Abstract: In order to explore the role of endogenous hormones in bulb development of freesia, Freesia hybrida ‘SN Huangjin’ was used as material to investigate the bulblet formation and development process, and study the dynamic changing rule of major endogenous hormones during bulb development. The results showed that there were 4 stages involved in the bulblet formation and development process of freesia, including the initial bulblet formation stage during 50~90 d after planting (DAP), early thickening stage (90~110 DAP), fast thickening stage (110~140 DAP), and maturing stage (140~190 DAP). Gibberellin (GA3) content showed a gradually increasing tendency at initial development stage, and reached to a peak at the early bulblet thickening stage (100 DAP), then dropped rapidly to a lowest GA3 level at middle bulblet thickening stage (120 DAP), increasing again at early bulblet maturing stage (150 DAP) reaching to the highest, followed by a gradual decline once again. The  level of abscisic acid (ABA) showed a decreasing trend. The peak of ABA level presented at initial new bulblet formation stage and reduced to the lowest when flower bud appeared, followed by a short increase, then dropped again. The changing trend of indoleacetic acid (IAA) was opposite to ABA, showing an overall increasing tendency. IAA maintained a stable low level during bulblet formation stage. Two peaks of IAA were observed during medium bulb thickening stage (120 DAP), and bulb maturing stage (as 2.5 times of the initial value). At late bulb thickening stage, IAA declined to a low value (140 DAP). A multi-peak ‘M-like’ tendency of zeatin riboside (ZR) content was observed. The correlation analysis revealed that there was a significant correlation between bulb development and the other hormone indexes, except ZR, indicating the levels of endogenous hormones GA3, IAA, ABA and their dynamic equilibrium all had close relation with the bulb development of Freesia hybrida. The results provided guidance for targeted regulation on  bulb development and production of freesia.

Key words: Freesia hybrida, bulb development, endogenous hormones, correlation analysis

摘要： 为了探讨内源激素在香雪兰球茎发育中的作用，以香雪兰品种‘上农黄金’为材料，对其球茎形成过程进行观测，并对其球茎形成过程主要内源激素的动态变化规律进行研究。结果显示，香雪兰球茎发育主要经历4个时期，分别为开始形成期（50~90 DAP）、增长初期（90~110 DAP）、快速膨大期（110~140 DAP）、成熟期（140~190 DAP）。赤霉素（gibberellin，GA）含量在发育初期呈现逐渐增长的趋势，球茎膨大前期（100 DAP）达到高峰，后迅速下降，至球茎膨大中期（120 DAP）降至低点后再次大幅上升，至球茎成熟初期（150 DAP）达到最高值，随后再次逐步下降；脱落酸（abscisic acid，ABA）水平整体呈现下降趋势，最高值出现在新球形成初期，现蕾期降到最低值后回升，然后再次下降；吲哚乙酸（indoleacetic acid，IAA）的变化趋势与ABA相反，整体呈上升趋势，球茎形成期IAA波动不大且维持较低水平，球茎膨大中期（120 DAP）和成熟期（为初始值的2.5倍）达到两个峰值，膨大后期（140 DAP）达到低值；玉米素核苷（zeatin riboside, ZR）含量变化则表现为多峰值“M”型趋势。相关分析表明，除ZR与发育进程无相关性外，其他激素指标均显著相关，说明内源激素GA3、IAA、ABA水平以及激素之间的动态平衡均与香雪兰球茎发育进程密切相关。结果为针对性调节香雪兰种球发育与生产提供理论指导。

关键词: 香雪兰, 球茎发育, 内源激素, 相关分析