Kedves, Miklós

Kocsicska, Ivana

Priskin, Katalin

Kedves Miklós

Kocsicska Ivana

Priskin Katalin

University of Szeged

6. TRANSMISSION ELECTRON MICROSCOPY OF THE CONNECTIVES OF THE POLLEN GRAINS OF GINKGO BILOBA L. M . K E D V E S , I . KOCSICSKA a n d K . PRISKIN Cell Biological and Evolutionary Micropaleontological Laboratory of the University of Szeged, H-6701, Szeged, P.O. Box 993. Hungary Short communication There are several publications concerning the pollen grains of Ginkgo biloba L. LM data of recent and fossil pollen grains was reviewed in 1 9 6 1 ( K E D V E S ) . Preservation of cycad and Ginkgo pollen was investigated by FREDERIKSEN ( 1 9 7 8 ) . TEM data by U E N O ( 1 9 6 0 ) , A U D R A N and M A S U R E ( 1 9 7 5 , 1 9 7 8 in this latter paper the differences between the exine ultrastructure of Ginkgo biloba and the Cycadales were emphasized), Further TEM data by XL Y I Z H E N and W A N G FU-HSIUNG ( 1 9 8 9 ) , X I YL-ZHEN ( 1 9 9 0 ) . K E D V E S and P Á R D U T Z ( 1 9 9 7 ) investigated the alterations in the ultrastructure of the pollen grains of Ginkgo biloba in consequence of the X-ray irradiation. During our ex-perimental studies on the high temperature etc. effect on gymnosperm pollen grains ( K E D V E S , T Ó T H and FARKAS, 1 9 9 1 ) peculiar connectives were observed between two pollen grains of Ginkgo biloba L. This feature was observed in 1 % of the pollen grains, and is believed to be an early characteristic. Stained with Toluidine blue the so-called pore or pseudopore was violet coloured, the other parts of the ectexine are greenish-blue. The stain acceptance indicated differences in the molecular structure of the differ-ent parts of the exine. During one of the programs of our laboratory, different kinds of partial degradation were carried out on the pollen grains of this species too, and a great number of TEM pictures were made. At a very few ultrathin sections of two experiments (T-12-224 and T-12-225) we observed of these peculiar connectives. Our up to date results following the different experiments may be summarized as follows: No important differences were found between the ultrastructure in the two experiments from this point of view. Fig. 1 (Plate 6.1.) illustrate well the ultrastructure of the inter-apertural and the aper-túra! area, and the extremely swollen intine. The reduction of the tectum and the infra-tectal layer is well shown. The ultrastructure of the connectives may be summarized as follows: The tectum around the pseudopores thickened in an important measure, ap-proximaltely twofold. (Plate 6.1., fig. 2). The elements of the infratectal layer are also longer than in the other part of the inter-apertural area. No alterations were observed in the ultrastructure of the foot layer and the intine (Plate 6.1., figs. 1-3). In the middle of the connectives there is a depression of the tectum or a complete disappearance of this layer (Plate 6.1-3.). i n t e r - a p e r t u r a l a r e a i n t 1 n e i n t i n e f i p p g p f o o t l a y e r » j • v e n d e x i n e Plate 6.1 Plate 6.1. 1- 3. Ginkgo biloba L. Ultrastructure of partially degraded pollen grains 1,2. Experiment: T-12-224 (5 mg dry pollen + 2 ml 2-aminoethanol, length of time: 48 hours, washing, + 2 ml merkaptoethanol. Temperature: 30°C). 1. lO.OOOx, Negative No.: 9468, 2. 25.000x, Negative No.: 9470. 3. Experiment: T-12-225 (5 mg dry pollen + 2 aminoethanol, length of time: 72 hours, washing, + 2 ml merkaptoethanol Temperature: 30°C). lOO.OOOx, Negative No.: 9510. In short we observed for the first time the ultrastructure of this really extremely scarce morphological characteristic feature of this early pollen type. This work was supported by Grant OTKA T 31715, and PRCH Student Science Foundation, DT 2001. nov./2.. We express our sincere thanks to Eric C A U L T O N (Direc-tor, Scottish Centre for Pollen Studies, Edinburgh, Scotland, UK) reviewing the manu-script and for his valuable comments. References AUDRAN, J.C. et MASURE, E. (1975): Ginkgoales, Ginkgo biloba. - Réunion du Groupe de Travail Mor-phologie Sporo-pollinique et Numériclature.6-7 octobre 1975. Paris. - Structure et terminologie de la paroi sporo-pollinique. - Talence, Association des Palynologues de Langue Française, 1975, 6. AUDRAN, J.C. et MASURE, E. (1978): La sculpture et l'infrastructure du sporoderme de Ginkgo biloba com-parées à celles des enveloppes polliniques des Cycadales. - Rev. Palaeobot. Palynol. 26, 363-387. FREDERIKSEN, N. O. (1978): Preservation of cycad and Ginkgo pollen. - Rev. Palaeobot. Palynol. 25, 163-179 . KEDVES, M. (1961): Beobachtungen an den Pollen des rezenten Ginkgo biloba L. mit besonderer Hinsicht auf die Fragen der Determination der fossilen Pollen der Ginkgoaceae. - Acta Biol. Szeged. 7, 31 -37. KEDVES, M. and PÁRDUTZ, Á. (1997): X-ray effect on the ultrastructure of the pollen grains of Ginkgo biloba L. - Plant Cell Biology and Development (Szeged) 8. 91-99. KEDVES, M. , TÓTH, A. a n d FARKAS, E. ( 1 9 9 1 ) : E f f ec t of the h igh t empera tu re on the m o r p h o l o g i c a l cha rac -teristic features of the sporomorphs II. - Acta Biol. Szeged. 37, 25-44. UENO, J. (1960): Studies of pollen grains of Gymnospermae. Concluding remarks to the relationships be-tween Coniferae. - J. Inst. Poly. Osaka City Univ. I I , 109-136. WANG, F.-H. (1990): Microsporogenesis in Cycads and Ginkgo. In: Microspores: Evolution and Ontogeny, E d s . : BLACKMORE, S. a n d KNOX, R . B . - Academic Press , 147-155. XI Yl-ZHEN (1990): Ultrastructure of exine of Cycas panzhihuanensis and Ginkgo biloba. - Yushania 7, 81-90. Xt Yl-ZHEN and WANG FU-HSIUNG ( 1 9 8 9 ) : Pollen ex ine u l t ras t ruc ture of ex tan t C h i n e s e g y m n o s p e r m s . -C a t h a y a / , 119 -142 . 50 

Transmission electron microscopy of the connectives of the pollen grains of Ginkgo biloba L.

http://acta.bibl.u-szeged.hu/47933/1/plant_cell_015_048-050.pdf

Transmission electron microscopy of the connectives of the pollen grains of Ginkgo biloba L.

Abstract

Similar works

Full text

Available Versions

University of Szeged