C/A值与甘薯丛枝病症状发生的关系

THE RATIO OF CYTOKININ TO AUXIN IN RELATION TO THE OCCURENCE OF SWEET POTATO WITCHES′ BROOM SYMPTOM

采用高效液相色谱（ＨＰＬＣ），对比测定了由植物类菌原体（ＭＬＯ）引起的甘薯丛枝病病株和甘薯健株中细胞分裂素和生长素含量在整个生长周期内的变化。结果显示：甘薯中细胞分裂素以玉米素为主。病株中玉米素含量一直处于较高水平，而吲哚乙酸含量仅在芽萌发时期病、健材料间存在明显差异，随着甘薯的生长，这种差异逐渐消失。结合甘薯丛枝病发病特点，讨论了植物激素Ｃ／Ａ值的改变对病状发生的作用。

The variations of cytokinin and auxin levels in the sweet potato associated with MLO were measured by using HPLC in the whole growing season. It was indicated that the cytokinin level of diseased sweet potato was much higher than that of healthy ones, and as to the auxin level, the diseased plants had drasticly lower concentration of auxin than healthy plants in the bud bursting stage. The auxin level in both healthy and diseased plants became almost the same as the sweet potato growing up. The cytokinin to auxin ratio during the growing season was calculated and its`effect on the witches′ broom symptoms was discussed.