HISTOLOGY OF ANOMALOUS GROWTH AND ADVENTITIOUS ROOTS ASSOCIATED WITH MAINSTEM GIRDLING BY THREECORNERED ALFALFA HOPPER, SPISSISTILUS FESTINUS (SAY) (HOMOPTERA: MEMBRACIDAE) ON SOYBEAN1

Abstract

Cell and tissue structure of undamaged soybean, Glycine max (L.) Merrill, stems were compared with those from the swollen area immediately above (< 1 cm) threecornered alfalfa hopper, Spissistilus festinus (Say), girdles. Examination of epoxy - resin embedded transverse sections from the swollen stems revealed growth that differed significantly from the normal dicot structure. The anomalous growth consisted of vascular bundles scattered in the secondary phloem surrounded by parenchyma cells. Examination of Paraplast® embedded transverse and longitudinal sections of adventitious root - like growths arising from or above the swollen hypocotyl area revealed normal root structure.