Department of Botany, Physiology and Plant Protection, Faculty of Biotechnology and Horticulture, University of Agriculture in Krakow, al. Mickiewicza 21, 31-120 Kraków, Poland.
Jagiellonian University, Faculty of Biochemistry, Biophysics and Biotechnology, Department of Plant Physiology and Biochemistry, Gronostajowa 7, 30-387 Kraków, Poland.
Sci Total Environ. 2024 Apr 20;922:171327. doi: 10.1016/j.scitotenv.2024.171327. Epub 2024 Feb 28.
Callitriche cophocarpa Sendtn. is a macrophyte widely distributed in aquatic systems of the temperate climate zone and a known hyperaccumulator of chromium. Ten pure symbiotic bacterial isolates of C. cophocarpa were obtained and identified. Three of the isolates showed the highest resistance to Cr(VI): Microbacterium sp. (Ct1), Aeromonas sp. (Ct3) and Acinetobacter sp. (Ct6). Acinetobacter sp. (Ct6) was able to survive up to a concentration of 104 mg/L (2 mM). The isolates were also able to effectively detoxify Cr(VI) by reducing it to Cr(III). We tested whether inoculation of plants with a consortium consisting of Ct1, Ct3 and Ct6 affects: (1) the phytoextraction of chromium from leachates, (2) the physiological state of plants after Cr(VI) treatment. The solutions were landfill leachates and contained 10.7 mg/L of Cr(VI) - an amount 530 times exceeding the legal limits. We influenced the plants with Cr in two steps, each lasting for 10 days, first using mature shoots and then apical ones. The highest Cr content concomitant with the highest bioconcentration factor (BCF) were found in the inoculated plants: 1274 and 119 mg/kg dry mass (d.m.), respectively. The physiological status of the plants was assessed by biometric tests and advanced chlorophyll fluorescence analyses. The photosynthetic activity of mature shoots was influenced by Cr(VI) more negatively than that of young apical shoots. The inoculation with the bacterial consortium significantly reduced the negative effect of Cr(VI) on mature organs. In some cases the inoculated mature plants exhibited photosynthetic activity that was even higher than in the control plants. The results unequivocally show a beneficial effect of C. cophocarpa inoculation with the tested isolates resulting in a significant improvement of the phytoremediation properties of this aquatic chromium hyperaccumulator.
角果藻是一种广泛分布于温带水生系统的大型植物，也是铬的已知超积累植物。从角果藻中获得并鉴定了 10 株纯共生细菌分离株。其中 3 株对 Cr(VI)表现出最高的抗性：微杆菌（Ct1）、气单胞菌（Ct3）和不动杆菌（Ct6）。不动杆菌（Ct6）能够在高达 104mg/L（2mM）的浓度下存活。这些分离株还能够通过将 Cr(VI)还原为 Cr(III)来有效解毒 Cr(VI)。我们测试了用由 Ct1、Ct3 和 Ct6 组成的混合物接种植物是否会影响：(1) 植物从浸出液中提取铬，(2) Cr(VI)处理后植物的生理状态。这些溶液是垃圾渗滤液，含有 10.7mg/L 的 Cr(VI)，这一含量是法定限量的 530 倍。我们用 Cr 分两步影响植物，每步持续 10 天，先用成熟的枝条，然后用顶端的枝条。接种植物的 Cr 含量最高，同时生物浓缩系数（BCF）也最高：分别为 1274 和 119mg/kg 干重（d.m.）。通过生物计量测试和先进的叶绿素荧光分析来评估植物的生理状态。成熟枝条的光合作用受到 Cr(VI)的负面影响大于幼嫩顶端枝条。用细菌混合物接种显著降低了 Cr(VI)对成熟器官的负面影响。在某些情况下，接种的成熟植物表现出的光合作用甚至高于对照植物。这些结果明确表明，角果藻接种测试分离株具有有益效果，显著提高了这种水生铬超积累植物的植物修复特性。
