SEM Studies on vessels in ferns 7. Microgramma nitida.

Abstract

USING SCANNING ELECTRON MICROSCOPY (SEM), WE SHOW THAT VESSELS OCCUR IN ROOTS AND STEMS OF MICROGRAMMA NITIDA, AN EPIPHYTE OF ELEMENTS OF ROOTS; TRACHEIDS ARE APPARENTLY LACKING. VESSEL ELEMENTS HAVE SEVERAL FACETS AT THEIR ENDS; EACH CAN BE A PERFORATION PLATE. PERFORATIONS ARE LARGER THAN THE PITS OF LATERAL WALLS. ALTERNATING WIDE AND NARROW PERFORMATIONS OCCUR IN SOME PERFORMATION PLATES. THE VESSELS OF MICROGRAMMA ARE SUITED TO RAPID FLOW, AS EXPECTED IN AN EPIPHYTE, NEVERTHELESS, TRACHEARY ELEMENTS OF MOST FERNS ARE UNKNOWN, SO CORRELATIONS BETWEEN STRUCTURE AND FUNCTION ARE TENTATIVE.