Freezing sections and immunogold_silver staining were employed to the study on the localization of IAA in petioles of Syringa oblata Lind. At different stages of leaf abscission, the distribution patterns of the silver particles varied in different tissues. In the earlier period of abscission, there were many silver particles in the proximal and distal tissues, but only a few in the abscission zone. The high density of silver particles was found in the phloem of the petiole. The number of silver particles in the abscission zone increase immediately after the protective layer was formed and began to decrease along with the development of the abscission zone. The density of the silver particles became very low when abscission was completed. The formation of protective layer may be the demarcation line of the Stage Ⅰ and Stage Ⅱ during the development of the abscission zone.
通过光镜观察发现:在离体条件下,嫁接后3 d 在自体嫁接假酸浆/假酸浆愈伤组织细胞中分化出管状分子和筛分子;贯通接穗和砧木的维管组织桥在嫁接后5 d 形成,整个嫁接发育过程约在嫁接后15 d 完成。用^(14)C 标记的蔗糖检验了同化物自接穗向砧木的输导,发现在嫁接后5 d 自接穗进入砧木的输导量有一个飞跃,揭示韧皮部桥在此期产生对同化物的输导能力。
