Research Articles

The nutrient composition and biostimulant properties of seaweed were determined as solid biofertilizer for cultivating tomato seedlings in a greenhouse. Seaweeds (Sargassum wightii, Sargassum longifolium, Laminaria digitata, and Gelidiella acerosa) were collected from rocky areas and turned into a powder, and their nutrient compositions were analyzed. The brown seaweed showed indoleacetic acid (IAA), gibberellic acid (GA₃), indole butyric acid (IBA), and abscisic acid (ABA). The amount of IAA ranged from 0.52 to 21.5 μg/mL. Compared with the other brown algae, the G. acerosa extract presented the maximum amount of GA₃ (149 μg/mL). The amount of IBA ranged from 1.5 to 15.3 μg/mL, and the ABA level was high in S. wightii (2.5 μg/mL). All algae powders were subjected to biofertilizer preparation and their biostimulant properties were studied. The algal biostimulant improved flower cluster number, fruit number, shoot dry weight, and root dry weight in tomato plants in a greenhouse. Macroalgae fertilizer improved urease, phosphatase, invertase, and catalase activities (p<0.05) and the microbial population in the soil. The results showed positive effects of biostimulants on soil physicochemical and biological properties.

Toxic metals/metalloids such as arsenic are environmental pollutants that are damaging to living organisms. Commonly found metals pose a serious threat to human health unless they are controlled. In this study, the accumulation of As metalloid, which has entered the food chain for specific reasons, in plant organs was determined, and it was examined whether plants are hyperaccumulators against As concentration. As a result, Pinus pinaster Aiton., Cupressus arizonica Greene., Picea orientalis (L.) Peterm., Cedrus atlantica (Endl.), and Pseudotsuga menziesii (Mirb.) species accumulated more than 1 mg/kg As concentration. The highest average As concentration (7.91 mg/kg) was found in the northern bark of P. menziesii. The highest As concentrations in wood were found in the eastern direction for P. pinaster (5.21 mg/kg), C. arizonica (4.99 mg/kg), and P. orientalis (4.02 mg/kg), and in the western direction for C. atlantica (3.56 mg/kg) and P. menziesii (3.88 mg/kg). Additionally, it was determined that As concentration varied depending on location, direction, species, and year.

Roof truss systems and wall panels are two examples of popular structural components made by cold-formed steel (CFS) which is classified as a steel-based building material available in a wide range of shapes, and thicknesses. The use of CFS is increasing due to its many desirable properties, including a high strength-to-weight ratio, low weight, resistance to corrosion, and fast installation. In contrast, the thin-surfaced and opened section of CFS buckles easily when utilised as a beam or column. When the load is applied directly, the CFS section fails in modes such as web crippling, torsion, and buckling. As a result, the new I-section with top and bottom flange elements was produced by using CFS channel section, and timber board from the type of oriented strand board (OSB) as a web element. The study aimed to determine the initial structural characteristics of the built-up I-section CFS with OSB short column. A single or double web element made by yellow and dark brown OSB was used to construct the I-section for determining the initial structural characteristics. The I-section with a double web of yellow OSB showed the highest value of ultimate load and compressive strength as compared to other specimens in the range of 8.00% to 14.00%.

Research on growth rings in tropical trees within flooded forests has unveiled the complexity of climate change in these ecosystems. However, there has been limited understanding regarding species and their potential for dendrochronology. This study assessed 20 species from 13 botanical families in a flooded forest in southeastern Peru. Wood samples were collected during the dry season using a non-destructive sampling with motorized drill, alongside botanical samples for identification. Growth ring features were described following the IAWA, at a macroscopic level. Thirteen species showed promise for dendrochronological studies, eight of which were previously undocumented. These findings are pivotal for prioritizing species in future dendrochronological investigations in the Peruvian Amazon.

The effect of air heat treatment was evaluated relative to the shrinkage and surface roughness of six Korean oak woods: Quercus serrata (Qs), Quercus mongolica (Qm), Quercus acutissima (Qac), Quercus aliena (Qal), Quercus dentata (Qd), and Quercus variabilis (Qv). The properties were examined using untreated and treated flat-sawn heartwood boards at 160, 180, 200, and 220 °C for 2 h. The shrinkage in the radial and tangential directions increased with increasing temperature, whereas the anisotropy coefficients decreased from 160 to 200 °C and increased at 220 °C. At all temperatures, Qm exhibited the smallest shrinkage, and Qv showed the highest shrinkage in the radial and tangential directions. The surface roughness of the oak wood decreased with increasing temperature, showing the highest average roughness (R_a) value in Qs at all temperatures. Qm and Qac showed the smallest R_a values at 160 to 200 °C and 220 °C, respectively. Qm showed the highest change in R_a value at 160 and 200 °C, while Qv had the highest change at 180 and 220 °C. In contrast, Qal consistently exhibited the smallest change in R_a at all temperatures.

