Physiological integration among tillers of Holcus lanatus: age‐dependence and responses to clipping and competition
Physiological integration among tillers of Holcus lanatus: age‐dependence and responses to clipping and competition
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DOI：
10.1111/j.1469-8137.1994.tb04037.x
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发表时间：
1994-12
期刊：
影响因子：
9.4
通讯作者：
J. Bullock;A. Mortimer;M. Begon
中科院分区：
文献类型：
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作者：
J. Bullock;A. Mortimer;M. Begon
在温室条件下，对无性系牧草Holcus lanatus L.进行了分蘖间生理整合的生态效应研究。测定了切断分蘖与其亲本的节间联系对其生长和存活的影响。用这种方法确定了三个因素对切断反应的影响：与母株的竞争，通过比较单独移栽的分蘖和留在亲本附近的分蘖；浸渍处理，包括不修剪，只修剪标记的分蘖及其子茎或整株修剪母株，包括标记的分蘖；以及在切断时反应随分蘖年龄的变化，使用四个分蘖年龄(1，2，4和8wk)。这些年龄、剪裁和切断处理是按事实应用的。在生长8wk后，对切断标记分蘖的反应取决于年龄和剪裁处理。切断总是降低最小分蘖(1和2wk龄)的存活和生长(分蘖产量、生物量和分蘖伸长)，表明他们依赖亲本来支持他们的早期生长。4岁的分耕者能够支持自己的生长，并在孤立的情况下生长最快；但当在父母的邻居中生长时，与父母的竞争会减少生长，尽管父母的支持会改善这些影响。一些最老的分蘖(8周龄)在不切断时表现出生长减慢。这表明资源外流到亲本，并表明整合允许控制和协调分蘖生长。在所有剪枝处理中，切断效果的模式相似，只是程度不同。几乎没有证据表明，当整株修剪时，对修剪的分蘖的支持增加或整合模式的改变，除了8龄分蘖表现出持续的连接好处，与其他两种修剪处理的积极效果相反。标记分蘖的延伸率对修剪和切断处理表现出复杂的反应，包括修剪后整合对再生的影响。这项实验表明，羊草分蘖的生长是高度整合的，但这种整合对分蘖年龄的反应是非常可塑性的，在较小程度上是修剪处理。
summary The ecological consequences of physiological integration among tillers were examined in a glasshouse experiment on the clonal grass Holcus lanatus L. We measured the effects of severing the internode connection between a tiller and its parent on the growth and survival of this marked tiller. The effects of three factors on the response to Severing were determined using this procedure: competition with the parent plant, by comparing tillers repotted in isolation with tillers remaining in the neighborhood of the parent; dipping treatment, comprising no clipping, clipping only the marked tiller and its daughter tillers or clipping the whole parent plant, including the marked tiller; and the change in the response with tiller age at severing, using four tiller ages (1, 2, 4 and 8 wk). These age, clipping and severing treatments wt-re applied factorially. After 8 wk of growth the responses to severing of the marked tillers, were dependent on the age and clipping treatments. Severing always decreased survival and growth (tiller production, biomass and tiller extension) of the youngest tillers (ages 1 and 2wk), indicating that they were dependent on the parent to support their early growth. Age 4 tillers were able to support their own growth and grew hest in isolation; but when grown in the parent's neighbourhood competition with the parent reduced growth, although parental support ameliorated these effects. Some of the oldest tillers (age 8 wk) showed decreased growth when unsevered. This indicated an outflow of resources to the parent and suggested that integration allowed the control and coordination of tiller growth. The pattern of the severing effects was similar in all clipping treatments, varying only in degree. There was little evidence of increased support for clipped tillers or for a change in the pattern of integration when the whole plant was clipped, except that age 8 tillers showed a continued benefit of the connection, in contrast to the positive effect of severing in the other two clipping treatments. The extension rate of the marked tiller showed complex responses to clipping and severing treatments, including effects of integration on regrowth after clipping. This experiment has shown that the growth of tillers in H. lanatus is highly integrated but that this integration is extremely plastic in response to tiller age and, to a lesser extent, clipping treatment.