Pollen Morphology in Various Life-form of Aquatic Macrophytes

Ability of angiosperms to produce flowers and seeds for the sexual reproduction is important also in aquatic plants. Pollination in aquatic plants is facilitated by insects, wind, and water, however, pollen morphology related to the plant’s life forms and pollen dispersal are not well described. This study investigates pollen morphology of selected aquatic macrophytes. Plants were collected and preserved as dried specimens. Mature pollen grains of each species were separated from the anthers and then placed on glass slides and mounted with distilled water. Pollen shape and size were observed under a light microscope (LM). Number of apertures and exine ornamentation were examined using scanning electron microscope (SEM). Closely related plant species had similar pollen morphology. Among the 28 species studied, pollen size varied from small to very large (range 10–200 µm) and their shapes were prolate-spheroidal, prolate, oblate, suboblate, and oblate-spheroidal. Some species had inaperturate pollen grains; the remainders were monoaperture, triaperture or polyaperture. Both colpate and porate apertures were found. The pollen surfaces were echinate, fovelate, granulate, lophate, plicate, regulate, regulate-fovelate, reticulate, striate, and verrucate, respectively. Keywords: Aquatic plants, Palynology, Pollen ornamentation, Pollination, SEM

Sharing the Agrarian Knowledge with Archaeology: First Evidence of the Dimorphism of Vitis Pollen from the Middle Bronze Age of N Italy (Terramara Santa Rosa di Poviglio)

The recovery of inaperturate pollen from functionally female flowers in archaeological layers opens the question of a possible pollen-based discrimination between wild and domesticated Vitis vinifera in prehistoric times. Pollen analysis applied to archaeology has not routinely considered the existence of pollen dimorphism in Vitis, a well-known trait in the field of agrarian studies. Therefore, the inaperturate shape of grapevine pollen is ignored by studies on the archaeobotanical history of viticulture. In this paper we investigate pollen morphology of the domesticated and wild subspecies of V. vinifera, and report the first evidence of inaperturate Vitis pollen from an archaeological site. We studied exemplar cases of plants with hermaphroditic flowers, belonging to the subspecies vinifera with fully developed male and female organs, cases of dioecious plants with male or female flowers, belonging to the wild subspecies sylvestris and cases of V. vinifera subsp. vinifera with morphologically hermaphroditic but functionally female flowers. The pollen produced by hermaphroditic and male flowers is usually trizonocolporate; the pollen produced by female flowers is inaperturate. This paper reports on the inaperturate pollen of Vitis found in an archeological site of the Po Plain, Northern Italy. The site dated to the Bronze Age, which is known to have been a critical age for the use of this plant with a transition from wild to domesticated Vitis in central Mediterranean. Can the inaperturate Vitis pollen be a marker of wild Vitis vinifera in prehistoric times? Palynology suggests a possible new investigation strategy on the ancient history of the wild and cultivated grapevine. The pollen dimorphism also implies a different production and dispersal of pollen of the wild and the domesticated subspecies. Grapevine plants are palynologically different from the other Mediterranean “cultural trees”. In fact, Olea, Juglans and Castanea, which are included in the OJC index, have the same pollen morphology and the same pollen dispersal, in wild and domesticated plants. In contrast, the signal of Vitis pollen in past records may be different depending on the hermaphroditic or dioecious subspecies.

Comparative Pollen Viability and Pollen Tube Growth of two Endemic Philippine Etlingera (Zingiberaceae, Alpinioideae)

The pollen viability and pollen tube growth of Etlingera dalican and Etlingera philippinensis (Zingiberaceae) were examined from fresh samples under the light microscope (LM) and scanning electron microscope (SEM). Pollen measurements were 68-75μm (E. dalican) and 60-65μm (E. philippinensis), having spheroidal shape for hydrated pollen and irregularly-shape for dry pollen for both species. E. dalican pollen has greenish-yellow color while that of E. philippinensis is greenish. Both species had inaperturate pollen but differ in their ornamentation which is gemmate in E. dalican while psilate in E. philippinensis. E. dalican has 88.56% pollen viability while E. philippinensis has only 40.69%. The rate of pollen tube growth was faster (17.75 μm per day) in E. dalican than E. philippinensis (8.17 μm per day). The possible pollinators observed for the two species were butterflies of the genus Catopsilia, ants and flies. Additional information on the inflorescence and flower description of the two species are herein presented.

Inaperturate pollen diversity in the arborescent taxa ofKarimnagar district, Telangana State, India

The present investigation deals with the study of inaperturate pollen taxa of eleven (11) tree species of Karimnagar district, Telangana State. These taxa belong to Annonaceae, Eupharbiaceae, Hernandiaceae, Musaceae and Fabaceae- Mimosoideae families. The pollen of these arborescent plants have diversity in pollen morphological characters viz., symmetry, shape, polarity and ornamentation, but significantly all the pollen taxa have inaperturate apertural partten. This study provides palynological data of the inaperturate pollen taxa, which will expensive help in future palynotaxonomic studies in Karimnagar district.

Deciphering the Neotropical Bignonia binata species complex (Bignoniaceae)

Bignonia is a genus of 28 species of Neotropical lianas. Most species are clearly characterized by morphological features, monophyletic and narrowly distributed. However Bignonia binata is polymorphic, polyphyletic and broadly distributed, from Mexico to Argentina. A detailed morphological survey of B. binata in the light of geographical and ecological data in its current circumscription recovered two clearly distinct morphological groups of plants. One group is found in Argentina, Paraguay and the Atlantic forest of Brazil, and characterized by non-winged stems, usually terminal inflorescences, usually non-glandular calyces, pantoaperturate pollen, narrowly elliptic fruits, and 1-winged seeds. The second group occurs in Central America and Amazonia and is characterized by winged young stems, usually axillary inflorescences, glandular calyces, inaperturate pollen, widely elliptic to circular fruits, and wingless seeds. The first group of plants corresponds to B. binata and the second group is recognized as another species, B. noterophila. Synonyms, morphology, distributions, and ecology are detailed for these newly circumscribed species. Lectotypes are designated for B. noterophila and several synonyms: Adenocalymma ocositense, Arrabidaea schumanniana, and Petastoma laurifolium.

Structure and systematics of Hanguana, a monocotyledon of uncertain affinity

Floral anatomy and some aspects of leaf and root anatomy of Hanguana are described for the first time and reviewed with respect to its systematic position in monocotyledons. Several characters support its placement in the commelinoid clade, including cell wall ferulates, silica bodies and tetracytic stomata with non-oblique cell divisions. Analysis of morphological data indicates that Hanguana is the sister taxon to Zingiberales. Characters supporting this association include spinulate inaperturate pollen, plasmodial tapetum type, mucilage-secreting intra-ovarian trichomes and modified septal nectaries. Gynoecial nectaries were present in male flowers (probably modified septal nectaries, as in some Zingiberales) and staminodial nectaries in female flowers examined.