LAUSR

Lignin content, composition, and linkage types were investigated in pear fruit cultivars and related species. Lignin content increased during early stages, then decreased toward ripening in the core and flesh of "Gold Nijisseiki" and "Alexandrine Douillard". Lignin content was highest at harvest in Chinese quince. Only trace amounts of lignin were detected in apple flesh. Lignin content was low in Japanese pear "Ohshu", "Hosui", and "Kosui" and the non-condensed lignin index was high in flesh. The lignin type was guaiacyl-syringyl (GS) in these pears and related species. The S/G ratio at harvest varied widely (0.75-2.64) and increased during early stages and remained constant toward harvest in "Gold Nijisseiki" and "Alexandrine Douillard". "Gold Nijisseiki" and "Alexandrine Douillard", were determined to be G- and S-lignin rich types, respectively. β-Aryl ether, phenylcoumaran, and resinol interunit linkage types were detected among monolignol bonds and β-Aryl ether units were the main linkages in pear.