Giridhar G, Thimann K V
The Thimann Laboratories, University of California, Santa Cruz, California 95064.
Plant Physiol. 1985 May;78(1):29-33. doi: 10.1104/pp.78.1.29.
A study was made of the influence of wounding on the senescence of standard oat leaf segments in the dark. Wounding was by either subdividing the 3 centimeter long segments into 5 millimeter subsegments, gently scraping the adaxial surface of the segments with a sharp blade, making transverse linear cuts, or by making many small holes with a needle. Wounding considerably delayed the loss of both chlorophyll and protein in the dark and the amount of inhibition was roughly proportional to the intensity of wounding. With surface wounding, the inhibition of senescence was detectable from the first day of dark incubation; other methods caused moderate promotion of senescence for the first 2 days but decreased the loss of chlorophyll and protein thereafter. A number of senescence-modifying substances acted similarly on both unwounded and wounded segments, but the amount of chlorophyll and protein in the wounded segments was always more than in the respective controls. Cytokinins, however, provided an exception, since their effect was actually decreased by wounding. The proteases operating at pH 4.1 and 6.6 were both clearly less active in the wounded leaves than in controls. The possible mechanism of this inhibitory effect of wounding on senescence is discussed.
研究了伤害对标准燕麦叶段在黑暗中衰老的影响。伤害方式包括将3厘米长的叶段细分为5毫米的子叶段、用锋利刀片轻轻刮擦叶段的近轴表面、进行横向直线切割或用针打许多小孔。伤害在很大程度上延迟了黑暗中叶绿素和蛋白质的损失，抑制程度大致与伤害强度成正比。对于表面伤害，从黑暗培养的第一天就可检测到对衰老的抑制作用；其他方法在最初2天会适度促进衰老，但之后会减少叶绿素和蛋白质的损失。一些衰老调节物质对未受伤和受伤叶段的作用相似，但受伤叶段中的叶绿素和蛋白质含量总是高于各自的对照。然而，细胞分裂素是个例外，因为伤害实际上降低了它们的作用效果。在pH 4.1和6.6下起作用的蛋白酶在受伤叶片中明显比在对照中活性更低。文中讨论了伤害对衰老产生这种抑制作用的可能机制。
