Kumar Adarsh, Borisova Galina, Maleva Maria, Shiryaev Grigory, Tugbaeva Anastasia, Sobenin Artem, Kiseleva Irina
Institute of Natural Sciences and Mathematics, Ural Federal University, 620002 Yekaterinburg, Russia.
Institute of Mining of the Ural Branch of RAS, 620075 Yekaterinburg, Russia.
Microorganisms. 2022 Oct 31;10(11):2164. doi: 10.3390/microorganisms10112164.
Metal tolerant plant growth-promoting (PGP) rhizobacteria are promising for enhancing plant productivity under copper (Cu) stress. Present pot scale experiment was conducted on L. to check the efficiency of rhizobacteria isolated from the rhizosphere of L. growing on Cu-contaminated soils. Out of fifty Cu tolerant strains, three isolates which showed multiple PGP traits such as indole-3-acetic acid (IAA) synthesis, phosphate (PS) solubilization, siderophore and ammonia production were identified preliminarily by morphological and physiological characteristics followed by 16S rRNA gene sequencing. The best strain TF16a which showed IAA: 15.5 mg L, PS: 215 mg L, siderophore halo zone ratio of 3.0 with high ammonia production was selected to prepare a biochar-based biofertilizer (BF). Seedling test showed maximum growth of shoot and root in presence of 5% of BF and this concentration was selected for further experiment. The pot experiment included four treatments: control (soil), 100Cu (100 mg Cu kg soil), 5%BF (), and 5%BF+100Cu, which were carried out for 30 days, after which the morphological, physiological, and biochemical parameters of were studied. The Cu treatment caused its accumulation in shoot and root up to 16.9 and 30.4 mg kg DW, respectively, and increased malondialdehyde (MDA) content by 20%. Application of BF with copper led to the decrease in the Cu accumulation by 20% for shoot and 28% for root while MDA content was the same as in the control. Both treatments of BF with and without Cu increased chlorophyll and content by 1.3 times on average as well as non-enzymatic antioxidants such as soluble phenolic compounds (1.3 times) and free proline (1.6 times). Moreover, BF + Cu led to the increase in the biomass of shoot and root by 30 and 60%, respectively, while there was no significant effect on the growth characteristics of plants after the addition of BF without Cu. The study elucidates that BF based on strain TF16a and biochar can be a promising bioformulation which could increase rapeseed growth under the moderate Cu concentration in soil.
耐金属促植物生长（PGP）根际细菌有望提高铜（Cu）胁迫下的植物生产力。本盆栽规模试验以油菜进行，以检测从生长在铜污染土壤中的油菜根际分离出的根际细菌的效率。在五十株耐铜菌株中，通过形态学和生理学特征以及16S rRNA基因测序初步鉴定出三株具有多种PGP特性的分离株，如吲哚-3-乙酸（IAA）合成、磷（PS）溶解、铁载体和氨产生。选择表现出IAA为15.5 mg/L、PS为215 mg/L、铁载体晕圈比为3.0且氨产量高的最佳菌株TF16a来制备基于生物炭的生物肥料（BF）。幼苗试验表明，在5%的BF存在下，地上部和根部生长最大，该浓度被选择用于进一步试验。盆栽试验包括四个处理：对照（土壤）、100Cu（100 mg Cu/kg土壤）、5%BF（）和5%BF+100Cu，进行30天，之后研究油菜的形态、生理和生化参数。铜处理导致其在地上部和根部的积累分别高达16.9和30.4 mg/kg干重，并使丙二醛（MDA）含量增加20%。将BF与铜一起施用导致地上部铜积累减少20%，根部减少28%，而MDA含量与对照相同。BF添加铜和不添加铜的两种处理均使叶绿素a和叶绿素b含量平均增加1.3倍，以及非酶抗氧化剂如可溶性酚类化合物（1.3倍）和游离脯氨酸（1.6倍）。此外，BF+Cu使地上部和根部生物量分别增加30%和60%，而添加不含铜的BF后对植物生长特性没有显著影响。该研究表明，基于菌株TF16a和生物炭的BF可能是一种有前景的生物制剂，可在土壤中铜浓度适中的情况下增加油菜生长。
