Taxonomic and Adaptive Significance of Hollow Plant Organs

许多种的植物，在完全不同的谱系中，以有间隔节的中空茎的规则生产为特征；竹子和马尾草（木贼属）都是典型的例子。在草或竹科的种中，空心茎比实心茎占优势；在古马尾科的物种中，所有现存的物种都有中空的茎。为了检验中空茎的生物力学特性，康奈尔大学的卡尔·尼克拉斯博士将使用一种被称为多重共振频谱（MRFS）分析的工程技术来研究几种马尾和禾本科植物。茎的机械刚性或弯曲刚性被认为与光拦截和繁殖（孢子或种子在茎上生长）有关。争论的焦点是假设的结构效率（中空茎被认为在代谢方面“更便宜”）和断裂安全性（固体茎被认为提供更大的强度）之间的权衡。茎的机械性能将被分析，和刚性方面的量化和测量，在一个物种从草和马尾科阵列。这两种距离较远的植物类群的中空茎结构的共同特征很可能提供趋同进化的例子。

Plants of many species, in quite different lineages, are characterized by the regular production of hollow stems with septate nodes; bamboos are classical examples, as are horsetails (the genus Equisetum). Among species of the grass or bamboo family, hollow stems predominate over solid stems; among species of the ancient horsetail family, all extant species produce hollow stems. In order to examine the biomechanical properties of hollow stems, Dr. Karl Niklas of Cornell University will use an engineering technique known as multiple resonance frequency spectra (MRFS) analysis in the study of several species of horsetails and of grasses. The mechanical rigidity, or flexural rigidity, of stems is thought to be related to light-interception and to reproduction (either spores or seeds borne on that stem). At issue is the hypothesized trade-off between efficiency in construction (hollow stems presumed to be "cheaper" metabolically) and safety from breakage (solid stems presumed to provide greater strength). The mechanical properties of stems will be analyzed, and aspects of rigidity quantified and measured, in an array of species from the grass and horsetail families. Common features of hollow-stem construction in these two phyletically distant groups of plants may well provide examples of convergent evolution.