Kedves, Miklós

English

Kedves Miklós

University of Szeged

A c t a Biol. S / c g c d . 32. pp . 207 208 (19861 E X P L O S I O N O F P O L L E N G R A I N S U N D E R T H E E L E C T R O N B E A M E F F E C T O F T H E S C A N N I N G E L E C T R O N M I C R O S C O P E M . K E D V E S (Received: March 15, 1985) The scanning electron microscope technique made it possible to demonstrate several surface ornamenta t ions of biological objects, too, which could not be investigated by the light microscope method. But some problems were pointed out concerning the S E M method. We should mention: M U I R and R A M P L E Y ( 1 9 6 9 ) studied the effect of the electron beam on various mounting and coating media, and wrote as follows; p. 145: . .The purpose of the experiments was to determine the extent of the damage, if any. produced by the beam, on the adhesive, and to try to discover the most damage resistant combinat ions ." L E F F I N G W E L L et al. ( 1 9 7 0 ) : „The use of polyurethane adhesive-coated coverslips permits visual observation through-out the mounting procedure, and significantly reduces the charging effects obtained when specimens are mounted on coverslips without a substrate." Several problems of techniques were discussed by L E F F I N G W E L L and H O D G K I N ( 1 9 7 1 ) . H A N K S and F A I R B R O T H E R S ( 1 9 7 0 ) pointed out; p. 8 8 6 : „The effect of various preparat ion techniques differ f rom species to species." N I L S S O N et al. ( 1 9 7 4 ) studied experimen-tally the collapse of pollen grains in scanning electron microscope. During our SEM studies on recent and fossil spores and pollen grains we observed several times the fly away and the explosion of our objects of investigation. This may be in consequence of the charging. By increasing the accelerating beam voltage the explosion of the pollen grains may increase. From 20 KV we have increased gradually the accelerating beam voltage and the number of the exploded pollen grains increased. After this procedure we studied by LM method the slide and we observed several types of damage and explosion. Our figure demonstrates the explosion of the pollen grains of the recent Eucommia ulmoides O L I V .. The dried pollen grains were mounted on polyvinilchlorid adhesive, and coated with gold palladium. The explosion process is a little similar to a „microscopic supernova" and it may be presumed, that under charging and during the acceleration of the fly away explode the pollen grain. Because we have observed other kind of damages of the palynomorphs after SEM studies we call attention of the palynologists for the LM studies of the palynomorphs after SEM investigations. 2 0 8 M KEDVES Fig. I LM picture of the coated polyvinilchlorid adhesive after the exp los ion of Eucommia ulmuides OLIV. pollen grains under the electron beam effect of the scanning electron microscope. xlOOO. References HANKS. S . and FAIRBROTHERS. D . E . (1970): Effects of preparation technique on pollen prepared for S E M observations. — Taxon . 19. 879 -886 . LEFFINGWELL. H . A . and HODGKIN. N . (1971): Techniques for preparing fossil pa lynomorphs for s tudy with the scanning and transmission electron microscopes . — Rev Palaeobotan. Palynol . / / . 177-199 . LEFFINGWELL. H . A . . LARSON. D A . and VALENCIA. M . J . (1970): A study of the fossil pol len Wodehouseiu spinala. I. Ultrastructure and compar i sons to selected modern taxa. II. Optical microscopic recognition o f foot layers in differentially stained fossil pollen and their significance. — Bull. Canad. Petroleum G e o l o g y 18. 238-262 . M u m . M . D . and RAMPLEY. D . N . (1969): The effect o f the electron beam on various mount ing and coat ing media in scanning electron microscopy. Journal of Microscopy 9)1. 145-150. NILSSON. S . . NYBOM. R . and PRAGLOWSKI. J . (1974): Experiments regarding col lapsing o f pol len grains in scanning electron microscopy. Grana 14. 2 3 - 2 5 . 

Explosion of pollen grains under the electron beam effect of the scanning electron microscope

http://acta.bibl.u-szeged.hu/22065/1/biologica_032_207-208.pdf

Explosion of pollen grains under the electron beam effect of the scanning electron microscope

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