STRUCTURE AND PHYSICOCHEMICAL PROPERTIES OF ENDOSPERM STARCHES OF A WAXY ALLELIC SERIES AND THEIR RESPECTIVE NORMAL COUNTERPARTS IN THE INBRED OH43 MAIZE BACKGROUND
N. Inouchi et al., STRUCTURE AND PHYSICOCHEMICAL PROPERTIES OF ENDOSPERM STARCHES OF A WAXY ALLELIC SERIES AND THEIR RESPECTIVE NORMAL COUNTERPARTS IN THE INBRED OH43 MAIZE BACKGROUND, Starke, 47(11), 1995, pp. 421-426
Research over the past three decades has greatly increased our underst
anding of the biochemical genetics of varoius waxy (wx) alleles of mai
ze, but our knowledge about the structure and physicochemical properti
es of endosperm starches obtained from the wx alleles is still incompl
ete. We further investigated the structure and physicochemical propert
ies of endosperm starches from a wx allelic series and their normal co
unterparts in the Oh43 inbred background. Starch granules were prepare
d from mature kernels of wx mutant alleles; wx-C31, wx-R, wx-90, wx-a,
wx-B3, wx-m-1, wx-m-8, and wx-S5, and their respective normal counter
parts in the inbred Oh43 maize background. Measurements of absorption
spectra of starch-iodine complexes and by gel permeation chromatograph
y of Pseudomonas-isoamylase-debranched starches showed that all of the
starches from the wx allelic series were uniquely waxy type in charac
teristics, and their normal counterparts were characteristically norma
l type. Pasting characteristics of starch granules and retrograded sta
rches of the wx allelic series and their respective normal counterpart
s were investigated by differential scanning calorimetry (DSC). The pe
ak temperature (Tp) and conclusion temperature (Tc) values from starch
es of the wx allelic series were slightly higher than those of their r
espective normal counterparts and the Delta Hs of starches of the wx a
llelic series were greater than those of their respective normal count
erparts. The onset temperature (To), Tp, and Tc of all retrograded sta
rches were very similar, however, the Delta Hs of the retrograded star
ches of the wx allelic series were greater than those of their respect
ive normal counterpart. Starch granules of the wx allelic series were
hydrolyzed more rapidly than those of their respective normal counterp
arts.