Pollen morphology of Indian Aponogeton (Aponogetonaceae, Alismatales) and the problem of recognizing palynotypes in a taxonomically diverse and ancient genus

Phytotaxa ◽  
2020 ◽  
Vol 475 (3) ◽  
pp. 187-200
Author(s):  
ELENA E. SEVEROVA ◽  
SHRIRANG RAMCHANDRA YADAV ◽  
DMITRY D. SOKOLOFF

Monogeneric Aponogetonaceae is sister to the rest of tepaloid core Alismatales and its members are characterized by a number of plesiomorphic features including monosulcate pollen. A recent study documented the earliest fossil pollen records of Aponogeton in late Cretaceous and early Cenozoic as well as recognized six pollen types in the genus. However, there are remaining gaps in palynological investivation of Aponogeton species. We present data on eight Indian species of the genus. Pollen of Aponogeton appendiculatus, A. crispus, A. bruggenii, A. microphyllus, A. natans, A. nateshii and A. wolfgangianus is reticulate with quite small lumina of irregular shape with short, convex and wide muri bearing small (up to 0.5 μm) echini. Pollen of Aponogeton satarensis clearly differs from that of the rest of examined species in larger lumina and muri bearing large (0.8–1 μm) and wide conical echini. These palynological differences fit well with molecular phylogenetic data and earlier ideas based on gross morphology. Our data suggest that although exine sculpturing is taxonomically significant in Aponogeton, the use of size of echini as a character distinguishing some palynotypes is problematic. Quantitative characters such as equatorial diameter and polar axis length showed no clear differences between examined species, but differences were found between analyzed samples (more precise, individuals) of the same species. Our new data support the earlier conclusion on the homoplastic nature of pollen evolution in Aponogeton.

Author(s):  
Rui Dong ◽  
Zhongjie Lu ◽  
Zhengyu Yang ◽  
Yanrong Wang ◽  
Chao Chen

Abstract Common vetch (Vicia sativa) is an important forage and green manure crop that is widely cultivated around the world. However, the large number of subspecies and accessions of common vetch has made taxonomic research on this species difficult. Pollen morphology data can provide important evidence in the study of plant phylogeny. Therefore, in this research, light microscopy and scanning electron microscopy were used to observe seven morphological traits of pollens from 22 common vetch accessions, and residual maximum likelihood and pattern analysis was conducted. The results showed that the pollen grains of the 22 accessions were all monad pollen and the polar view revealed three-lobed circular and triangular shapes, while the equatorial view mainly revealed an oblate shape; only one accession showed an oblate spherical shape. All accessions were 3-zonocolporate and the colpus length extended close to the poles. The polar axis length was (19.39 ± 0.97)–(42.12 ± 0.76) μm and the equatorial axis length was (35.97 ± 1.27)–(45.25 ± 0.81) μm. We found that qualitative traits of pollen shape, aperture polar view and ornamentation were highly stable. Among them, polar axis length, equatorial axis length and colpus length and width had significant differences among the accessions. The ratios of the equatorial and polar axes had significant differences among the subspecies. This trait information could be used for the classification and identification of common vetch accessions and subspecies.


2012 ◽  
Vol 299 (3) ◽  
pp. 499-513 ◽  
Author(s):  
Diana Salles Sampaio ◽  
Maria Cecília de Chiara Moço ◽  
Jorge Ernesto Araujo Mariath

Phytotaxa ◽  
2021 ◽  
Vol 500 (2) ◽  
pp. 142-146
Author(s):  
IHSAN A. AL-SHEHBAZ ◽  
BARIŞ ÖZÜDOĞRU ◽  
DMITRY A. GERMAN

Iljinskaea is described as a new monospecific genus based on a critical evaluation of morphology and in light of the extensive molecular phylogenetic data. The new combination I. planisiliqua is proposed, and the distinguishing characters separating the new genus from Conringia are discussed. The new tribal assignment of Iljinskaea in the Isatideae is discussed and compared with the previous placement in the Conringieae.


Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 508
Author(s):  
Jie Qiu ◽  
Chao Gao ◽  
Hongli Wei ◽  
Biao Wang ◽  
Yang Hu ◽  
...  

To study the flowering biology of Rhododendron pulchrum, we used scanning electron microscopy (SEM) and paraffin sectioning to observe the microstructures of its floral organs, a methyl thiazolyl tetrazolium (MTT) colorimetric assay to detect pollen viability in different periods, continuous observations to study flowering phenology, and artificial pollination and a benzidine-hydrogen peroxide method to determine stigma receptivity. R. pulchrum exhibited a centralized flowering phenology. The protogynous stigmas of R. pulchrum were able to receive pollen before flowering. The pollen grains of R. pulchrum fused into tetrads, the average ratio of the polar axis length to the equatorial axis length (P/E) was 1.05, and the pollen viability was highest in the initial flowering period, reaching 88.98%. The pollen/ovule (P/O) ratio was 266–328, and the outcrossing index (OCI) was 4; the vitality of R. pulchrum pollen remained high in the initial flowering and blooming periods. Compared with the lifespan of a single flower, pollen vitality remained high for most of the experimental period, thereby improving male fitness. The P/O ratio suggests that R. pulchrum may have a facultative outcrossing breeding system. The OCI estimation suggests that R. pulchrum is partially self-compatible, most likely requiring pollinators to complete pollination.


2018 ◽  
Vol 61 (1) ◽  
pp. 47-64 ◽  
Author(s):  
Wilfred John E. Santiañez ◽  
Erasmo C. Macaya ◽  
Kyung Min Lee ◽  
Ga Youn Cho ◽  
Sung Min Boo ◽  
...  

