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Purpose: Phytostabilization is known to be a promising technique to prevent the off-site movement of cadmium (Cd) from severely contaminated arable soils. Previous studies have recognized plants and amendments that could be potentially used for phytostabilization, such as non-edible fiber and energy crops and biochar. However, there is a paucity of information on the performance of these candidate crops and amendments for the application in the field. Methods: Twelve plant-amendment systems were established on the farmland severely contaminated with Cd in the South China karst area, which comprises cash crops kenaf (Hibiscus cannabinus), ramie (Boehmeria nivea), and sorghum (Sorghum bicolor) together with the application of lime, coconut shell biochar, and rice straw biochar at different rates. A comprehensive score was introduced to evaluate the performance of the studied plant-amendment systems, considering not only the indicators related to soil Cd mobility but also the costs. Results: After one crop cycle, a 40% median rate of reduction was achieved in soil available Cd. An intensive application of biochar lowered the comprehensive performance since a significantly increased cost gained only a slight improvement in the reduction of soil available Cd. Sorghum with 0.5% (w/w) rice straw biochar showed the best performance in the study site, which effectively sequestrated Cd in the roots and reduced soil available Cd at a relatively low cost. Conclusion: This work shows the performance and the comprehensive evaluation of candidate plant-amendment systems for the in situ phytostabilization. [ABSTRACT FROM AUTHOR]

Kenaf (Hibiscus cannabinus L.) is suitable for growing in heavy metal-polluted soil for non-food purposes and can be used as a potential crop to remediate heavy metal-contaminated soil. The main objective of this study was to investigate kenaf phytoextraction of cadmium (Cd), including uptake, translocation, and accumulation differences in tissues among kenaf cultivars. A field experiment was conducted in a Cd contaminated paddy field in southern China area with 13 kenaf cultivars in 2015 and 2016. Agronomic performance, Cd concentrations in plant tissues (root, xylem, and phloem), and biomass of different tissues of each cultivar were measured and evaluated. Significant differences in Cd concentrations and accumulation among tissues and cultivars were observed. The phloem had the highest Cd accumulation and transfer capability compared with the roots and xylem. Approximately 35 ~ 65 g of Cd could be taken up by the aerial parts of different kenaf cultivars within every hectare of soil. The percentage of Cd uptake by the phloem ranged from 47 to 61% and by the xylem ranged from 38 to 53%. By evaluating the agronomic traits and Cd bioaccumulation capacity, Fuhong 952, Fuhong 992, and Fuhong R1 were regarded as Cd accumulators for the phytoremediation of Cd-contaminated soil. Our study clearly demonstrated that a significant level of Cd in the soil was taken up through the phytoremediation with kenaf. In addition, harmless utilization of kenaf planting in Cd-contaminated paddy soil was discussed. [ABSTRACT FROM AUTHOR]

Given the rising domestic demand and increasing global prices of corn and soybean, China is looking for alternatives for these imports to produce animal fodder. Kenaf (Hibiscus cannabinus L.) has great potential as a new forage source, due to abundant proteins, phenols and flavonoids in its leaves. However, few studies have evaluated the mechanism of protein synthesis in kenaf leaves. In the current work, compared with kenaf material "L332," the percentage of crude protein content in leaves of material "Q303" increased by 6.13%; combined with transcriptome and proteome data, the kenaf samples were systematically studied to obtain mRNA-protein correlation. Then, the genes/proteins related to protein synthesis in the kenaf leaves were obtained. Moreover, this work detected mRNA expression of 20 differentially expressed genes (DEGs). Meanwhile, 20 differentially expressed proteins (DEPs) related to protein synthesis were performed parallel reaction monitoring. Fructose-1,6-bisphosphatase (FBP), nitrite reductase (NirA), prolyl tRNA synthase (PARS) and glycine dehydrogenase (GLDC) presented increased mRNA and protein levels within kenaf leaves with high protein content. Based on the obtained findings, FBP , NirA , PARS , and GLDC genes may exert a vital function in the protein synthesis of kenaf leaves. The results provide a new idea for further studying the potential genes affecting the quality trait of protein content in kenaf leaves and provide gene resources and a theoretical foundation for further cultivating high protein kenaf varieties. [ABSTRACT FROM AUTHOR]

