RESUMEN
Manglietiastrum sinicum Y.W. Law is a critically endangered species with great ornamental and commercial value, which urgently requires protection. We tested different combinations of basal media and plant growth regulators to determine (i) the optimal conditions for bud induction and proliferation of explants and (ii) optimal rooting conditions. RAPD- and ISSR-PCR were used to assess the genetic fidelity of regenerated plantlets. Murashige and Skoog medium (MS) supplemented with 0.5 mg/L 6-benzyladenine (BA) and 0.05 mg/L indole-3-butyric acid (IBA) is the optimal medium for bud induction (100% induction). MSM medium (a special basal medium for M. sinicum) was more suitable for the efficient proliferation and rooting of M. sinicum. Maximum bud proliferation rate (446.20%) was obtained on MSM, with 0.4 mg/L BA, 0.5 mg/L kinetin, and 0.06 mg/L IBA, while maximum root induction rate (88.89%) was obtained on MSM supplemented with 0.4 mg/L 1-naphthylacetic acid and 1.0 mg/L IBA with a 7-day initial darkness treatment. The rooted plantlets were transferred to a substrate containing peat soil, perlite, coconut chaff, and bark (volume ratio 2:1:1:1), with a resulting survival rate of 92.2%. RAPD and ISSR markers confirmed the genetic uniformity and stability of regenerated plants.
RESUMEN
The highly efficient removal of heavy metals is one of the important factors to evaluate adsorbents. In our study, carbon@chitosan@montmorillonite nanosheet (C@CS@MTN) was successfully prepared via layer-by-layer assembly for the removal of Cu2+ and Cd2+ from solution. High-intensity ultrasound peeling technology was used to release Si-O tetrahedron and Al-O octahedron from montmorillonite in order to exert their optimal adsorption potential. Fourier transform infrared spectroscopy, an X-ray diffractometer, BET surface area measurement, and the inductively coupled plasma emission spectrometry were adopted to investigate the morphology, functional groups, and adsorption capacity of C@CS@MTN. Batch experiment results indicated that both Cu2+ and Cd2+ were effectively removed from solution with the range of pH from 2 to 6. The removal ratio of Cu2+ and Cd2+ onto C@CS@MTN increased with the rise of reaction temperature and their maximum adsorption capacities reached 1108.8 mg·g-1 and 237.4 mg·g-1, respectively, under the condition of the reaction temperature 40 °C, the reaction time 4 h, and the pH = 6. The molecular simulation calculation indicated that there was an obvious electron transfer between Si-O tetrahedron and metal cations, but not for Al-O octahedron. In comparison to Al-O octahedron, the bonding of Cu-O and Cd-O caused the Si-O bond to be broken, resulting in the deconstruction of Si-O tetrahedron and their recombination via the junction of O atoms. It was exactly the deconstruction and recombination of endogenous active units that provide more sites for metal ion adsorption.
