Department of Biochemistry and Genetics, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06504.
Plant Physiol. 1992 Apr;98(4):1330-5. doi: 10.1104/pp.98.4.1330.
Tobacco (Nicotiana tabacum) mutants with 40 to 50% more catalase activity than wild type show O(2)-resistant photosynthesis under conditions of high photorespiration. More than 90% of the population of mutant plants of an M(7) and M(8) generation had enhanced catalase activity, and nearly 40% had activities >3 standard deviations above the mean of wild type. Superoxide dismutase activity was the same in mutant and wild-type leaves. The greater photosynthetic rate of mutant leaves previously observed in the laboratory was confirmed with field-grown plants that showed significantly higher rates (8%) than wild type during 8 days of measurements during a 19-day period of active growth. The tip region of expanding mutant leaves had higher catalase activity than the base of the lamina, and photosynthesis was O(2) resistant in 42% O(2) in the tip compared with the base, thus further supporting the hypothesis that there is a biochemical linkage between these traits. Plants grown in high light (270 micromole photons per square meter per second) had greater catalase activity and an activity ratio of mutant to wild type of 1.45 compared with 1.22 for those grown in low light (130 micromole photons per square meter per second). After acclimation for 3 weeks, plants transferred from low to high light showed increasing activities, and after 5 days the activity ratio of mutant to wild type was the same as in plants acclimated in higher light. The role of enhanced catalase activity in reducing photorespiratory CO(2) is discussed.
烟草（Nicotiana tabacum）突变体的过氧化氢酶活性比野生型高 40%至 50%，在高光呼吸条件下表现出对 O2 的抗性光合作用。M（7）和 M（8）代突变体植物的 90%以上具有增强的过氧化氢酶活性，近 40%的活性比野生型高出 3 个标准差以上。突变体和野生型叶片中的超氧化物歧化酶活性相同。之前在实验室中观察到的突变体叶片光合作用速率更高，这一结果在田间生长的植物中得到了证实，在 19 天的活跃生长期内进行了 8 天的测量，突变体叶片的光合速率比野生型高出 8%。展开中的突变体叶片的顶端区域的过氧化氢酶活性高于叶片基部，并且在 42%的 O2 中，光合作用对 O2 具有抗性，而在叶片基部则没有，这进一步支持了这样一种假设，即这些性状之间存在生化联系。在高光（270 微摩尔光子/平方米/秒）下生长的植物具有更高的过氧化氢酶活性，并且突变体与野生型的活性比值为 1.45，而在低光（130 微摩尔光子/平方米/秒）下生长的植物的活性比值为 1.22。经过 3 周的适应期后，从低光转移到高光的植物的活性增加，适应 5 天后，突变体与野生型的活性比值与在高光下适应的植物相同。增强的过氧化氢酶活性在减少光呼吸 CO2 方面的作用也进行了讨论。
