Palynological study of Asian Thismia (Thismiaceae: Dioscoreales) reveals an unusual pollen type

Severova, Elena; Polevova, Svetlana; Yudina, Sophia V.; Trương, Bá Vương; Xuyen, Thi; Chantanaorrapint, Sahut; Suetsugu, Kenji; Tagane, Shuichiro; Guo, Xing; Schelkunov, Mikhail I.; Nuraliev, Maxim S.

doi:10.1007/s00606-021-01778-9

Cited by 3 publications

(4 citation statements)

References 36 publications

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“…3 K, L) showing a mucilagenous mass of germinating pollen tubes growing directly into the style between the carpel margins. Severova et al (2021) also commented that the pollen of Thismia is highly unusual for biotically pollinated plants; they followed Yudina et al (2021) and other authors in suggesting possible autogamy in flowers of Thismia and some other Dioscoreales.…”

Section: Pollination Biologymentioning

confidence: 78%

“…To date, the most detailed studies of pollen structure and development in Afrothismia, Thismia and related taxa are those of Rübsamen (1986), Caddick et al (1998) and Severova et al (2021). Rübsamen (1986) made an SEM study of the pollen of two species of Afrothismia, A. winkleri (based on Zenker 3613, B) and A.…”

Section: Pollen Structurementioning

confidence: 99%

“…Afrothismia pachyantha has subsequently been discovered to be extinct (Cheek et al 2019) (ulcerate), with pollen lengths of the two species 24 μm and 14 -16 μm, respectively (Rübsamen 1986). The surface sculpture is coarsely reticulate, the muri "caterpillar like," occasionally with tiny pores, compared with more finely perforate, psilate or reticulate in Thismia and finely reticulate in Tacca (Rübsamen 1986;Caddick et al 1998;Severova et al 2021), indicating clear separation between Afrothismia and related taxa. Severova et al (2021) also noted that Thismia is highly unusual among seed plants in possessing a single aperture in an equatorial position.…”

Section: Pollen Structurementioning

confidence: 99%

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Afrothismiaceae (Dioscoreales), a new fully mycoheterotrophic family endemic to tropical Africa

Cheek,

Soto Gomez,

Graham

et al. 2023

Kew Bull

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SummaryAfrothismia is a genus of non-photosynthetic mycoheterotrophs from the forests of continental tropical Africa. Multiple phylogenetic inferences using molecular data recover the genus as sister to a clade comprising mycoheterotrophic Thismiaceae and the photosynthetic family Taccaceae, contrary to earlier placements of Afrothismia and Thismiaceae within Burmanniaceae. Morphological support for separating Afrothismia from the rest of Thismiaceae has depended on the zygomorphic flowers of Afrothismia (although some species of Thismia are also zygomorphic), and their clusters of root tubers, each with a terminal rootlet. The number of described species of Afrothismia has recently increased from four to 16, with seven more species as yet undescribed; these discoveries have added morphological characters that support its distinction from Thismiaceae. Most notably, the ovary in Afrothismia has a single stalked placenta, and circumscissile fruits from which seeds are exserted by placental elevation (vs in Thismiaceae, three placentas, a deliquescing fruit lid, and seeds not exserted). Afrothismia stamens are inserted in the lower part of the floral tube, where they are attached to the stigma, and individual flowers are subtended by a single large dorsal bract. In contrast, in Thismiaceae, stamens are inserted at the mouth of the tube, free of and distant from the stigma, and each flower is subtended by a loose whorl of (2 –) 3 (– 4) bracts. Here we formally characterise Afrothismiaceae and review what is known of its development, seed germination, interactions with mycorrhizal Glomeromycota, biogeography, phylogeny and pollination biology. All but one (Afrothismia insignis; Vulnerable) of the 13 species assessed on the IUCN Red List of Threatened Species are either Endangered or Critically Endangered; one species (A. pachyantha) is considered extinct.

