ABSTRACT:
In this presented work, the pollen morphologies of twenty-one taxa, nine of them endemic from Turkey, belonging to the genus Salvia (Lamiaceae: sub-family Nepetoideae: tribe Mentheae: sub-tribe Salviinae), S. aethiopis L., S. argentea L., S. aytachii Vural & Adigüzel, S. blepharochlaena Hedge & Hub.-Mor., S. cadmica Boiss., S. ceratophylla L., S. cryptantha Montbret & Aucher, S. frigida Boiss., S. fructicosa Miller, S. halophile Hedge, S. napifolia Jacq., S. microstegia Boiss. & Bal., S. recognita Fisch. & Mey. S. sclarea L., S. smyrnaea Boiss. S. suffruticosa Montbret & Aucher, S. tchihatcheffii (Fisch. & Mey.) Boiss., S. tometosa Bertol, S. verbenaca L., S. viridis L., and S. wiedemanni Boiss. and collected throughout the Turkey, have been intensively studied by using light (LM) and a scanning electron (SEM) microscopy. The objectives of this study are to investigate the pollen morphologies of twenty-one taxa of Turkish Salvia (nine of which are endemic) and to present similar and different characteristics of the taxa. The investigated whole pollen grains had a structure of both isopolar and radial symmetry. Overall, types of aperture were mostly hexacolpate, but it was also determined that the aperture type of S. viridis was both hexacolpate and octacolpate. The pollen grains had characteristic shapes of spheroidal, suboblate, prolate and subprolate. The exine ornamentation was bireticulate and reticulate-perforate. It was determined by the results of palynological studies that pollen morphology changed amongst these studied taxa. As a conclusion, the results of the present study show that palynological characters such as pollen shape, polar axis length (P), equatorial axis length (E), aperture numbers and types and exine ornamentation, exhibit remarkable differences amongst the studied taxa.
Keywords: exine ornamentation; Lamiaceae; palynology; Salvia; Turkey
RESUMO:
Neste trabalho, as morfologias polínicas de 21 táxons, nove delas endêmicas da Turquia, pertencentes ao gênero Salvia (Lamiaceae: subfamília Nepetoideae: tribo Mentheae: subtribo Salviinae): S. aethiopis L., S. argentea L., S. aytachii Vural & Adigüzel, S. blepharochlaena Hedge & Hub.-Mor., S. cadmica Boiss., S. ceratophylla L., S. cryptantha Montbret & Aucher, S. frigida Boiss., S. fructicosa Miller, S. halophile Hedge, S. napifolia Jacq., S. microstegia Boiss. & Bal., S. recognita Fisch. & Mey. S. sclarea L., S. smyrnaea Boiss., S. suffruticosa Montbret & Aucher, S. tchihatcheffii (Fisch. & Mey.) Boiss., S. tometosa Bertol, S. verbenaca L., S. viridis L. e S. wiedemanni Boiss., coletados em toda a Turquia, foram intensamente estudadas usando luz (LM) e uma microscopia eletrônica de varredura (MEV). Os objetivos deste estudo foram investigar as morfologias polínicas de 21 táxons da sálvia turca (nove dos quais são endêmicos) e apresentar características semelhantes e diferentes dos táxons. Os grãos de pólen inteiros investigados tinham uma estrutura de simetria tanto isopolar como radial. No geral, os tipos de abertura foram principalmente hexacolpato, mas também foi determinado que o tipo de abertura de S. viridis era hexacolpato e octacolpato. Os grãos de pólen tinham formas características de esferoide, suboblato, prolato e subprolato. A ornamentação exina era birreticulada e reticulado-perfurada. Foi determinado pelos resultados de estudos palinológicos que a morfologia do pólen mudou entre os táxons estudados. Como conclusão, os resultados do presente estudo mostram que caracteres palinológicos, como formato do pólen, comprimento do eixo polar (P), comprimento do eixo equatorial (E), números de abertura e tipos e ornamentação exótica, exibem diferenças notáveis entre os táxons estudados.
