Płachno Bartosz J, Stpiczyńska Małgorzata, Davies Kevin L, Świątek Piotr, de Miranda Vitor Fernandes Oliveira
Department of Plant Cytology and Embryology, Jagiellonian University in Kraków, 9 Gronostajowa St., 30-387, Kraków, Poland.
Faculty of Biology, University of Warsaw, Botanic Garden Al. Ujazdowskie 4, 00-478, Warsaw, Poland.
Protoplasma. 2017 Jan;254(1):353-366. doi: 10.1007/s00709-016-0956-0. Epub 2016 Mar 5.
Utricularia cornigera and Utricularia nelumbifolia are giant, aquatic-epiphytic species of carnivorous bladderwort from southeastern Brazil that grow in the central 'urns' of bromeliads. Both species have large, colourful flowers. The main aim of our study is to ascertain whether the prominent floral palate of U. cornigera and U. nelumbifolia functions as an unguentarius-i.e. an organ that bears osmophores. Floral tissues of both species were investigated using light microscopy, scanning electron microscopy, transmission electron microscopy and histochemistry. Floral palates of U. cornigera and U. nelumbifolia provide clear visual signals for pollinating insects. In both species, the palate possesses diverse micro-morphology, comprising unicellular, conical to villiform papillae and multicellular, uniseriate, glandular trichomes that frequently display terminal branching. The most characteristic ultrastructural feature of these papillae was the presence of relatively large, polymorphic plastids (chromoplasts) containing many plastoglobuli. Similar plastids are known to occur in the fragrance-producing (osmophores) and oil-producing (elaiophores) tissues of several orchid species. Thus, these palate papillae may play a key role in providing the olfactory stimulus for the attraction of insect pollinators. Nectariferous trichomes were observed in the floral spurs of both species, and in U. nelumbifolia, free nectar was also recorded. The location, micro-morphology, anatomy and ultrastructure of the floral palate of the two species investigated may thus indicate that the palate functions as an unguentarius. Furthermore, the flowers of these taxa, like those of U. reniformis, have features consistent with bee pollination.
角状狸藻和莲座狸藻是来自巴西东南部的大型水生附生食肉狸藻物种，生长在凤梨科植物的中央“叶腋”中。这两个物种都有大而色彩鲜艳的花朵。我们研究的主要目的是确定角状狸藻和莲座狸藻突出的花腭是否起到香腺的作用，即一个带有渗透压感受器的器官。使用光学显微镜、扫描电子显微镜、透射电子显微镜和组织化学方法对这两个物种的花组织进行了研究。角状狸藻和莲座狸藻的花腭为传粉昆虫提供了清晰的视觉信号。在这两个物种中，花腭具有多样的微观形态，包括单细胞的、圆锥形至绒毛状的乳头以及多细胞的、单列的腺毛，这些腺毛经常呈现末端分支。这些乳头最具特征的超微结构特征是存在相对较大的、多形的质体（有色体），其中含有许多质体小球。已知在几种兰花物种的产生香味（渗透压感受器）和产生油脂（油体）的组织中也存在类似的质体。因此，这些花腭乳头可能在为吸引昆虫传粉者提供嗅觉刺激方面发挥关键作用。在这两个物种的花距中都观察到了产蜜腺毛，并且在莲座狸藻中还记录到了游离花蜜。因此，所研究的这两个物种花腭的位置、微观形态、解剖结构和超微结构可能表明花腭起到了香腺的作用。此外，这些分类群的花，就像肾形狸藻的花一样，具有与蜜蜂传粉相一致的特征。
