Root exposures to cadmium: morphological, physiological and embryological consequences in Datura stramonium L.

Cadmium (Cd) is regarded as one of the most toxic metals and environmental pollutants. The aim of the study was to investigate the effect of cadmium root treatments (۰, ۷۵, ۱۵۰ and ۲۲۵ mgkg-۱) on morphological, physiological and embryological characteristics of Datura stramonium. The results showed that BCF and TF increased from ۰.۱۹ and ۰.۲ in the control group to ۰.۷۱ and ۱.۱۲ in the experimental group of ۲۲۵ mgkg-۱Cd, respectively. In the group treated with ۲۲۵ mgkg-۱of Cd, fresh and dry weight of root, fresh and dry weight of shoot, shoot length, root length, leaf area, cell membrane stability index and relative water content of tissue decreased ۵۰.۸۹, ۴۳.۷۵, ۵۲.۵۷, ۴۶.۲۷, ۱۰.۱۴, ۲۴.۰۴, ۵۵.۴۱, ۳۱.۳۵ and ۲۴.۲۱ percent respectively. The photosynthetic pigments content and soluble carbohydrate content in the Cd-treated plants were decreased in comparison to the control ones. The total protein content in the treatment group with ۲۲۵ mgkg-۱Cd was ۶.۷ times of the control group. The highest peroxidase and polyphenol oxidase activity was also determined in the group treated by ۲۲۵ mgkg-۱Cd. The results showed that Cd can cause to some abnormalities during the developmental process of pollen grains and ovule. Under Cd treatment, fragility, vacuolization and size of pollen grains were increased in comparison with control ones. Decreasing in the bioavailability of pollens and degeneration of embryo sac cells were the result of Cd pollution. It was found that Cd is capable of inducing chromosomal aberrations. The results was also indicated that D. stramonium has the Cd-accumulation and phytoremediation potency. It seemed that D. stramonium was able to resist the damages caused by Cd toxicity, via altering some physiological parameters and changing the protein content.

Keywords:

phytoremediation , morphological parameters , physiological parameters , pollen grains