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Astragalus hamosus and A. glycyphyllos species have been investigated karyologically (the somatic chromo- some numbers) and palynologically in this study. Chromosome numbers were found as 2n = 44 for A. hamo- sus and 2n = 16 for A. glycyphyllos. The chromosome bridges were observed in the mitotic cells of adventive root tips of A. hamosus. In both...
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... The sections of the genus are determined based on morphological characteristics such as stem length, stipule connection, leaf shape, inflorescence form and fruit state [6]. Although there are some systematical [7,8], anatomical [5,[9][10][11][12][13], palynological [5,[13][14][15][16][17][18][19][20] and micromorphological [5,[20][21][22] studies, some systematic problems with Astragalus species are still unresolved [16]. ...
... The sections of the genus are determined based on morphological characteristics such as stem length, stipule connection, leaf shape, inflorescence form and fruit state [6]. Although there are some systematical [7,8], anatomical [5,[9][10][11][12][13], palynological [5,[13][14][15][16][17][18][19][20] and micromorphological [5,[20][21][22] studies, some systematic problems with Astragalus species are still unresolved [16]. ...
... Exine sculpturing is microreticulate with perforate. In Turkey, pollen grains of Astragalus species are generally stenolapynous and radial symmetry, isopolar, tricolpate (rarely tetracolpate) and microreticulate, microreticulate-perforate (rarely reticulate or rugulate) show ornamentation [5,[13][14][15][16][17][18][19][20]. Our pollen findings are similar to the previous evidence. ...
... μm) were studied(Ceter et al., 2013). Pollen grains in both the species namely, A. hamosus and A. glycyphyllos were tricolporate having reticulate type of surface ornamentation(Dane et al., 2007). Pollen grains wereF I G U R E 1 0 Percentage of pollen sterility of different plant species F I G U R E 1 1 Dendrogram showing the relationship of different species based on quantitative pollen characters described as a tricolpate, subprolate, or prolate spheroidal with microreticulate exine ornamentation and semiangular amb for the section Alopecuroidei of Astragalus (Akan et al., 2005). ...
Palynological characterization is considered to be one of the significant taxonomic tools for the delimitation and identification of morphologically complicated taxa. Hence, the pollen morphology of 12 species of spineless Astragalus L. was examined using light and scanning electron microscopy. Studied pollen were small to medium, monad, prolate to per‐prolate and tricolporate type in all studied taxa. The exine sculpturing varied from reticulate to microreticulate whereas colpus ornamentation ranged from scabrate to granulate. Furthermore, maximum polar and equatorial diameter was recorded in Astragalus leucocephalus Bunge. (45.00 μm) and A. pyrrhotrichus Boiss. (22.91 μm) while minimum in A. amherstianus Benth. ex Royle (28.75 μm) and A. amherstianus Benth. ex Royle (15.00 μm), respectively. Similarly, the ratio of polar to equatorial diameter was recorded maximum in A. ophiocarpus Boiss. (2.05). The width of colpi was larger in A. hamosus L. (1.29 μm) and smaller in A. ophiocarpus Boiss. (0.62 μm). We have also found the maximum value of mesocolpium in A. retamocarpus Boiss. (2.08 μm) while minimum in A. oxyglottis Steven ex M.Bieb. (1.87 μm). The quantitative pollen attributes helped in the development of pollen keys for the accurate and quick identification of the studied species. Furthermore, ordination and cluster analysis were performed for the differentiation of the investigated taxa at species level. Based on our results, we conclude that pollen features can be used for the delimitation and identification of the studied taxa.
Research Highlights
Pollen micromorphology is a useful tool for classifying complicated taxa.
The pollen micromorphology of 12 spineless species of Astragalus L. was studied using LM and SEM.
The observed pollen characteristics aided in Astragalus L. serve for the identification and classification of taxa at specific level.
... Thus, the basic chromosome number of the species is x = 8 (Table 1, Figure 1). According to literatures [18,19,20], all of the Astragalus species in New World have aneuploid chromosome numbers (x = 11-15). However, most of the species in old world are euploid (x = 8). ...
... The chromosome numbers were determined as 2n=16, (13764) counts, based on x=8, have been reported in the vast majority in Astragalus genus of old world while counts based x=7 or x=6 have been encountered in few species (Maassoumi, 1987;Badr et al., 1996;Malallah et al., 2001;Badr and Sharawy, 2007). Chromosome number 2n=2x=16, with the proposed basic number of x=8, were found in A. stella (Luque and Lifante, 1991), A. glycyphyllus (Dane et al., 2007), A. pelecinus, A. sinaicus, A. spruneri (Kamari et al., 2006), A. submitis, A. raddei, A. crassispinus, A. ebenoides, 32 and 48, with a basic chromosome number x=8, and three ploidy levels (diploid, tetraploid and hexaploid). The frequencies of the chromosome numbers varied considerably, with 2n=2x=16 (78.26%) being found in most of the taxa, 2n=4x=32 (17.39%), and 2n=6x=48(4.35%) ...
