Thompson John D, Dommée Bertrand
Centre d'Ecologie Fonctionelle et Evolutive, C.N.R.S., Route de Mende, B.P. 5051, 34033, Montpellier Cedex, France.
Oecologia. 1993 Jul;94(4):480-487. doi: 10.1007/BF00566962.
A 2-year study of three natural populations of the distylousJasminum fruticans showed that mean fruit and seed production were significantly greater in shortstyled plants (thrums) than in long-styled plants (pins). In this study, we investigated the role of four sequential factors which may differentially influence fruit and seed set in the two floral morphs: (1) differences in flowering phenology, (2) a limitation of pollen transfer towards pins, (3) a differential capacity of the two morphs to act through famale and male function and (4) differential fruit abortion in the two morphs. Fruit set was significantly influenced by differences in flowering phenology although there were no differences in flowering time between the two morphs. supplementary pollinations in a natural population significantly increased fruit set and reduced the difference in fruit set between the two morphs in relation to controls, indicating a limitation on pollen transfer which was most severe towards pin stigmas. In reciprocal crosses, seed set was significantly dependent on the paternal and maternal identity of the pin parent. There was no significant variation among thrums for their performance as male or female parent. Furthermore, individual pin plants with relatively high percentage seed set as female parents gave poor seed set as male parents and vice-versa. Whereas fruit removal had no effect on seed number in thrum plants, a greater proportion of viable seeds were produced on pin plants which were left to naturally mature their fruits than on pins which had fruits artificially removed, suggesting the occurrence of selective fruit abortion in pins but not in thrums. The initially greater maternal fitness of thrums due to their greater success as pollen recipients may thus be opposed by increased viable seed set in the pins due to factors acting after the pollination stage. The relative reproductive success of floral morphs in the distylousJ. fruticans is thus differentially influenced by ecological factors occurring at different stages of the reproductive process.
一项针对三群自然分布的二型花柱植物——野生茉莉的为期两年的研究表明，短花柱植株（针型花）的平均果实和种子产量显著高于长花柱植株（柱型花）。在本研究中，我们调查了四个连续因素的作用，这些因素可能对两种花型的坐果和结籽产生不同影响：（1）开花物候差异，（2）花粉向柱型花转移受限，（3）两种花型通过雌性功能和雄性功能发挥作用的能力差异，（4）两种花型的果实败育差异。尽管两种花型的开花时间没有差异，但开花物候差异对坐果有显著影响。在一个自然种群中进行补充授粉显著提高了坐果率，并缩小了与对照相比两种花型在坐果率上的差异，这表明花粉转移存在限制，对柱型花柱头的限制最为严重。在正反交中，结籽显著依赖于柱型花亲本的父本和母本身份。针型花作为父本或母本的表现，在柱型花之间没有显著差异。此外，作为母本时种子结实率相对较高的单个柱型花植株，作为父本时种子结实率较低，反之亦然。虽然摘除果实对柱型花植株的种子数量没有影响，但与人工摘除果实的柱型花相比，自然成熟果实的柱型花植株产生的有活力种子比例更高，这表明柱型花存在选择性果实败育，而柱型花不存在。因此，最初由于柱型花作为花粉接受者更成功而具有更高的母本适合度，可能会被授粉阶段之后起作用的因素导致的柱型花有活力种子结实率增加所抵消。因此，二型花柱野生茉莉中花型的相对繁殖成功率受到生殖过程不同阶段出现的生态因素的不同影响。
