Jurik Thomas W
Section of Ecology and Systematics, Cornell University, 14853, Ithaca, N.Y., USA.
Oecologia. 1985 Jun;66(3):394-403. doi: 10.1007/BF00378305.
The CO costs of producing sexual and vegetative reproductive propagules were calculated for two species of wild strawberry, Fragaria virginiana and F. vesca. Five populations on sites representing a gradient of successional regrowth near Ithaca, New York, USA, were studied for two or three years each. Field studies of phenology, biomass, demography, and environment and laboratory studies of CO exchange were integrated using a computerbased model of CO dynamics to estimate costs of propagules.The percentage of plants flowering and the number of flower buds produced were highest in an open, recently disturbed habitat and lowest in a forest habitat. The openhabitat plants had the greatest success in converting flower buds into ripe fruits and also produced the highest numbers of runners and runner plantlets. On the basis of total investments in structure and respiration minus any photosynthetic gain of all reproductive structures, the cost per seed was lowest in the most open habitats and highest and increasingly variable in the more closed habitats. The cost of plantlets also was lowest in the most open habitat. The differences among habitats in cost of plantlets alive after one or two growing seasons increased due to differential survivorship of plantlets, with the open habitat continuing to have the lowest cost per plantlet. Theoretical treatments of life history characteristics such as reproductive effort should recognize that costs of equivalent type and size of propagule may vary among environments.
针对两种野生草莓——弗州草莓（Fragaria virginiana）和野草莓（F. vesca），计算了产生有性和无性繁殖体的碳成本。在美国纽约州伊萨卡附近，选取了代表演替再生梯度的五个地点的种群，对每个种群进行了两到三年的研究。利用基于计算机的碳动态模型，将物候、生物量、种群统计学和环境的实地研究与碳交换的实验室研究相结合，以估算繁殖体的成本。开花植物的百分比和产生的花芽数量在开阔的、近期受到干扰的栖息地中最高，而在森林栖息地中最低。开阔栖息地的植物在将花芽转化为成熟果实方面最为成功，并且还产生了最多数量的匍匐茎和匍匐茎幼苗。基于对所有生殖结构的结构和呼吸的总投资减去任何光合收益，每粒种子的成本在最开阔的栖息地中最低，而在更封闭的栖息地中最高且变化越来越大。幼苗的成本在最开阔的栖息地中也最低。由于幼苗的存活率不同，在一个或两个生长季节后存活的幼苗成本在不同栖息地之间的差异增加，开阔栖息地的每株幼苗成本仍然最低。对繁殖努力等生活史特征的理论处理应该认识到，同等类型和大小的繁殖体的成本在不同环境中可能会有所不同。
