A cyclic nucleotide-gated channel gene HcCNGC21 positively regulates salt and drought stress responses in kenaf (Hibiscus cannabinus L.).

Cyclic Nucleotide-Gated Channels (CNGCs) serve as Ca2+ permeable cation transport pathways, which are involved in the regulation of various biological functions such as plant cell ion selective permeability, growth and development, responses to biotic and abiotic stresses. At the present study, a total of 31 CNGC genes were identified and bioinformatically analyzed in kenaf. Among these genes, HcCNGC21 characterized to localize at the plasma membrane, with the highest expression levels in leaves, followed by roots. In addition, HcCNGC21 could be significantly induced under salt or drought stress. Virus-induced gene silencing (VIGS) of HcCNGC21 in kenaf caused notable growth inhibition under salt or drought stress, characterized by reductions in plant height, stem diameter, leaf area, root length, root surface area, and root tip number. Meanwhile, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were significantly decreased, accompanied by reduced levels of osmoregulatory substances and total chlorophyll content. However, ROS accumulation and Na+ content increased. The expression of stress-responsive genes, such as HcSOD, HcPOD, HcCAT, HcERF3, HcNAC29, HcP5CS, HcLTP, and HcNCED, was significantly downregulated in these silenced lines. However, under salt or drought stress, the physiological performance and expression of stress-related genes in transgenic Arabidopsis thaliana plants overexpressing HcCNGC21 were diametrically opposite to those of TRV2-HcCNGC21 kenaf line. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays revealed that HcCNGC21 interacts with HcAnnexin D1. These findings collectively underscore the positive role of HcCNGC21 in plant resistance to salt and drought stress.

Antioxidant Activities in Kenaf (Hibiscus cannabinus) Shoots during Growth Stages and Destination of Chlorogenic Acid and Kaempferol Glycosides.

Apart from being utilized as a commercial fiber at maturity, kenaf shoots have potential as a food and feed source because of their diverse bioactivities. Previous studies have focused on mature stems because of their high biomass, whereas the antioxidant activities (AA) and the destination of AA contributors of kenaf stems and their high-yielding byproduct leaves during the growth stage have rarely been studied. Therefore, we investigated changes in AA and its relative components in kenaf leaves and stems during the four vital growth stages. Higher ABTS radical cation and DPPH radical scavenging abilities and ferric reducing antioxidant power, total phenolic content, total flavonoid content, and total polysaccharide content were observed at all leaf stages and in the late stem stages. Chlorogenic acid (CGA) and kaempferol glycosides, especially kaempferitrin (Kfr), were identified as representative phenolic acids and flavonoids in both kenaf leaves and stems. The content of CGA in both leaves and stems increased corresponding to the plant's growth stage, whereas kaempferol glycosides were enhanced in leaves but declined in stems. The highest correlation was observed between TPC and AA in all organs. Further evaluation of CGA and Kfr verified that CGA was the predominant contributor to AA, surpassing Kfr. These findings suggest that kenaf leaves increase antioxidant levels as they grow and can be a useful source of stem harvesting byproducts.

Isolation and characterisation of lignin using natural deep eutectic solvents pretreated kenaf fibre biomass.

Extraction of lignin via green methods is a crucial step in promoting the bioconversion of lignocellulosic biomasses. In the present study, utilisation of natural deep eutectic solvent for the pretreatment of kenaf fibres biomass is performed. Furthermore, extracted lignin from natural deep eutectic solvent pretreated kenaf biomass was carried out and its comparative study with commercial lignin was studied. The extracted lignin was characterized and investigated through Infrared Fourier transform spectroscopy, X-ray Diffraction, thermogravimetric analysis, UV-Vis spectroscopy, and scanning electron microscopy. FTIR Spectra shows that all samples have almost same set of absorption bands with slight difference in frequencies. CHNS analysis of natural deep eutectic solvent pretreated kenaf fibre showed a slight increase in carbon % from 42.36 to 43.17% and an increase in nitrogen % from - 0.0939 to - 0.1377%. Morphological analysis of commercial lignin shows irregular/uneven surfaces whereas natural deep eutectic solvent extracted lignin shows smooth and wavy surface. EDX analysis indicated noticeable peaks for oxygen and carbon elements which are present in lignocellulosic biomass. Thermal properties showed that lignin is constant at higher temperatures due to more branching and production of extremely condensed aromatic structures. In UV-VIS spectroscopy, commercial lignin shows slightly broad peak between 300 and 400 nm due to presence of carbonyl bond whereas, natural deep eutectic solvent extracted lignin does not show up any peak in this range. XRD results showed that the crystallinity index percentage for kenaf and natural deep eutectic solvent treated kenaf was 70.33 and 69.5% respectively. Therefore, these innovative solvents will undoubtedly have significant impact on the development of clean, green, and sustainable products for biocatalysts, extraction, electrochemistry, adsorption applications.

