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

Anastasia Akoumianaki-Ioannidou,Dafni Ioannou,Sofia Markou,Zoe Dalaka,Nicholas K Moustakas

doi:10.15835/nbha48111781

Abstract

Experiments were conducted on valerian (Valeriana officinalis L.) grown under glasshouse conditions to evaluate the effect of Cadmium (Cd) on plant morphological characteristics and Cd uptake. Valerian 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) over two periods. Pots were arranged in a completely randomized block design within two groups (moderately acid substrate and slightly alkaline substrate) with four Cd treatments (0, 1, 2 and 5 mg Cd L-1) and six replications per treatment. Cadmium was applied as CdSO4*8/3H2O. No visual symptoms of toxicity or nutrient deficiency were attributed to Cd application irrespective of the growth stage or substrate in either experimental period. Cadmium did not affect the dry mass of shoots or roots. Cd concentration in both shoots and roots increased with increasing Cd application, indicating valerian to be a Cd accumulator with accumulation occurring mainly in the roots both in moderately acidic or slightly alkaline substrates. The amount of Cd extracted by Diethylene triamine penta acetic acid-triethanol amine (DTPA-TEA) increased with increasing Cd doses and significantly correlates with the Cd concentrations within the shoots and roots indicating that this extractant could be used to predict Cd concentrations within the plant parts.

Highlights

Cadmium is a heavy metal that remains in the soil for a much longer period than other heavy metals of the biosphere, so soil pollution tends to be permanent (Alloway, 1995); for example, the half-life of Cd in soil varies from 15-1100 years (Oliver, 1997)
No differences in plant height were attributed to Cd application irrespective of the growth stage or substrate in either experimental period. 1st experimental period In the moderately acidic and the slightly alkaline substrate, shoot and root dry matter was not affected by Cd doses up to 5 mg L-1
Cd uptake by valerian increased with Cd doses, independent of substrate acidity (Figures 3, 4)

Summary

Introduction

Cadmium is a heavy metal that remains in the soil for a much longer period than other heavy metals of the biosphere, so soil pollution tends to be permanent (Alloway, 1995); for example, the half-life of Cd in soil varies from 15-1100 years (Oliver, 1997). Heavy metals are not biodegradable but become converted to other forms that accumulate in the soil and plants and are washed away to only a small extent. The mobility of heavy metals within plants varies and generally depends on the particular metal, the type of plant, the plant organ and the age of the plant (Oliver, 1997). Cadmium can enter the soil through mining, metallurgical activities, Received: 13 Jan 2020. Received in revised form: 14 Mar 2020.

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