Flue gas desulfurization gypsum by-products alters cytosolic Ca^{2 +} distribution and Ca²⁺-ATPase activity in leaf cells of oil sunflower in alkaline soil

Abstract

Soil salinization in arid zones is a major factor that resulted in the reduction in the yield and quality of many important crops in Northwestern China. In this study, the potential mechanism of flue gas desulfurization gypsum by-product (FGDB) mediated amendment of alkaline soils was investigated in an oil sunflower model by accessing the Ca²⁺ distribution and Ca²⁺-ATPase activity in leaf cells. Our results demonstrated an increased calcium concentration, as well as intact chloroplast structure with increasing calcium precipitates in the cell wall, intercellular space, and vacuole of leaf cells in the plants grown in alkaline soils supplied with FGDB or CaSO₄. Additionally, a dose-dependent Ca²⁺-ATPase activity was detected in the plasma membrane and tonoplast of leaf cells from the plants grown in FGDB or CaSO₄ supplemented soils. These results implied that the Ca²⁺-ATPase activity cause cytosolic Ca²⁺ efflux. The Ca²⁺ influx is through the Ca²⁺-channels, and increasing cytosolic Ca²⁺ concentration might benefit the stability and integrity of cell membrane and cell wall, sequentially alleviated the injury of oil sunflower against alkali stress.

Keywords:

• flue gas desulfurization gypsum by-products
• CaSO₄
• alkaline soils
• Ca²⁺ distribution
• oil sunflower

Acknowledgments

We thank Drs. Liu HH and Jia JZ (College of Biological Sciences, Agricultural University of China) for their helpful suggestions, technical assistance for ultrathin sections, and transmission electron microscopy. This work was supported by grants from the National Basic Research Program of China (973 program) (2012CB723206) and National Key Technology R&D Program of the Ministry of Science and Technology (2013BAC02B04 and 2011BAC07B03).