Coordinated effects of lead toxicity and nutrient deprivation on growth, oxidative status, and elemental composition of primed and non-primed rice seedlings

• Published in: Environmental science and pollution research international 2018-07, Vol.25 (21), p.21185-21194
• Main Authors: Khan, Fahad, Hussain, Saddam, Tanveer, Mohsin, Khan, Sehrish, Hussain, Hafiz Athar, Iqbal, Biland, Geng, Mingjian
• Format: Article
• Language: English
• Subjects: Accumulation; Agriculture; Antioxidants; Antioxidants - metabolism; Aquatic plants; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Catalase; Catalase - metabolism; Cell division; Cereal crops; Chemical composition; Deprivation; Dietary minerals; Distilled water; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Essential nutrients; Glutathione; Glutathione - metabolism; Hydrogen peroxide; Hydrogen Peroxide - metabolism; Lead; Lead - metabolism; Lead - toxicity; Lead chlorides; Lipid Peroxidation - drug effects; Lipids; Metabolism; Morphology; Nitrogen; Nutrient availability; Nutrient status; Nutrients; Oryza; Oryza - chemistry; Oryza - drug effects; Oryza - growth & development; Oryza - metabolism; Oxidative Stress - drug effects; Peroxidase; Peroxidase - metabolism; Peroxidases - metabolism; Peroxidation; Plant growth; Plant Leaves - chemistry; Plant Leaves - drug effects; Plant Leaves - growth & development; Plant Leaves - metabolism; Potassium; Priming; Reactive oxygen species; Reactive Oxygen Species - metabolism; Research Article; Rice; Salicylic acid; Salicylic Acid - metabolism; Seedlings; Seedlings - chemistry; Seedlings - drug effects; Seedlings - growth & development; Seedlings - metabolism; Seeds; Selenium; Superoxide dismutase; Superoxide Dismutase - metabolism; Toxicity; Translocation; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-018-2262-1

Rice crop is highly susceptible to the toxic levels of lead (Pb) during early growth stages. Moreover, a sufficient availability of mineral nutrients is critical for survival of plants particularly under stressful conditions. An experiment was carried out to unravel the coordinated effects of Pb stress (1-mM PbCl 2 ) and different nutrient treatments (sufficient nutrient supply, nitrogen (N) deprivation, phosphorus (P) deprivation, and potassium (K) deprivation) on morphological growth, reactive oxygen species (ROS), antioxidants, and nutrient status in primed and non-primed rice seedlings. Seeding were primed with distilled water, 60-μM selenium, or 100-mg L −1 salicylic acid. Results indicated that Pb toxicity did not affect the root growth, but severely reduced the shoot growth (length and biomass) of rice in N- or P-deprived seedlings. Rice seedlings grown with sufficient supply of nutrients or K-deprivation showed no growth reduction under Pb toxicity. Exposure of Pb stress triggered the production of ROS (H 2 O 2 , O 2 ˙ − , OH − ) and lipid peroxidation rate particularly under N- or P-deprivation. Moreover, the shoot accumulations of macronutrients (P in particular) were also restricted under Pb toxicity. Seed priming treatments effectively alleviated the undesirable effects of Pb stress on rice growth. The primed rice seedlings showed minimal oxidative damage caused by excessive generation of ROS under Pb stress and/or nutrient deprivation. Seed priming strengthened the antioxidative defense system of rice seedlings by regulating the activities/levels of superoxide dismutase, catalase, peroxidase, and glutathione in rice leaves. Moreover, better accumulation of essential nutrients in primed rice seedlings prevented the excess uptake and translocation of Pb, as evident by the lowered shoot accumulation of Pb.