Paradoxical effects of nanomaterials on plants: Phytohormonal perspective exposes hidden risks amidst potential benefits.

The rapid growth of nanotechnology has led to the production of a significant amount of engineered nanomaterials (NMs), raising concerns about their impact on various domains. This study investigates the negative interactions between NMs and phytohormones in plants, revealing the changes in signaling crosstalk, integrated responses and ecological repercussions caused by NM pollution. Phytohormones, which include auxins, cytokinins, gibberellins, abscisic acid, ethylene, jasmonic acid, salicylic acid and brassinosteroids are essential for plant growth, development, and stress responses. This review examines the intricate relationships between NMs and phytohormones, highlighting disruptions in signaling crosstalk, integrated responses, and ecological consequences in plants due to NM pollution. Various studies demonstrate that exposure to NMs can lead to alterations in gene expression, enzyme functions, and ultimately affect plant growth and stress tolerance. Exposure to NMs has the capacity to affect plant phytohormone reactions by changing their levels, biosynthesis, and signaling mechanisms, indicating a complex interrelation between NMs and phytohormone pathways. The complexity of the relationships between NMs and phytohormones necessitates further research, utilizing modern molecular techniques, to unravel the intricate molecular mechanisms and develop strategies to mitigate the ecological consequences of NM pollution. This review provides valuable insights for researchers and environmentalists concerned about the disruptive effects of NMs on regulating phytohormone networks in plants.

Influence of different seed priming techniques on oxidative and antioxidative responses during the germination of Oryza sativa varieties.

NaCl and PEG stresses have negative impacts on seed germination and early seedling establishment in Oryza sativa. The present study was designed to ascertain the influence of different priming techniques (Hydro priming-HyP, Halo priming-HP, UV-B priming-UP) in enhancing oxidative and anti-oxidative mechanisms during seed germination phase in response to NaCl and PEG stresses tolerance of three rice varieties (Neeraja, Vaisakh and Vyttila 6). NaCl and PEG stresses caused delayed germination rate, enhanced reactive oxygen species content and thereby increased lipid peroxidation rate. Different priming techniques significantly hastened the metabolites/non enzymatic antioxidant contents (total sugars, total phenolics, free amino acids, proline, ascorbate and glutathione) as well as activities of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and guaiacol peroxidase), and thus reduced oxidative stress damages caused by NaCl and PEG stresses in rice seedlings. Seed priming techniques imparted abiotic stress tolerance not only to sensitive varieties but also additional tolerance potential to tolerant varieties. All three priming techniques protects the plants from toxicity caused by NaCl and PEG stresses but halo priming had proved to be more successful.