Indian J. Applied & Pure Bio. Vol. 32(2), 121-130 (2017).

Pollen morphological study of some selected Indian taxa of

Asok Ghosh* and Ishita Saha**

*UGC-CAS Department of Botany, the University of Burdwan, Golapbag-713104, West Bengal, (India) E-mail: [email protected], [email protected] ** Post Graduate Department of Botany, Darjeeling Govt. College, Darjeeling (W.B.). PIN-734101 (India)

Abstract

In present study pollen morphology of 24 taxa from 12 genera of the family Rosaceae were investigated by using Scanning Electron Microscope (SEM) and Light Microscope (LM). Except the surface ornamentation the pollen data supports the general classification. Based on surface ornamentation three general types (A, B and C) were recorded, i.e. striae, perforate-reticulate and granulate-microscabrate. The striae ornamentations were again categorized into six subtypes on the basis of arrangement of muri and perforations along with structure of the muri. Type A includes Striae: I. Faint to striae-found in Cotonester sp., Eriobotrya elliptica etc.; II. Distinct striae found in Fragaria daltoniana; III. Striato-reticulate found in Rosa sp., Fragaria sp.; IV. Irregular striae- found in kleiniana, Potentilla fulgens, Potentilla atrosanguinea; V. Regular striae-found in Pyracantha crenulata, Rubus paniculatus and VI.Y-shaped striae-recorded in Rubus hypargyrus, while type B represents Perforate-reticulate: as recorded in Rubus acuminatus, Rubus ellipticus and Rubus lineatus, and C type exhibits granulate- microscabrate features observed in Rosa sp., Ribes sp., Pyrus sp., and Pyrus sikkimensis.

With the advancement of Scanning Palynological studies of the family Electoron Microscopy (SEM) surface Rosaceae L. have been conducted earlier ornamentation of exine became more which include Erdtman8, Szafer and important along with apertual types as because Pawlowski24, Gerstberger11, Kurtto et al.15, these are more or less fixed or stable characters Muntzing18, Asker and Frost5, Asker 4, and generally do not vary much with the 2 13 variation of the environmental parameter. Ascherson and Graebner , Juzepezuk , 23 6,7 10 Moreover scanning electron microscopy Sojak , Eide , Faegri and Iversen , Kumar (SEM) used on the pollen morphology provides and Panigrahi19, Leht17, Asker and Jerling3, a useful tool for identification. Pilarek and Boratynska20, Kolodziejek and (122)

14 P Gabara . Keys based on pollen grain /E was multiplied with 100, from value, the morphology are included in: Reitsma21, Eide6. shape of pollen grain was determined. In the key prepared by Reitsma21, he had To determine the length of the colpus distinguished 13 types of pollen grains in that is either small or moderate or long the Rosaceae. Classes of exine thickness were colpus length (average) was divided by the determined on the basis of its thickness in ‘length of polar axes (average) and then selected species of the family Rosaceae by multiplied with 100, that is {(CA/PA) x100} Eide6. Reitsma21 had opined that shapes of the (it is a percentage of the length of polar axis pollen grain of Rosaceae are oblate, Prolate, 6 covered by each colpus) and shown as discrete spheroidal; while Eide considered these as variables. A colpus is considered as small spheroidal, prolate and subprolate. However, when the value is  50 or moderate when it is the pollen morphology has been used to > 50 but < 70 or long when it is  50. Diameter elucidate taxonomic relationships in many of pore, exine thickness, width of colpi was 8 6,21 angiosperm taxa , including Rosaceae . The also measured. principal aim of this study was to describe the morphology of pollen grains of the investigated For the Scanning Electron Microscopic species and to characterize the exine sculpturing analysis of exine sculpture, pollen grains were with the help of LM and SEM analysis. mounted on metal stubs, sputtered with technical gold, examined and photographed in In the present study 24 taxa from 12 a S530-Hitachi SEM. genera of the family Rosaceae have been studied. Fresh polliniferous samples were The pollen morphology of the 24 obtained from field collection. The investigated studied taxa of Rosaceae showed diversity in materials are shown in Table-1. size, shape, exine characters but not in aperture types (Table-2). The present study showed that Fresh materials were acetolysed for the main characteristic features of pollen of L M investigation. The method used, as Rosaceae are isopolar, radially symmetric, 8,9 suggested by Erdtman after slight modification. prolate/subprolate/ob-prolate in shape, a zona- In all cases measurement and other obser- colporate/zona-colpate aperture in all genera vations were based on acetolysed grains unless and species with fixed (three) number of otherwise mentioned. The measurements apertures. The exine sculpturing pattern is quoted in the pollen descriptions are generally striae mainly with few exceptions. These based on an average of 5/10/15 reading characters agree well with those reported randomly chosen. In case of scanty occurrence, earlier for Rosaceae12,25,14,16. however, fewer gains were measured. For the determination of shape, a shape class of The SEM observations within the Erdtman8 was followed. To determine the family showed a variation (synapomorphic shape the values of PA (Polar axis length) and character) in the exine sculpture only (Plate ED (Equatorial diameter) were measured and 1; table 2). Other characters are more or less P the /E ratio was calculated. Then the ratio of uniform in the family (symplesiomorphic (123)

