SUN-TRACKING FLOWER MOVEMENT AND SEED PRODUCTION
Abstract: I observed the sun-tracking behavior, temperature increment within flowers, and seed production of mountain avens, Dryus octopetulu L., occurring near Bregger glacier in ~ ~- A l e s u n d (78'55'N, 1 Ip56'E), Svalbard in Norway. The flowers showed sun-tracking movement on s...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.595.8099 http://www3.u-toyama.ac.jp/cfes/wada/pdf_papers/Wada1998PB.pdf |
| Summary: | Abstract: I observed the sun-tracking behavior, temperature increment within flowers, and seed production of mountain avens, Dryus octopetulu L., occurring near Bregger glacier in ~ ~- A l e s u n d (78'55'N, 1 Ip56'E), Svalbard in Norway. The flowers showed sun-tracking movement on sunny days, but the movement was mostly found around noon and was not so active throughout a sunny day. The temperature increment of the gynoecium in flowers facing the sun was ca. 2 C higher than in flowers with their back to the sun. Petal removal resulted in considerable reduction of the gynoecium temperature. Insects (mostly mosquitoes) visiting flowers were very infrequent, suggesting that a severe pollinator limitation restricted the cross-pollination. During the experiments, flowers of Dryas octopetalu did not produce any developed seeds under natural condition (0 % seed-set). Cross-pollinated flowers showed 8 % seed-set, while flowers which were artificially warmed by small green-houses during the flowering period showed 60 % seed-set, indicating that the re-production of D. octopetulu is strongly restricted by low temperature during the flowering period, rather than by pollinator limitation, in the population of Ny-Alesund, Svalbard. These results suggest that the sun-tracking behavior and parabola-shaped flower structure with large petals are important for seed-setting success by increasing the gynoecium temperature. key words: artificial warming, cross pollination, flower heliotropism, High Arctic, seed production |
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