Xiaobao Li,Zhengjie Tang,Zhenbing Sun,John Simonsen,Zhinan Luo,Xiaoping Li,Jeffery J. Morrell
Carboxymethyl cellulose (CMC) is a cellulose derivative that can be obtained from wood, bamboo, rattan, straw, and other cellulosic materials. CMC can be used to produce biofilms for many purposes, but the properties of these resulting films make them unsuitable for some applications. The effects of three kinds of plant fiber addition on CMC film properties was investigated using CMC derived from eucalyptus bark cellulose. Tensile strength (TS) and elongation at break (EB) of CMC/sodium alginate/glycerol composite films were 26.2 MPa and 7.35%, respectively. Tensile strength of CMC composite films substantially increased, reaching an optimum at 0.50 g of fiber. The enhancement due to industrial hemp hurd fiber on CMC composite films was more obvious. Pretreatment with hydrogen peroxide (H2O2) and glacial acetic acid (CH3COOH) produced films with a TS of 35.9 MPa and an EB of 1.61%. TS values with pectinase pretreated fiber films was 41.3 MPa and EB was 1.76%. TS of films pretreated with pectinase and hemicellulase was 45.2 MPa and EB was 4.18%. Chemical and enzymatic treatment both improved fiber crystallinity, but film tensile strength was improved to a greater extent by enzymatic treatment. Surface roughness and pyrolysis residue of the film increased after fiber addition, but Fourier transform infrared spectroscopy (FTIR), opacity, and water vapor transmission coefficients were largely unchanged. Adding fiber improved tensile strength of CMC/sodium alginate/glycerol composite films and broadened the application range of CMC composite films without adversely affecting film performance.Keywords:eucalyptus bark;Yunnan pine wood;bamboo culms;industrial hemp hurd;FTIR;XRD;TG;mechanical properties
Kai Su,Jing Yuan,Ran Wang,Lanlan Huang,Jian Zhan,Xueqiong Zhang,Shanping Wan,Xinhua He,Hans Lambers,Fuqiang Yu,Yanliang Wang
Ectomycorrhizal (EM) fungi play important roles in nutrient cycling and plant community establishment in forest ecosystems. Effects of EM formation on global alterations of the transcriptome and metabolome during plant-fungal interaction and the key metabolites involved in EM development are largely unknown. Here, dual RNA-Seq and untargeted metabolomic analyses were used to reveal stage-specific and core responses of Pinus yunnanensis and Lactarius deliciosus during mycorrhizal colonization. We found that L. deliciosus colonization in P. yunnanensis roots induced different transcriptional changes across three interaction stages, with a small core of genes consistently regulated at all stages. Concentrations of retinol (vitamin A) and retinoic acid increased while that of B group vitamins decreased during EM formation, which was coordinately regulated by these two plant-fungus partners, with L. deliciosus possibly playing a dominant role. Exogenous retinol altered the diameter and mantle thickness of P. yunnanensis - L. deliciosus EM tips and affected host plant growth and phosphorus acquisition . In the absence of L. deliciosus, exogenous retinol increased the root diameter and the number of root tips of P. yunnanensis . Furthermore, the concentration of auxin increased, but that of abscisic acid decreased during EM formation, and the genes involved in plant hormone signal transduction were gradually activated, and auxin and cytokinin signal transduction potentially played a positive role in this EM symbiosis. In conclusion, we propose that the interaction of P. yunnanensis and L. deliciosus alters vitamin metabolism, which may further affect plant hormone biosynthesis and signal transduction, modulating root morphology and EM traits.
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