Plant-Derived Smoke Solution Alleviates Cellular Oxidative Stress Caused by Arsenic and Mercury by Modulating the Cellular Antioxidative Defense System in Wheat

Abstract

Heavy metal stress is a significant factor in diminishing crop yield. Plant-derived smoke (PDS) has been used as a growth promoter and abiotic stress alleviator for the last two decades. Although the roles of PDS have been determined in various plants, its role in ameliorating heavy metal stress in wheat has not been reported so far. Therefore, the present work was conducted to investigate the effect of smoke solution extracted from a wild lemongrass Cymbopogon jwarancusa (C. jwarncusa) on physiological and biochemical features of wheat under arsenic (As) and mercury (Hg) stress. The results showed that higher concentrations of As and Hg pose inhibitory effects on wheat seed germination and seedling growth, including shoot/root length and shoot/root fresh weight. Photosynthetic pigments, such as chlorophyll a and b and carotenoids, were significantly decreased under As and Hg stress. Importantly, the levels of H2O2, lipid peroxidation, and TBARS were increased in wheat seedlings. The activity of antioxidant enzymes, such as CAT, was decreased by As and Hg stress, while the levels of SOD, POD, and APX antioxidant enzymes were increased in root and shoot. Interestingly, the application of PDS (2000 ppm), individually or in combination with either As or Hg stress, enhanced wheat seed germination rate, shoot/root length, and shoot/root fresh weight. However, the levels of H2O2, lipid peroxidation, and TBARS were decreased. Similarly, the levels of SOD, POD, and APX were decreased by PDS under As and Hg stress, while the level of CAT was enhanced by PDS under As and Hg stress. Interestingly, the levels of chlorophyll a and b, and total carotenoids were increased with the application of PDS under As and Hg stress. It is concluded that PDS has the capability to alleviate the phytotoxic effects of As and Hg stress in wheat by modulating the antioxidative defense system and could be an economical solution to reduce the heavy metal stress in crops.

Germination and Early Seedling Growth of High Andean Native Plants under Heavy Metal Stress

“…Germination decreased by 23% compared to the control and took 4.20 days. Our results are supported by previous findings, which state that germination was reduced remarkably in certain species subjected to As, like Oryza sativa [52], Cymbopogon jwarancusa [53], and Helichrysum tyrrhenicum [54]. High concentrations of As might have an adverse effect on α-amylase, which is an important enzyme responsible for seed germination, ultimately leading to a decrease in the percentage of germination [51].…”

“…In contrast, the inhibition of seedling biomass was stronger for A. subterranea than for A. pinifolia, showing that the latter species is less tolerant of As. Reduced root length and seedling growth in response to As exposure has been frequently reported in Chenopodium quinua, Cistus salviifolius, and Cymbopogon jwarancusa [53,55,56].…”

Ecotoxicological Assessment of Heavy Metal and Its Biochemical Effect in Fishes

“…Their high concentration affects the physiology and biochemical parameters of fish tissues, and heavy metals disturb body biochemistry in normal metabolic processes. These heavy metals not only accumulated in fish but also in plants in the environment and cause damage to animal and plant tissues [11][12][13][14]. In aquatic animals, heavy metals cause sublethal pathology of the liver, kidneys, reproductive, respiratory, and nervous systems [15].…”

Mercury Content and Amelioration of Its Toxicity by Nitric Oxide in Lichens

“…The presence of heavy metals stimulates excessive production of reactive oxygen species (ROS) which is often metal-specific [ 14 , 15 ] and concentration-dependent, also in non-vascular plants and lichens [ 12 , 16 ]. To cope with ROS overproduction, all cells use mainly non-enzymatic antioxidant ascorbic acid and thiol metabolites, and its significance under metal excess is also known in lichens [ 17 ].…”