AbstractA new and putatively endemic species ofHydroclathrus,Hydroclathrus rapanuii, is described from the geographically isolated Easter Island in the southeastern Pacific based on morphological and molecular phylogenetic data. It is distinguished from otherHydroclathrusby thalli of unevenly furrowed thin membranes, and angular, block-like plurangial sori. Our phylogenetic analyses indicated thatH. rapanuiiis closely related to the generitypeHydroclathrus clathratus. We also report on the morphology and phylogeny ofChnoospora minimafrom Easter I. and elsewhere in the Indo-Pacific Ocean, noting the previously unreported presence of hollow portions in its medulla. Although not collected from Easter I., we herein propose the recognition of two new genera,Dactylosiphongen. nov. andPseudochnoosporagen. nov., based on our three-gene phylogeny and their known morphologies and anatomies.Dactylosiphonis based on the three species currently assigned toColpomenia(C. bullosa,C. durvillei, andC. wynnei) that are genetically and morphologically (i.e. thalli with erect and finger-like tubes arising from a common saccate base) distinct from other members ofColpomenia. The monotypic genusPseudochnoosporais represented by the decumbent, branching, and inter-adhesive species currently known asChnoospora implexa. With the above proposals, we further increase the genus-level diversity of Scytosiphonaceae in the Indo-Pacific Ocean.


2021 ◽  
Author(s):  
Hamzeh Mafakheri ◽  
S. Mohsen Taghavi ◽  
Kamran Khezerpour ◽  
Nemanja Kuzmanović ◽  
Ebrahim Osdaghi

Agrobacterium tumefaciens species complex contains a set of diverse bacterial strains most of which are well known for their pathogenicity on agricultural plants causing crown gall diseases. Members of A. tumefaciens species complex are classified into several taxonomically distinct lineages called “genomospecies” (13 genomospecies until early 2021). Recently, two genomospecies, i.e., G19 (strains RnrT, Rew and Rnw) and G20 (strains OT33T and R13) infecting Rose sp. plants in Iran were described based on biochemical and molecular-phylogenetic data. Whole genome sequence-based core-genome phylogeny followed by average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) calculations performed in this study suggested that genomospecies G19 and G20 could be described as two novel and standalone species. In the phylogenetic tree, these two new genomospecies were clustered separately from other genomospecies/species of A. tumefaciens species complex. Moreover, both ANI and dDDH indices between the G19/G20 strains and other Rhizobiaceae members are clearly below the accepted thresholds for prokaryotic species description. Hence, Agrobacterium burrii sp. nov. is proposed to encompass the G19 strains, with RnrT = CFBP 8705T = DSM 112541T as type strain. Agrobacterium shirazense sp. nov. is also proposed to include G20 strains, with OT33T = CFBP 8901T = DSM 112540T as type strain.


Author(s):  
Thomas A. Hegna ◽  
Javier Luque ◽  
Joanna M. Wolfe

Fossils are critically important for evolutionary studies as they provide the link between geological ages and the phylogeny of life. The Pancrustacea are an incredibly diverse clade, representing over 800,000 described extant species, encompassing a variety of familiar and unfamiliar forms, such as ostracods, tongue worms, crabs, lobsters, shrimps, copepods, barnacles, branchiopods, remipedes, and insects. Having colonized nearly every environment on Earth, from hydrothermal vents to terrestrial habitats, they have a diverse fossil record dating back to the Cambrian (540–485 Ma). The quality of the fossil record of each clade is variable and related to their lifestyle (e.g., free-living versus parasitic, benthic versus pelagic) and the degree of mineralization of their cuticle. We review the systematics, morphology, preservation, and paleoecology of pancrustacean fossils; each major clade is discussed in turn, and, where possible, fossil systematics are compared with more recent data from molecular phylogenetics. We show that the three epic clades of the Pancrustacea—Allotriocarida, Multicrustacea, and Oligostraca—all have Cambrian roots, but the diversification of those clades did not take place until the Middle and Late Paleozoic. We also address the potential affinities of three “problematic” clades: euthycarcinoids, thylacocephalans, and cyclids. We conclude by assessing the future of pancrustacean paleobiology, discussing new morphological imaging techniques and further integration with growing molecular phylogenetic data.


Taxon ◽  
2011 ◽  
Vol 60 (4) ◽  
pp. 1104-1112 ◽  
Author(s):  
Pan Li ◽  
Zhechen Qi ◽  
Shichao Chen ◽  
Kenneth M. Cameron ◽  
Chengxin Fu

Zootaxa ◽  
2019 ◽  
Vol 4565 (2) ◽  
pp. 171
Author(s):  
MARCELO KOVAČIĆ ◽  
SERGEY V. BOGORODSKY ◽  
EMILY M. TROYER ◽  
LUKE TORNABENE

A new genus and species of cryptobenthic goby, Cerogobius petrophilus is described from the Red Sea based on nine specimens not exceeding 2.5 cm in total length, collected from a stone-rubble habitat at Thuwal, Saudi Arabia, at depths of 8–15 m. It was also observed underwater at the southern tip of Ras Mohammed and Marsa Alam in Egypt. Cerogobius petrophilus sp. nov. is unique among other gobies in its habitat, and in this regard it superficially resembles some species of blennies, occupying tight holes in stones covered with short algae. Molecular phylogenetic data suggest a close relationship between Cerogobius petrophilus sp. nov. and Hetereleotris, but the former differs from the latter morphologically in head shape with specific proportions of orbit and snout, forward-set position of eyes, a moderately large mouth, a long horn-like tentacle at the nostrils in the middle of snout, caudal peduncle deep and short, and in details of cephalic sensory system. A full description of the new genus and species is provided and is accompanied with osteological data that potentially can be informative in further comparisons with Hetereleotris. 


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