Lead-induced modification of growth and yield of Linum usitatissimum L. and its soil remediation potential.

This study was designed to evaluate the pre-reproductive and reproductive responses of Linum usitatissimum L. (flax, linseed plant) to different levels of Pb in the soil. Flax seeds were sown in garden soil-filled earthen pots and treated with three different levels of lead as lead chloride (150, 450, and 750 mg Pb kg-1 soil) except control, and each treatment was replicated three times. Growth and reproductive parameters and photosynthetic pigments were significantly reduced (p ≤ 0.05) for all treatments. Quantitatively, Chlorophyll b content decreased more than chlorophyll a and the amount of proline content in the leaves increased in lockstep with the increase of Pb levels in the soil. Pb was found in substantial amounts in the roots, shoots, and seeds. The pattern of Pb accumulation in different organs was root > shoot > seeds. Pb levels in seeds obtained from 750 mg Pb kg-1 soil-treated plants exceeded the permissible limits. Biological concentration factor (BCF), biological accumulation coefficient (BAC) and translocation factor (TF) values showed that roots of L. usitatissimum absorbed and accumulated a substantial quantity of Pb but translocated only a fraction of that to the shoots. Therefore, L. usitatissimum L. can be used in phytostabilization rather than phytoextraction of Pb.

This manuscript evaluates the potential of flaxseeds to cause biomagnification of lead (Pb) in the human body when grown under different concentrations of Pb and assessment of the risk posed to consumer health in a food chain. This study also provides insight to evaluate the uptake and extraction efficiency of Linum usitatissimum L. to remediate the Pb-polluted soil and use of Pb contaminated plant products (stem fibers and linseed oil) in an ecofriendly manner.

Does seed size and surface anatomy play role in combating phytotoxicity of nanoparticles?

Rapid utilization of nano-based products will inevitably release nanoparticles into the environment with unidentified consequences. Plants, being an integral part of ecosystem play a vital role in the incorporation of nanoparticles in food chain and thus, need to be critically assessed. The present study assesses the comparative phytotoxicity of nanoparticle, bulk and ionic forms of zinc at different concentrations on selected plant species with varying seed size and surface anatomy. ZnO nanoparticles were chosen in view of their wide spread use in cosmetics and health care products, which allow their direct release in the environment. The impact on germination rate, shoot & root length and vigour index were evaluated. A concentration dependent inhibition of seed germination as well as seedling length was observed in all the tested plants. Due to the presence of thick cuticle on testa and root, pearl millet (xerophytic plant) was found to be relatively less sensitive to ZnO nanoparticles as compared to wheat and tomato (mesophytic plants) with normal cuticle layer. No correlation was observed between nanoparticles toxicity and seed size. The results indicated that variations in surface anatomy of seeds play a crucial role in determining the phytotoxicity of nanoparticles. The present findings significantly contribute to assess potential consequences of nanoparticle release in environment particularly with major emphasis on plant systems. It is the first report which suggests that variations observed in phytotoxicity of nanoparticles is mainly due to the predominant differences in size and surface anatomy of tested plant seeds and root architecture. Effect of various concentrations of nano ZnO, bulk ZnO and zinc sulphate on the growth of pearl millet (A), tomato (B) and wheat (C) seedlings.