Flower orientation influences floral temperature, pollinator visits and plant fitness
Flower orientation influences floral temperature, pollinator visits and plant fitness
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DOI：
10.1111/nph.17627
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发表时间：
2021-08-05
期刊：
影响因子：
9.4
通讯作者：
Harmer, Stacey L.
中科院分区：
文献类型：
--
作者：
Creux, Nicky M.;Brown, Evan A.;Harmer, Stacey L.
有效的昆虫授粉需要对植物和传粉者的内部和外部环境线索做出适当的反应。向日葵是一种高度异交的物种，其特征是成熟的假丹花或头状花序一致向东。在这里，我们调查这种取向如何影响花的小气候和随之而来的影响植物和传粉者的相互作用和生殖适合度。我们人工操纵向日葵头状花序的方向和温度在两个领域和控制条件下，并评估花生理，传粉者访问，种子性状和繁殖成功。朝东的头状花序被发现有较早的花柱伸长，花粉介绍和传粉者访问相比，操纵头状花序朝西。朝东的头状花序也比朝西的头状花序产生更多的后代，在某些条件下产生更重和更好的填充种子。柱头上的局部环境温度变化被认为是调节花柱伸长、花粉出现和传粉者访问时间的关键因素。这些结果表明，东向头状花序的方向有助于控制每日的花温节奏，与花柱伸长和花粉出现的时间，传粉者的访问，和植物健身的直接后果。
Effective insect pollination requires appropriate responses to internal and external environmental cues in both the plant and the pollinator. Helianthus annuus, a highly outcrossing species, is marked for its uniform eastward orientation of mature pseudanthia, or capitula. Here we investigate how this orientation affects floral microclimate and the consequent effects on plant and pollinator interactions and reproductive fitness. We artificially manipulated sunflower capitulum orientation and temperature in both field and controlled conditions and assessed flower physiology, pollinator visits, seed traits and siring success. East-facing capitula were found to have earlier style elongation, pollen presentation and pollinator visits compared with capitula manipulated to face west. East-facing capitula also sired more offspring than west-facing capitula and under some conditions produced heavier and better-filled seeds. Local ambient temperature change on the capitulum was found to be a key factor regulating the timing of style elongation, pollen emergence and pollinator visits. These results indicate that eastward capitulum orientation helps to control daily rhythms in floral temperature, with direct consequences on the timing of style elongation and pollen emergence, pollinator visitation, and plant fitness.