Rao I M, Amundson R G, Alscher-Herman R, Anderson L E
Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60680.
Plant Physiol. 1983 Jun;72(2):573-7. doi: 10.1104/pp.72.2.573.
Pea (Pisum sativum L. cv ;Little Marvel') plants were exposed to SO(2) for short term (3 hours) and long term (2 days) at 0.2 and at 0.5 microliter per liter (ppm) levels. The effect of this treatment on the activity of phosphoenolpyruvate carboxylase, NAD- and NADP-malate dehydrogenases, and alanine aminotransferase from epidermis and whole leaves was investigated. Short-term exposure to SO(2) at 0.2 or 0.5 ppm decreased the activity of the carboxylase and the dehydrogenases in the epidermis. In contrast, the activity of the same three enzymes increased in whole leaves with either short- or long-term exposure to SO(2). Alanine aminotransferase in epidermis or whole leaves was not much affected by short-term exposure, but the epidermal activity was decreased and whole leaf activity was increased with long-term exposure. SO(2) exposure which was initiated prior to illumination decreased the free thiol content of both epidermis and of whole leaf. Net photosynthesis was reversibly inhibited by long-term exposure to SO(2) at 0.5 ppm. No effect of 0.5 ppm SO(2) on stomatal conductance was detectable after 3 hours. Stomatal conductance appeared to decrease after longer exposure times (2 days) at 0.5 ppm.
将豌豆（豌豆品种‘小奇迹’）植株在0.2和0.5微升/升（ppm）水平下短期（3小时）和长期（2天）暴露于二氧化硫中。研究了这种处理对表皮和全叶中磷酸烯醇丙酮酸羧化酶、NAD - 苹果酸脱氢酶、NADP - 苹果酸脱氢酶以及丙氨酸转氨酶活性的影响。在0.2或0.5 ppm下短期暴露于二氧化硫会降低表皮中羧化酶和脱氢酶的活性。相反，短期或长期暴露于二氧化硫后，全叶中相同三种酶的活性会增加。短期暴露对表皮或全叶中的丙氨酸转氨酶影响不大，但长期暴露会使表皮活性降低，全叶活性增加。在光照前开始暴露于二氧化硫会降低表皮和全叶的游离巯基含量。长期暴露于0.5 ppm的二氧化硫会可逆地抑制净光合作用。3小时后未检测到0.5 ppm二氧化硫对气孔导度有影响。在0.5 ppm下暴露较长时间（2天）后，气孔导度似乎会降低。
