Madigan M T, Brock T D
Arch Microbiol. 1977 May 13;113(1-2):111-20. doi: 10.1007/BF00428590.
Photosynthesis was measured by the 14C method on natural as well as low light adapted populations of Chloroflexus (a photosynthetic bacterium) and Synechococcus (a blue-green alga) from hot springs in Yellowstone National Park (Wyoming U.S.A.), to test the ability of these phototrophs to photosynthesize at a variety of light intensities. The herbicide 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU) was used to distinguish uptake of the blue-green alga from that of the photosynthetic bacterium, while measurements of chlorophyll a and bacteriochlorophyll c served to quantitate the standing crops of these organisms. Natural populations of Synechococcus were found to be slightly inhibited by full sunlight intensities (summer values can surpass 90000 Lux), whereas the Chloroflexus populations were not. Populations of both phototrophs subjected to reduced light intensities through the use of neutral density filters were found to adapt to low light, and then become severely inhibited by high light intensities. Adaptation to various light regimes may be an important ecological phenomenon to the survival of these hot spring phototrophs.
采用¹⁴C法对来自美国怀俄明州黄石国家公园温泉中的自然群体以及适应低光照的绿弯菌（一种光合细菌）和聚球藻（一种蓝绿藻）群体进行光合作用测定，以测试这些光合生物在各种光照强度下进行光合作用的能力。使用除草剂3-(3,4-二氯苯基)-1,1-二甲基脲（DCMU）来区分蓝绿藻和光合细菌的摄取情况，而叶绿素a和细菌叶绿素c的测量则用于定量这些生物的现存生物量。发现聚球藻的自然群体受到全日照强度（夏季值可超过90000勒克斯）的轻微抑制，而绿弯菌群体则不受影响。通过使用中性密度滤光片使两种光合生物群体受到降低的光照强度影响，发现它们能适应低光照，然后受到高光照强度的严重抑制。适应各种光照条件可能是这些温泉光合生物生存的一种重要生态现象。
