Chemical Composition of Viscin Mucilage from Three Mistletoe Species--A comparison

The viscin of mistletoes is a unique tissue which serves toprovide strong adherence of the seed of the parasite to thehost branch. The viscin mucilage of three species, Phoradendroncalifornicum and Arceuthobium americanum (Viscaceae) and Phthirusapyrifolia (Loranthaceae), was analysed. The major componentof the mucilage of Pho. californicum and A. americanum was polysaccharidic;of this, neutral sugars comprised the largest portion, but substantialamounts of uronic acids and proteins were also present. Xyloseand arabinose were the most abundant of the neutral sugars,and analysis showed glycine to be the most abundant amino acidas well as the presence of higher-than-average amounts of histidine.In contrast, in the mucilage of Pht. pyrifolia glucose was themost abundant neutral sugar and the protein content was substantiallyhigher. Based on the differences in composition observed amongthe different species the future use of viscin components astaxonomic markers is suggested. Viscin mucilage, mistletoes, Arceuthobium americanum, Phthirusa pyrifolia, Phoradendron californicum, g.l.c., amino acid analysis