Abstract
Pollen - ovule ratios and percentages of stigmatic pollen germination (SPG) were measured for over 160 taxa of the Polemoniaceae. When related to taxa with known breeding systems, it is found that low SPGs and high P:O ratios characterize xenogamous plants, high SPGs and low P:Os characterize autogamous plants. There is a significant negative correlation between P:O ratio and SPG in the whole family as well as in certain genera. Both measures can serve as reliable indicators of the breeding systems in taxa of the Polemoniaceae and can be measured in dried or living specimens. Accordingly, most polemons feature "mixed" breeding system, i.e. facultative xenogamy or facultative autogamy. Xenogamy is common among the tropical genera and in the Leptodactylon, Phlox and Polemonium. Autogamy is more frequent in the tribe Gilieae (particularly in Gilia) than in the other tribes. Annual taxa tend to be autogamous, showing on the average higher SPG and lower P:O ratio. The lepidopteran-pollinated group of species have a higher mean P:O ratio and lower mean SPG thus indicating that such plants are associated with crosspollination more than the others.
Original language | English |
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Pages (from-to) | 205-214 |
Number of pages | 10 |
Journal | Plant Systematics and Evolution |
Volume | 170 |
Issue number | 3-4 |
DOIs | |
State | Published - Sep 1990 |
Keywords
- Angiosperms
- breeding systems
- ovule ratio
- Polemoniaceae
- Pollen
- stigmatic pollen germination