Table-1. List of specimens used in investigation Sl.No. Name of the species/taxa Locality 1. Cotonester sp. Linn. Lloyd Botanic Garden; Darjeeling (W.B.) 2. Eriobotrya elliptica Lindl. Kucheri Compound, Darjeeling (W.B.). 3. Fragaria daltoniana J. Gay. Tiger Hill, Darjeeling (W.B.). 4. Fragaria sp. Linn. Tiger Hill, Darjeeling (W.B.). 5. Fragaria sp. Linn. Tiger Hill, Darjeeling (W.B.). 6. Malus baccata (L.) Borkh. Pankha Bari Road, Darjeeling (W.B.). 7. Neillia thyrsiflora D. Don North Point, Darjeeling (W.B.). 8. Photinia integrifolia Lindl. Lloyd Botanic Garden, Darjeeling (W.B.). 9. Potentilla atrosanguinea Tiger Hill, Darjeeling (W.B.). G.Lodd. ex D. Don 10. Potentilla fulgens Wall. ex Sims Tiger Hill, Lebong, Darjeeling (W.B.). 11. Potentilla kleiniana Wight & Arn. Tiger Hill, Darjeeling (W.B.) 12. Pyracantha crenulata Lloyd Botanic Garden, Darjeeling (W.B.) (Roxb.ex D. Don) Roem. 13. Pyrus sikkimensis (Wenz.)Hook. f. Darjeeling (W.B.) 14. Pyrus sp. Linn. Darjeeling (W.B.) 15. Ribes sp. Linn. Ghoom, Sonada, Darjeeling (W.B.) 16. Rosa sericea Wall. ex Lindl. Tiger Hill, Sandakpheu, Darjeeling (W.B.) 17. Rosa sp. Linn. Lloyd Botanic Garden, Darjeeling (W.B.) 18. Rosa sp. Linn. Lloyd Botanic Garden, Darjeeling (W.B.) 19. Rubus acuminatus Sm. Darjeeling, Ghoom (W.B.) 20. Rubus ellipticus Sm. Tiger Hill, Ghoom, Darjeeling (W.B.) 21. Rubus hypargyrus Edgew. Ghoom, Sonada, Darjeeling (W.B.) 22. Rubus lineatus Reinw. ex Blume Tiger Hill, Darjeeling (W.B.) 23. Rubus paniculatus Sm. Darjeeling (W.B.) 24. Rubus wardii Merr. Darjeeling (W.B.) characters), so palynologically the family is sizes. Two deferent types of pollen sizes have heterobathmic, in nature (with both primitive been identified. Some of the species with larger and advanced characters in a single taxa). The pollen grain (20.48 µm to 30.4µm) e.g. are overall observations revealed that pollen of found in Rosa sp., Rubus paniculatus, Rosa Rosaceae are admixture of wide variety of sericea and Rubus hypargyrus and other morphological characters. The present species with comparatively smaller pollen description of the pollen grain under L M (8µm to 10.08µm) are found in Rosa sp., showed a significant difference found in grain Pyracantha crenulata, Cotonester sp. It is (124)

