Ferrous sulfate

Enrofloxacin lactate (EFX) (99.0 %, purity) was purchased from HETIAN Biotech Co., LTD (Zhengzhou). Copper sulfate (Cu) (99.0 %, purity) was purchased from YONGDA Chemical Reagent Co., LTD (Tianjin). LB broth agar was purchased from Sangon Biotech (Shanghai) Co., Ltd. Other chemicals used for the culture medium, including glucose, sodium chloride, magnesium sulfate, ferrous sulfate, dipotassium phosphate, and sodium nitrate were of analytical grade and purchased from Sinopharm Chemical Reagent Co., Ltd.
The experiments were performed with topsoil (0–20 cm) from a peanut experimental field. The soil samples classified as Argosols were collected from Shandong Agricultural University in Taian, China (117.16°E, 36.16°N) during the slack farming seasons in November, 2012. This soil had never been treated with organic fertilizer or exposed to heavy metals. The soil samples were air-dried and ground to pass a 2-mm sieve to remove stones and plant roots. Soil physical and chemical parameters were measured according to the soil agro-chemistrical analysis methods⁴⁶ .

Acetonitrile, methanol, and acetic acid were chromatographically pure and purchased from Tedia, Fairfield, OH, USA; o-phthalaldehyde (OPA), methyl chloroformate (FMOC), gallic acid, 8 catechin monomers, 3 alkaloid monomers, 16 kinds of flavonoids, and 20 kinds of amino acid standards were purchased from Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China); and potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium potassium tartrate, ferrous sulfate, and anthrone were analytically pure and purchased from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China).

The chemicals and regents used were: Choline chloride, sodium phosphate dibasic dodecahydrate, diethyl ether, iron chloride hexahydrate, ferrous sulfate, sulfuric acid (98%), hydrochloric acid (36%), ammonium hydroxide solution, and tetraethyl orthosilicate (Sinopharm Chemical Reagent Co. Ltd., Shanghai, China); sodium metavanadate, sodium molybdate dihydrate, dimethyl sulfoxide, anhydride, pyridine, and oleic acid (Shanghai Macklin Biochemical Technology Co., Ltd., Shanghai, China); Tetrahydrofuran, ethanol, and toluene (Tianjin Hengxing Chemical Reagent Co., Ltd., Tianjin, China); lactic acid, and potassium bromide (Tianjin Kemiou Chemical Reagents Co. Ltd., Tianjin, China).

Isoeugenol, shikonin, baicalein, rosmarinic acid, dihydromyricetin, l-3,4-dihydroxyphenylalanine (l-DOPA), tyrosinase (EC 1.14.18.1), phenanthroline, pyrogallol, 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), diphenyl-2-picrylhydrazyl (DPPH), thiobarbituric acid (TBA), and 2,2′-azobis(2-methylpropionamidine)dihydrochloride (AAPH) were purchased from the Sigma Chemical Company (St. Louis, MO, USA). C3606 reagent kit for organization mitochondria separation was purchased from Shanghai Biyuntian company. Disodium phosphate, sodium dihydrogen phosphate, K₂S₂O₈, potassium sulfate, and ferrous sulfate were purchased from Sinopharm Chemical Reagent Co., Ltd (Shanghai, China). All other solvents and chemicals with analytical grade were commercially available. The Minimum Standards of Reporting Checklist contains details of the experimental design, and statistics, and resources used in this study (Additional file 1).

Multi-T probe 1 was 5′-TTT GCT TGT TGC GCT TCT TGC TTT-NH₂-3′, Multi-T probe 2 was 5′-NH₂-GAT AGC TTT GCT TGT TGC GCT TCT TGC TTT -FAM-3′, Multi-T probe 3 was 3’-NH₂-CTA TCG-5’. The probes were purchased from Sangon Biotech Company (Shanghai, China) and purified by HPLC. Mercuric nitrate (Hg(NO₃)₂) was purchased from Shandong West Asia Chemical Industry Co., Ltd. (Lin Yi, China) and zinc chloride (ZnCl₂), Nickel Chloride (NiCl₂), Potassium Chloride (KCl), Lead Acetate ((CH3COO)₂Pb), Magnesium Chloride (MgCl₂), and Manganese Chloride (MnCl₂) were purchased from Suzhou Asia Pacific Chemical Glass Instrument Co., Ltd. (Suzhou, China) Cadmium (CdCl₂), calcium chloride (CaCl₂), cobalt chloride (CoCl₂), ferrous sulfate (FeSO₄), ferric chloride (FeCl₃), sodium chloride (NaCl), chromium trichloride (CrCl₃), barium chloride (BaCl₂), silver chloride (AgCl) were purchased from Sinopharm Chemicals (Shanghai, China), N-hydroxysuccinimide (NHS) and 1-3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) was purchased from Sigma Co., Ltd. (St. Louis, MO, USA) SYBR Gree+-n I was purchased from Xiamen Zhishan Biotechnology Co., Ltd. (Xiamen, China) The Synergy H4 Multiplate Reader was used for fluorescence detection and Origin 8.0 was used for data analysis.

WBY paste was provided by Tsingtao Brewery Co., Ltd. (Huangshi, Hubei). BCA protein concentration determination kit, SDS-PAGE gel quick preparation kit, SDS-PAGE electrophoresis buffer, coomassie brilliant blue R–250 and 5× SDS-PAGE sample loading buffer were purchased from Beyotime Institute of Biotechnology Co., Ltd. M5 Prestained Plus Protein Ladder (10–250 kDa) with 40 kD was obtained from Mei5 Biotechology. CO., Ltd. (Beijing, China). Trypsin (1:250) and alkaline protease (1:20,000) were purchased from Saiguo biotech CO., Ltd. (Guangzhou, China) and Solarbio Science and Technology CO., Ltd. (Beijing, China), respectively. Methanol acid, sulfuric acid, hydrochloric acid, glacial acetic acid, ethanol, ferrous sulfate, hydrogen peroxide, salicylic acid, DPPH, ABTS, potassium persulfate, PBS (pH 7.4), disodium edetate, and pyrogallic acid were obtained from Sinopharm Chemical Reagent Co., Ltd. (Shanghai, China). All chemicals used in this study were of analytical grade (AR) or guaranteed grade (GR).