Nectar secretion dynamic links pollinator behavior to consequences for plant reproductive success in the ornithophilous mistletoe Psittacanthus robustus
Nectar secretion dynamic links pollinator behavior to consequences for plant reproductive success in the ornithophilous mistletoe Psittacanthus robustus
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DOI：
10.1111/plb.12146
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发表时间：
2014-09-01
期刊：
影响因子：
3.9
通讯作者：
Silva, W. R.
中科院分区：
文献类型：
--
作者：
Guerra, T. J.;Galetto, L.;Silva, W. R.
槲寄生Psittacanthus robustus作为一个模型进行了研究，花物候和花蜜分泌策略传粉行为和植物的生殖后果。鲜艳的花朵呈现昼夜开花，在整个雨季异步开放，并产生丰富的稀释花蜜作为传粉者的主要奖励。大多数花蜜分泌后，花开放，与糖补充后，实验去除。在套袋花开花的第二天，花迅速重新吸收提供的花蜜。开放的花朵中记录的花蜜现存量的低值可以与鸟类传粉者的高访问率联系起来。八蜂鸟和两个雀形目观察到潜在的传粉者。最频繁的花访客是蜂鸟Eupe-tomena macroura和Colibri serrirostris，它们积极地保护开花的槲寄生。花药、柱头和花蜜室之间的空间分离促进了盘旋的蜂鸟扑翼上的花粉沉积，蜂鸟通常每次访问都会探测许多花朵。种子集没有不同的手，自花和异花授粉的花朵，但这些治疗设置显着更多的种子比花自然暴露于花游客。我们认为，这种植物的繁殖成功的限制是不相关的传粉者稀缺，但可能是领土蜂鸟的访问频率极高。我们的结论是，植物繁殖的成本和效益取决于花和传粉者之间的相互作用强度，花蜜分泌动态，传粉者的行为和植物育种系统的评估可以澄清这种协会的复杂性。
The mistletoe Psittacanthus robustus was studied as a model to link flower phenology and nectar secretion strategy to pollinator behaviour and the reproductive consequences for the plant. The bright-coloured flowers presented diurnal anthesis, opened asynchronously throughout the rainy season and produced copious dilute nectar as the main reward for pollinators. Most nectar was secreted just after flower opening, with little sugar replenishment after experimental removals. During the second day of anthesis in bagged flowers, the flowers quickly reabsorbed the offered nectar. Low values of nectar standing crop recorded in open flowers can be linked with high visitation rates by bird pollinators. Eight hummingbirds and two passerines were observed as potential pollinators. The most frequent flower visitors were the hummingbirds Eupe-tomena macroura and Colibri serrirostris, which actively defended flowering mistletoes. The spatial separation between anthers, stigma and nectar chamber promotes pollen deposition on flapping wings of hovering hummingbirds that usually probe many flowers per visit. Seed set did not differ between hand-, self- and cross-pollinated flowers, but these treatments set significantly more seeds than flowers naturally exposed to flower visitors. We suggest that the limitation observed in the reproductive success of this plant is not related to pollinator scarcity, but probably to the extreme frequency of visitation by territorial hummingbirds. We conclude that the costs and benefits of plant reproduction depend on the interaction strength between flowers and pollinators, and the assessment of nectar secretion dynamics, pollinator behaviour and plant breeding system allows clarification of the complexity of such associations.