关键词: 次生物质, 解毒酶, 营养物质, 西花蓟马, 保护酶

Abstract: We analyzed the contents of total sulfur (S), SO₄^2-S, total reduced inorganic sulfur (TRIS), organic S, and sulfatereducing bacteria (SRB) groups and quantities in yellow soil to examine the distribution patterns of sulfur forms and SRBs in soils under acid deposition in the karst areas of Southwest China. The results showed that organic sulfur was the major sulfur form, and SO₄^2- was the major inorganic sulfur form in yellow soil. DesulfovibrioDesulfomicrobium was detected at different soil depths, indicating that DesulfovibrioDesulfomicrobium is the dominant SRB group in yellow soil. The soil depths of increasing SRB quantity and TRIS contents corresponded well to the depths of decreasing SO₄^2--S contents, indicating that dissimilatory SO₄^2- reduction occurred in yellow soil with TRIS as the main product. The residual SO₄^2- after biological S retention was firstly adsorbed and then desorbed; desorbed SO₄^2- could transport downward and was subsequently re-adsorbed and accumulated in deep soil layers. This explained the increasing SO₄^2-S contents in bottom layers of yellow soil profiles. The deposited SO₄^2- was retained as organic sulfur and adsorbed SO₄^2- in yellow soil, then yellow soil may release more S into rivers by organic sulfur mineralization and desorption of the adsorbed SO₄^2- in a long period after a large decrease in annual sulfur deposition rate. Therefore, the environmental implications such as changes of soil properties and chemical compositions of river water in southwest China should be investigated in the future.

Key words: nutritional substance, protective enzyme, Frankliniella occidentalis., secondary substance, detoxification enzyme