Exogenous methyl jasmonate enhanced kenaf (Hibiscus cannabinus) tolerance against lead (Pb) toxicity by improving antioxidant capacity and osmoregulators.

In this study, the effects of exogenous methyl jasmonate (MeJA) on metal uptake and its ability to attenuate metal toxicity in kenaf plants under Pb stress were investigated. The experiment was conducted with five different MeJA concentrations (0, 40, 80, 160, and 320 µM) as a foilar application to kenaf plants exposed to 200 µM Pb stress. The results revealed that pretreatmen of MeJA significantly increased plant dry weight, plant height, and root architecture at all concentrations tested, with the most significant increase at 320 µM. Foliar application of MeJA at 160 µM and 320 µM increased the Pb concentrations in leaves and stems as well as the translocation factor (TF) from root to leaf. However, the bioaccumulation factor in the shoot initially decreased and then increased with increasing MeJA concentration. By increasing enzymatic (SOD, POD, and CAT) and non-enzymatic (AsA and non-protein thiols) antioxidants, MeJA pretreatment decreased lipid peroxidation, O2- and H2O2 accumulation and recovered photosynthetic pigment content under Pb stress. Increased osmolytes (proline, sugar, and starch) and protein content after MeJA pretreatment under Pb stress restore cellular homeostasis and improved kenaf tolerance. Our results suggest that MeJA pretreatment modifies the antioxidant machinery of kenaf and inhibits stress-related processes that cause lipid peroxidation, hence enhancing plant tolerance to Pb stress.

Kenaf-based activated carbon: A sustainable solution for high-performance aqueous symmetric supercapacitors.

This study presents an innovative method for synthesizing activated carbon with an exceptionally high surface area (3359 m2 g-1) using kenaf fiber-based biochar through chemical activation. The achieved specific surface area surpasses activated carbon derived from other reported fiber-based precursors. The resulting activated carbon was investigated as electrodes for supercapacitors, revealing a remarkable maximum capacitance of 312 F g-1 at a current density of 0.5 A g-1. An aqueous symmetric supercapacitor employing these high-surface-area electrodes exhibited an outstanding energy density of 18.9 Wh kg-1 at a power density of 250 W kg-1. Notably, the supercapacitor retained exceptional capacitance, maintaining 93% of its initial capacitance even after 5000 charge-discharge cycles.

Determination of carbohydrate content in kenaf degumming wastewater and converting them to carbon dots.

The traditional textile degumming process produces abundant wastewater, which contains a lot of monosaccharides and oligosaccharides. It is of great economic and environmental significance to utilize these carbohydrates in high value. In this study, high performance liquid chromatography (HPLC) was used to analyze the carbohydrate components in kenaf degumming wastewater, and then the production of C-dots using the wastewater was explored. The results showed that the types and content in the degumming wastewater were monosaccharides (glucose, xylose and arabinose) and oligosaccharides (dextran, xylan and araban). The carbohydrate (mainly glucan and xylan) content in wastewater accounted for 91.16 % of the total carbohydrates weight loss in kenaf degumming process. By using hydrolysis and hydrothermal reaction on kenaf degumming wastewater, blue-green carbon dots (C-dots) with good performance were prepared and successfully applied to anti-counterfeiting printing. In particular, the as-prepared C-dots prepared from kenaf degumming wastewater with urea added (WUC-dots) showed an excitation-dependent photoluminescence (PL) spectrum and quantum yield (QY) of 2.4 % in aqueous solution. The fluorescent code exhibited a clear outline, excitation-tunable color and good stability, showing a great potential for anti-counterfeiting system.

