郁金香更新鳞茎发育的碳同化物积累与内源激素变化研究

Distribution of ^(14)C-photosynthate and Changes of Endogenous Phytohormone in the Bulb Development of Tulip (Tulipa gesneriana L.)

应用扫描电镜和14C同位素标记技术,并结合内源激素测定,考察郁金香更新鳞茎膨大发育与碳同化物积累、分配的关系。结果表明:在鳞片细胞内观察到明显的淀粉颗粒,并随鳞茎的发育进程充满整个细胞腔。在盛花期前,14C同化物主要分配到地上部;进入叶枯期后14C同化物以向地下部运输为主,分配比例达66.01%,其中更新鳞茎中14C同化物的分配占60.85%,这时14C库活性表现为:鳞茎>叶片>花茎>根系。在郁金香更新鳞茎发育进程中,叶片中GA、IAA含量呈下降趋势,ABA含量则不断增高并在盛花期出现峰值,达65.86ng·g-1FM。比较不同生育期的GA3/ABA比值,在发叶期的叶片和盛花期的更新鳞茎中均出现高比值,表明内源激素的平衡可能是郁金香更新鳞茎发生和发育的调节因子。

Using the scanning electron microscope(SEM)and  14 C-labelling techniques, the accumulation and distribution of  14 C-photosynthates in bulb development of tulip(Tulipa gesneriana L.‘Golden Apeldoorn’)were studied. The starch granules,which were gathering and stuffing in the cell of scales were observed during bulb development. Distribution of  14 C-photosynthates among plant organs was different in various growth stages. At the growth stages before blooming,  14 C-photosynthates were mainly allocated into leaves and shoot. At the stage of leaf withering,about 66.01% of the total  14 C-photosynthates were transported to bulbs and roots, which indicated that the regenerated bulbs became the main‘sink’of  14 C-photosynthates, particularly in daughter bulbs distributed 60.85%. Sink activity of  14 C-photosynthates at stage of leaf withering decreased as followed: bulbs>leaves>shoots>roots. The contents of endogenous GA and IAA in leaves decreased continuously after sprouting. Meanwhile, the ABA content in leaves increased dramatically with a maximum value of 65.86 ng·g -1 FM at the stage of blooming. Higher GA_3/ABA ratios in the leaves at stage of frondescence and in the daughter bulbs at the stage of blooming were observed, which indicated that the balance of endogenous phytohormones may be an important factor for the regulation of leaf senescence and the initiation of daughter bulb in tulip.