The ecological significance of rapid wound-induced changes in plants: insect grazing and plant competition
The ecological significance of rapid wound-induced changes in plants: insect grazing and plant competition
复制标题
植物伤口引起的快速变化的生态意义：昆虫吃草和植物竞争
作者：
P. Edwards;S. Wratten;E. A. Parker
SummaryThis本文调查的假设，即迅速诱导的植物化学反应放牧损害，如番茄，服务于偏离昆虫食草动物离开叶片后不久，损害他们（放牧扩散假说）。因此，放牧损害比其他情况更加分散，并且对植物竞争光可能特别重要的幼叶不会受到过度损害。在第一个实验中，人工去除C。与未受损的对照相比，15%的叶面积导致植物性能显著降低，但仅当植物一起生长以竞争光照时。第二个实验表明，植物内的放牧损害的分布是一个重要的因素，在竞争的结果，在这些植物中，放牧被施加到下叶有没有影响的损害后的性能与未受损的控制相比，而放牧到上叶显着降低植物的性能。第三个实验提供了一些关于损害和竞争之间的相互作用是如何发生的。结果表明，叶片受损导致主枝的延伸生长速率迅速下降，特别是当上部叶片受损时，并且至少3天内不能恢复正常生长速率。有人认为，在一个快速增长的冠层，这种影响可能意味着受损的植物失去了它的位置在高度层次。最后的实验表明，以前对植物的损害可以影响随后的草地贪夜蛾幼虫的分布，显然是通过伤口引起的叶适口性降低。植物已被人为损害48小时前被放牧显着低于对照，避免效果是最大的幼叶。这些结果是一致的放牧扩散假说，并表明，快速伤口诱导的反应可能是最重要的肥沃的环境中，光的竞争是特别激烈的物种特征。
SummaryThis paper investigates the hypothesis that a rapidly induced phytochemical response to grazing damage, such as that seen in tomato, serves to deflect insect herbivores away from leaves soon after damaging them (the grazing dispersal hypothesis). As a result, grazing damage is more dispersed than it otherwise would be, and young leaves, which may be of particular importance to a plant in competition for light, are not damaged excessively. In the first experiment, artificial removal of c. 15% of leaf area led to a significant reduction in plant performance compared with undamaged controls, but only when the plants were grown together in competition for light. The second experiment demonstrated that the distribution of grazing damage within the plant was an important factor in the outcome of competition; in those plants in which grazing was applied to the lower leaves there was no effect of damage upon performance compared with undamaged controls, whereas grazing to the upper leaves significantly reduced plant performance. A third experiment provided some insight into how this interaction between damage and competition comes about. It was shown that damage to leaves led to a rapid drop in the rate of extension growth of the main shoot, especially when the upper leaves were damaged, and normal rates of growth were not resumed for at least 3 days. It is argued that in a rapidly growing canopy, such an effect may mean that a damaged plant loses its position in the height hierarchy. The final experiment showed that previous damage to plants can affect the distribution of subsequent grazing by larvae of Spodoptera littoralis, apparently through a wound-induced reduction in leaf palatability. Plants which had been artificially damaged 48 h previously were grazed significantly less than controls, and the avoidance effect was greatest in the young leaves. These results are consistent with the grazing dispersal hypothesis, and suggest that rapid wound-induced responses may be of greatest significance in species characteristic of fertile environments where competition for light is particularly intense.