B A C

D E

F G

Plate 1 Microphotographs of pollen surface of different investigated taxa of Rosaceae A. Malus baccata (X1000) ; B. and C. Pyrus sikkimensis (x1000); D. Rubus hypargyrus (x1000); E. and F. Rosa sericea; G. Rubus ellipticus. (A-D-LM photographs; E-G-SEM photographs) . (125) well known that pollen grain dimensions in general types were recorded (i.e. striae, many genera of Rosaceae are correlated with perforate-reticulate and granulate- chromosome number (Muntzing18, Anchev and microscabrate). The striae ornamentation Deneva1) but we have not studied the again categorised in to six subtypes on the basic correlation between pollen sizes in the studied of arrangement of muri and perforation along taxa of Rosaceae. with structure of the muri. Types are as follows- A. Striae: i. Faintly striae- found in Apertures are more or less homogenous Cotonester sp., Eriobotrya elliptica etc.; ii. with tri-colporate, zona-perturate pollen grains Distinct striae- found in Fragaria daltoniana; (in 23 taxa) and tricolpate pollen grain is found iii. Striato-reticulate- found in Rosa sp., in Potentilla fulgens, considering this apertual Fragaria sp.; iv. Irregular striae- found in types there are colporate pollen in Cotonester Potentilla kleiniana, Potentilla fulgens, sp., Eriobotrya elliptica, Malus baccata, Potentilla atrosanguinea; v. Regular striae- Photinia integrifolia, Pyrus sikkimensis, found in Pyracantha crenulata, Rubus Rosa sericea etc., colpate in Potentilla paniculatus; vi.Y-Shaped striae-recorded in fulgens. The pollen of 23 taxa (out of 24 taxa) Rubus hypargyrus; B. Perforate-reticulate: is with tri-colporate aperture. This complex Recorded in Rubus acuminatus, Rubus aperture is considered to be as advanced ellipticus and Rubus lineatus; C. Granulate- character and is found in numerous advanced microscubrate: Observed in Rosa sp., Ribes families of dicotyledonous, though these tri- sp., Pyrus sp., and Pyrus sikkimensis. colporate pollen grains are also found in some primitive families also. In SEM, apocalpial exine sculpture varies from granulate-reticulate to striae, from The present result showed (Table 2) faintly striae to clearly striae. Exine sculpture a considerable proportion of sub-prolate along the colpi is similar to that appearing at (Malus baccata, Eriobotrya elliptica, distal pole, but the mesocolpal exine has a Potentilla atrosanguinea, Potentilla fulgens, tendency to decrease in lateral extension and sometimes forming ‘Y’-shaped striae (Rubus Pyracantha crenulata, Rubus paniculatus, hypargyrus). Rubus hypargyrus) and prolate (Rubus lineatus, Rubus acuminatus, Rosa sp., Potentilla Most exine sculptures in the studied kleiniana, Cotonester sp.) grains, with an taxa of the family were classified into 6 sub- average frequency of prolate-spheroidal types within 3 types based on tendency from (Rubus wardii, Rosa sericea, Pyrus secondary sculpturing. The genus Rubus sikkimensis, Fragaria sp. etc.) grains and hypargyrus shows a peculiarity among the very rarely spheroidal grains and agreed with species. Exine is clearly, deeply perforate or the opinion of Reitsma21 and Edie6. The striae (Rubus ellipticus to Rubus paniculatus). morphology of pollen is more or less circular The exine sculpture sometime varies among in polar view in all the studied species. the species and sometime within a species and sometimes form a unique ‘Y’-shaped striae On surface ornamentation three ornamentations (Rubus hypargyrus). (126) SURFACE ATATION xxi Faintly striae Faintly striae Distinctly striae Striato- reticulate or striae Striae Striae Scabrulate Striae Irregularly striae Irregular Irregular Regularl Slightly granulate to ate A xx - - .2 - - linear striae - linear striae - linear striae microscabr- NEXINE ORNAMEN R xix 0.4-0.8 .8 - 1.2 .2- .4 .1-.3 .8-1.6 0.8-1.2 .4-.8 .4-.8 A xviii - - - .66 - - - - SEXINE R xvii 1.2- 1.6 1.2 - 2.4 1.6- 2.4 1.6 - 2.4 1.6 - 2.8 .66-.8 .4-1 1.6 - 3.2 1.2- 1.6 1.6- 2.4 1.2- 1.6 1.2- 1.6 1.2-3.2 EXINE (In µm) A xvi 1.6 - - - - . ------P0RE (In µm) R xv - 1.6- 2.4 2.4- 3.2 3.2-4 1.6-2 - 1.6- 2.4 1.6- 3.2 2.4 - 3.2 .8- 1.6 .8- 1.2 1.2- 1.6 (CL/ PA)x 100 xiv 64.18 84.62 89.52 85.45 62.86 75 85.57 83.33 80 81.73 70.15 81.63 A xiii - 1.6 - - .4 ------BREADTH R xii 1.2- 1.6 - .8 -1.6 1.6-2 - 1-1.2 .8-1.6 1.2-2.4 1.6-2.4 1.2-1.6 .8-1.2 .8-1.6 A xi 6.88 17.6 15.04 15.04 8.8 6.6 13.28 12.8 14.08 13.6 8.64 19.2 COLPUS (In µm) LENTH R x 6.4- 7.2 16.8- 19.2 14.4- 16 14.4- 16 - 6.4- 6.8 12.8- 14.4 1.2- 117.6 12.8 - 15.2 12.8- 14.4 8-9.6 18.4- 20 APERTURE ix Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolpus Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate SHAPE viii Prolate Subprolate Prolate- spheroidal Prolate- spheroidal Subprolate Subprolate Prolate- pheroidal / Subprolate Subprolate Subprolate Prolate Subprolate Prolate- spheroidal Table-2 Table-2 Pollen morphology of the investigated taxa of Rosaceae P/E RA TIO vii 134 118.19 108 107.84 116.67 122.22 114.12 128 115.78 136.84 128.33 113.07 A vi 8 17.6 16 12 7.2 13.18 12 15.2 12.16 9.6 20.8 E.D. (In µm) R v 7.2- 8.8 16- 18.4 16- 16.8 16- 16.32 16.8 - - 12.8- 14.4 9.6- 14.4 14.4-16 11.2- 12.8 8-11.2 19.2- 22.4 A iv 10.72 20.8 17.28 17.6 14 8.8 15.52 15.36 17.6 16.64 12.32 23.52 P.A. (In µm) R iii 10.4- 11.2 20- 21.6 16-18.4 - - - 14.4-16 12.8- 17.6 16.8- 18.4 16-17.6 11.2- 14.4 22.4- 24.8 . sp. sp. sp TAXA ii Cotonester Eriobotryaelliptica daltonianaFragaria Fragaria Fragaria Malusbaccata thyrsifloraNeillia integrifoliaPhotinia Potentilla atrosanguinea Potentillafulgens Potentillakleiniana Pyracanthacrenulata Pyrussikkimensis Sl. No. i 1 2 3 4 5 6. 7. 8. 9. 10. 11. 12. 13. (127) ch Granulate Striato- granulate or striato- reticulate Roughly striae Striato- reticulate Granulate or striato- granulate Slightly perforated Perforated ‘Y’-shaped striae Perforated Regularly striae Not detected - .4 to retiuculate to reticulate - - to reticulate - - .4-.8 - .4 - .8 0.3 1.2-1.6 .8-1.2 1.2-1.6 ------1.6-3.2 .8-1.6 1.2-2.4 1.2-2.4 1.6-2.4 1.2-1.6 1.2-2.4 .6-.8 1.6-2.4 1.6-2.4 1.6-2.4 - 1.2 - - - 1.4 - - - 1.2- 1.6 - 2.4 - 4 3.2-4 1.2- 2.4 1.2- 1.6 2.4- 3.2 2.4- 3.2 2.4- 3.2 80 85 84.34 83 83.33 62.5 79 78.96 84.57 1.6 - - - - .8 - - - - 1.2-1.6 1.2-1.6 .8-1.6 1.2-2 - 1.2-1.6 1.2-1.6 1.6-2.4 10.24 15.52 22.4 20.32 19.2 10 16.96 16.8 23.68 9.6- 11.2 14.4- 16 21.6- 24 19.2- 20.8 17.6- 12.4 - 16- 17.6 16- 17.6 22.4- 14 (average) and then multiplied with 100 (it is a percentage of the length of polar axis covered by ea iameter; Shape= Based on the shape classes (Erdtman, 1952); P/E = Ratio of andP.A E.D; R = Range; Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Tricolporate, zonoaperturate Prolate- pheroidal / Subprolate Prolate- pheroidal / Subprolate Prolate- spheroidal Prolate Prolate Subprolate Prolate Subprolate Prolate- spheroidal 114.29 114 107.10 147.12 156.52 125 136.73 121 106.76 11.2 16 12.8 14.72 12.8 15.68 17.6 25.28 - 14.4- 16.8 24- 26.4 16- 16.64 17.6 12.8- 16 - 14.4- 16 16.8- 18.4 24.8- 25.6 12.8 18.24 16.56 24.48 23.04 16 21.44 21.28 28 12.8- 13.6 17.6- 19.2 25.6-28 24-25.6 20.8 25.6- - 20.8- 22.4 20.8- 21.6 27.2- 28.8 sp. sp. sp. sp. Pyrus Ribes Rosasericea Rosa Rosa Rubusacuminatus Rubusellipticus Rubushypargyrus Rubuslineatus Rubuspaniculatus wardii Rubus 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. Sl.No. = Serial number; Taxa = Name of the investigated taxa; P.A. = Polar axis; A E.D. = Average; = µm= EquatorialMicrometer; d (CL/PA) x100 = Colpus length (average) divided by colpus)length andof alsopolar shownaxis as discrete variables. (128)

