Immunohistochernical localization of IAA in graft union of explanted internode grafting

The dynamic changes of IAA in graft union of explanted internode autografting of Cucumber (Cucumis sativus Linn.) have been investigated using the immunohistochemical localization technique. It is shown that the efficiency of IAA fixation using lyophilization-gas fixation is higher than that using liquid chemical fixation. In contrast to few silver particles and no significant changes during the development of graft union cultured in hormone-free medium, more silver particles in graft union and significant changes of IAA related to graft union development have been found when graft union was cultured in medium supplemented with appropriate hormones. The fixation procedure of plant hormones and the roles of IAA in graft union are discussed.