Effects of Zn Stress on Growth, Zn Accumulation, Translocation, and Subcellular Distribution of Spartina alterniflora Loisel

Abstract

Spartina alterniflora plays an important role in heavy metal phytoremediation of estuary salt marshes. A study quantifying the effects of different Zn concentrations (100, 500, and 1000 μg · g−1) on growth, Zn accumulation, translocation, and subcellular distribution of S. alterniflora was conducted. The results showed that plant height and dry biomass increased under the 100 and 500 μg · g−1 Zn stress test. The Zn concentration in the same tissues increased with increasing Zn concentration. In addition, the Zn concentrations under the same Zn stress increased in the following order: Fine roots > leaves > stems > rhizomes. For example, it was found that the Zn concentration in fine roots reached up to 60.64 μg · g−1, and this concentration was significantly higher than in other tissues. However, the highest accumulation was detected in leaves under the 500 μg · g−1 Zn stress test, regardless of other tissues and Zn treatments. The Zn translocation factor increased with increasing Zn treatment concentrations and reached 1.05 under 1000 μg · g−1 Zn stress. This result suggests that Zn was easily transported to the shoots of S. alterniflora. Moreover, the cell wall and cytoplasmic supernatant played important roles in Zn stabilization and detoxification. This was a result of Zn mainly distributed in the cell wall and cytoplasmic supernatant but not in cell organelles.