Palavras-chave: ornamentação exina; Lamiaceae; palinologia; Salvia; Turquia
INTRODUCTION
Salvia L. is the largest genus of the Lamiaceae family and comprises of nearly 1000 species with various cosmopolitan assemblages of this family (Walker et al., 2004; Walker and Sytsma, 2007). This genus consists of nearly 500 spp. in Central and South America, 250 spp. in Central Asia and the Mediterranean and 90 spp. in Eastern Asia (Walker et al., 2004). In Asia, Turkey is one of the main centres for diversity for Salvia (Vural and Adigüzel, 1996). After the most recent reviews, four new species have been discovered, identifying the genus in Turkey and thus the total number for this species has now reached 90. Forty-seven of these Salvia species grow as an endemic in Turkey (Hedge, 1982; Davis et al., 1988; Duman, 2000; Dönmez, 2001; Hamzaoğlu et al., 2005).
In this work, nine of the twenty-one taxa investigated here are endemic to Turkey.
Pollen morphologies for the family Lamiaceae have been investigated by several workers, such as Erdtman (1945), Cantino et al. (1992), Harley et al. (1992), Abu-Asab and Cantino (1993, 1994), Perveen and Qaiser (2003), Celenk et al. (2008), Moon et al. (2008a,b), Salmaki et al. (2008), Hassan et al. (2009) and Doaigey et al. (2018). Although studies on pollen morphology in Salvia have been conducted by many researchers worldwide (Henderson et al., 1968; Hassan et al., 2009; Kahraman et al., 2009, 2010; Özler et al., 2011,2013), there are still shortcomings and unstudied taxa in Turkey.
Henderson et al. (1968) described the pollen morphologies of 59 Salvia taxa. Twenty of these 59 taxa grow locally in Turkey and researchers demonstrated here that the pollen grains were hexacolpate, prolate to spheroidal and reticulate in shape. Moon et al. (2008b) studied the subtribe Nepetinae of the tribe Mentheae and examined the pollen morphologies; however, these researchers did not work with any taxa of Salvia.
Özler et al. (2011) also examined the 30Salvia taxa distributed in Turkey and investigated the pollen morphologies of S. fruticosa, S. halophila, S. recognita, S. suffruticosa, S. tchihatcheffii, S. tomentosa, S. viridis and S. wiedemannii. The same group (Özler et al., 2013) also studied another 30 Salvia taxa, which grew in Turkey and examined pollen morphologies of S. aethiopis, S. argentea, S. blepharochlaena, S. cadmica, S. ceratophylla, S. frigida, S. microstegia, S. sclarea and S. smyrnaea.
This presented study aims to investigate the pollen morphologies of twenty-one taxa of Turkish Salvia (nine of which are endemic) and to present similar and different characteristics of the taxa.
MATERIALS AND METHODS
Plant material
In the present study, twenty-one different taxa of Salvia were gathered from different localities in Turkey (Table 1). Plant material was dried, prepared as herbarium material and identified with the help of previous literature (Hedge, 1982). Collected specimens are kept in Manisa Celal Bayar University, Faculty of Art and Science, Herbarium of Department of Biology.
Pollen analysis
Pollen descriptions are carried out based on the LM and SEM findings. For light LM studies, the pollen grains were prepared by the standard method based on the Erdtman procedure (Erdtman, 1960). For this purpose, the pollen grains were first mounted in clear glycerine jelly. Observations and measurements were carried out by a Hunt type binocular microscope with oil immersion using 16x eyepiece. The glycerine jelly photographs (LM) were taken by using an Olympus trinocular microscope equipped with a Nikon camera. The light microscope (with a magnification of 1000x) was preferred to measure the polar length (P), the equatorial length (E), the colpus length (Clg), colpus width (Clt) and the exine thickness for 30 pollen grains. The P/E ratios were calculated by using these measurements. For SEM analysis, pollen grains were first covered with a thin film of gold by a Polaron SC7620 sputter coater and SEM pictures were taken at magnifications of 2000x and 10000x with the help of the JEOL JSM-6060 SEM. SEM observations were used to determine the exine sculpturing of the individual pollen. These prepared slides are stored at Manisa Celal Bayar University, Faculty of Art and Science, Department of Biology.
The terminology used is in accordance with Henderson et al. (1968), Faegri and Iversen (1989), Punt et al. (2007) and Özler et al. (2011, 2013) and pollen shape classification follows that of Erdtman (1969) based on the ratio of polar axis/equatorial diameter (Table 2).
RESULTS AND DISCUSSION
Tables 2 and 3 summarise the main characteristics of the pollens, which were investigated for this presented study. Figures 1, 2, 3, 4, 5 and 6 demonstrate the SEM micrographs of the pollen grains. Below, the main pollen features such as size and shape, apertures and exine sculpturing are described.
