Effect of IBA and NAA on Trifolium ambiguum seed germination and growth of creeping-root

In order to study the general and physiological effects of exogenous hormones on the seed germination and root and shoot growth of Caucasian clover (Trifolium ambiguum), two hormones, indole butyric acid (IBA) and 1-naphthaleneacetic acid (NAA), were used to treat the seeds and roots of Caucasian clover plants. The following results were obtained 1) NAA soaking treatment effectively enhanced the germination of Caucasian clover seeds, with a concentration of 10 mg·L^–1 having the most significant effect (P < 0.05). The germination rate increased from 37% to 55%, and the germination power increased from 38% to 45%. IBA and NAA soaking also increased the seed vigor index to a level that was more than double that of the control. 2) Both IBA and NAA treatment accelerated the growth of the aerial parts of root buds, with the effect of IBA being more pronounced. 3) Soaking in 2 500 mg·L^–1 and 3 000 mg·L^–1 NAA increased the accumulation of soluble sugar and starch in plants. In summary, treatment with NAA at a concentration of 10 mg·L^–1 is optimal for promoting the germination of Caucasian clover seeds, 2 000 mg·L^–1 IBA is the optimal concentration for promoting the rapid growth of the aerial parts of roots, and high concentrations of NAA are more effective for promoting the accumulation of non-structural carbohydrates in the root pods of Caucasian clover plants.