抄録
We measured the δ34S values of plant leaves and of water-soluble SO42- in soil collected on the islands of Kyushu and Okinawa, Japan, and clarified the pathways of sulfur from the atmosphere to the plant-soil system by comparing the δ34S values with those of atmospheric sulfur. Most of the water-soluble SO42- in the soil was considered to derive from atmospheric sulfur by dry and wet deposition and it was assumed that the amounts of sulfur by dry deposition would be comparable to those by wet deposition. The δ34S values of water-soluble SO42- in the soil differed from site to site. This was attributed to the variability of (1) the δ34S values of sulfur by dry and wet deposition and (2) the ratio of dry deposition to wet deposition at each site. The δ34S values of the plant leaves at sites other than the town of Kokonoe were fairly close to those of water-soluble SO42- in the soil, suggesting that the plants absorb sulfur mainly as watersoluble SO42- from the soil. On the other hand, the δ34S values of the plant leaves at Kokonoe were considerably lower than those of water-soluble SO42- in the soil and were close to those of atmospheric SO2. The plants at Kokonoe were considered to depend on atmospheric SO2 for sulfur, which is essential for their growth.