SEM micrographs of pollen grains in the Salvia taxa examined. S. aethiopis (A-B), S. argentea (C-D), S. aytachii (E-F); S. blepharochlaena (G-H).
SEM micrographs of pollen grains in the Salvia taxa examined. S. cadmica (A-B), S. ceratophylla (C-D), S. cryptantha (E-F), S. frigida (G-H).
SEM micrographs of pollen grains in the Salvia taxa examined. S. fruticosa (A-B), S. halophila (C-D), S. napifolia (E-F), S. microstegia (G-H).
SEM micrographs of pollen grains in the Salvia taxa examined. S. recognita (A-B), S. sclarea (C-D), S. smyrnaea (E-F), S. suffruticosa (G-H).
SEM micrographs of pollen grains in the Salvia taxa examined. S. tchihatcheffii (A-B), S. tomentosa (C-D), S. verbenaca (E-F).
SEM micrographs of pollen grains in the Salvia taxa examined. S. viridis (A-D), S. wiedemannii (E-F).
Pollen Size and Shape
The pollen grains are dispersed as monads. The polar axis (P) size of the samples changed between 30.05 µm (Salvia fructicosa and S. microstegia) and 62.01 µm (S. blepharochlaena). The equatorial axis (E) size of the pollen grains was found to be in the range of 21.70 µm (S. tometosa) to 47.38 µm (S. argentea) (Table 2). The pollen grains also had variable shapes such as spheroidal, suboblate, prolate and subprolate (Table 3).
Apertures
The studied whole pollen grains have radial symmetry with isopolar character. The pollen grains mostly have a hexacolpate structure, but some of them are both hexacolpate and octacolpate as in S. viridis (Figures 1and2). Colpi are observed to be distributed as symmetric. Length of colpus (Clg) changed between 22.11 µm (S. suffruticosa) and 58.00 µm (S. blepharochlaena). Colpus width (Clt) was found to be in the range of 0.20 µm (S. aytachii) to 7.57 µm (S. sclarea) (Table 2).
Exine
Exine shows bireticulate (S. argentea, S. aytachii, S. blepharochlaena, S. cadmica, S. ceratophylla, S. cryptantha, S. halophila, S. napifolia, S. recognita, S. sclarea, S. suffruticosa, S. verbenaca, S. viridis) and bireticulate-perforate (S. aethiopis, S. frigida, S. fructicosa, S. microstegia, S. smyrnaea, S. tchihatcheffii, S. tometosa, S. wiedemanni) ornamentation. The thickness of exine varies between 1.00 µm (S. fruticosa) and 3.15 µm (S. argentea and S. ceratophylla) (Table 2).
This presented study demonstrates that the investigated whole pollen grains are hexacolpate except S. viridis. The pollen grain of S. viridis has both hexacolpate and octacolpate (Figure 6A-D). These results agree with some previous studies (Perveen and Qaiser, 2003; Özler et al., 2011, 2013).
The pollen sizes of the examined samples are very variable, with small to large characteristics (P = 30.05-61.00 µm, E = 21.70-51.59 µm). The smallest pollen grain occurs in S. fruticosa, whereas the largest is observed in S. blepharochlaena (Tables 2and3; Figure 1). Similarly, Özler et al. (2011) observed that S. blepharochlaena has the largest pollen grain.
The thickness of the exine changed between 1.00 µm (S. fruticosa) and 3.15 µm (S. argentea and S. ceratophylla). According to our results, the exine ornamentation displays two types: bireticulate and reticulate-perforate. The pollen morphology of some Lamiaceae taxa, including S. aethiopis, S. fructicosa, S. sclarea and S. verbenaca, have been examined by Moon et al. (2008b). They determined that the exine ornamentation of S. aethiopis, S. fructicosa, S. sclarea and S. verbenaca is bireticulate (Tables 4and5). According to our study, it was shown that exine ornamentation of S. sclarea and S. verbenaca are bireticulate but exine ornamentation of S. fructicosa is reticulate-perforate. Hassan et al. (2009) studied some Salvia species distributed in Egypt, including Salvia sclarea and S. verbenaca and examined the pollen morphology of the samples. They determined the exine ornamentation of Salvia sclarea and S. verbenaca to be bireticulate. In our presented work, SEM microphotographs demonstrated that the exine ornamentations of S. sclarea and S. verbenaca are also bireticulate. Özler et al. (2011, 2013) studied some Salvia taxa distributed in Turkey, such as S. aethiopis, S. argentea, S. blepharochlaena, S. cadmica, S. ceratophylla, S. frigida, S. fructicosa, S. halophila, S. microstegia, S. recognita, S. sclarea, S. smyrnaea, S. suffruticosa, S. tchihatcheffii, S. tometosa, S. viridis and S. wiedemanni and a researcher examined the pollen morphology of the whole samples. They determined that the exine ornamentation in S. argentea, S. ceratophylla, S. halophila, S. microstegia, S. recognita, S. sclarea, S. suffruticosa, S. blepharochlaena and S. cadmica as bireticulate and S. aethiopis, S. frigida, S. fructicosa, S. smyrnaea, S. tchihatcheffii, S. tometosa, S. viridis and S. wiedemanni was reticulate-perforate (Tables 4and5). Our findings also confirm the exine ornamentation results of Özler et al. (2011, 2013).
