modelling of the extent of potential-natural woodland (sensu Peterken, 1981, 1996) indicates that below 600 m all terrestrial habitats are potentially capable of supporting some degree of tree and scrub cover. 899 vascular plant taxa have been recorded here, of which 693 are native to the area. 7.6% of native taxa are endemic to Great Britain (and Ireland) or to Scotland; these are mainly Hieracia (Hawkweeds). Of the native taxa, 23% are of national, and 11% of regional conservation concern. Few native taxa are widespread within the Cairngorms Connect area, most are local or rare. 40% of native taxa have been recorded in five or less monads (1 km squares), with 16% recorded from just a single monad. 12% of native taxa are associated with shaded locations or semi-shade (Ellenberg Light values 3-5). 51% of taxa are found in partial shade to well lit locations (values 6 and 7) and 37% of taxa in well lit to fully lit locations (values 8 and 9). Native taxa with Light values of 6-7 are the most frequent in 92% of monads with more than 10 recorded taxa. 65% of taxa of national conservation concern favour well lit to fully lit locations (Light values 8-9). Shading of plants, at altitudes below the potential tree line, is strongly influenced by the extent of woodland and scrub and its structure, and by herbivore grazing levels determining height and structure of the field layer. To achieve forest expansion to the natural tree line by natural regeneration will require sustained low levels of grazing and browsing, for decades, or longer. This is already leading to a taller field layer and an increased density of tree regeneration. 40% of native taxa may be negatively impacted, if existing and new woodland becomes dense with a high level of shading. Of these 'at risk' taxa, 50% have maximum height less than 50 cm and may be especially at risk from sustained periods of low grazing. Limited disturbance and lack of open sites and bare ground for seedling recruitment is another potential constraint on vascular plants. The issue of vegetation succession and shading, leading to possible loss of plant diversity is likely to be much less of an issue at altitudes around and above the tree line. Here there are likely to be benefits, with possible expansion of tall herb communities.

Unexpectedly, Creation of Temporary Water Bodies Has Increased the Availability of Food and Nesting Sites for Bees (Apiformes)

Earthworks, such as embankments or excavations, because of their transient nature, usually do not play any important role in biodiversity protection and promotion in urban areas. However, the results of this study show that pits playing the role of infiltration basins, which are filled with water only in some periods, can provide bees with food resources and nesting sites. They are particularly important in habitats with simplified vegetation structures, e.g., in monoculture habitats. The attractiveness of infiltration basins and ditches as habitats for bees was assessed by comparing species richness and abundance of bee communities found there with those of coniferous forests—pine monocultures (where the reservoirs were created) and clearings. The species richness and abundance of bees in clearings, infiltration ditches, and basins were higher than in forests. Simultaneously, we found that an increase in woody vegetation coverage and the level of shading in the daytime had a negative effect on bee abundance. In contrast, it was positively affected by increasing the mean radius of a belt of predominantly open habitats around sampling sites (herbaceous plants and seedlings of woody plants <60%). In this case, food resources were not a limiting factor of bee occurrence in the study area.

Plant water status, plant growth, and fruit yield in bell pepper (Capsicum annum L.) under shade nets

Shade nettings can be an effective technology for producing bell pepper under warm conditions. The physiological mechanisms through which shade nets improve plant growth and fruit yield are still not fully understood. The objectives were to determine the effects of shade level on plant and soil water status, plant growth and fruit yield of ‘Aristotle’ bell pepper. Trials were conducted in the spring/summer of 2017 and 2018 in Tifton, GA, following a randomized complete block design with five shade levels [0% (open field), 30%, 47%, 63%, and 80%]. Photosynthetic photon flux rate (PPFR) and leaf temperature decreased while soil water content and leaf water potential increased with shade level, indicating reduced plant water use due to reduced evaporative demand under shaded conditions. Increased shade levels resulted in enhanced plant growth in part because of improved plant water status. Total fruit yield and number of sunscalded fruit diminished with increasing shade level, while marketable yield was maximal at 30% shade. The incidences of soil-borne diseases [Phytophthora blight (Phytophthora capsici) and southern blight (Sclerotium rolfsii)] decreased with increasing shade levels. Overall, a shade level of 30% was found to be optimal and allowed production of maximal fruit yield through improving water availability (plant and soil water) and minimizing abiotic (drought, light, temperature) and biotic (pathogens) stresses.

Agronomic evaluation of shade tolerance of 16 spring Camelina sativa (L.) Crantz genotypes under different artificial shade levels using a modified membership function.

