枣花芽分化过程中营养物质和内源激素含量及抗氧化酶活性变化研究

以新疆主栽品种灰枣和骏枣的花芽为材料,测定不同分化时期花芽的可溶性糖、还原糖、淀粉、可溶性蛋白含量,SOD、POD、PPO、CAT活性以及内源GA₃、IAA、ABA、ZT水平的变化,并分析它们与花芽分化的关系,为枣花芽分化调控提供理论参考。结果表明:(1)灰枣和骏枣花芽可溶性糖、还原糖和淀粉含量在花芽分化过程的变化趋势基本相似,于花原基分化期至雌蕊分化期先降低后升高,至雌蕊分化期到达峰值;而可溶性蛋白质含量变化趋势相反,在花原基分化期至雌蕊分化期先上升再降低。(2)在整个花芽分化过程中,其POD、PPO、CAT活性变化趋势基本一致,从花芽开始分化后逐步降低,最低点出现在雌蕊分化期;两个品种花芽SOD活性在花原基分化期至分化初期时显著上升,之后SOD活性在灰枣中不断降低,而在骏枣中则显著上升。(3)两品种花芽IAA、GA₃、ZT含量在分化过程中的变化规律基本相似,它们均在萼片分化期前呈下降趋势,之后GA₃、ZT含量及灰枣中IAA含量逐渐上升,而骏枣IAA含量在萼片分化期至花瓣分化期呈先显著上升后下降再上升;灰枣ABA含量在花原基分化期至萼片分化期显著上升,而同期骏枣则显著降低,随着分化进程的推进,灰枣ABA含量在萼片分化期后逐步降低,而骏枣则逐步上升并在雌蕊分化期达到峰值。(4)花芽分化开始后,骏枣ABA/IAA、ZT/IAA、GA₃/IAA比值快速上升,但GA₃/ABA、ZT/ABA的比值呈下降趋势;灰枣ZT/IAA、GA₃/IAA在花原基分化期至萼片分化期显著上升后降低,分化结束后低于花原基分化期。研究认为,枣花芽开始分化后会消耗大量的营养物质,导致花芽的可溶性糖、淀粉和还原糖含量降低,且整个分化过程中淀粉含量始终高于可溶性糖和还原糖含量;两个品种枣花芽分化过程中POD、CAT、PPO活性下降以及骏枣花芽分化过程中SOD活性的上升均有利于枣营养生长向生殖生长的转变,且枣花芽分化过程中低水平的GA₃和IAA、中等水平的ABA、较高水平的ZT,以及较高的ZT/IAA、ABA/IAA和GA₃/IAA有利于枣花芽分化和花芽形成。

Changes of Nutrients, Endogenous Hormones and Antioxidant Enzymes Activities during Flower Bud Differentiation Process of Ziziphus jujuba

Using the flower buds of Huizao and Junzao as materials, we determined the changes of soluble sugar, reducing sugar, starch, soluble protein contents, SOD, POD, PPO, CAT activities and endogenous GA₃, IAA, ABA, ZT contents in flower buds at different differentiation stages, and discussed their relations with flower bud differentiation, so as to provide theoretical reference for the regulation of flower bud differentiation of Zizyphus jujuba. The results showed that: (1) the changes of soluble sugar, reducing sugar and starch contents of Huizao and Junzao during flower bud differentiation were basically similar. The contents of soluble sugar, reducing sugar and starch first decreased and then increased from flower primordium differentiation stage to pistil differentiation stage, and reached the peak at pistil differentiation stage; On the contrary, the contents of protein and carbohydrate first increased and then decreased from flower primordium differentiation stage to pistil differentiation stage. (2) With the beginning of flower bud differentiation, the activities of POD, PPO and CAT decreased gradually, and the lowest point appeared in pistil differentiation stage; the activity of SOD increased significantly from primordium differentiation stage to early differentiation stage, and then the activity of SOD decreased in Huizao, while increased in Junzao significantly. (3) The changes of IAA, GA₃, and ZT contents during flower bud differentiation are basically similar. IAA, GA₃, and ZT show a downward trend before the sepal differentiation stage, and then the contents of GA₃, ZT and content of IAA in Huizao increased gradually, while the content of IAA in Junzao first increased significantly, then decreased and then increased from sepal differentiation stage to petals differentiation stage; the content of ABA increased significantly from primordium differentiation to sepal differentiation, but decreased significantly in Junzao. With the advance of differentiation, ABA content of Huizao decreased gradually after sepal differentiation, while increased gradually in Junzao and reached the peak at pistil differentiation. (4) With the beginning of flower bud differentiation, the ratios of ABA/IAA, ZT/IAA and GA₃/IAA increased rapidly, but the ratios of GA₃/ABA and ZT/ABA decreased; The ratios of ZT/IAA and GA₃/IAA were significantly increased and then decreased from primordial differentiation stage to sepal differentiation stage. After differentiation, the ratios of ZT/IAA and GA₃/IAA were lower than those at primordial differentiation stage. The results suggested that after the flower buds of jujube start to differentiate, they consume a lot of nutrients, the soluble sugar, starch and reducing sugar contents of the flower buds are reduced, and the starch content is always higher than the soluble sugar and reducing sugar during the whole differentiation process. The decrease of POD, CAT, PPO activities during the flower bud differentiation process of the two varieties, and the increase of SOD activity during the flower bud differentiation process of Junzao, are conducive to the transition from vegetative growth to reproductive growth; In the process of jujube flower bud differentiation, low levels of GA₃ and IAA, medium level of ABA, higher level of ZT and high ratios of ZT/IAA, ABA/IAA and GA₃/IAA are beneficial to the differentiation and formation of jujube flower buds.