Effects of the Position on Floral Traits and Reproductive Success of Comastoma pulmonarium (Gentianaceae)
Variations in flower traits and reproductive success among differently positioned flowers within one plant might result from resource competition and/or architecture effect, but this argument needs to be further demonstrated in more species. We studied the flower traits and reproductive success of flowers from different positions in Comas-toma pulmonarium (Cenetianaceae) , an alpine selling annual herb of the Qinghai-Tibet Plateau. Our results showed that the flower diameter, flower height, number of pollen grains and ovules from the top flower, were all much more than those from flowers positioned lower within the inflorescence. After removing the top flower buds, we found nosignificant changes in either flower diameter or flower height in the remained flowers compared with the same positioned flowers on control plants, indicating architectural effect on flower traits. Meanwhile, seed number, seed weight and seed germination rate in the top fruits were higher than those in other positioned fruits. Given the removal of the top flower buds, furthermore, seed number of other positioned fruits increased compared with those fruits in the same positions on control plants, suggesting resource competition and resource reallocation happened among the developing fruits when the available resources within a plant was changed. This mechanism could, to some extent, assure reproductive success of the late-developed fruits. Our results showed architectural effect on flower traits and resource competition during the development of fruits in C. Pulmonarium, which was quite different from some previous reports. We speculated the short life history ( annual) and the alpine environments of the Qinghai-Tibet Plateau (resource limitation) could be the main factors to explain this phenomenon.
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万方数据
维普