... Incani, which is endemic to Iran, was a mixoploid plant with the ploidy levels 2n=2x=16 and 2n=4x=32 (Ranjbar et al., 2011). A. hamosus showed Chromosome number 2n=44 and 48 (Luque and Lifante, 1991;Dane et al., 2007). ...
In this study, chromosome numbers, ploidy levels and karyotype criteria of 23 taxa representing 13 Astragalus species from different ecological regions of Iran were analyzed and discussed. The basic chromosome number was found as x=8 and all the studied taxa were diploid, tetraploid or hexaploid. Among the species, eighteen were diploid (2n= 16), four were tetraploid (2n=32) and one was hexaploid (2n=48). The karyotype in the studied taxa was mostly comprised of metacentric to submetacentric chromosomes as indicated by their mean arm ratio that ranged between 1.376 in A. megalotropis (in accession 14929) and 2.453 in A. vegetus (in accession 3421). The degrees of karyotype asymmetry were indicated by the values of A¹ ranging between 0.236 in A. megalotropis (in accession 14929) and 0.540 in A. vegetus (in accession 3421) , and the values of TF%, ranging between 30.697 in A. vegetus (in accession 3421) and 42.50 0 in A. megalotropis (in accession 14929). Based on the values of A¹, TF% and karyotype formula, A. vegetus (accession 3421) and A. megalotropis (accession 14929) had an asymmetric and symmetric karyotype respectively. The chromosomes in the studied species of Astragalus were generally small with mean sizes ranging between 2.475 and 4.515 μm. Shorter chromosomes were found in A. aduncus (in accession 14995, TL=2.475 μm), A. vanilla (in accession 13764, TL=2.670 μm) and A. dactylocarpus (in accession 1734, TL=2.743 μm), whereas longer chromosomes were recognised in A. vegetus (in accession 25786, TL=4.515 μm). Based on the analyses of karyotype features, the relationships among the taxa were constructed using PCA analysis. The grouping of the species examined in these plots is discussed in the light of their traditional systematic classification.
... studied morphology, seed, and pollen structure and karyological characters of A. ovalis Boissier & Balansa (1859a: 52). Dane et al. (2007) investigated A. glycyphyllos Linnaeus (1753: 58) and A. hamosus Linnaeus (1753: 758) karyologically and palynologically. Pınar et al. (2009) examined pollen morphology of 29 species of Astragalus. ...
... The pollen shape ranging from peroblate to prolate in the Fabaceae (Erdtman 1969). Present palynological findings are consistent with the above mentioned studies and some other Astragalus species (Ekici & Çelik 2005, Dane et al. 2007. ...
Astragalus argaeus is a critically endangered endemic species growing only on Erciyes Mountain in Kayseri, Turkey. In this study, morphology, anatomy, ecology, pollen and seed morphology and karyology of this species were investigated. The previous description of the species has been expanded and amended. Anatomically, cross-sections of root, stem and leaflet were investigated for the first time. The pith of the root is exactly covered by xylem tissue. The cross-section of stem has a periderm as the protective tissue at the outermost layer. The leaflets are equifacial (isobilateral) and amphistomatic. The pollen grains are tricolporate, isopolar and radially symmetrical, shape prolate, ornamentation faevolate-reticulate. The seeds are brownish and dark dotted in colour and oblate in shape, with rugulate-reticulate ornamentation. Number of somatic chromosomes was identified as 2n = 16 in A. argaeus. The karyotype formula of this species consists of three median chromosome pairs and five submedian chromosome pairs. The plant grows in slightly acidic or alkaline soils with loamy-sand texture, high organic matter and CaCO3 contents.
In this study, pollen morphologies of 5 species (Astragalus guttatus Banks & Sol., A. cretaceus Boiss., A. caprinus L., A. brachystachys DC. and A. ancistrocarpus Boiss. & Hausskn.) belonging to the Astragalus genus of the family Fabaceae, which are distributed in Şanlıurfa province, were exemined by light and electron microscope. As a result of the study, it was determined that the pollen of the taxa were monad, radial symmetrical and isopolar. Pollen of all studied species are trizonocolporate, colpus length (Clg) 16.5-27.62 µm, colpus width (Clt) 2.15-4.16 µm, pore length (Plg) 6.69-9.32 µm, pore width (Plt) was detected between 6.69-11.44 µm. Polar axis length was measured between 19.23-33.66 µm and equatorial axis diameter was measured as 14.95-28.61 µm. Ornamentation was determined as psilate, psilate-perforate, psilate-microreticulate, microreticulate in the polar region and aperture surround the while microreticulate in the equatorial region. As a result of the study, it was determined that the characters such as pollen shape, pollen size and surface ornamentation differ between species and these characters have taxonmic value in the systematic separation of species.