Camelina [Camelina sativa (L.) Crantz] is currently gaining considerable attention as a potential oilseed feedstock for biofuel, oil and feed source, and bioproducts. Studies have shown the potential of using camelina in an intercropping system. However, there are no camelina genotypes evaluated or bred for shade tolerance. The objective of this study was to evaluate and determine the shade tolerance of sixteen spring camelina genotypes (growth stage: BBCH 103; the plants with 4–5 leaves) for intercropping systems. In this study, we simulated three different shade levels, including low (LST), medium (MST), and high shade treatments (HST; 15, 25, and 50% reduction of natural light intensity, respectively), and evaluated the photosynthetic and physiological parameters, seed production, and seed quality. The mean chlorophyll pigments, including the total chlorophyll and chlorophyll a and b across the 16 genotypes increased as shade level increased, while the chlorophyll fluorescence parameter Fv/Fm, chlorophyll a/b, leaf area, the number of silicles and branches plant−1 decreased as shade level increased. The first day of anthesis and days of flowering duration of camelina treated with shade were significantly delayed and shortened, respectively, as shade increased. The shortened lifecycle and altered flowering phenology decreased camelina seed yield. Additionally, the shade under MST and HST reduced the seed oil content and unsaturated fatty acids, but not saturated fatty acids. The dendrograms constructed using the comprehensive tolerance membership values revealed that CamK9, CamC4, and ‘SO-40’ were the relatively shade-tolerant genotypes among the 16 camelina genotypes. These camelina genotypes can grow under the shade level up to a 25% reduction in natural light intensity producing a similar seed yield and seed oil quality, indicating the potential to intercrop with maize or other small grain crops. The present study provided the baseline information on the response of camelina genotypes to different shade levels, which would help in selecting or breeding shade-tolerant genotypes.

Productivity of ClonalIlex paraguariensisGenotypes in a Semi-Hydroponic System Is Reduced by Shading

AbstractYerba mate (Ilex paraguariensis A. St.-Hil.) is a South American tree cultivated in systems with or without shading at different intensities; however, there is no consensus about shading effect on leaf biomass production. Therefore, we evaluated yerba mate clones under different shading levels over one year to determine the influence of shading and genotype on biomass production. Two yerba mate genotypes (EC22 and EC40), cultivated in a semi-hydroponic system, were subjected to five shading levels (0%, 40%, 51%, 76%, and 82%) in a greenhouse. We determined total fresh biomass (branches and leaves) and fresh biomass of young and mature leaves on six harvests. Biomass production was influenced by harvest season, genotype, and shading levels. Spring and summer harvests provided higher biomass production than the other seasons. EC40 genotype produced higher total fresh and young leaf biomass than EC22. Although we observed differences among genotypes and harvest seasons, shading was the factor that most influenced biomass production. Total fresh biomass productivity was reduced 6.8 times between 0% and 82% shading for the EC40 genotype. Thus, we do not recommend high levels of shade, such as 76% and 82%, in this new yerba mate cultivation system.

Analysis effect of shade level on the physiological and anatomical characteristics of hybrid Phalaenopsis orchid at the acclimatization stage

