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.