Document Type

Dissertation - Open Access

Award Date

1975

Degree Name

Doctor of Philosophy (PhD)

Department

Agronomy

First Advisor

W.S. Gardner

Abstract

The distribution of the ND18 strain of barley stripe mosaic virus (BSMV) in barley (Hordeum vulgare L.) and corn (Zea mays L.) leaf tissue was studied with light and electron microscopes. Virions were detected in the cytoplasm of barley mesophyll cells, subsidiary, guard and epidermal cells, vascular parenchyma cells, sieve and tracheary elements. Nuclear virus was found in barley mesophyll cells. Ultrastructural cytopathological changes were greatest in the inoculated leaf of barley which contained fewer virus particles than either primary acute or chronically infected tissues. Primary acute and chronically infected barley tissues contained intracellular virions scattered in the cytoplasm, in amorphous inclusion bodies or in crystals. Several types of virus inclusion bodies were located in primary acute or chronic barley leaf tissue. "Tubular aggregates" of virus particles were located in mesophyll cells of barley leaves exhibiting primary acute symptoms. Numerous aberrations of barley chloroplasts were found: swelling, deformation of membranes, cytoplasmic invaginations, peripheral vesicles and BSMV particles attached to the limiting membrane. Several phenotypically different plastids were located in single cells. Two defective types were characterized by the pellucid appearance of the stroma. Cell wall thickenings, "extended plasmodesmata, " extraprotoplasmic sacs, and paramural bodies were found in early systemic barley leaf tissue (primary acute). Few ND18 BSMV particles were found in systemically infected corn leaf tissue. Paramural bodies, intraprotoplasmic osmiophilic bodies, and extraprotoplasmic sacs, similar to those found in barley, were located in corn leaf cells. Mesophyll chloroplasts in corn tissue were often swollen, contained deranged membrane systems and had BSMV particles attached to their limiting membrane. Bundle sheath chloroplasts were swollen and contained unusual peripheral reticulum and stroma lamellae arrangement.

Library of Congress Subject Headings

Mosaic diseases
Barley
Corn

Format

application/pdf

Publisher

South Dakota State University

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