This study aimed to assess the applicability of the extract and hydrosol obtained from the yarrow (Achillea millefolium) plant, which has grown widely in places where the Mediterranean climate prevails, as an impregnation agent for wooden materials. Red pine (Pinus brutia), oriental beech (Fagus orientalis), and walnut (Juglans regia) were selected as test samples of wood. An immersion method was used for the impregnation process that was performed for different time periods, 30 min (short), 3 h, (medium), and 24 h (long). Following the impregnation process, test samples were soaked in water for 6, 24, 48, 72, and 96 h to determine some physical properties of wooden material (retention, specific gravity, shrinkage, swelling, and water uptake). The results revealed that the highest retention after yarrow extract impregnation was achieved with red pine at 10% hydrosol concentration (2.29%) in a 30 min period whereas the lowest retention was observed with walnut material at 10% hydrosol concentration (1.17%) within a 24 h period. Yarrow extract did not have a significant effect on the physical properties of impregnated wooden materials; however, it was argued that the hydrosol was effective in the dimensional stability of all test samples due to its water-repellent properties.

In a 16-month study addressing global agricultural soil heavy metal contamination, researchers explored plant-centered solutions using Jacaranda plants. The impact of different combinations of cadmium nitrate (40, 80, and 120 mg) and lead nitrate (400, 800, and 1200 mg/kg soil) were evaluated relative to Jacaranda’s remediation capabilities. Employing a randomized complete block design with 8 applications across 3 repetitions, the study assessed growth traits and chemical characteristics. Untreated plants showed higher growth values, contrasting with reduced values in plants exposed to elevated cadmium (Cd) and lead (Pb) levels. For instance, the treatment with 120 mg Cd/kg soil + 1200 mg Pb/kg soil led to a 28% reduction in plant height, 13% in main stem diameter, 41% in branch number, and 35% in leaf area compared to the control. Despite these challenges, Jacaranda plants demonstrated resilience with a 100% survival rate. Plant organs showed increased Cd and Pb contents, with fallen leaves having lower metal content, mitigating pollution hazards. Post-planting, soil characteristics shifted, indicating Jacaranda‘s potential for Cd phytoextraction (BCF < 1 and, TF > 1) and Pb phytostabilization (BCF and TF < 1). The study establishes Jacaranda as a promising candidate for phytoremediation due to its resilience to elevated metal levels.

Cellulose is photosynthesized by plants from carbon dioxide and water, and it is the most abundant organic compound available. It is present in the plant cells as structural component in the form of elementary fibrils known as nanofibers. Cellulose nanofibers can be easily extracted from parenchyma tissues of agricultural waste. Although thin sheets made of cellulose nanofibers can be readily obtained by a papermaking method, thicker plates are difficult to make. Here we propose a papermaking-like method to fabricate 1 to 2 mm-thick plates from citrus fruit residue-derived cellulose pulp initially having a solids content of about 1%. The protocol is simple, easy, requires affordable devices and relies on water evaporation to consolidate the fibrils by hydrogen bond interconnections. The pulp morphology seems to consist mostly of cellulose nanofibers and the bending strength and modulus of obtained plates reached 190 ± 30 MPa and 9.6 ± 1.5 GPa, respectively, values that approach those reported in a previous study that molded microfibrillated cellulose but relying on a complex process. This streamlined protocol could be groundwork for further studies aiming the difficult task of molding cellulosic materials.

The large old tree population of Barringtonia racemosa (L.) Spreng plays a crucial ecological and cultural role in rural areas (Danzhou, tropical China). This study investigates the population structure, demographic characteristics, and conservation status of B. racemosa in remnant forest stands. The findings reveal a skewed distribution towards smaller to intermediate-size classes, with a significant decline in larger-size classes. The static life table highlights high mortality rates in the early stages and moderate survivorship in mid-size classes, indicating a bottleneck in the transition from medium to larger-size classes. The study identifies external interference as a potential threat to the B. racemosa population. Based on these findings, a multifaceted conservation approach is proposed to integrate traditional ecological knowledge, implement community-based conservation programs, enhance habitat protection and restoration, and strengthen legal protection and policy support. This research underscores the critical role of large old trees in ecosystem health. It highlights the need for targeted conservation strategies to preserve these vital components of natural landscapes in rural China.

Defect-free, highly-densified panels without springback were prepared from Hyun aspen (Populus alba × glandulosa) wood with different delignification levels by alkaline hydrogen peroxide (AHP) pretreatment. The AHP concentrations were adjusted to 3%, 7%, 10%, while the temperature (100 °C), time (3 h), pH (11), liquor ratio (6.25), and stabilizer (0.5% EDTA) remained constant. The delignification of Hyun aspen wood panels was indirectly quantified by analyzing the UV absorbance of the spent liquor after AHP treatment, wherein delignification ranged from 12% to 58% depending on the AHP concentration. To achieve highly-densified panels, the densification conditions, such as pressure, temperature, and time, were examined. Panels subjected to cold-pressing (25 °C) at 30 MPa for 1 h, followed by hot-pressing (105 °C) at 30 MPa for 6 h, then immediately removed after heating, resulted in durable, highly-densified panels with no springback or cracks.