Systematic implications of pollen morphology
Hedge (1982), “Flora of Turkey and the East Aegean Islands”, reports that S. argentea and S. microstegia show very similar morphological characteristics. In our presented study, it was determined that the pollen morphology of these two species was different even for same exine ornamentation. According to our results, the pollen of S. argentea showed the characteristics of P = 36.50 µm, E = 42.00 µm, Clg = 27.37 µm, Clt = 2.84 µm and Exine thickness = 2.36 with the pollen shape of S. argentea being determined as suboblate (P/E = 0.87); the characteristics of the pollen of S. microstegia were; P = 44.92 µm, E = 35.08 µm, Clg = 36.32 µm, Clt = 3.82 µm and Exine thickness = 2.58 µm with the pollen shape of S. microstegia determined as subprolate (P/E = 1.27).
S. cadmica and S. smyrnaea are also stated as morphologically very similar in “Flora of Turkey and the East Aegean Islands”, but they have not been recognised according to palynological data. We determined that the pollen size and pollen shape of these two species were also quite similar. Their exine ornamentation is, however, of a different type. We determined the exine ornamentation in S. cadmica as bireticulate and in S. smyrnaea as reticulate perforate. According to our results, the pollen of S. cadmica had characteristics of; P = 42.54 µm, E = 36.85 µm, Clg = 30.74 µm, Clt = 1.15 µm and Exine thickness = 1.99 µm with the pollen shape of S. cadmica determined as subprolate (P/E = 1.18); whereas the pollen of S. smyrnaea had characteristics of; P = 43.50 µm, E = 37.50 µm, Clg = 33.50 µm, Clt = 1.10 µm and Exine thickness = 1.62 µm with the pollen shape of S. smyrnaea determined as subprolate (P/E = 1.16).
As a conclusion, the results of the present study show that palynological characters such as pollen shape, polar axis length (P), equatorial axis length (E), aperture numbers and types and exine ornamentation, exhibit remarkable differences amongst the studied taxa, as already reported in previous studies.
ACKNOWLEDGEMENTS
This work was supported by Scientific Research Projects Offices of Manisa Celal Bayar University (MCBU-BAP) through the research project (project No. FEF- 2009/030).
REFERENCES
- Abu-Asab MS, Cantino PD. Phylogenetic implications of pollen morphology in tribe Ajugeae (Labiatae). Syst Bot. 1993;18:100-22.
- Abu-Asab MS, Cantino PD. Systematic implications of pollen morphology in subfamilies Lamioideae and Pogostemonoideae (Labiatae). Ann Miss Bot Garden. 1994;81:653-86.
- Cantino PD, Harley RM, Wagstaff SJ. Genera of Labiatae: Status classification. In: Harley RM, Reynolds T, editors. Advances in Labiatae Science. Kew: Royal Botanical Gardens; 1992. p.27-37.
- Celenk S, Dirmenci T, Malyer H, Bicakci A. A palynological study of the genus Nepeta L. (Lamiaceae). Plant Syst Evol. 2008;276:105-23.
- Davis PH, Mill RR, Tan K. Flora of Turkey and the East Aegean Islands. Edinburgh: Edinburgh University Press; 1988. v.10.
- Doaigey AR, El-Zaidy MA, Alfarhan AE, Milagy S, Jacob T. Pollen morphology of certain species of the family Lamiaceae in Saudi Arabia. Saudi J Biol Sci. 2018;25:354-60.
- Dönmez AA. A new Turkish species of Salvia L. (Lamiaceae). Bot J Linnean Soc. 2001;137:413-6.
