INTERSPECIFIC POLLEN COMPETITION AS A REPRODUCTIVE BARRIER BETWEEN SYMPATRIC SPECIES OF HELIANTHUS (ASTERACEAE)
INTERSPECIFIC POLLEN COMPETITION AS A REPRODUCTIVE BARRIER BETWEEN SYMPATRIC SPECIES OF HELIANTHUS (ASTERACEAE)
复制标题
种间花粉竞争作为向日葵（菊科）同域物种之间的繁殖障碍
DOI：
10.1002/j.1537-2197.1995.tb15672.x
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发表时间：
1995
影响因子：
3
通讯作者：
Sue J. Youn
中科院分区：
文献类型：
--
作者：
L. Rieseberg;A. Desrochers;Sue J. Youn
利用向日葵（Helianthus annuus）与向日葵（H.以向日葵属（Helianthus）1,245个瘦果为试材，采用1：9、1：1和9：1的种内：种间花粉混合物进行花粉竞争试验，研究种间花粉竞争作为繁殖障碍的作用，结果表明，在1,245个瘦果中，只有49个是杂种。观察到的杂种数量显著低于所有三种花粉混合物的预期值，无论母本的身份如何（P< 0.01）。柱头年龄和花粉比例对杂种频率无显著影响。然而，杂交种与H. annuusthan与H.叶柄为母本（P< 0.01）。花粉管生长速率的分析表明，种内与种间花粉的生长速率没有差异。同样，授粉与种内或种间花粉或不同的花粉比例并没有影响填充瘦果的百分比。因此，在混合花粉负载中，种内花粉选择性受精的机制仍不清楚。尽管如此，这些研究结果表明，种间花粉竞争在控制H. annuusandH.可能部分解释了向日葵中细胞质与细胞核基因渗入的差异。
Artificial crosses betweenHelianthus annuusandH. petiolarisusing 1:9, 1:1, and 9:1 mixtures of intraspecific: interspecific pollen were conducted to determine the role of interspecific pollen competition as a reproductive barrier inHelianthus.Of 1,245 achenes analyzed from the pollen competition experiments, only 49 were hybrids. The number of hybrids observed was significantly less than expectations for all three pollen mixtures, regardless of the identity of maternal parent (P< 0.01). Stigma age and pollen ratio had no significant impact on hybrid frequency. However, hybrids were significantly more frequent withH. annuusthan withH. petiolarisas the maternal parent (P< 0.01). Analysis of pollen tube growth rates revealed no differences in the rate of growth of intraspecific vs. interspecific pollen. Likewise, pollinations with either intraspecific or interspecific pollen or with different pollen ratios did not affect the percentage of filled achenes. Thus, the mechanism responsible for selective fertilization by intraspecific pollen in mixed pollen loads remains unclear. Nonetheless, these findings suggest that interspecific pollen competition plays an important role in controlling the formation of hybrids betweenH. annuusandH. petiolarisand may partially account for patterns or differential cytoplasmic vs. nuclear introgression inHelianthus.