Shahraki Atefeh, Mohammadi-Sichani Maryam, Ranjbar Monireh
Department of Microbiology, Falavarjan Branch, Islamic Azad University, Isfahan, Iran.
Department of Biology, Falavarjan Branch, Islamic Azad University, Isfahan, Iran.
J Appl Microbiol. 2022 Apr;132(4):3073-3080. doi: 10.1111/jam.15410. Epub 2022 Jan 3.
Using rhizobacteria as plant growth-promoting agents for improving heavy-metal phytoremediation processes in contaminated soil has attracted a lot of attention mainly because of their eco-friendliness. The aim of this study was the evaluation of lead phytoremediation by Carthamus tinctorius improved with the isolated and molecularly identified lead-resistant rhizobacteria.
Rhizobacteria were isolated from C. tinctorius root and was identified using macroscopic and microscopic characteristics, biochemical testing and PCR. Then, the indole acetic acid production and phosphate-solubilizing activity were determined. Finally, the amount of lead in the plant was measured by atomic absorption method. Five strains of Bacillus cereus, Bacillus muralis, Bacillus sp., Pseudomonas fluorescens and Brevibacterium frigoritolerans with the ability of mineral phosphate solubilizing, high levels of indole acetic acid production and resistance to lead were isolated from the rhizosphere of C. tinctorius. The amount of produced indole acetic acid and the level of phosphate solubilizing by the isolates were 7.1-69.54 µg ml and 91-147.3 µg ml respectively. Lead assimilation in aerial part of safflower ranged from 925 to 2175 ppm. P. fluorescens and B. cereus strains had the highest effect on Lead assimilation with 2175 and 1862 ppm respectively.
The results showed that different bacterial treatments influenced the rate of lead absorption by C. tinctorius exposed to lead stress.
Use of rhizosphere isolates of C. tinctorius can improve phytoremediation capability and lead absorption in lead-contaminated soil.
利用根际细菌作为植物生长促进剂来改善污染土壤中的重金属植物修复过程，因其生态友好性而备受关注。本研究的目的是评估经分离和分子鉴定的抗铅根际细菌改良后，红花对铅的植物修复效果。
从红花根部分离根际细菌，并通过宏观和微观特征、生化测试及聚合酶链反应进行鉴定。然后，测定吲哚乙酸产量和溶磷活性。最后，采用原子吸收法测定植物中的铅含量。从红花根际分离出五株蜡样芽孢杆菌、壁芽孢杆菌、芽孢杆菌属、荧光假单胞菌和耐冷短杆菌，它们具有溶解无机磷、高产吲哚乙酸和抗铅的能力。分离菌株产生的吲哚乙酸量和溶磷水平分别为7.1 - 69.54μg/ml和91 - 147.3μg/ml。红花地上部分的铅同化量在925至2175ppm之间。荧光假单胞菌和蜡样芽孢杆菌菌株对铅同化的影响最大，分别为2175ppm和1862ppm。
结果表明，不同的细菌处理影响了受铅胁迫的红花对铅的吸收速率。
利用红花根际分离物可提高铅污染土壤中的植物修复能力和铅吸收量。
