Abstract:

The purpose of this paper was to research the mobile direction and approach of exogenous JA as well as regularity of distribution in Hevea brasiliensis. The shoots of clone CATAS7-33-97 were used as the experimental material, which had been treated respectively by applying exogenous 3H-JA, mechanical wounding and exogenous 3H-JA. By using radioisotope technique, the radioactivity in the different sites of shoot was studied. The results showed that the most radioactivity of 3H-JA sustained in the bark of treated site within one hour , and mechanical wounding hindered the entrance of exogenous JA meanwhile held back the entered JA to the around regions. The radioactivity in the sample of extending new shoot was obviously lower than the radioactivity of the treated site bark, but significantly higher than the other four sites. Exogenous JA could be transported upwards and downwards through phloem mainly and xylem secondary. Thus it could be seen that exogenous JA was rapidly transported to the regions around wounded site after entrance, and the vigorous tender site accumulated JA easily. Moreover, mechanical wounding affected obviously the distribution of JA in the shoot.