PLANT PHYSIOLOGY , Vol 109, Issue 4 1491-1495, Copyright © 1995 by American Society of Plant Biologists
Morphometric Analysis of Rice Seed Protein Bodies (Implication for a Significant Contribution of Prolamine to the Total Protein Content of Rice Endosperm)
H. B. Krishnan and J. A. White
Department of Plant Pathology, University of Missouri, Columbia, Missouri 65211
Electron microscopic observation of thin sections of rice (Oryza sativa L.)
endosperm revealed two types of protein bodies (PBs): spherical and
irregular-shaped ones. Immunocytochemical localization studies using
antibodies raised against purified glutelins, prolamines, and globulins
indicated that the prolamines were localized in the spherical PB, whereas
the irregular-shaped PB contained glutelins and globulins. We counted and
measured the surface area and the relative volume of 2303 PBs randomly
selected from two different developmental stages and from different
locations within the endosperm. The ratio of spherical to irregular-shaped
PBs was 1:1.6. Double-label immunogold electron microscopic localization
indicated that the globulins represented about 18% of the surface area of
the irregular-shaped PBs. Based on our morphometric analysis, we estimate
the relative contribution of glutelin as 53%, that of prolamine as 35%, and
that of globulin as 12% of the total seed protein.