摘要
小麦（Ｔｒｉｔｉｃｕｍ ａｅｓｔｉｖｕｍ Ｌ．）与玉米（Ｚｅａ ｍ ａｙｓＬ．）及鸭茅状摩擦禾（Ｔｒｉｐｓａｃｕｍ ｄａｃｔｙｌｏｉｄｅｓ Ｌ．）杂交后，由于胚乳组织不能正常形成，从而导致胚很难在母本小麦植株上发育至成熟。通过对杂交后的胚不同发育时期的子房内源ＩＡＡ、玉米素（Ｚ）及玉米素核苷（ＺＲ）和ＡＢＡ 的ＥＬＩＳＡ 分析，发现远缘杂交后的胚发育过程中子房内源ＩＡＡ 的浓度明显低于正常发育的子房；而且Ｚ＋ ＺＲ 和ＡＢＡ 的含量的动态变化也和正常自交发育的子房不同，然而ＩＡＡ／（Ｚ＋ ＺＲ）和ＩＡＡ／ＡＢＡ 的比率变化在远缘杂交与正常自交的子房之间有某些相似趋势。ＩＡＡ、Ｚ＋ ＺＲ和ＡＢＡ 与这３ 种激素之和的比率变化在上述两类子房中也有相似之处。可以推断，植物胚胎的正常发育需要多种激素的动态平衡及某一时期某一激素的主导性作用。远缘杂交后的胚之所以不能够顺利发育至成熟，除了缺乏胚乳组织的营养保护之外。
The embryos derived from intergeneric crosses between Triticum aestivum L.(2n=6x=42) and Zea mays L.(2n=20), Tripsacum dactyloides L.(2n=4x=72), as results of the elimination of paternal chromosome and having no endosperm as normal,are difficult to develop completely in vivo.Hormonal analyses in such intergeneric hybridized ovaries have been carried out including indole 3 acetic acid (IAA),zeatin (Z) and zeatin riboside (ZR),and abscisic acid (ABA) during different developmental stages of embryo.The results indicated that IAA level in hybridized ovaries was much lower than that in self pollinated ovaries .Moreover,the active changes of Z+ZR and ABA contents were also different between the above two types of ovary.Nevertheless,the ratio changes of IAA/(Z+ZR) and IAA/ABA were similar between the two types of ovary,the same was true in the ratio changs of IAA,Z+ZR, and ABA to the sum of these three types of endogenous hormones.But the three types of ratios in hybridized ovaries were varied far more greater than those in self pollinated ones.It suggested the importance to maintain dynamic equilibrium of multiple hormones and sequential regulation during the embryo development.That the distantly hybridized embryos failed to mature successfully was probably associated with a deviation from the normal changes of endogenous hormones levels and balance system of multiple hormones in addition to the lack of endosperm nourishment.
基金
中国科学院重大项目