Genome-Wide Association Study for Agronomic Traits in Gamma-Ray-Derived Mutant Kenaf (Hibiscus cannabinus L.).

Kenaf (Hibiscus cannabinus L.), in the Malvaceae family, is an important crop for not only fiber production, but also various other industrial materials. We performed phylogenetic analysis and a genome-wide association study (GWAS) of seven agronomic traits: days to flowering, plant height, fresh weight, dry weight, flower color, stem color, and leaf shape, using 96 kenaf genotypes, including gamma-irradiation-derived mutant lines. Genotypes were determined by genotyping-by-sequencing (GBS) and a total of 49,241 single-nucleotide polymorphisms (SNPs) were used in the analysis. Days to flowering, plant height, fresh weight, and dry weight were positively correlated with each other, and stem color was also correlated with fresh weight and dry weight. The phylogenetic analysis divided the 96 lines into nine related groups within two independent groups, and the GWAS analysis detected a total of 49 SNPs for days to flowering, plant height, fresh weight, dry weight, flower color, stem color, and leaf shape with -log10(P) ≥ 4, of which 22 were located in genic regions. The detected SNPs were located in genes with homology ranging from 45% to 96% to plants of the Malvaceae and Betulaceae, and these genes were found to be involved in plant growth and development via various pathways. Our identification of SNP markers related to agronomic traits is expected to help improve the quality of selective breeding programs for kenaf.

Fundamental investigation of micro-nano cellulose and lignin interaction for transparent paper: Experiment and electrostatic potential calculation.

Plastic has significant negative consequences for the environment and human health, demanding greener alternatives. Lignocellulose is a sustainable biomass material, and its paper has been considered as a potential material to replace plastics. Micro-nano lignocellulose, derived from natural plants, possesses a small size and abundant hydrogen bonding capacity. However, there is no clear explanation for the interactions between lignin and micro-nano cellulose, and little understanding of how the interaction can affect the papers' structure and optical properties. Electrostatic potential calculation is a reliable tool to explain non-covalent interactions, and can explore the binding between lignin and micro-nano cellulose. In this paper, kenaf - a non-wood fiber raw material - was employed to prepare micro-nano lignocellulose. The resulting slurry facilitated the production of transparent paper via a simple casting method. The prepared transparent micro-nano paper exhibited high transparency (~90 %), UVA resistance (~80 %), and hydrophobicity (~114°). More importantly, the electrostatic potential calculation demonstrates the inherent relationship between structure and performance, providing practical knowledge for constructing film materials.

Influence of Nitrogen Supply on Growth, Antioxidant Capacity and Cadmium Absorption of Kenaf (Hibiscus cannabinus L.) Seedlings.

Kenaf (Hibiscus cannabinus L.) is considered suitable for the remediation of cadmium (Cd)-contaminated farmlands, because of its large biomass and resistance to Cd stress. The addition of nitrogen (N) fertilizer is an important measure used to increase crop yields, and it may also affect Cd accumulation in plants. To clarify the effects of different forms and concentrations of N on plant growth and Cd absorption in kenaf, a hydroponic experiment was conducted using three N forms (NH4+-N, NO3--N and urea-N) at four concentrations (0, 2, 4 and 8 mM, 0 mM as control) under Cd stress (30 µM). The plant growth, the antioxidant enzyme activity and the Cd contents of various parts of the kenaf seedlings were measured. The results showed that the N form had the greatest impact on the growth of the kenaf and the absorption and transport of the Cd, followed by the interaction effect between the N type and the concentration. Compared to the control, the addition of N fertilizer promoted the growth of kenaf to varying degrees. Among all the treatments, the use of 2 mM of NO3--N enhanced the biomass and Cd accumulation to the greatest extent compared to CK from 2.02 g to 4.35 g and 341.30 µg to 809.22 µg per plant, respectively. The NH4+-N significantly reduced the Cd contents of different parts but enhanced the translocation factors of Cd stem to root (TF S/R) and leaf to stem (TF L/S) by 34.29~78.57% and 45.10~72.55%, respectively. The peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) enzyme activities of the kenaf increased with the N treatments, especially with NH4+-N. Overall, applying low concentrations of NO3--N can better promote the extraction of Cd by kenaf.