Production of hybrid Phalaenopsis seedlings is generally applied by in vitro culture techniques. The final stage of in vitro culture is acclimatization. The acclimatization stage is crucial because the plantlets must adapt to the ex-vitro environment. Shade supports plantlet growth during the early stages of acclimatization. This study aims to determine the effect of shade level on the physiological and anatomical characteristics of the Phalaenopsis hybrid orchid at the acclimatization stage. The research used Phalaenopsis plantlet hybrid and shading level. Plantlets were shaded at 40%, 55%, and 70%. Parameters measured included: photosynthetic pigment content, number and area of leaves, number and length of roots, stomata density, size of stomata and fresh weight. This study used a completely randomized design with one factor and ten replications. Data were analyzed using the ANOVA test and LSD test at a significance level of 5% (p<0.05). The results showed the highest photosynthetic pigment content in the 55% shade, and there was a difference in the size of the stomatal guard cells between ex vitro and in vitro leaves at 40% shade. Shade level did not affect leaf growth, roots, fresh weight and stomata density. However, it affected photosynthetic pigment content and size of guard cells in the ex vitro leaves of Phalaenopsis hybrid orchids. The most optimal growth of the Phalaenopsis hybrid was at 55% shade. Keywords : acclimatization , ex vitro leaves , shade Abstrak Produksi bibit Phalaenopsis hibrid umumnya dilakukan dengan teknik kultur in vitro . Tahap akhir dari kultur in vitro adalah aklimatisasi. Aklimatisasi merupakan tahap paling penting karena planlet harus beradaptasi di lingkungan ex vitro . Naungan menunjang pertumbuhan planlet selama tahap awal aklimatisasi. Penelitian ini bertujuan untuk mengetahui pengaruh tingkat naungan terhadap karakteristik fisiologis dan anatomis anggrek Phalaenopsis hibrid pada tahap aklimatisasi. Penelitian menggunakan planlet Phalaenopsis hibrid dan tingkat naungan. Planlet diberi paranet 40%, 55%, dan 70%. Parameter yang diukur meliputi: kandungan pigmen fotosintesis, jumlah dan luas daun, jumlah dan panjang akar, densitas stomata, ukuran stomata dan berat segar. Penelitian ini menggunakan rancangan acak lengkap dengan satu faktor dan 10 ulangan. Data dianalisis menggunakan Uji ANOVA dan Uji LSD pada taraf signifikasi 5% (p< 0,05). Hasil penelitian menunjukkan bahwa kandungan pigmen fotosintesis tertinggi terdapat pada naungan 55% danterdapat perbedaan ukuran sel penutup stomata antara daun ex vitro dan in vitro pada naungan 40%. Tingkat naungan tidak mempengaruhi pertumbuhan daun, akar, berat segar serta densitas stomata, namun mempengaruhi kandungan pigmen fotosintesis serta ukuran sel penutup stomata daun ex vitro pada anggrek Phalaenopsis hibrid. Pertumbuhan Phalaenopsis hibrid yang paling optimal berada pada naungan 55%. Kata Kunci : aklimatisasi, daun ex vitro , naungan

Crop Cultivation Underneath Agro-Photovoltaic Systems and Its Effects on Crop Growth, Yield, and Photosynthetic Efficiency

Agro-photovoltaics (APV) could be the optimal means of sustainable development in agricultural areas once a few challenges are overcome, perhaps the greatest of which is the constant shading from AVP structures. This study examined how the growth and yield of rice, potato, sesame, and soybean crops could be optimized when grown underneath different APV systems. The solar radiation, shading levels, and temperatures during crop cultivation were measured. In addition, the photosynthetic efficiency was measured at different growth stages. Adjacent to the APV systems were the control plots with full sun. In these studies with potato crops grown under APV systems, most growth and yield parameters were similar to those grown in the control plot except for the plant height. On the other hand, sesame crops grown underneath the APV systems had a lower stem length, effective branching number, 1000 seed weight, and a reduced yield of 19% compared to the crops from the control plot. In two distant locations (Paju and Youngkwang), soybean crops grown underneath APV systems at both sites showed increased ungrained ratios per pod and a reduced yield of 18–20% compared to the control plot. Finally, rice crops cultivated underneath the APV systems had a lower panicle number per hill, spikelet number per panicle, 1000 seed weight, and yield reduction of 13–30% compared to the control plot. Overall, crops grown underneath the APV systems had a greater plant height and stem length. Moreover, the solar radiation and PAR underneath the APV systems were also lower than in the control plots. The photosynthetic efficacy in rice plants grown underneath the APV systems was lower than in the control plots. The photosynthetic efficacy may help lower the crop yield when cultivation is underneath an APV system.

Morphophysiological adjustments to shade of jaboticaba tree saplings

We aimed to verify the morphophysiological changes in jaboticaba tree (Plinia peruviana (Poir.) Govaerts) saplings under shade gradient to improve knowledge on the appropriate light environmental conditions for the saplings production and field homogeneous or intercropping cultivation of this species. The saplings were grown under full sun and artificial shade levels (30%, 50%, and 80%). Growth, photosynthetic pigments, gas exchanges, chlorophyll fluorescence, and leaf anatomy characters were evaluated. Our results showed that jaboticaba tree saplings growth was improved under full sun and 30% of shade. Under 50% and 80% shade the saplings demonstrate phenotypic plasticity, such as larger and thinner leaves. Chlorophyll fluorescence, chlorophyll content, and quantum yield of photosystem II were higher under higher shade level, but the CO2 assimilation rate was not different between light conditions. These changes are typically found in shade-tolerant plants and is related to perform photosynthesis more efficiently in highly variable light conditions. Despite that, we recommend that cultivation be carried out under full sun or up to 30% shade to maximize jaboticaba tree saplings growth in nurseries and orchards.