Seasonal changes in antioxidative/oxidative profile of mining and non-mining populations of Syrian beancaper as determined by soil conditions

Abstract

Soil pollution by heavy metals/metalloids (HMMs) is a problem worldwide. To prevent dispersion of contaminated particles by erosion, the maintenance of a vegetative cover is needed. Successful plant establishment in multi-polluted soils can be hampered not only by HMM toxicities, but also by soil nutrient deficiencies and the co-occurrence of abiotic stresses. Some plant species are able to thrive under these multi-stress scenarios often linked to marked fluctuations in environmental factors. This study aimed to investigate the metabolic adjustments involved in Zygophyllum fabago acclimative responses to conditions prevailing in HMM-enriched mine-tailings piles, during Mediterranean spring and summer. To this end, fully expanded leaves, and rhizosphere soil, of three contrasting mining and non-mining populations of Z. fabago grown spontaneously in south-eastern Spain were sampled in two consecutive years. Approximately 50 biochemical, physiological and edaphic parameters were examined, including leaf redox components, primary and secondary metabolites, endogenous levels of salicylic acid, and physicochemical properties of soil (fertility parameters and total concentration of HMMs). Multivariate data analysis showed a clear distinction in antioxidative/oxidative profiles between and within the populations studied. Levels of chlorophylls, proteins and proline characterized control plants whereas antioxidant capacity and C- and S-based antioxidant compounds were biomarkers of mining plants. Seasonal variations were characterized by higher levels of alkaloids and PAL and soluble peroxidase activities in summer, and by soluble sugars and hydroxycinnamic acids in spring irrespective of the population considered. Although the antioxidant systems are subjected to seasonal variations, the way and the intensity with which every population changes its antioxidative/oxidative profile seem to be determined by soil conditions. In short, Z. fabago displays a high physiological plasticity that allow it to successfully shift its metabolism to withstand the multiple stresses that plants must cope with in mine tailings piles under Mediterranean climatic conditions.

Plant Origin, but Not Phylogeny, Drive Species Ecophysiological Response to Projected Climate

“…L-ascorbate peroxidase, superoxide dismutases and catalase represent the most important enzymes eliminating harmful reactive oxygen species (ROS). Accumulation of ROS is an important consequence of unfavorable conditions (Van Breusegem and Dat, 2006;Farrant and Ruelland, 2015;Lopez-Orenes et al, 2017;Soares et al, 2019). Proper function of the defense system is thus crucial for efficient functioning of plant cells (Das and Roychoudhury, 2014;Kapoor et al, 2015).…”

Ecological Potential of Plants for Phytoremediation and Ecorestoration of Fly Ash Deposits and Mine Wastes

“…The knowledge related to plant metabolite response can be useful for mine land reclamation programs. Thus, changes in antioxidative/oxidative parameters in Zygophylum fabago growing on mine tailings revealed significant decrease of chlorophylls content, reduction of MDA content, H 2 O 2 and O − 2 levels, proline content and the ionically-bound cell wall peroxidases (iPRX) whereas the total antioxidant capacity, particularly content of phenolic compounds (flavonoids, proanthocyanidins, hydroxycinnamic acids), ascorbic acid, GSH, NPT (total non-protein thiol), soluble sugars and activity of PAL (phenylalanine ammonia lyase) as well as activity of soluble peroxidases (sPRX) significantly increased (Lopez-Orenes et al, 2017). Therefore, reduction of oxidative stress is associated with the activation of plant antioxidant system to cope with unforable multielement pollution and harsh climatic conditions on mine tailings.…”

Expression patterns of antioxidant network in pioneer plants from mine tailings polluted with high levels of heavy metals

“…Thus, by increasing the accumulation of these photoprotective pigments, Agustin leaves seemed to be more capable of avoiding the production of 1 O 2 and, consequently, to maintain a high photosynthetic efficiency even in the dry season. This finding contrasts with the significant decline in Chl content found in Agustin Zygophyllum fabago populations under the same stressful conditions (López-Orenes et al, 2017). Comparing with D. viscosa, this species exhibited lower foliar contents of Zn and Pb (~300 and ~7 mg kg -1 DW, respectively, which fell within the critical range) (Párraga-Aguado et al, 2016), indicating that both species presented a different adaptive strategy to withstand the adverse conditions of the mine tailing and the seasonal variations in this Mediterranean area.…”

“…Nevertheless, it is important to highlight that the total antioxidant capacity in Agustin D. viscosa leaves was ca. 25-fold higher than that found in Agustin Z. fabago plants growing in the same conditions (López-Orenes et al, 2017), and also that the levels of soluble TPC noticed in summer Agustin leaves were ca. 4-fold higher than the ones reported in leaves of Cdexposed D. viscosa plants grown under hydroponics (Fernández et al, 2013).…”

“…Supernatants of methanolic extracts, obtained as explained in section 2.3, were used for the spectrophotometric determination of different types of phenolics basically as described in a previous report (López-Orenes et al, 2017). Briefly, the content of soluble total phenol compounds (TPC) was measured by the Folin-Ciocalteu method (Everette et al, 2010) and expressed as gallic acid equivalents (GAE).…”