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Section: Pollination Biologymentioning

confidence: 78%

Section: Pollen Structurementioning

confidence: 99%

Section: Pollen Structurementioning

confidence: 99%

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Afrothismiaceae (Dioscoreales), a new fully mycoheterotrophic family endemic to tropical Africa

Cheek,

Soto Gomez,

Graham

et al. 2023

Kew Bull

View full text Add to dashboard Cite

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“…Palynology assists in correct identification and classification of the problematic taxa at species and generic level, and also have vital role in other field of science like mellisoplaynology, aeropalynology, and pharmacopalynology (Gul et al, 2021;Khan et al, 2021). It has been confirmed from the literature that palynological traits provide the basis of phylogenetic evidences for the systematics study of plant taxa (Ali et al, 2021;Severova et al, 2021). Various palynological features such as pollen size, ornamentation, shape, aperture, and sculpturing are important for the correct identification of plants species (Salamma, Kailas, Naik, Rao, & Hari, 2019).…”

mentioning

confidence: 98%

Palyno‐anatomical characters and their systematic significance in the family Apiaceae from Chitral, eastern Hindu Kush, Pakistan

Birjees

Ahmad

Zafar

et al. 2021

Microscopy Res & Technique

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The present study was performed to provide a detailed explanation of leaf epidermal anatomy and pollen micromorphological features of selected species of family Apiaceae from Chitral, eastern Hindu Kush region as the basis of forthcoming studies.In the present article pollen morphology of eight species and foliar epidermal of seven species of family Apiaceae have been examined through microscopic techniques. In results two types of pollen prolate (five species) and perprolate (three species) with three colpi have been recorded. The exine ornamentation was found to be regulate, striate, and cerebroid. Largest pollen was found in Heracleum leucocarpum with the polar diameter of 43.25 μm and equatorial diameter of 21.6 μm. Smallest pollen was observed in Elaeosticta chitralica with the polar diameter of 18.4 μm. The P/E ratio varied from 1.59 to 2.16. Regarding to foliar epidermal anatomy, three types of epidermal cells including rectangular, irregular, and polygonal with variation in anticlinal wall pattern were determined. In the selected species three kinds of stomata comprising anisocytic, anomocytic, and paracytic type were reported in the current research. The size of epidermal cells ranged from 106 Â 42.50 μm in Bupleurum falcatum subsp. cernuum and 77.25 Â 26.35 μm in Prangos pabularia in adaxial surface. Largest stomatal complex was found in Prangos pabularia both in adaxial 33.55 Â 20.05 μm and abaxial 50.25 Â 39.40 μm. All the observed quantitative and qualitative features of the species were proved to be useful in the delimitation of species at generic and species level.

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Mycorrhizal structures in mycoheterotrophic Thismia spp. (Thismiaceae): functional and evolutionary interpretations

et al. 2022

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Achlorophyllous, mycoheterotrophic plants often have an elaborate mycorrhizal colonization pattern, allowing a sustained benefit from external fungal root penetrations. The present study reveals the root anatomy and mycorrhizal pattern of eight mycoheterotrophic Thismia spp. (Thismiaceae), all of which show separate tissue compartments segregating different hyphal shapes of the mycorrhizal colonization, as there are intact straight, coiled and peculiarly knotted hyphae as well as degenerated clumps of hyphal material. Those tissue compartments in Thismia roots potentially comprise exo-, meso- and endoepidermae, and exo-, meso- and endocortices, although not all species develop all these root layers. Differences in details among species according to anatomy (number of root layers, cell sizes and shapes) and colonization pattern (hyphal shapes within cells) are striking and can be discussed as an evolutionary series towards increasing mycorrhizal complexity which roughly parallels the recently established phylogeny of Thismia. We suggest functional explanations for why the distinct elements of the associations can contribute to the mycorrhizal advantage for the plants and, thus, we emphasize the relevance of structural traits for mycorrhizae.

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Palynological study of Asian Thismia (Thismiaceae: Dioscoreales) reveals an unusual pollen type

Cited by 3 publications

References 36 publications

Afrothismiaceae (Dioscoreales), a new fully mycoheterotrophic family endemic to tropical Africa

Afrothismiaceae (Dioscoreales), a new fully mycoheterotrophic family endemic to tropical Africa

Palyno‐anatomical characters and their systematic significance in the family Apiaceae from Chitral, eastern Hindu Kush, Pakistan

Mycorrhizal structures in mycoheterotrophic Thismia spp. (Thismiaceae): functional and evolutionary interpretations

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