Kline Biology Tower, Department of Biology, Yale University, New Haven, Connecticut 06520.
Plant Physiol. 1973 Apr;51(4):691-701. doi: 10.1104/pp.51.4.691.
Lipids which are active oleanimins, i.e., those which stimulate respiration and auxin-induced cell elongation of pea stem sections, also initiate a period of ethylene formation in them after a lag period of at least 1 hour. Production of ethylene requires auxin, is inhibited by cycloheximide and dinitrophenol applied during or before the lag period, and is greatly stimulated by lipids longer than 20 Angstroms in length such as heptadecyl-benzene, chloro- or iodohexadecane, triolein, and vitamins E and K(1), but not by the shorter chloro- and iododecane. beta-Stigmasterol at 10 to 40 mum concentrations depresses both oleanimin-induced growth and ethylene formation.The effect of oleanimins on the growth rate steadily declines and disappears after 6 hours, whereas oleanimin induction of ethylene stays at a high level until it rapidly disappears after 6 hours. Nongrowing second internode sections also produce ethylene on oleanimin treatment, so ethylene formation is not dependent on cell elongation even though it requires auxin. Preincubation with heptadecylbenzene or auxin does not change the delay of an hour or more before ethylene is produced, whereas increases in growth are noted at the earliest measurements. Oleanimins stimulate growth at less than optimal auxin concentration, even as low as 20 nm, where a proportional ethylene formation is not noted. It is concluded that ethylene formation is not causally related to growth in these tissues.The decline in oleanimin-induced ethylene formation is not changed by renewal of the incubation medium, and sucrose which is required to maintain growth for 20 hours does not influence growth or ethylene formation up to 6 hours. l-Methionine increases ethylene formed after heptadecylbenzene treatment, but unexpectedly, malonate is much more effective.Auxin concentrations supraoptimal for growth cause no growth rate reductions for the first 10 hours, but they greatly enhance oleanimin-induced ethylene formation even when heptadecylbenzene is added after 6 hours. Applied ethylene even at concentrations much above those produced by the tissue itself fails to stimulate or inhibit short term pea stem section growth. It is concluded that the effect of oleanmins on growth is not mediated by ethylene. The similarities in concentration and molecular dimensions of these structurally diverse lipids which simultaneously stimulate respiration, growth, and ethylene formation, suggest a single site of action located in a regulatory membrane.
具有活性的油脂烯丙胺，即那些刺激豌豆茎切段呼吸和生长素诱导细胞伸长的物质，在经过至少 1 小时的潜伏期后，也会引发它们的乙烯形成期。乙烯的产生需要生长素，在潜伏期内或之前用环己酰亚胺和二硝基酚处理会抑制它的产生，并且会被长度超过 20 埃的油脂如十七烷基苯、氯代或碘代十六烷、三油酸甘油酯和维生素 E 和 K(1)极大地刺激，但短链的氯代和碘代十二烷则不会。β-豆甾醇在 10 到 40 微米的浓度下会抑制油烯丙胺诱导的生长和乙烯形成。油烯丙胺对生长速度的影响在 6 小时后稳步下降并消失，而油烯丙胺诱导的乙烯生成则保持在较高水平，直到 6 小时后迅速消失。在油烯丙胺处理下，非生长的第二节间段也会产生乙烯，因此乙烯的形成不依赖于细胞伸长，尽管它需要生长素。用十七烷基苯或生长素预孵育不会改变产生乙烯之前 1 小时或更长时间的延迟，而在最早的测量中则会注意到生长的增加。油烯丙胺在低于最佳生长素浓度下刺激生长，甚至低至 20nm，在这种情况下不会注意到比例的乙烯形成。因此，在这些组织中，乙烯的形成与生长没有因果关系。重新更换孵育介质不会改变油烯丙胺诱导的乙烯形成的下降，而维持 20 小时生长所需的蔗糖在 6 小时内也不会影响生长或乙烯形成。L-蛋氨酸增加了十七烷基苯处理后的乙烯形成，但出乎意料的是，丙二酸酯更为有效。对生长超最佳的生长素浓度在前 10 小时内不会导致生长速率降低，但即使在 6 小时后加入十七烷基苯，它们也会极大地增强油烯丙胺诱导的乙烯形成。即使应用远高于组织自身产生的浓度的乙烯也不能刺激或抑制豌豆茎切段的短期生长。因此，油烯丙胺对生长的影响不是通过乙烯介导的。这些结构多样的油脂在同时刺激呼吸、生长和乙烯形成方面具有相似的浓度和分子尺寸，这表明它们的作用位点位于一个调节膜上。
