L. Buendía-González

Tolerance, arsenic uptake, and oxidative stress in Acacia farnesiana under arsenate-stress

ABSTRACT Acacia farnesiana is a shrub widely distributed in soils heavily polluted with arsenic in Mexico. However, the mechanisms by which this species tolerates the phytotoxic effects of arsenic are unknown. This study aimed to investigate the tolerance and bioaccumulation of As by A. farnesiana seedlings exposed to high doses of arsenate (AsV) and the role of peroxidases (POX) and glutathione S-transferases (GST) in alleviating As-stress. For that, long-period tests were performed in vitro under different AsV treatments. A. farnesiana showed a remarkable tolerance to AsV, achieving a half-inhibitory concentration (IC50) of about 2.8 mM. Bioaccumulation reached about 940 and 4380 mg As·kg−1 of dry weight in shoots and roots, respectively, exposed for 60 days to 0.58 mM AsV. Seedlings exposed to such conditions registered a growth delay during the first 15 days, when the fastest As uptake rate (117 mg kg−1 day−1) occurred, coinciding with both the highest rate of lipid peroxidation and the strongest up-regulation of enzyme activities. GST activity showed a strong correlation with the As bioaccumulated, suggesting its role in imparting AsV tolerance. This study demonstrated that besides tolerance to AsV, A. farnesiana bioaccumulates considerable amounts of As, suggesting that it may be useful for phytostabilization purposes.

Effect of A Saprophytic Fungus on the Growth and the Lead Uptake, Translocation and Immobilization in Dodonaea Viscosa

Phytoremediation is a feasible alternative to remediate soils polluted with toxic elements, which can be enhanced by manipulating plant-microbe interactions. Regarding this, free-living saprophytic fungi that interact beneficially with roots have been scarcely studied. Thus, the aim of this study was to assess the effect of a saprophytic fungus, Lewia sp., on the plant growth and the ability of Dodonaea viscosa to phytoaccumulate or phytostabilize soluble and insoluble sources of lead in a solid support.The growth of D. viscosa was influenced by both Pb and Lewia sp. While seedlings exposed to Pb showed a decrease in biomass production, in seedlings grown without Pb the biomass was stimulated by Lewia sp. The fungus strongly stimulated the weight-to-length ratio in roots. Regardless of the treatment, D. viscosa accumulated 4.4–6.5 times more Pb in roots than in shoots, conducting to low translocation factors (<0.2). The presence of Lewia sp. significantly improved Pb accumulation, achieving high bioconcentration factors (>22), which was attributed to an increased bioavailability and uptake of Pb due to the fungus. This study demonstrated that Lewia sp. could improve Pb-phytostabilization by D. viscosa in soils polluted with soluble and insoluble forms of Pb.

Procedure for Estimating the Tolerance and Accumulation of Heavy Metals Using Plant Cell Cultures

The tolerance index (TI) and the bioaccumulation factor (BF) for the estimation of accumulation and tolerance of different heavy metals in cell suspension cultures are reviewed. Procedures for measuring these parameters are described for the purposes of phytoremediation research.

Evaluation of the protection and release rate of bougainvillea (Bougainvillea spectabilis) extracts encapsulated in alginate beads

Abstract There is a growing demand in the food industry for natural food products to replace synthetic ingredients. Motivated by this fact, the present work studied the extraction of coloring compounds from Bougainvillea spectabilis under aqueous and ethanolic conditions, and the encapsulation of the extract in alginate beads. Ethanolic extraction was more efficient as reflected by the higher values for total phenols (6.78 ± 0.24 mg EAG/g), betacyanins (5.04 ± 0.13 mg/g), betaxanthines (1.35 ± 0.06 mg/g,) and inhibition capacity (81.31 ± 4.23%). FTIR analysis suggested the presence of interactions between the extract and the alginate chains. The release kinetics of compounds in alginate beads was measured under aqueous and ethanolic conditions at 25.0 °C and at 70.0 °C. Color was also monitored, showing that the color parameters followed a kinetics pattern similar to the released extract. However, the release of betalains exhibited a mixed behavior, reflecting interactions between the different compounds of the bougainvillea extract and the alginate chains. The extracts released from the beads were characterized to determine the preservation of their properties during encapsulation, concluding that the encapsulation is efficient to protect and release the bioactive compounds from bougainvillea extracts. GRAPHICAL ABSTRACT