Abstract: The experiment results of the cuttage propagation of larix olgensis have shown that shoot cuttings root better than hardwood cuttings, and seed-tree age is an important factor which affect the rooting. Seed-tree of two, the rate of rooting got more than 95%. On the basis of these experiments, the paper determined the contents of endogenous plant hormones levels in hardwood and shoot cuttings. It is shown that the contents of IAA、CTKs in shoot cuttings are higher than that in hardwood cuttings, and reduce with raising the age of seed-tree; on the other hand, the content of ABA in shoot cuttings is lower than that in hardwood cuttings, and increase with raising the age of seed-tree. The results demonstrate that the contents of IAA、ABA are closely related to rooting of Larix olgensis, IAA promotes rooting and ABA inhibits rooting. The experiments point out that IAA:ABA ratio maybe taken for a standard to express the capability of rooting of larix olgensis.

Key words: Larix olgensis, endogenous plant hormones, rooting