Department of Biology, Princeton University, Princeton, New Jersey 08540.
Plant Physiol. 1978 Mar;61(3):307-10. doi: 10.1104/pp.61.3.307.
To test the hypothesis that photoinduction acts by changing the ability of the plant to transport hormones, rather than by changing the ability of organs to synthesize them, the transport of carboxy-labeled indole-3-acetic acid was measured in the short day plant Xanthium pensylvanicum. Plants grown under noninductive conditions were matched for developmental stage, then assigned by a mathematically random method to either short day or noninductive conditions of "short day + light break." After the plants had been subjected to one to seven cycles, the movement of auxin was followed through sections cut from the middle of petioles of various ages. Photoinduction, even with as many as seven cycles, had no effect on auxin movement in either the basipetal or acropetal direction. Auxin movement in vegetative Xanthium was similar to that in Coleus and Phaseolus: strongly polar in a basipetal direction through younger petioles, but with polarity declining with increasing petiole age and concomitant decreasing elongation.
为了验证光诱导是通过改变植物运输激素的能力而不是通过改变器官合成激素的能力来起作用的假设，我们在短日植物苍耳中测量了带有羧基标记的吲哚-3-乙酸的运输。在非诱导条件下生长的植物按照发育阶段进行匹配，然后通过数学随机方法将其分配到短日或非诱导条件下的“短日+光中断”。在植物经历了一到七个周期后，通过从不同年龄叶柄中间切下的切片来跟踪生长素的移动。光诱导，即使进行了多达七个周期，对生长素在向基或向顶方向的移动也没有影响。苍耳中生长素的移动与长春花和菜豆相似：在较年轻的叶柄中强烈地向基移动，但随着叶柄年龄的增加和伴随的伸长减少，极性逐渐降低。
