Cadmium Effects on Hyssop (Hyssopus officinalis L.) Morphology and Cd Uptake in Relation to Substrate Acidity/Alkalinity

Abstract

Hyssop (Hyssopus officinalis), is a herb with a wide range of use in food preparation and herbal medicine. It is a perennial shrub through which pollutants such as Cd may enter the human food chain Therefore, the aim of this research was to examine the extent to which Cd added to the growth substrate is accumulated by hyssop plants and whether Cd affects the plant’s morphology. Hyssop plants were grown in pots containing a uniform mixture of either moderately acidic or slightly alkaline substrate consisting of peat and perlite (1:1 v/v) to which Cd (CdSO4*8/3H2O) was added (0-control, 1, 2 and 5 mg Cd L-1) during the course of growth. No symptoms of toxicity or nutrient deficiency as well as no differences in plant height were attributed to Cd application irrespective of the growth stage or substrate. Cadmium uptake by aerial organs (shoots) and underground organs (roots) of hyssop increased with Cd application and was higher in the moderately acidic than in the slightly alkaline soil environment. Hyssop is a Cd accumulator and accumulation occurred mainly in the roots in the acidic substrate. Measurement of extractable Cd by diethylene triamine penta acetic acid – triethanol amine (DTPA-TEA) could be used to predict Cd uptake by hyssop plants.

Cadmium effects on valerian (Valeriana officinalis L.) morphology and Cd uptake in relation to substrate acidity/alkalinity

“…Note: see Figure 1 In both experimental periods shoot, root and total Cd uptake by valerian plants increased with increasing Cd application (Figures 3,4,5,6). These results are in accordance with those reported by Akoumianaki-Ioannidou et al (2019) for hyssop. Moustakas et al (2001) and Akoumianakis et al (2008) reported that Cd application increased Cd concentrations in the leaves of lettuce, radish and cucumber, and in endive and rocket, respectively.…”

“…In addition, no growth inhibition was detected even though considerable Cd concentrations were found within the plants. Overall, therefore, valerian can be considered a Cd accumulating plant, like hyssop, rocket, endive, lettuce, spinach, turnip grass, celery and cabbage (Bingham et al, 1983;Davis 1984;Akoumianakis et al, 2008;Akoumianaki-Ioannidou et al, 2019). The amount of Cd extractable by DTPA-TEA in the moderately acidic substrate ranged from 0.1 to 0.7 mg kg -1 and from 0.3 to 0.9 mg kg -1 for the 1 st and 2 nd experimental period, respectively (Table 1).…”

“…Regression analysis between the amount of Cd in the substrate that was extractable by DTPA-TEA and total Cd uptake by valerian independently of the experimental period, indicated that this extractant could be used effectively to predict Cd uptake in valerian grown in this substrate (Table 2, 3). Moustakas et al (2001), Akoumianakis et al (2008) and Akoumianaki-Ioannidou et al (2019) reported that DTPA-TEA could also be used to predict Cd uptake by lettuce, radish, cucumber, endive, rocket and hyssop.…”