Morphological, anatomical, and ultrastructural changes (visualized through scanning electron microscopy) inducedin Triticum aestivum by Pb2+ treatment
Lead (Pb) causes severe damage to crops, ecosystems, and humans, and alters the physiology and biochemistry of various plant species. It is hypothesized that Pb-induced metabolic alterations could manifest as structural variations in the roots of plants. In light of this, the morphological, anatomical, and ultrastructural variations (through scanning electron microscopy, SEM) were studied in 4-day-old seedlings of Triticum aestivum grown under Pb stress (0, 8, 16, 40, and 80 mg Pb2+ l−1; mild to highly toxic). The toxic effect was more pronounced in radicle growth than on the plumule growth. The SEM of the root of T. aestivum depicted morphological alterations and surface ultrastructural changes. Compared to intact and uniform surface cells in the control roots, cells were irregular and desiccated in Pb2+-treated roots. In Pb2+-treated roots, the number of root hairs increased manifold, showing dense growth, and these were apparently longer. Apart from the deformity in surface morphology and anatomy of the roots in response to Pb2+ toxicity, considerable anatomical alterations were also observed. Pb2+-treated root exhibited signs of injury in the form of cell distortion, particularly in the cortical cells. The endodermis and pericycle region showed loss of uniformity post Pb2+ exposure (at 80 mg l−1 Pb2+). The cells appeared to be squeezed with greater depositions observed all over the tissue. The study concludes that Pb2+ treatment caused structural anomalies and induced anatomical and surface ultrastructural changes in T. aestivum.
KeywordsPb2+ toxicity Morphological changes Anatomical changes Scanning electron microscopy
Gurpreet Kaur is thankful to University Grants Commission, New Delhi, India, for financial support in the form of research fellowship. We are grateful to the in-charge, Central Instrumentation Laboratory, Panjab University, Chandigarh, and in-charge, Electron Microscopy Facility at All India Institute of Medical Sciences, New Delhi, for necessary help in getting the samples analyzed by SEM and providing assistance in getting the samples analyzed by ultramicrotomy, respectively.
Conflict of interest
The authors declare that they have no conflict of interest.
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