Root profiles and competition between the invasive, exotic perennial, Carpobrotus edulis, and two native shrub species in California coastal scrub
Root profiles and competition between the invasive, exotic perennial, Carpobrotus edulis, and two native shrub species in California coastal scrub
复制标题
加州沿海灌木丛中入侵性外来多年生植物 Carpobrotus edulis 与两种本地灌木物种之间的根系概况和竞争
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
B. E. Mahall
中科院分区：
文献类型：
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作者：
C. D’Antonio;B. E. Mahall
这种垫状的多肉植物Carpobrotus edulis(Aizoaceae)包围并生长在加州沿海社区的许多本地植物物种上。两个灌木种：Haplopappus ericoides和H.ventus var.Sedoides的根系较浅，其土壤深度与西洋参相同。在西洋参的存在下，灌木的正常生根轮廓向下移动，但与西洋参仍有部分重叠。与对照相比，去除两种灌木个体周围的水葫芦会导致灌木在黎明前的木质部压力势更高，这表明周围的水葫芦正在利用这些灌木本来可以利用的水分。除草处理灌木的黎明前木质部压力势在整个旱季的剩余时间里一直高于对照灌木，尽管在除草后这些灌木的冠层面积显著增加。与对照相比，去除文脉草周围的甜瓜也会导致黎明前灌木的木质部压力势更高，并增加新叶的产量。经过这一初始阶段后，去除灌木的黎明前木质部压力势与对照没有显著差异，这表明叶面积增加对水分的需求最终与去除毛果灌木提高的水分利用率相匹配。此外，文氏草灌木的形态也改变为更典型的未受影响的个体。因此，甜瓜不仅对这两种灌木的水分关系有显著影响，而且对它们的枝条大小和整体形态也有显著的影响。
The mat-forming succulent, Carpobrotus edulis (Aizoaceae), surrounds and grows over many native plant species in California coastal communities. Two shrub species, Haplopappus ericoides and H. venetus var. sedoides, were found to have shallow root systems that occupied the same soil depths as those of C. edulis. In the presence of C. edulis, the normal rooting profiles of the shrubs were displaced downward, although partial overlap with C. edulis remained. Removal of C. edulis from around individuals of both shrub species resulted in higher predawn xylem pressure potentials in shrubs from the removal treatments as compared to controls, suggesting that the surrounding C. edulis was utilizing water that would otherwise have been available to these shrubs. In H. ericoides, predawn xylem pressure potentials of removal treatment shrubs remained higher than those of the controls throughout the remainder of the dry season even though these shrubs showed a marked increase in canopy area after removal of surrounding C. edulis. Removal of C. edulis from around H. venetus also initially led to higher predawn xylem pressure potentials in the removal shrubs as compared to the controls and increased production of new leaves. After this initial period the predawn xylem pressure potentials of the removal shrubs were not significantly different from those of controls, suggesting that the demand for water by the increased leaf areas eventually matched the enhanced water availability resulting from C. edulis removal. Also, the morphology of H. venetus shrubs changed to that more typical of unaffected individuals. Thus, C. edulis significantly affected not only the water relations of these two shrub species but also their shoot sizes and overall morphologies.