A simple and rapid method for isolating high-quality RNA from kenaf with high polysaccharide and polyphenol contents.

The extraction of high-quality RNA from kenaf is essential for genetic and molecular biology research. However, the presence of high levels of polysaccharide and polyphenol compounds in kenaf poses challenges for RNA isolation. We proposed a simplified, time-saving and cost-effective method for isolating high quantities of RNA from various kenaf tissues. This method exhibited superior efficiency in RNA isolation compared with the conventional cetyltrimethylammonium bromide method and demonstrated greater adaptability to different samples than commercial kits. Furthermore, the high-quality RNA obtained from this method was successfully utilized for RT-PCR, real-time RT-PCR and northern blot analysis. Moreover, this proposed protocol also enables the acquisition of both high-quality and -quantity gDNA through RNase A treatment. In addition, the effectiveness of this approach in isolating high-quality RNA from other plant species has been experimentally confirmed.

Performance of Malaysian kenaf Hibiscus cannabinus callus biomass and exopolysaccharide production in a novel liquid culture.

The versatility of a well-known fibrous crop, Hibiscus cannabinus (kenaf) is still relatively new to many. Kenaf's potential applications, which can be extended even into critical industries such as pharmaceutical and food industries, have always been overshadowed by its traditionally grown fiber. Therefore, this study aimed to venture into the biotechnological approach in reaping the benefits of kenaf through plant cell suspension culture to maximize the production of kenaf callus biomass (KCB) and exopolysaccharide (EPS), which is deemed to be more sustainable. A growth curve was established which indicates that cultivating kenaf callus in suspension culture for 22 days gives the highest KCB (9.09 ± 1.2 g/L) and EPS (1.1 ± 0.02 g/L). Using response surface methodology (RSM), it was found that sucrose concentration, agitation speed, and naphthalene acetic acid (NAA) concentration can affect the production of KCB and EPS significantly (p < 0.05) while 2,4-dichlorophenoxy acetic acid (2,4-D) was deemed insignificant. To maximize the final yield of KCB and EPS, the final optimized variables are 50 g/L sucrose, 147.02 rpm, and 2 mg/L of NAA. To conclude, the optimized parameters for the cell suspension culture of kenaf callus serve as the blueprint for any sustainable large-scale production in the future and provide an alternative cultivating method to kenaf traditional farming.

The optimized cell cultivation for plant kenaf callus is 22 daysSucrose, agitation and NAA concentration stimulates the production of KCB and EPSHighest KCB and EPS was generated at 13.41 g/L and 1.86 g/L, respectivelyMaximum production blueprint for KCB and EPS require 50 g/L sucrose, 2 mg/L of NAA and 147.02 rpm.

A review of recent developments in kenaf fiber/polylactic acid composites research.

Kenaf fiber has recently garnered exponential interest as reinforcement in composite materials across diverse industries owing to its superior mechanical attributes, ease of manufacture, and inherent biodegradability. In the discourse of this review, various methods of manufacturing kenaf/Polylactic acid (PLA) composites have been discussed meticulously, as delineated in recently published scientific literatures. This paper delves into the chemical modification of kenaf fiber, examining its consequential impact on tensile strength and thermal stability of the kenaf/PLA composites. Further, this review illuminates the role of innovative 3D printing techniques and fiber orientation in augmenting the mechanical robustness of the kenaf/PLA composites. Simultaneously, recent insightful explorations into the acoustic properties of the kenaf/PLA composites, underscoring their potential as sustainable alternative to conventional materials have been reviewed. Serving as a comprehensive repository of knowledge, this review paper holds immense value for researchers aiming to utilize the capabilities of kenaf fiber reinforced PLA composites.

Intercropping of kenaf and soybean affects plant growth, antioxidant capacity, and uptake of cadmium and lead in contaminated mining soil.

