Influence of simulated acid snow stress on leaf tissue of wintering herbaceous plants.
Acid snow might be an environmental stress factor for wintering plants since acid precipitates are locally concentrated in snow and the period in which ice crystals are in contact with shoots might be longer than that of acid precipitates in rain. In this study, 'equilibrium' and 'prolonged' freezing tests with sulfuric acid, which simulate situations of temperature depression and chronic freezing at a subzero temperature with acid precipitate as acid snow stress, respectively, were carried out using leaf segments of cold-acclimated winter wheat. When leaf segments were frozen in the presence of sulfuric acid solution (pH 4.0, 3.0 or 2.0) by equilibrium freezing with ice seeding, the survival rate of leaf samples treated with sulfuric acid solution of pH 2.0 decreased markedly. Leaf samples after supercooling to -4 and -8 degrees C in the presence of sulfuric acid solution (pH 2.0) without ice seeding were less damaged. When leaf samples were subjected to prolonged freezing at -4 and -8 degrees C for 7 d with sulfuric acid (pH 2.0), the survival rates of leaf samples exposed to sulfuric acid decreased more than those of leaf samples treated with water. On the other hand, leaf samples were less damaged by prolonged supercooling at -4 and -8 degrees C for 7 d with sulfuric acid (pH 2.0). The results suggest that an acid condition (pH 2.0) in the process of extracellular freezing and/or thawing promotes freezing injury of wheat leaves.
Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan.
Hidetoshi
H
Inada
Manabu
M
Nagao
Seizo
S
Fujikawa
Keita
K
Arakawa
D000143:Acids / Q000032:analysis / Q000494:pharmacology*; D003080:Cold Temperature; D004781:Environmental Exposure / Q000009:adverse effects; D005615:Freezing; D006863:Hydrogen-Ion Concentration; D018515:Plant Leaves / Q000187:drug effects* / Q000502:physiology; D011891:Rain; D012621:Seasons; D036226:Seedlings / Q000187:drug effects / Q000502:physiology; D012914:Snow / Q000737:chemistry*; D013464:Sulfuric Acids / Q000494:pharmacology; D013997:Time Factors; D014908:Triticum / Q000187:drug effects / Q000502:physiology*
D000143:Acids; D013464:Sulfuric Acids; C033158:sulfuric acid