Guimarães Elza, di Stasi Luiz Claudio, Maimoni-Rodella Rita de Cassia Sindrônia
Departamento de Botânica, Instituto de Biociencias, Universidade Estadual Paulista (UNESP), Campus de Botucatu, PO Box 510, SP, 18618-000, Brazil.
Ann Bot. 2008 Nov;102(5):699-711. doi: 10.1093/aob/mcn152. Epub 2008 Sep 2.
Bignoniaceae is a Neotropical family with >100 genera, only two of which, Jacaranda and Digomphia, have a developed staminode. Jacaranda oxyphylla, whose flowers possess a conspicuous glandular staminode, is a zoophilous cerrado species. Here, the composition of the secretion of the glandular trichome and the influence of the staminode on the pollination biology and reproductive success of J. oxyphylla were studied.
The floral morphology, pollen viability, stigma receptivity, nectar volume and nectar concentration were studied. Compatibility system experiments were performed and floral visitors were observed and identified. Experiments comparing the effect of staminode presence and absence on pollen removal and pollen deposition efficiency were conducted in open-pollinated flowers. Histochemistry, thin-layer chromatography (TLC) and gas chromatography coupled to flame ionization detection (GC-FID) analyses were performed to determine the main chemical components of the staminode's glandular trichome secretion.
Flower anthesis lasted 2 d and, despite the low frequency of flower visitation, pollination seemed to be effected mainly by medium-sized Eulaema nigrita and Bombus morio bees, by the small bee Exomalopsis fulvofasciata and occasionally by hummingbirds. Small bees belonging to the genera Ceratina, Augochlora and Trigona were frequent visitors, collecting pollen. Jacaranda oxyphylla is predominantly allogamous. Staminode removal resulted in fewer pollen grains deposited on stigmas but did not affect total pollen removal. The secretion of capitate glandular trichome occurs continually; the main chemical compounds detected histochemically were phenolic and terpenoid (essential oils and resins). Monoterpene cineole, pentacyclic triterpenes and steroids were identified by TLC and GC-FID.
The staminode of J. oxyphyllla is multifunctional and its importance for female reproductive success was attributed mainly to the secretion produced by capitate glandular trichomes. This secretion is involved in complex chemical interactions with pollinating bees, including the solitary bees Euglossini. These bees are common pollinators of various species of Jacaranda.
紫葳科是一个新热带科，有100多个属，其中只有蓝花楹属（Jacaranda）和双柱蓝花楹属（Digomphia）具有发育完全的退化雄蕊。蓝花楹（Jacaranda oxyphylla）的花具有明显的腺状退化雄蕊，是一种虫媒塞拉多植物。在此，研究了腺毛的分泌物组成以及退化雄蕊对蓝花楹授粉生物学和繁殖成功的影响。
研究了花的形态、花粉活力、柱头可授性、花蜜量和花蜜浓度。进行了亲和性系统实验，并观察和鉴定了访花者。在开放授粉的花朵中进行了比较有无退化雄蕊对花粉去除和花粉沉积效率影响的实验。进行了组织化学、薄层色谱（TLC）和气相色谱-火焰离子化检测（GC-FID）分析，以确定退化雄蕊腺毛分泌物的主要化学成分。
花期持续2天，尽管访花频率较低，但授粉似乎主要由中型的黑大蜜蜂（Eulaema nigrita）和毛足熊蜂（Bombus morio）、小型蜜蜂黄褐外颚叶蜂（Exomalopsis fulvofasciata）以及偶尔的蜂鸟完成。属于隧蜂属（Ceratina）、绿彩带蜂属（Augochlora）和无刺蜂属（Trigona）的小型蜜蜂是常见的访花者，采集花粉。蓝花楹主要为异花授粉。去除退化雄蕊导致落在柱头上的花粉粒减少，但不影响总花粉去除量。头状腺毛的分泌持续发生；组织化学检测到的主要化合物为酚类和萜类（精油和树脂）。通过TLC和GC-FID鉴定出单萜桉叶油素、五环三萜和甾体。
蓝花楹的退化雄蕊具有多种功能，其对雌蕊繁殖成功的重要性主要归因于头状腺毛产生的分泌物。这种分泌物参与了与传粉蜜蜂，包括独居蜂尤加利西尼蜂（Euglossini）的复杂化学相互作用。这些蜜蜂是各种蓝花楹物种的常见传粉者。