The striae ornamentation is consisting similar pollen characters in size, shape, of elongated muri and separated by lamina. aperatual patten and also in ornamentation (i.e. Muri may be arranged parallel and without any Perforate-reticulate type of ornamentation) but branching as found in Pyrancantha sp., on the pollen grains of R. paniculatus are totally the other hand the muri may be arranged in different more or less in all parameters (size, overlapping condition, wavy and discontinuous shape, apertual patten and even in surface fashion (Rosa sericea, Potentilla fulgens and ornamentation). So palynologically, the other species of Potentilla). Sometimes placement of the species R. paniculatus branched muri are also found (Cotonester sp.). under the genus Rubus cannot be supported and it is palynologically much more related with Pollen grains of some species (Rosa, Rubus ellipticus, R. acumimatus, R. linearis different species of Rosa sp., Potentilla and and R. paniculatus) have also been studied Fragaria. But before concluding anything we by Samanta and Das22. Their observations more should consider the characters from other or less support our view but differ in surface disciplines also and on the basis of ornamentation ornamentation as reticulate in Rosa sericea of the pollen grain two sub-taxa may be under LM but SEM investigation of Rosa created under the genus Rubus. Elongated sericea showed distinctly striae and other apertures with faintly striae (e.g. Cotonester species represent faintly striae ornamentation. sp. Eriobotria elliptica) or striae ornamentation On the other hand Samanta and Das 22 (e.g. Potentilla kleiniana, Potentilla fulgens described surface ornamentation of two and Potentilla atrosanguinea) suggested species of Rubus linearies and Rubus that these species are palynologically primitive paniculatus as granulated. This differs from in comparison to scabrate or perforated- our observation and SEM analysis showed that reticulate and granulated ornamentation as surface of Rubus pollen either perforate- found in Rubus acuminatus, Rubus ellipticus, reticulated (Rubus acuminatus, Rubus ellipticus Rubus lineatus, Rosa sp., Ribes sp., Pyrus and Rubus lineatus), granulated to scabrate, sp., Pyrus sikkimensis etc. and the reticulate though LM study exhibited result different and striae ornamentation helps in entomophily features. According to many authors18, 3 a high (advance character). So palynologically the number of irregularly shaped and sterile pollen family is an admixture of both primitive and grain is a reliable apomictic indicator. It has advance characters. also reflected in our investigation and present observation detected high number of ill- The result of the present study demons- developed sterile pollen. trated that surface sculpture of the pollen grains is a good criterion for the identification Under the genus Rubus, 4-species of different genera of the family Rosaceae but have been investigated using SEM e.g. Rubus not for the different species under the same ellipticus, R. acuminatus, R. paniculatus and genus. But for the taxa Rubus acuminatus, R. lineatus of which R. ellipticus, R. Rubus ellipticus and Rubus lineatus are acuminatus and R. lineatus have shown characterized by perforate-reticulate while (129)

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