Department of Ecology, Evolution, and Natural Resources, Rutgers, The State University, 1 College Farm Road, New Brunswick, New Jersey 08901-1582 USA.
Am J Bot. 2000 Dec;87(12):1821-6.
The interaction between simulated cotyledon herbivory and interspecific competition was studied in a greenhouse experiment using two species of trees, Acer rubrum and Quercus palustris, which commonly invade abandoned agricultural fields. Herbivory treatments were applied as a gradient of cotyledon removal for A. rubrum with 0, 25, 50, 75, and 100% of cotyledon tissue removed. Cotyledons from Q. palustris were clipped and removed (control, early, and late removal) to create a gradient of seed reserve availability. The competition treatment consisted of plugs of old-field vegetation that filled the pots with perennial cover. Mortality of seedlings was higher with competition. There was a significant interaction between herbivory and competition with the highest mortality occurring with competition at the highest intensity of herbivory in both species. Herbivory reduced biomass for Q. palustris only, while competition reduced biomass in both species. Neither species showed an interaction between herbivory and competition for growth. There was a significant interaction between herbivory and competition on allocation patterns for both species, with greater allocation to roots with competition at the highest intensity of herbivory. This study demonstrates the potential for cotyledon herbivory and competition to interact, altering the invasion of tree seedlings into abandoned agricultural land.
在温室实验中，研究了模拟子叶食草和种间竞争之间的相互作用，实验使用了两种常见于废弃农田的树种：红枫（Acer rubrum）和沼泽栎（Quercus palustris）。对红枫的子叶进行了去除处理，从完全保留子叶（0%去除）到去除 25%、50%、75%和 100%的子叶组织，形成了一个子叶去除梯度。沼泽栎的子叶被修剪和去除（对照、早期去除和晚期去除），以形成种子储备可用性的梯度。竞争处理包括填充花盆的多年生植物插条。有竞争的情况下，幼苗死亡率更高。在两种树种中，食草和竞争之间都存在显著的相互作用，随着食草强度的增加，死亡率最高。食草仅降低了沼泽栎的生物量，而竞争则降低了两种树种的生物量。对于生长，两种树种都没有表现出食草和竞争之间的相互作用。对于两种树种，食草和竞争之间的分配模式存在显著的相互作用，在食草强度最高的情况下，更多的资源分配给了根。这项研究表明，子叶食草和竞争有可能相互作用，从而改变树种幼苗入侵废弃农田的情况。
