Abstract:

Phenolic glycosides were main defense chemicals for Salicaceae. The variation of phenolic glycosides in leaves, height and diameter for all individuals of a whole Populus deltoides back cross population was studied. The result indicated that salicin, salicortin, deltoidin, height and diameter all followed normal distribution, so these traits displayed in quantitative fashion. The concentration of total phenolic glycosides showed negative correlation with height and the correlation coefficient was r=-0 304. Tremulacin was discovered for the first time in P.deltoides. The plant defenses were at the cost of growth only in some degree. The individuals with high phenolic glycosides concentration and higher height could be selected from the population. Mechanical wounding on the stem bark induced significant increases in concentrations of phenolic glycosides, especially for salicortin, and the increase was 78.9% within 48h. The increase of phenolic glycosides under wounding was the main mechanism for poplar resistance to animal, insects as well as pathogenic bacteria.

Key words: Populus deltoides, Back-cross population, Phenolic glycosides, Variation