Cultivation Experiment of Chinese Fir Bark Compound Matrix in Dendrobium officinale

Purpose: This research was aimed to screen and identify multifunctional phosphorus-dissolving bacteria of a Chinese fir (Cunninghamia lanceolata) plantation and study its phosphorus-dissolving characteristics in order to provide strain resources and a theoretical basis for developing the appropriate bacterial fertilizer of a Chinese fir plantation. Methods: First, phosphorus-dissolving bacteria were isolated from the woodland soil of a Chinese fir plantation by Pikovskava inorganic phosphorus medium (PVK). Then, some growth-promoting indicators of primary screening strains were determined, including the capacity of phosphorus-solubilized, nitrogenase activity, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity, production of indole-3-acetic acid (IAA), secretion of iron carrier and so on. Finally, the screening multifunctional phosphorus-dissolving bacteria were identified, which were combined with colony characteristics, physiological and biochemical tests and molecular biotechnology. Results: (1) Thirteen phosphorus-dissolving bacteria were isolated and screened in total, and P5 (195.61 mg·L−1) had the strongest capacity of phosphorus-solubilized. Five phosphorus-dissolving bacteria were provided with nitrogenase activity, and the highest activity of nitrogenase was P10 and P5 (71.90 C2H4 nmol·mL−1·h−1 and 71.00 C2H4 nmol·mL−1·h−1, respectively). Four strains were provided with ACC deaminase activity, and the highest activity of ACC deaminase was P5 and P9, (0.74 μmol·mg−1·h−1 and 0.54 μmol·mg−1·h−1, respectively). Most strains could secrete IAA, and three strains of bacteria had a strong secretory ability, which could secrete IAA with a concentration greater than 15 mg·mL−1, and P5 was 18.00, P2 was 17.30, P6 was 15.59 (mg·mL−1). P5 produced carriers of iron better than others, and the ratio of the diameter of the iron production carrier ring to the diameter of the colony was 1.80, respectively, which was significantly higher than other strains. Combining all kinds of factors, P5 multifunctional phosphorus-dissolving bacteria were screened for eventual further study. (2) Strain P5 was identified as Burkholderia ubonensis, based on the colony characteristics, physiological and biochemical tests, 16SrDNA sequence analysis and phylogenetic tree construction. Conclusion: P5 has a variety of high-efficiency growth-promoting capabilities, and the ability to produce IAA, ACC deaminase activity and siderophore performance are significantly higher than other strains, which had great potential in the development of microbial fertilizer.

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Metabolic accumulation and related synthetic genes of O-acetyl groups in mannan polysaccharides of Dendrobium officinale

PROTOPLASMA ◽

10.1007/s00709-021-01672-8 ◽

2021 ◽

Author(s):

Can Si ◽

Chunmei He ◽

Jaime A. Teixeira da Silva ◽

Zhenming Yu ◽

Jun Duan

Keyword(s):

Dendrobium Officinale ◽

Synthetic Genes

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Comparison of silicate impregnation methods to reinforce Chinese fir wood

Holzforschung ◽

10.1515/hf-2020-0016 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Ping Li ◽

Yuan Zhang ◽

Yingfeng Zuo ◽

Yiqiang Wu ◽

Guangming Yuan ◽

...

Keyword(s):

Thermal Stability ◽

Heat Release ◽

Flame Retardancy ◽

Chinese Fir ◽

Smoke Suppression ◽

Impregnation Method ◽

Residual Rate ◽

Smoke Production ◽

Human Respiration ◽

Strengthen Effect

AbstractInorganic impregnation strengthening of Chinese fir wood was carried out to improve the strength, dimensional stability, flame retardancy, and smoke suppression of Chinese fir wood. Sodium silicate was used as reinforcement, a sulfate and phosphate mixtures were used as a curing agent, and Chinese fir wood was reinforced by the respiratory impregnation method (RIM) that imitating human respiration and vacuum progressive impregnation method (VPIM). The weight percentage gain (WPG), density increase rate, distribution of modifier, bending strength (BS), compressive strength (CS), hardness, and water resistance of unreinforced Chinese fir wood from the VPIM and RIM were compared. It was found that RIM could effectively open the aspirated pits in Chinese fir wood, so its impregnation effect, strengthen effect and dimension stabilization effects were the best. RIM-reinforced Chinese fir wood was filled with silicate both horizontally and vertically. At the same time, the transverse permeability of silicate through aspirated pits was significantly improved. The chemical structure, crystalline structure, flame retardancy, smoke suppression, and thermal stability of VPIM- and RIM-reinforced Chinese fir wood were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), cone calorimeter (CONE), and thermogravimetric analysis (TGA). The results indicated that although the crystallinity of RIM-reinforced Chinese fir wood decreased the most, more chemical crosslinking and hydrogen bonding were formed in the wood, and the strengthen effect was still the best. Compared with VPIM-reinforced Chinese fir wood, RIM-reinforced Chinese fir wood had lower heat release rate (HRR), peak-HRR, mean-HRR, total heat release (THR), smoke production rate (SPR), and total smoke production (TSP), higher thermal decomposition temperature and residual rate. It was indicated that RIM-reinforced Chinese fir wood was a better flame retardant, and has a smoke suppression effect, thermal stability, and safety performance in the case of fire.

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