Int J Phytoremediation. 2014;16(7-12):643-59. doi: 10.1080/15226514.2013.837027.
We examined whether long-term Cd exposure leads to beneficial changes in the cultivable endophytic bacteria present in the seeds of Agrostis capillaris. Therefore the cultivable seed endophytes of Agrostis capillaris growing on a long-term Cd/Ni-contaminated plot (Cd/Ni seeds) were compared with those originating from a non-contaminated plot (control seeds). We observed plant- and contaminant-dependent effects on the population composition between control and Cd/Ni seeds. Also differences in phenotypic characteristics were found: endophytes from Cd/Ni seeds exhibited more ACC deaminase activity and production of siderophores and IAA, while endophytes from control seeds, very surprisingly, showed more metal tolerance. Finally, the 3 most promising seed endophytes were selected based on their metal tolerance and plant growth promoting potential, and inoculated in Agrostis capillaris seedlings. In case of non-exposed plants, inoculation resulted in a significantly improved plant growth; after inoculation of Cd-exposed plants an increased Cd uptake was achieved without affecting plant growth. This indicates that inoculation of Agrostis with its seed endophytes might be beneficial for its establishment during phytoextraction and phytostabilisation of Cd-contaminated soils.
我们研究了长期镉暴露是否会导致生长在羊茅草种子中的可培养内生细菌产生有益变化。因此，我们比较了在长期镉/镍污染区（Cd/Ni 种子）生长的羊茅草的可培养种子内生菌，以及来自非污染区（对照种子）的内生菌。我们观察到植物和污染物对对照和 Cd/Ni 种子之间的种群组成有依赖性影响。还发现了表型特征的差异：来自 Cd/Ni 种子的内生菌表现出更高的 ACC 脱氨酶活性和铁载体和 IAA 的产生，而来自对照种子的内生菌，非常令人惊讶的是，表现出更高的金属耐受性。最后，根据其金属耐受性和植物生长促进潜力，选择了 3 株最有前途的种子内生菌，并接种在羊茅草幼苗中。在未暴露的植物中，接种显著促进了植物生长；在接种镉暴露的植物后，在不影响植物生长的情况下，增加了镉的吸收。这表明，在植物修复和镉污染土壤的植物稳定化过程中，接种羊茅草的种子内生菌可能对其定植有益。