Intercropping is considered a sustainable agricultural practice that can reduce the environmental impacts on agriculture. Our study investigated the morphology, physiology, and cadmium (Cd) and lead (Pb) uptake of kenaf (Hibiscus cannabinus L.) and soybean (Glycine max L.) under intercropping in mining soil. Results showed that mutual intercropping is conducive to the growth and biomass accumulation of kenaf and soybean, compared to their respective monoculture. Intercropping increased the relative chlorophyll index in kenaf, while that in soybean had no significant effect. Furthermore, intercropping increased the antioxidant enzyme activity of kenaf, while that of soybean reduced or had no significant effect. The content of malondialdehyde (MDA) was decreased in both of the species. Compared to their respective monoculture, Cd content was increased in kenaf leaves and reduced in soybean roots. Moreover, intercropping decreased the Pb content in tissues of both the species, except that Pb content of kenaf roots was increased. At the same time, root, leaf, or stem bioconcentration factors also performed the same trend, and TF was less than 1. These results indicated that intercropping can increase the plant growth and decrease the metal content in plant tissues. Present findings could provide support for future research on kenaf and soybean cultivation in contaminated lands. In addition, the present study strengthens our understanding about the effectiveness of intercropping system on heavy metal-contaminated lands for sustainable agricultural production.

Exogenous glutathione can alleviate chromium toxicity in kenaf by activating antioxidant system and regulating DNA methylation.

Glutathione (GSH) participates in plant response to heavy metals (HMs) stress, however, the epigenetic regulating mechanisms of GSH in HMs detoxification remains unclear. In this study, to reveal the potential epigenetic regulating mechanisms, kenaf seedlings were treated with/without GSH under chromium (Cr) stress. A comprehensive physiological, genome-wide DNA methylation and gene functional analysis were performed. Results showed that external GSH obviously recovered Cr-induced growth inhibition, significantly decreased H2O2, O2.- and MDA accumulation, increased the activities of antioxidant enzymes (SOD, CAT, GR and APX) in kenaf exposed to Cr. In addition, the expression level of the main DNA methyltransferase (MET1, CMT3 and DRM1) and demethylase (ROS1, DEM, DML2, DML3 and DDM1) genes were investigated by qRT-PCR. The result indicated that Cr stress decreased DNA methyltransferase genes expression while increased demethylase genes expression; however, apply exogenous GSH led to the recovery trend. These indicating exogenous GSH alleviation Cr stress on kenaf seedlings by increasing DNA methylation level. At the same time, the MethylRAD-seq genome-wide DNA methylation analysis showed the DNA methylation level was significantly increased after GSH treatment compared with Cr treatment alone. The differentially methylated genes (DMGs) were uniquely enriched in DNA repair, flavin adenine dinucleotide binding and oxidoreductase activity. Furthermore, a ROS homeostasis-associated DMG, HcTrx, was selected for further functional analysis. Results showed that the knock-down of HcTrx kenaf seedlings displayed yellow-green phenotype and impaired antioxidant enzyme activity; in contrast, the overexpression lines of HcTrx improved chlorophyll levels and enhanced Cr tolerance in Arabidopsis. Taken together, our results illustrate the novel role of GSH-mediated Cr detoxification in kenaf by modulating the DNA methylation, and thus further affect the activation of antioxidant defense systems. The present characterized Cr tolerant gene resource could be further used for kenaf Cr tolerant breeding via genetic improvement.

The Effects of Self-Polymerized Polydopamine Coating on Mechanical Properties of Polylactic Acid (PLA)-Kenaf Fiber (KF) in Fused Deposition Modeling (FDM).

