Tolerance Mechanisms of the Aromatic and Medicinal Plant Salvia sclarea L. to Excess Zinc

Abstract

In recent years, due to the development of industrial and agricultural production, heavy metal contamination has attracted increasing attention. Aromatic and medicinal plant Salvia sclarea L. (clary sage) is classified to zinc (Zn) accumulators and considered as a potential plant for the phytoremediation of heavy metal polluted soils. In this study, an adaptation of clary sage to 900 µM (excess) Zn exposure for eight days in a hydroponic culture was investigated. The tolerance mechanisms under excess Zn exposure were assessed by evaluating changes in the nutrient uptake, leaf pigment and phenolic content, photosynthetic activity and leaf structural characteristics. The uptake and the distribution of Zn, as well as some essential elements such as: Ca, Mg, Fe, Mn and Cu, were examined by inductively coupled plasma mass spectrometry. The results revealed that Salvia sclarea is a Zn-accumulator plant that tolerates significantly high toxic levels of Zn in the leaves by increasing the leaf contents of Fe, Ca and Mn ions to protect the photosynthetic function and to stimulate the photosystem I (PSI) and photosystem II (PSII) activities. The exposure of clary sage to excess Zn significantly increased the synthesis of total phenolics and anthocyanins in the leaves; these play an important role in Zn detoxification and protection against oxidative stress. The lipid peroxidation and electrolyte leakage in leaves, used as clear indicators for heavy metal damage, were slightly increased. All these data highlight that Salvia sclarea is an economically interesting plant for the phytoextraction and/or phytostabilization of Zn-contaminated soils.

Excess Zinc Supply Reduces Cadmium Uptake and Mitigates Cadmium Toxicity Effects on Chloroplast Structure, Oxidative Stress, and Photosystem II Photochemical Efficiency in Salvia sclarea Plants

“…Zinc (Zn 2+ ) belongs to a group of eight essential micronutrients that are required for normal plant growth, development, and defense [9,10]. Zinc is involved in various metabolic processes, playing catalytic, regulatory, and structural roles with several crucial functions in the cell [9][10][11][12][13][14][15][16]. It performs a fundamental role in anti-oxidative defense and retains the membranous structure of various cell organelles [14,17].…”

“…Zinc is involved in various metabolic processes, playing catalytic, regulatory, and structural roles with several crucial functions in the cell [9][10][11][12][13][14][15][16]. It performs a fundamental role in anti-oxidative defense and retains the membranous structure of various cell organelles [14,17]. Zn 2+ deficiency or Zn 2+ at high concentration in the soil, which occurs in various habitats, ranging from deficient to toxic levels can cause inhibition of numerous plant metabolic processes, reduce plant growth and photosynthesis, and decrease chlorophyll content in the leaf, provoking chlorosis and leaf necrosis [9,[11][12][13][14].…”

“…It performs a fundamental role in anti-oxidative defense and retains the membranous structure of various cell organelles [14,17]. Zn 2+ deficiency or Zn 2+ at high concentration in the soil, which occurs in various habitats, ranging from deficient to toxic levels can cause inhibition of numerous plant metabolic processes, reduce plant growth and photosynthesis, and decrease chlorophyll content in the leaf, provoking chlorosis and leaf necrosis [9,[11][12][13][14]. The zinc homeostasis mechanism is not global within plants since most plants contain between 30 and 100 µg Zn 2+ g −1 dry weight (DW), but some other species are accumulating more than 10,000 µg Zn 2+ g −1 DW without showing symptoms of toxicity [18], despite the fact that concentrations above 300 µg Zn 2+ g −1 DW are considered toxic to plants [1,9].…”

Biological activity and profiling of Salvia sclarea essential oil obtained by steam and hydrodistillation extraction methods via chemometrics tools

“…Apart from this, recent studies reported anti‐inflammatory, antimicrobial and analgesic, as well as antidiabetic and cytotoxic effects 2 . In addition to biological activities, S. sclarea is one of the most economically important plants for phytoextraction and phytostabilization of zinc and cadmium contaminated soils, 28,29 and because of this, there is growing interest in cultivation of this plant.…”

Epigenetic and Physiological Responses to Varying Root-Zone Temperatures in Greenhouse Rocket

“…For statistical analysis, chlorophyll fluorescence measurements are introduced as the mean ± SD. Paired t -tests at a level of p < 0.05 were performed with the StatView software (computer package, Abacus Concepts, Inc., Berkley, CA, USA) as before [ 11 , 47 , 48 ].…”