Kohn Joshua R
Biology Department, University of Pennsylvania, Philadelphia, PA, 19104.
Evolution. 1989 Nov;43(7):1424-1434. doi: 10.1111/j.1558-5646.1989.tb02593.x.
In the gynodioecious plant Cucurbita foetidissima (Cucurbitaceae), females were common in all eight populations examined and made up 32% of adult plants. Females produced 1.5 (SE = 0.2) times as many seeds as did hermaphrodites. The observed difference in seed production alone is not great enough to explain the maintenance of females, especially at their current frequency. Females and hermaphrodites did not differ in number of nodes per stem, stems per plant, internode length, or size of leaves. Females produced more female biomass (fresh or dry weight) than hermaphrodites, but total investment in sexual biomass did not differ. Thus, the biomass of male flowers produced by hermaphrodites was about equal to the extra female biomass produced by females. The results support the existence of a trade-off between male and female reproduction.
在雌雄异株植物恶臭南瓜（葫芦科）中，在所研究的全部8个种群中雌性植株都很常见，占成年植株的32%。雌性植株产生的种子数量是雌雄同株的1.5倍（标准误 = 0.2）。仅观察到的种子产量差异还不足以解释雌性植株得以维持的原因，尤其是在其当前的频率下。雌性植株和雌雄同株在每根茎的节数、每株的茎数、节间长度或叶片大小方面并无差异。雌性植株产生的雌性生物量（鲜重或干重）比雌雄同株更多，但在有性生物量上的总投入并无差异。因此，雌雄同株产生的雄花生物量与雌性植株产生的额外雌性生物量大致相等。这些结果支持了在雄性和雌性繁殖之间存在权衡的观点。
