Am J Bot. 1997 Sep;84(9):1275.
We examined the patterns of variation in wing-loading and its related characteristics in Cardiocrinum cordatum to clarify the factors that determine the variation in seed dispersal ability in this species. The square root of wing-loading of a seed of a plant was not significantly correlated with basal stem diameter of a plant, indicating that large plants did not necessarily produce seeds with high dispersal ability. This result was inconsistent with the hypothesis that large plants produce seeds with high dispersal ability to avoid high mortality of seeds and seedlings in the vicinity of the parents. On the other hand, the square root of wing-loading of a seed of a fruit was negatively dependent on seed number of a fruit. Thus, many-seeded fruits produced seeds with high dispersal ability. This was because the projected surface area per seed was large in large fruits and large fruits contained large numbers of seeds. The cost per seed of producing fruit structures was small for many-seeded fruits. Thus, high dispersal ability of seeds in many-seeded fruits may be a result of an effective resource allocation pattern in which a high proportion of resources are allocated to those many-seeded fruits, enabling seeds to develop large wings and thus reducing the structural cost of fruits per seed.
我们研究了兜兰属植物（Cardiocrinum cordatum）中翼载及其相关特征的变异模式，以阐明决定该物种种子扩散能力变异的因素。植物种子的翼载平方根与植物基部茎直径没有显著相关性，这表明大型植物不一定产生具有高扩散能力的种子。这一结果与大型植物产生具有高扩散能力的种子以避免种子和幼苗在亲本附近高死亡率的假设不一致。另一方面，果实中种子的翼载平方根与果实中的种子数呈负相关。因此，多籽果实产生了具有高扩散能力的种子。这是因为大果实中每个种子的投影表面积大，而大果实中含有大量的种子。对于多籽果实来说，产生果实结构的每个种子的成本很小。因此，多籽果实中种子的高扩散能力可能是一种有效的资源分配模式的结果，其中高比例的资源分配给多籽果实，使种子发育出大的翅膀，从而降低每个种子的果实结构成本。
