Zainab Nida, Din Bashir Ud, Javed Muhammad Tariq, Afridi Muhammad Siddique, Mukhtar Tehmeena, Kamran Muhammad Aqeel, Khan Amir Abdullah, Ali Javed, Jatoi Wajid Nasim, Hussain Munis Muhammad Farooq, Chaudhary Hassan Javed
Department of Plant Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
Department of Botany, Government College University, 38000, Faisalabad, Pakistan.
Plant Physiol Biochem. 2020 May 3;152:90-99. doi: 10.1016/j.plaphy.2020.04.039.
Rapid industrialization is the main reason of heavy metals contamination of soil colloids and water reservoirs. Heavy metals are persistent inorganic pollutants; deleterious to plants, animals and human beings because of accumulation in food chain. The aim of the current work was to evaluate the role of indole acetic acid (IAA), exopolysaccharide (EPS) and ACC-deaminase producing plant growth promoting rhizobacteria (PGPR) i.e .B. gibsonii PM11 and B. xiamenensis PM14 in metal phytoremediation of metals, their survival and plant growth promotion potential in metal polluted environment as well as alterations in physio-biochemical responses of inoculated L. usitatissimum plants towards heavy metal toxicity. Two bacterial strains Bacillus gibsonii (PM11) and Bacillus xiamenensis (PM14), previously isolated from sugarcane's rhizosphere, were screened for metal tolerance (50 mg/l to 1000 mg/l) and plant growth promoting traits like IAA, ACC-deaminase, EPS production and nitrogen fixing ability under metal stress. The response of flax plant (Linum usitatissimum L.) was analyzed in a pot experiment containing both industrially contaminated and non-contaminated soils. Experiment was comprised of six different treatments, each with three replicates. At the end of the experiment, role of metal tolerant plant growth promoting bacterial inoculation was elucidated by analyzing the plant growth parameters, chlorophyll contents, antioxidative enzymes, and metal uptake both under standard and metal contaminated rhizospheres. Results revealed that root and shoot length, plant's fresh and dry weight, proline content, chlorophyll content, antioxidant enzymatic activity was increased in plants inoculated with plant growth promoting bacteria as compared to non-inoculated ones both in non-contaminated and industrial contaminated soils. In current study, inoculation of IAA, EPS and ACC-deaminase producing bacteria enhances plant growth and nutrient availability by minimizing metal-induced stressed conditions. Moreover, elevated phytoextraction of multi-metals from industrial contaminated soils by PGPR inoculated L. usitatissimum plants reveal that these strains could be used as sweepers in heavy metals polluted environment.
快速工业化是土壤胶体和水库中重金属污染的主要原因。重金属是持久性无机污染物，由于在食物链中积累，对植物、动物和人类有害。当前工作的目的是评估吲哚乙酸（IAA）、胞外多糖（EPS）和产生ACC脱氨酶的植物促生根际细菌（PGPR），即吉氏芽孢杆菌PM11和厦门芽孢杆菌PM14在金属植物修复中的作用、它们在金属污染环境中的存活及促进植物生长的潜力，以及接种的亚麻植株对重金属毒性的生理生化反应变化。从甘蔗根际分离出的两株细菌菌株，吉氏芽孢杆菌（PM11）和厦门芽孢杆菌（PM14），在金属胁迫下进行了金属耐受性（50毫克/升至1000毫克/升）以及诸如IAA、ACC脱氨酶、EPS产生和固氮能力等植物促生特性的筛选。在包含工业污染土壤和未污染土壤的盆栽试验中分析了亚麻植株（亚麻）的反应。试验由六种不同处理组成，每个处理有三个重复。在试验结束时，通过分析标准和金属污染根际条件下的植物生长参数、叶绿素含量、抗氧化酶和金属吸收，阐明了耐金属促植物生长细菌接种的作用。结果表明，与未接种的植株相比，接种促植物生长细菌的植株在未污染和工业污染土壤中的根和茎长度、植株鲜重和干重、脯氨酸含量、叶绿素含量、抗氧化酶活性均有所增加。在当前研究中，接种产生IAA、EPS和ACC脱氨酶的细菌通过最小化金属诱导的胁迫条件来促进植物生长和养分有效性。此外，接种PGPR的亚麻植株对工业污染土壤中多种金属的植物提取量增加，表明这些菌株可在重金属污染环境中用作清除剂。