This research examines the impact of self-polymerized polydopamine (PDA) coating on the mechanical properties and microstructural behavior of polylactic acid (PLA)/kenaf fiber (KF) composites in fused deposition modeling (FDM). A biodegradable FDM model of natural fiber-reinforced composite (NFRC) filaments, coated with dopamine and reinforced with 5 to 20 wt.% bast kenaf fibers, was developed for 3D printing applications. Tensile, compression, and flexural test specimens were 3D printed, and the influence of kenaf fiber content on their mechanical properties was assessed. A comprehensive characterization of the blended pellets and printed composite materials was performed, encompassing chemical, physical, and microscopic analyses. The results demonstrate that the self-polymerized polydopamine coating acted as a coupling agent, enhancing the interfacial adhesion between kenaf fibers and the PLA matrix and leading to improved mechanical properties. An increase in density and porosity was observed in the FDM specimens of the PLA-PDA-KF composites, proportional to their kenaf fiber content. The enhanced bonding between kenaf fiber particles and the PLA matrix contributed to an increase of up to 13.4% for tensile and 15.3% for flexural in the Young's modulus of PLA-PDA-KF composites and an increase of up to 30% in compressive stress. The incorporation of polydopamine as a coupling agent in the FDM filament composite led to an improvement in tensile, compressive, and flexural stresses and strain at break, surpassing that of pure PLA, while the reinforcement provided by kenaf fibers was enhanced more by delayed crack growth, resulting in a higher strain at break. The self-polymerized polydopamine coatings exhibit remarkable mechanical properties, suggesting their potential as a sustainable material for diverse applications in FDM.

The Capabilities of Honeycomb Core Structures Made of Kenaf/Polylactic Acid Composite under Compression Loading.

This study investigated the capability of honeycomb core structures made of kenaf fibre-reinforced polylactic acid (PLA) composite. Two types of kenaf fibre were used in this study, these being woven kenaf and non-woven cotton/kenaf. Initially, the corrugated shape panel was manufactured using a hot moulding compression method. The panel was then cut into corrugated strips, bonded together using epoxy resin to form the honeycomb core structure, and balsa wood used as their skins. The effects of core height and crosshead displacement rate were investigated. The honeycomb core consisted of 20 mm, 30 mm and 40 mm core heights, and the crosshead displacement rate ranged from 2 mm/min to 500 min/min. Of all the samples, core structure with a height of 20 mm tested at 500 mm/min offered the highest value of compressive strength and specific energy absorption, which were 6.23 MPa and 12.36 kJ/kg, respectively. It was also discovered that the core height and loading rate have significant effects on the mechanical properties of the kenaf/PLA honeycomb core structure.

Effect of fiber layer formation on mechanical and wear properties of natural fiber filled epoxy hybrid composites.

Natural fiber-reinforced polymer matrix composites are gathering significance in future trend applications such as automotive, aerospace, sport, and other engineering applications due to their superior enhanced mechanical, wear, and thermal properties. Compared to synthetic fiber, natural fiber is low adhesive and flexural strength properties. The research aims to synthesize the epoxy hybrid composites by utilizing the silane (pH = 4) treated Kenaf (KF) and sisal fiber (SF) as layering by uni, bi, and multi-unidirectional via hand layup techniques. Thirteen composite samples have been prepared by three-layer formation adopted with different weight ratios of E/KF/SF such as 100E/0KF/0SF, 70E/30KF/0SF, 70E/0KF/30SF, 70E/20KF/10SF, and 70E/10KF/20SF respectively. The effect of layer formation on the tensile, flexural, and impact strength of composites is studied by ASTM D638, D790, and D256 standards. The unidirectional fiber layer formed (sample 5) 70E/10KF/20SF composite is found maximum tensile and flexural strength of 57.9 ± 1.2 MPa and 78.65 ± 1.8 MPa. This composite is subjected to wear studies by pin-on-disc wear apparatus configured with a hardened grey cast-iron plate under an applied load of 10, 20, 30, and 40 N at different sliding velocities of 0.1, 0.3, 0.5, and 0.7 m/s. The wear rate of the sample progressively increases with increasing load and sliding speed of the composite. The minimum wear rate of 0.012 mg/min (sample 4) is found on 7.6 N frictional force at 0.1 m/s sliding speed. Moreover, sample 4 at a high velocity of 0.7 m/s with a low load (10 N) shows a wear rate of 0.034 mg/min. The wear-worn surface is examined and found adhesive and abrasive wear on a high frictional force of 18.54 N at 0.7 m/s. The enhanced mechanical and wear behavior of sample 5 is recommended for automotive seat frame applications.

Heterogeneity Assessment of Kenaf Breeding Field through Spatial Dependence Analysis on Crop Growth Status Map Derived by Unmanned Aerial Vehicle.

