HEMICELLULOSE IS AN IMPORTANT LEAF-FEEDING RESISTANCE FACTOR IN CORN TO THE FALL ARMYWORM

Citation
Pa. Hedin et al., HEMICELLULOSE IS AN IMPORTANT LEAF-FEEDING RESISTANCE FACTOR IN CORN TO THE FALL ARMYWORM, Journal of chemical ecology, 22(9), 1996, pp. 1655-1668
Citations number
43
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Ecology,Biology
Journal title
ISSN journal
0098-0331
Volume
22
Issue
9
Year of publication
1996
Pages
1655 - 1668
Database
ISI
SICI code
0098-0331(1996)22:9<1655:HIAILR>2.0.ZU;2-0
Abstract
The fall armyworm, Spodoptera frugiperda (J. E. Smith), (FAW) is a maj or pest of corn, Zea mays L., in the southeastern United States. The d amage to pretassel corn is caused by larvae feeding primarily on immat ure inner whorls. In this study, resistant lines were found to contain more crude fiber in whorls, mostly hemicellulose and cellulose. While hemicellulose, chiefly an arabinoxylan, was higher in resistant (R) l ines than in susceptible (S) lines, the distribution of constituent ne utral sugars was very similar in the lines. Both lines also contained p-coumaric and ferulic acids. These phenolic acids are known to occur both in the free state and in the cell wall as complexes bound by este r linkages to the arabinose moiety of the arabinoxylan. C-13 NMR data showed that the intensity of the carbonyl carbon (184 ppm) in resistan t hemicellulose was stronger, indicating a greater degree of cross-lin king. Thus, resistant hemicellulose is both structurally different fro m susceptible hemicellulose and present in greater quantities. In two of three laboratory dietary tests, FAW larval weight gains were signif icantly higher on diets with (S) hemicellulose incorporated at the sam e level as (R) hemicellulose. Therefore, resistance to the FAW appears to be correlated with both a greater amount and a higher degree of cr oss-linking of the hemicellulose of (R) lines.