Pioneering Research Laboratory, Crops Research Division, Agricultural Research Service, United States Department of Agriculture, Department of Plant Pathology, University of Wisconsin, Madison, Wisconsin 53706.
Plant Physiol. 1969 Feb;44(2):193-8. doi: 10.1104/pp.44.2.193.
The growth rates of tobacco callus tissues on media containing 10(-6) to 10 mum 6-(gamma,gamma-dimethylallylamino)purine (2iP) were measured. At concentrations of 10(-4) mum and above growth rates were exponential and dependent on cytokinin concentration. At 2iP concentrations of 10(-4) to 0.33 mum, the exponential rate was maintained for 4 to 5 doublings of fresh and dry weight. After this period a linear phase, resulting in approximately 1 doubling of weight, occurred. The growth of tissues on media containing higher than 0.33 mum 2iP was exponential for only about 15 days. At the end of this time, and well before they achieved half their final weight, they exhibited growth which was less rapid than logarithmic but more rapid than linear. Comparisons with zeatin, 6-benzylaminopurine and kinetin indicated that, although the maximum growth rates obtained with relatively high concentrations (0.1-1 mum) were similar, the naturally occurring cytokinins, 2iP and zeatin, promoted faster rates at lower concentrations (10(-3)-10(-2) mum) than did 6-benzylaminopurine and kinetin.
测定了含有 10(-6)至 10 mum 6-(γ,γ-二甲基烯丙基氨基)嘌呤（2iP）的培养基中烟草愈伤组织的生长速度。在 10(-4) mum 及以上浓度下，生长速度呈指数增长，且依赖于细胞分裂素浓度。在 2iP 浓度为 10(-4)至 0.33 mum 时，新鲜和干燥重量的指数增长率保持了 4 至 5 倍。在此期间之后，会出现一个线性阶段，导致重量大约增加 1 倍。在含有高于 0.33 mum 2iP 的培养基上，组织的生长仅呈指数增长约 15 天。此时，它们还远未达到最终重量的一半，其生长速度就已经比对数生长更慢，但比线性生长更快。与玉米素、6-苄基氨基嘌呤和激动素的比较表明，虽然在相对较高浓度（0.1-1 mum）下获得的最大生长速度相似，但天然存在的细胞分裂素 2iP 和玉米素在较低浓度（10(-3)-10(-2) mum）下促进更快的生长速度，而 6-苄基氨基嘌呤和激动素则不然。