- Duman H. Salvia L. In: Güner A., Özhatay N., Ekim T., Baser K.H.C., editors. Flora of Turkey and the east Aegean islands. Edinburgh: Edinburgh University Press, 2000. v.11. p.197-209.
- Erdtman G. Pollen morphology and plant taxonomy. IV. Labiatae, Verbanaceae and Avicenniaceae. Sven Bot Tidskrift. 1945;39:279-85.
- Erdtman G. The acetolysis method: revised description. Sven Bot Tidskrift 1960;54:561-4.
- Erdtman G. Handbook of palynology morphology, taxonomy, ecology. An introduction to the study of pollen grains and spores. New York: Hafner Publication; 1969. 486p.
- Faegri K, Iversen J. Textbook of pollen analysis. 4th. ed. New York: John Wiley & Sons, 1989. 328p.
- Hamzaoğlu E, Duran A, Pinar NM. Salvia anatolica (Lamiaceae), a new species from East Anatolia, Turkey. Ann Bot Fennici. 2005;42:215-20.
- Harley MM, Paton A, Harley RM, Cade PG. Pollen morphological studies in tribe Ocimeae (Nepetoideae: Labiatae): I. Ocimum L. Grana Palynol. 1992;31:161-176.
- Hassan N, Osman AK, El Garf IA. Pollen types of the Egyptian species of the genus Salvia (Lamiaceae). Feddes Repert. 2009;120:394-404.
- Hedge IC. Salvia L. In: Davis PH, Mill RR, Tan K, editors. Flora of Turkey and the East Aegean Islands. Edinburgh: Edinburgh University Press; 1982. v.7. p.400-61.
- Henderson DM, Prentice H, Hedge IC. Pollen morphology of Salvia and some related taxa. Grana Palynol. 1968;8:70-85.
- Kahraman A, Celep F, Dogan M. Morphology, anatomy and palynology of Salvia indica L. (Labiatae). World Appl Sci J. 2009;6:289-96.
- Kahraman A, Celep F, Dogan M, Anatomy, trichome morphology and palynology of Salvia chrysophylla Stapf (Lamiaceae). South Afr J Bot. 2010;76:187-95.
- Moon HK, Vinckier S, Smets E, Huysmans S. Palynological evolutionary trends within the tribe Mentheae with special emphasis on subtribe Menthinae (Nepetoideae: Lamiaceae). Plant Syst Evol. 2008a;275:93-108.
- Moon HK, Vinckier S, Walker JB, Smets E, Huysmans S.A Search for phlogenetically informative pollen characters in the subtribe Salviinae (Mentheae: Lamiaceae). Int J Plant Sci. 2008b;169:455-71.
- Özler H, Pehlivan S, Kahraman A, Dogan M, Celep F, Baser B, et al. Pollen morphology of the genus Salvia L. (Lamiaceae) in Turkey. Flora. 2011;206:316-27.
- Özler H, Pehlivan S, Celep F, Dogan M, Kahraman A, Yavru Fiþne A, et al. Pollen morphology of Hymenosphace and Aethiops section of the genus Salvia L. (Lamiaceae) in Turkey. Turk J Bot. 2013;37:1070-84.
- Perveen A, Qaiser M. Pollen morphology of the family Labiatae from Pakistan. Pak J Bot. 2003;35:671-93.
- Punt W, Hoen PP, Blackmore S, Nilsson S, Le Thomas A. Glossary of pollen and spore terminology. Rev Palaeobot Palynol. 2007;143:1-81.
- Salmaki Y, Jamzad Z, Zarre S, Bräuchler C. Pollen morphology of Stachys (Lamiaceae) in Iran and its systematic implication. Flora. 2008;203:627-39.
- Vural A, Adiguzel N. A new species from Central Anatolia: Salvia aytachii M. Vural et N. Adiguzel (Labiatae). Turk J Bot. 1996;20:531-4.
- Walker JB, Sytsma KJ, Treutlein J, Wink M. Salvia (Lamiaceae) is not monophyletic: implications for the systematics, radiation, and ecological specializations of Salvia and tribe Mentheae. Am J Bot. 2004;91:1115-25.
- Walker JB, Sytsma KJ. Staminal evolution in the genus Salvia (Lamiaceae): Molecular phylogenetic evidence for multiple origins of the staminal lever. Ann Bot. 2007;100:375-91.
Publication Dates
-
Publication in this collection
10 Feb 2020 -
Date of issue
2020
History
-
Received
09 Oct 2018 -
Accepted
26 Nov 2018