Department of Plant Genetics, The Weizmann Institute of Science, Rehovot, IL-76100 Israel.
Plant Physiol. 1989 Nov;91(3):1174-8. doi: 10.1104/pp.91.3.1174.
Tolerance to photoinhibition was compared between a paraquat-resistant and a sensitive biotype of Conyza bonariensis (L.). Cronq. Photoinhibitory damage was measured as a decrease in oxygen evolution or energy storage using photoacoustic spectroscopy, or as a decrease of (14)CO(2)-fixation. Prior to exposure to high fluence rates, both biotypes had similar quantum yields of oxygen evolution and energy storage. After exposure to high intensity light, the resistant biotype continued to evolve oxygen and to store energy with a high quantum yield while both energy storage and oxygen evolution were severely reduced in the sensitive biotype. CO(2)-fixation was less rapidly inhibited in the resistant biotype compared to the sensitive one. The data show that the paraquat resistant biotype with its high constitutive levels of the chloroplast localized enzymes of the oxygen detoxification pathway, is also partially protected from photoinhibition. This supports the theory that an enhanced radical scavenging system can give temporary protection against photooxidative damage from a variety of sources.
比较了对百草枯具有抗性和敏感的苣荬菜（Conyza bonariensis（L.）Cronq.）生物型之间的光抑制耐受性。用光声光谱法测量光抑制损伤作为氧演化或能量储存的减少，或作为（14）CO（2）固定的减少。在暴露于高流量率之前，两种生物型的氧演化和能量储存的量子产率相似。在高强度光照射后，抗性生物型继续以高量子产率演化氧气并储存能量，而敏感生物型的能量储存和氧气演化则严重减少。与敏感生物型相比，CO（2）固定在抗性生物型中抑制得较慢。这些数据表明，具有高水平组成型叶绿体定位的氧解毒途径酶的百草枯抗性生物型，也部分受到光抑制的保护。这支持了这样一种理论，即增强的自由基清除系统可以提供对各种来源的光氧化损伤的暂时保护。
