Influence of Heavy Metals on Seed Germination and Early Seedling Growth in Crambe abyssinica, a Potential Industrial Oil Crop for Phytoremediation

Abstract

The influence of essential (Cu, Ni and Zn) and non-essential heavy metals (Hg, Cr, Pb and Cd) on seed germination and early seedling growth in industrial oil crop Crambe abyssinica was evaluated under laboratory conditions. Our results indicated that among the 7 heavy metals tested only Cu and Hg significantly (P < 0.01) decreased Crambe seed germination in a dose-dependent manner at higher concentrations while certain Cr concentrations significantly increased the seed germination (P < 0.05). All the 7 heavy metals decreased significantly relative root length, shoot length and fresh seedling weight in a dose-dependent manner (P < 0.01). The heavy metals except Ni decreased relative root length first, then shoot length or fresh seedling weight, and finally seed germination. Ni seemed to influence the relative fresh seedling weight first, then shoot length, root length and finally seed germination at lower concentrations, but the decrease in relative root length became faster when the Ni concentrations were increased. Our results indicated that Crambe is tolerant or moderately tolerant to the heavy metals tested except Ni and can be improved for phytoremediation of soils contaminated by heavy metals.

Influence of Heavy Metals on Seed Germination and Early Seedling Growth in &lt;i&gt;Eruca sativa&lt;/i&gt; Mill.

“…In alfalfa, 40 mg•L −1 Cu inhibited significantly seed germination by 39.0% [25]. In Crambe, higher Cu concentration (0.7 mM or 44.8 mg•L −1 and above) decreased Crambe seed germination significantly [26]. In our experiment, all Cu concentrations tested (0.3 -1.2 mM) did not decrease the Eruca seed germination significantly (P > 0.05).…”

“…In Salicornia brachiata the seed germination was decreased by 49.36% at 50 μM Ni [18]. In Crambe the root growth was completely inhibited at over 80 μM Ni [26]. In our experiment the Eruca seed germination was only significantly influenced by higher Ni concentrations (1 mM and above, Figure 1).…”

“…In Arabidopsis, 0.2 mM Cu inhibited the seedling growth by about 60% [29]. In Crambe, 0.3 mM Cu decreased root length by 75.33%, shoot length by 29.44% and fresh seedling weight by 22.26% [26]. In our experiment, 0.…”

“…Schaaf et al [37] found that fresh weight of Arabidopsis thaliana was almost not affected by 50 μM Ni. In Crambe only 0.4 μM Ni significantly decreased root length by 5.33% and 1.2 μM Ni decreased root length by 71%, shoot length by 60% and fresh seedling weight by 73.42% [26]. In our experiment 0.4mM Ni significantly increased the root length by 35%, shoot length by 24.67%, and fresh seedling weight also by 24.67%; only 3.0 mM Ni significantly decreased the root length by 63.67%, shoot length by 8.33%, and fresh seedling weight by 20.33% (Figures 2-4), suggesting that Eruca is highly tolerant to Ni regarding early seedling growth.…”

“…In another study on Arabidopsis thaliana, the Zn concentration required for a 50% inhibition of root growth was 98 μM [33]. In Crambe, Zn inhibited root length by about 76.33%, shoot length by 43.48% and fresh seedling weight by 47.84% at 0.1 mM concentration [26]. In the hyperaccumulator species Thlaspi goesingense, the Zn concentration required for a 50% inhibition of root growth was higher than 500 μM.…”