The investigation of quantitative phenotypic traits resulting from the interaction between targeted genotypic traits and environmental factors is essential for breeding selection. Therefore, plot-wise controlled environmental factors must be invariable for accurate identification of phenotypes. However, the assumption of homogeneous variables within the open-field is not always accepted, and requires a spatial dependence analysis to determine whether site-specific environmental factors exist. In this study, spatial dependence within the kenaf breeding field was assessed in a geo-tagged height map derived from an unmanned aerial vehicle (UAV). Local indicators of spatial autocorrelation (LISA) were applied to the height map using Geoda software, and the LISA map was generated in order to recognize the existence of kenaf height status clusters. The spatial dependence of the breeding field used in this study appeared in a specific region. The cluster pattern was similar to the terrain elevation pattern of this field and highly correlated with drainage capacity. The cluster pattern could be utilized to design random blocks based on regions that have similar spatial dependence. We confirmed the potential of spatial dependence analysis on a crop growth status map, derived by UAV, for breeding strategy design with a tight budget.

Effect of corn husk fibre loading on thermal and biodegradable properties of kenaf/cornhusk fibre reinforced corn starch-based hybrid composites.

This paper documents the thermal and biodegradation behaviour of kenaf/cornhusk fiber reinforced corn starch-based hybrid composites film (CS/K-CH) produced by solution casting method. To develop both components as biodegradable hybrid composite, this research used corn starch as matrix, kenaf fiber and cornhusk fibre as a filler. Changes in physical structure and weight from the soil burial test were measured using Mettler Toledo digital balance ME. Films produced from physically blended corn starch reinforced kenaf biocomposites films (CS/K) biocomposite film had faster biodegradation and lost 96.18% of weight within 10 days compared with corn starch hybrid composites that only lost 83.82% of total weight. It was observed that the control film, CS/K biocomposite film was completely degraded after 10 days, meanwhile it took 12 days for hybrid composite films to be fully degrade. The thermal properties such as TGA and DTG were also measured. Addition of corn husk fiber significantly improve the film's thermal properties. Glass transition temperatures of corn starch hybrid films were significantly lowered when cornhusk compositions were increased from 0.2% wt to 0.8% wt. Importantly, the current work has demonstrated that hybrid films made of corn starch can be a suitable biodegradable material for substitute synthetic plastic.

Effects of Fiber Loading on Mechanical Properties of Kenaf Nanocellulose Reinforced Nanohybrid Dental Composite Made of Rice Husk Silica.

The innovation of nanocellulose as reinforcement filler in composites has been a topic of interest in the development of new biomaterials. The objective of this study was to investigate the mechanical properties of a nanohybrid dental composite made of rice husk silica and loaded with different percentages of kenaf nanocellulose. Kenaf cellulose nanocrystals (CNC) were isolated and characterized using a transmission electron microscope (TEM) (Libra 120, Carl Zeiss, Germany). The experimental composite was fabricated with fiber loadings of 1 wt%, 2 wt%, 3 wt%, 4 wt%, and 6 wt% silane-treated kenaf CNC, and subjected to a flexural and compressive strength test (n = 7) using an Instron Universal Testing Machine (Shimadzu, Kyoto, Japan), followed by a scanning electron microscopic assessment of the flexural specimen's fracture surface using a scanning electron microscope (SEM) (FEI Quanta FEG 450, Hillsborough, OR, USA). Commercial composites Filtek Z350XT (3M ESPE, St. Paul, MN, USA), Neofil (Kerr Corporation, Orange, CA, USA) and Ever-X Posterior (GC Corporation, Tokyo, Japan) were used as a comparison. The average diameter of kenaf CNC under TEM was 6 nm. For flexural and compressive strength tests, one-way ANOVA showed a statistically significant difference (p < 0.05) between all groups. Compared to the control group (0 wt%), the incorporation of kenaf CNC (1 wt%) into rice husk silica nanohybrid dental composite showed a slight improvement in mechanical properties and modes of reinforcement, which was reflected in SEM images of the fracture surface. The optimum dental composite reinforcement made of rice husk was 1 wt% kenaf CNC. Excessive fiber loading results in a decline in mechanical properties. CNC derived from natural sources may be a viable alternative as a reinforcement co-filler at low concentrations.