Department of Biology, Indiana University, 47401, Bloomington, IN, USA.
Planta. 1979 Sep;146(4):503-11. doi: 10.1007/BF00380866.
Cells of a soybean tissue strain, suspended in an aerated liquid medium, caused disappearance of p-coumaric acid from the medium and oxidation of guaiacol, benzidine, pyrogallol, L-dihydroxyphenylalanine and L-epinephrine. Both the disappearance and the oxidations were inhibited by 6-benzylaminopurine (BAP) at a concentration of 0.5 mM. BAP at other concentrations either promoted or inhibited oxidation of epinephrine in precisely the pattern reported earlier for the disappearance of coumarate; therefore, the disappearance of coumarate probably involves its oxidation. The effectiveness of other cytokinins in inhibiting the oxidation was studied.At 0.5 mM, and perhaps even at 0.5 μM, some of the several cytokinins tested inhibited oxygen consumption by the soybean cells. This inhibition, which did not require any of the above metabolizable compounds, was especially marked in the presence of cyanide, azide or Antimycin A, and was detectable in 10 min or less. Either Antimycin A or salicylhydroxamic acid alone promoted O2 consumption but together they were quite inhibitory. The soybean cells apparently have an alternate respiratory pathway and cytokinins may influence its operation.Several cytokinins at 0.5 mM, and perhaps at 0.5 μM, also inhibited oxygen consumption by mitochondrial preparations from the soybean cells, the inhibition being evident in about 20 s. The consumption required a substrate such as malate, succinate or NADH. Cytokinins and related compounds varied in effectiveness as follows: BAP and 6-isopentenyla-minopurine ≥ 9-tetrahydropyranyl-BAP > kinetin, ribosyl-isopentenylaminopurine, 9-methyl-BAP and 9-methoxymethyl-BAP > 6,6-dimethylaminopurine and zeatin (slight activity) > 6-methylaminopurine, nicotinamide and adenine (ineffective). To a great extent this order parallels the order of effectiveness of the compounds in causing cell division. Mitochondria, therefore, may contain a site for an important cytokinin action.
悬浮在充气液体培养基中的大豆组织细胞会使介质中的对香豆酸消失，并氧化愈创木酚、联苯胺、焦儿茶酚、L-二羟基苯丙氨酸和 L-肾上腺素。在浓度为 0.5mM 的情况下，6-苄基氨基嘌呤 (BAP) 抑制了这两种物质的消失和氧化。在其他浓度下，BAP 要么促进要么抑制肾上腺素的氧化，这种模式与之前报道的香豆酸盐消失的模式完全一致；因此，香豆酸盐的消失可能涉及到它的氧化。其他细胞分裂素抑制氧化的有效性也进行了研究。在 0.5mM 的浓度下，甚至在 0.5μM 的浓度下，测试的几种细胞分裂素之一抑制了大豆细胞的耗氧量。这种抑制作用不需要上述任何可代谢化合物，在氰化物、叠氮化物或安密妥 A 的存在下尤其明显，在 10 分钟或更短的时间内即可检测到。安密妥 A 或水杨羟肟酸单独使用会促进 O2 的消耗，但两者一起使用时则具有很强的抑制作用。大豆细胞显然有替代的呼吸途径，细胞分裂素可能会影响其运作。在 0.5mM 的浓度下，几种细胞分裂素，也许在 0.5μM 的浓度下，也抑制了来自大豆细胞的线粒体制剂的耗氧量，抑制作用在大约 20 秒内显现。这种消耗需要像苹果酸、琥珀酸或 NADH 这样的底物。细胞分裂素和相关化合物的有效性如下：BAP 和 6-异戊烯基氨基嘌呤≥9-四氢吡喃基-BAP＞激动素、核糖基异戊烯基氨基嘌呤、9-甲基-BAP 和 9-甲氧基甲基-BAP＞6,6-二甲基氨基嘌呤和玉米素（轻微活性）＞6-甲基氨基嘌呤、烟酰胺和腺嘌呤（无效）。在很大程度上，这种顺序与化合物在引起细胞分裂方面的有效性顺序相吻合。因此，线粒体可能含有一个重要细胞分裂素作用的位点。
