Delph Lynda F
Department of Ecology and Evolutionary Biology, University of Arizona, 85721, Tucson, AZ, USA.
Oecologia. 1986 Jun;69(3):471-476. doi: 10.1007/BF00377071.
This study examines the pattern of reproduction and factors that limit the maternal reproductive output in the self-incompatible annual, Lesquerella gordonii. Greenhouse experiments showed that fruits do not abscise and they mature if they contain at least one fertilized (outcrossed) ovule. Field studies showed that flowering increased to a peak and then fell off rapidly, while seed production/fruit decreased through the season. Pollen addition did not increase the number of fruit or seeds per fruit, suggesting that fruit and seed production are not pollinator limited. Addition of water increased fruit and seed production by extending the life of the plant, by increasing the number of stalks which flowered, and by increasing the number of seeds per fruit. This indicates that fruit and seed production are resource limited. Fruits are relatively inexpensive as compared to seeds as over 93% of the water in fruits is contained in the seeds. Fifty-three percent of the plants were lost to herbivory as were 64.6% of the fruits on the remaining plants, indicating that herbivory also limited fruit and seed production. It is hypothesized that high fruit set coupled with variable seed set in L. gordonii is an adaptive response to unpredictable, variable resource levels, and high herbivory risk.
本研究调查了自交不亲和一年生植物戈登亚麻芥的繁殖模式以及限制母体繁殖输出的因素。温室实验表明，如果果实中至少含有一枚受精（异交）胚珠，果实就不会脱落并会成熟。田间研究表明，开花先增加至峰值，然后迅速下降，而每个季节的种子产量/果实数量则减少。添加花粉并未增加果实数量或单个果实的种子数量，这表明果实和种子产量不受传粉者限制。浇水通过延长植株寿命、增加开花茎的数量以及增加单个果实的种子数量，从而提高了果实和种子产量。这表明果实和种子产量受资源限制。与种子相比，果实成本相对较低，因为果实中超过93%的水分都包含在种子中。53%的植株被食草动物啃食，其余植株上64.6%的果实也被啃食，这表明食草动物也限制了果实和种子产量。据推测，戈登亚麻芥的高坐果率和可变的结实率是对不可预测、变化的资源水平以及高食草风险的一种适应性反应。