Kenaf (Hibiscus cannabinus) is an annual fiber crop grown mainly in India and China. This crop is becoming a new bio‐based energy source because of its fast growth rate, excellent CO2 absorption ability, and large productivity per unit area. In this study, we evaluated 10 different cultivars of kenaf for their potential as biomass for cellulosic ethanol production. First, kenaf samples were hydrolyzed using dilute sulfuric acid, which is the most simple and cost‐effective pretreatment method. Next, simultaneous saccharification and fermentation (SSF) of the hydrolysates were performed by wild‐type and engineered xylose‐fermenting yeast strains. The results of compositional analysis of the biomass, the hydrolysates, and the fermented products suggested that ethanol yield and productivity were significantly affected by a type of kenaf cultivars, which was not predictable based on the biomass compositions. Also, the ethanol production was maximized when the xylose fraction was utilized by engineered yeast under the control of pH to avoid acetate inhibition. Considering the sugar compositions and their fermentability, kenaf can be a promising energy‐dedicated crop for cellulosic ethanol production. [ABSTRACT FROM AUTHOR]

Protein feed shortage is one of the most important factors that limit the development of animal husbandry in China. Kenaf (Hibiscus cannabinus L.) can be used as a high-quality protein feed for livestock. The aims of this study were to evaluate the yield and quality characters of seven kenaf varieties harvested on the basis of stubble height and to screen the varieties with high nutritive value. A reasonable stubble height was selected, and then kenaf varieties were cut leaving the selected stubble height and their nutritive value was determined. The results showed that stubble height of 90 cm was the most appropriate for improving the biomass content and nutritive value of kenaf. The dry matter yield of the whole plants, crude protein content and crude fibre content of the seven kenaf varieties ranged from 15,359.31 kg/ha to 18,502.18 kg/ha, 8.99% to 16.23% and 16.71% to 37.43%, respectively. The nutritive value of the seven kenaf varieties was the same for the first two harvests, but was slightly different for the third harvest due to the cold climate during this harvest time. Variety SZHP35 had the highest nutritive value, dry matter yield (18,502.18 kg/ha) and crude protein yield content (2,027 kg/ha), while variety 4A-4B had higher leaf proportion and yield and significantly higher crude protein content (P<0.05) than that of other varieties. Correspondence analysis suggested that 4A-4B was closely related to leaf yield and crude protein content, while SZHP35 was closely related to high yield. Our findings suggested that4A-4B and SZHP35 could be used as forage material in China. [ABSTRACT FROM AUTHOR]

About two thousand species of plants are known in the world to yield natural fibers, but just a few are commercially important, providing nearly 90% of the global production of natural fibers. Since ancient times, humans required fiber to produce cordage, tools, clothes, nets, etc., in order to provide food and shelter. Among the most productive fiber plants, the bast fiber crops are undoubtedly considered as major contributors. The bast fibers are sclerenchyma fibers associated with the phloem of crops such as flax, hemp, kenaf, ramie, nettle, jute, etc. Currently, in both Europe and China, bast fibers are used for industrial applications in textile, construction, automotive, and other industries. Recently, bast fibers gained importance also as a renewable feedstock for the production of strong, lightweight, composite materials. However, there are factors in agro-industrial chain that limit the broad commercialization of these crops and their products. From an agronomical point of view, a part of the problems are associated with technological gaps in harvesting technologies, which impede the full exploitation of some crops. For instance, the production of high-quality fibers for textile firstly depends on the quality of the raw material, which in turn is linked, among the others, with the efficiency of the harvesting system adopted. In most cases, these systems were developed locally, based on available solutions in connection with specific local agricultural practice. The aim of this paper is to present a review of the existing mechanical harvesting systems for bast fiber crops in Europe and China, with special reference to hemp, flax, and kenaf. In addition, the work will furnish a description of the innovations that have been adopted in recent years to improve the harvesting processes in order to increase the value of these crops and their products. [ABSTRACT FROM AUTHOR]