WEIGHT-DENSITY RELATIONSHIPS IN RAMET POPULATIONS OF CLONAL PERENNIAL HERBS, WITH SPECIAL REFERENCE TO THE -3-2 POWER LAW
WEIGHT-DENSITY RELATIONSHIPS IN RAMET POPULATIONS OF CLONAL PERENNIAL HERBS, WITH SPECIAL REFERENCE TO THE -3-2 POWER LAW
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DOI：
10.2307/2259334
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发表时间：
1979-01-01
影响因子：
5.5
通讯作者：
HUTCHINGS, MJ
中科院分区：
文献类型：
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作者：
HUTCHINGS, MJ
在种群经历疏伐时，平均株重和密度随时间的变化关系符合-3/2幂定律。它描述了以基因为基本种群单位的各种物种的种群增长。然而，在多年生无性系草本植物种群中，分株密度受到环境控制和植物内部控制的限制，并且分株的稀疏不会直接由于其生长而发生。因此，-3/2幂律不适用于多年生无性系草本植物[多年生墨丘利（Mercurialisperennis）、大甜茅（Glyceriamaxima）、芦苇（Phragmites communis）、狭叶香蒲（Typhaangustifolia）、湖生苔草（Carexlacustris）、长叶苔草（C. lucifolia）]的分株种群。chordorrhiza，C. rostrata，尖吻隐翅虫C. aquatilis和一枝黄花altissima]，并提出了几组数据来说明这一事实。除了一个例外，数据集分为3个曲线族。大多数关系遵循Hutchings和Barkham（1976）提出的模型曲线，或者表现出一种循环形式，在12个月时回到图上大致相同的位置。的间隔在前一种类型中，枝条的队列在时间上完全分开，而在后一种类型中，队列overalp，因此该站点连续被枝条占据。物种表现出介于这两个极端之间的一系列行为类型。有效利用生物空间的基因群体沿梯度为-3/2的“极限”疏伐线沿着自疏。在成熟期，大多数多年生无性系草本植物接近这条疏伐线，但不越过它。这是一种有效的策略，结合了最大限度地利用环境资源和高产量的生物量，而不会自我疏伐。当生物量年复一年达到稳定状态时，-3/2幂律可能已经起作用，以确定每个地点的枝数和生物量之间的最佳关系。
The -3/2 power law relates the logarithms of mean plant weight and plant density through time as a population undergoes thinning. It describes the growth of populations of a wide variety of species with genets as their basic population units. In populations of clonal perennial herbes, however, ramet density is restricted by environmental controls and controls internal to the plant, and thinning of ramets does not occur as a direct result of their growth. The -3/2 power law, therefore, is not applicable to the ramet populations of clonal perennial herbs [Mercurialis perennis, Glyceria maxima, Phragmites communis, Typha angustifolia, Carex lacustris, C. chordorrhiza, C. rostrata, C. aquatilis, and Solidago altissima], and several sets of data are presented to illustrate this fact. The sets of data fall, with one exception, into 3 families of curves. Most relationships follow the model curve presented by Hutchings and Barkham (1976), or exhibit a cyclic form returning to approximately the same position on the graph at 12 mo. intervals. In the former type, cohorts of shoots are completely separated in time, whereas in the latter type cohorts overalp, so that the site is continuously occupied by shoots. Species exhibit a range of types of behavior between these 2 extremes. Genet populations with efficient utilization of biological space self-thin along an ''ultimate'' thinning line with a gradient of -3/2. At maturity, most clonal perennial herbs closely approach this thinning line, but do not transgress it. This is an efficient strategy incorporating maximum utilization of environmental resources and high production of biomass without self-thinning. The -3/2 power law may have operated to determine the optimum relationship between shoot number and biomass for each site when it has achieved a steady state with constant biomass from year to year.