Effects of Zn Stress on Growth, Zn Accumulation, Translocation, and Subcellular Distribution of <i>Spartina alterniflora</i> 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 &gt; leaves &gt; stems &gt; 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.