Effect of N-acetyl cysteine coated CdS:Mn/ZnS quantum dots on seed germination and seedling growth of snow pea (Pisum sativum L.): imaging and spectroscopic studies

Abstract

Anthropogenic nanomaterials (ANMs), once produced, will inevitably be present in the environment. Depending on their environmental stability and level of toxicity, ANMs raise some concern regarding their potential impact on the surrounding animal, aquatic and plant life. In this study, we demonstrate for the first time the effect of ultra-small size (<5 nm) semiconductor ANMs on the germination and growth of seeds of a snow pea model plant system (Pisum sativum) using a N-acetyl cysteine (NAC) coated core–shell CdS:Mn/ZnS Qdots as a heavy metal ion containing model ANM. We present combined results of fluorescence confocal, atomic force microscopy (AFM) and Raman imaging of quantum dot (Qdot) to track the uptake and localization (translocation) in plant tissue. It was found that Qdots were localized on the surface seed coat, epidermis and intercellular regions. The germination, growth and chlorophyll content of the seedlings were found to be strongly dependent on Qdot dosage and time of seed incubation with Qdots. Interestingly, no acute Cd metal toxicity was observed at Qdot concentration below 40 μg mL⁻¹, and seed germination and growth processes were promoted.