凍結過程に存在する酸性物質が植物細胞の生存に及ぼす影響

抄録

The objective of this study was to clarify the mechanism of injury caused by acid snow stress in wintering plants. In this study, influence of simulated acid snow stress on leaf tissues of wintering plant was conveniently estimated by extracellular freezing tests under acid conditions in vitro. The survival rates of leaf tissues after freeze-thawing with 0.3 ml of sulfuric acid solution of pH 2.0 were significantly decreased, compared with the survival rates under acid condition of pH 3.0 or pure water. In this study, the initial volume of sulfuric acid solutions was the same in the treatments. Therefore, it is thought that the more acidic the initial pH of sulfuric acid solution becomes, the greater the volume of residual unfrozen solution with concentrated sulfuric acid in the extracellular part at a subzero temperature would be, consequently, the survival rate of leaf tissues were decreased. When leaf tissues were freeze-thawed with a large volume of sulfuric acid solution of pH 3.0, the survival rate of leaf tissues was comparable to the survival rate using pH 2.0. These results suggest that an increase in the volume of acid meltwater derived from snow cover will enhance the damage to wintering plants even the mild acidity of the acid snow.