Lead (Pb) is one of the most toxic and persistent elements, with no known biological role. High concentrations of lead enter saline soils through anthropogenic activities and industrial waste. The decontamination of Pb polluted sites through phytoremediation, especially by using woody plants, is an attractive approach. Eucalyptus camaldulensis is a good accumulator of Pb and a recommended tree species for reclamation of saline soils. However, there is very limited knowledge about the Pb-uptake behavior of Eucalyptus camaldulensis under saline conditions. The objective of this study was to examine the simultaneous impact of NaCl salinity and Pb stress on the phytoremedial potential and growth behavior of E. camaldulensis. Six-week-old Eucalyptus camaldulensis plants with uniform morphological features were transferred into hydroponic conditions, and they were exposed to the NaCl salinity stress at 200 mM and Pb stress at 10 mg L-1 and 20 mg L-1 (Pb1 and Pb2, respectively). The plants showed a 100% survival rate in all treatments. All the morphological parameters (plant height, plant diameter, and shoot dry weight) for E. camaldulensis were significantly affected when exposed to Pb or Pb + NaCl-salinity, with the exception of root length which was 36% higher in Pb2 as compared to the control. The Pb uptake (mg Pb plant-1) was much higher (49.3) under Pb2 + NaCl-salinity, as compared to the control (1.2) and other treatments, which shows that saline conditions increased the Pb-uptake in E. camaldulensis. The order of deposition of Pb (mg Pb kg-1 of dry weight) in plant parts was root (103.4) >> shoot (17.5) > leaves (13.6). Similarly, the bioconcentration factor (BCF) of the roots was 4 to 6 times higher than shoot BCF.
The present work aimed to develop and investigate microbial consortia for petroleum hydrocarbons (PHCs) detoxification and plant growth improvement in hydrocarbons-contaminated soil. Here, we isolated several bacteria from PHCs-contaminated soils to make bacterial consortia and two of the best consortia were tested in a pot experiment to evaluate their potential for PHCs removal and chickpea growth promotion in PHCs-contaminated soil. Results demonstrated that the PHCs exerted considerable phytotoxic effects on chickpea growth and physiology by causing a 13–29% and a 12–43% reduction in agronomic and physiological traits, respectively. However, in the presence of bacterial consortia, the phytotoxicity of PHCs to chickpea plants was minimized, resulting in a 7.0–24% and a 6.0–35% increase in agronomic and physiological traits, respectively over un-inoculated controls. Bacterial consortia also boosted nutrient uptake and the antioxidant mechanism of the chickpea. In addition, chickpea plants alone phytoremediated 52% of initial PHCs concentration. The addition of bacterial consortia in the presence of chickpea plants could remove 74–80% of the initial PHCs concentration in soil. Based on our research findings, we suggest that the use of multi-trait bacterial consortia could be a sustainable and environmentally friendly strategy for PHCs remediation and plant growth promotion in hydrocarbons in contaminated soil.
The relationship between ethylene and cyanide (HCN) and karrikin 1 (KAR1) in dormancy release was studied in secondary dormant Brassica oleracea L. (Chinese cabbage) seeds. Freshly harvested seeds of Brassica oleracea usually have poor germination potential. Karrikin1 (KAR1) and cyanide (HCN) are able to stimulate seed germination. However, the stimulatory effects of these two chemicals depend on the activation of the ethylene biosynthesis pathway and on ethylene perception. In this study, KAR1 and HCN application increased the activity of ethylene and of two ethylene biosynthesis enzymes, ACC synthase (ACS) and ACC oxidase (ACO). KAR1 and HCN collectively promoted the accumulation of 1 aminocyclopropane-1-carboxylic acid (ACC). In the presence of NO (nitric oxide) and KAR1, ACS and ACO activities reached their maximum levels after 36 and 42 h, respectively. Ethylene inhibitors suppressed seed germination by approximately 55%, whereas the respiratory inhibitors SHAM and NaN3 inhibited seed germination by 5-10% in the presence of HCN and KAR1. KAR1 and HCN collectively reduced the abscisic acid (ABA) content in seeds, increased the gibberellic acid (GA) content and released seed dormancy. The expression of ethylene biosynthesis genes and ethylene receptor genes (BOACO1,
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.