Metal Contamination Influences Morphology and Reproductive Strategies of Seeds
Jan. 18, 2023
Research by PhD student Kamila Murawska-Wlodarczyk and Dr. Alicja Babst-Kostecka, University of Arizona Superfund Research Center (UA SRC) Co-Investigator for Project 5, looks at how some hyperaccumulating plants – plants that collect a high concentration of metals – adjust reproductive traits to ensure plant survival at metal-contaminated sites.
To better anticipate the early plant establishment in phytoremediation efforts, the team of investigators for this study evaluated the seed shape characteristics, dormancy, and germination rate in two non-metallicolous and two metallicolous populations of the zinc and cadmium hyperaccumulator Arabidopsis halleri. Metallicolous plants have adapted to grow preferentially in soils containing a higher-than-normal concentration of a particular metal. The team also examined the potential influence of seed surface-associated microbes and endophytic fungi on germination success.
The study found that seeds from non-metallicolous populations were about 20 percent bigger than those from metal-contaminated legacy mine sites. Irrespective of their origin, surface-sterilized seeds had up to about 20 percent higher germination rates and germinated earlier than non-sterilized seeds, hinting at a negative effect of seed-associated microbial communities. Surface sterilization also facilitated the emergence of an endophytic fungus (Aspergillus niger) that is a known seed-borne pathogen.
These findings demonstrate that despite species-wide metal tolerance in A. halleri, metalliferous conditions negatively affect reproductive traits compared to non-metalliferous environments (e.g., smaller seeds). Yet, higher germination rates in these populations hint at the potential of A. halleri to successfully colonize post-mining habitats – a process that is modulated by site-specific interactions with seed microbiota.
Publication:
Murawska-Wlodarczyk K, Korzeniak U, Chlebicki A, Mazur E, Dietrich CC, Babst-Kostecka A. Metalliferous habitats and seed microbes affect the seed morphology and reproductive strategy of Arabidopsis halleri. Plant Soil. 2022 Mar;472(1-2):175-192. doi: 10.1007/s11104-021-05203-5. Epub 2022 Jan 31. PMID: 36389645; PMCID: PMC9648182.