籼稻体细胞胚胎发生及器官发生的比较研究

SOME REGULATIONS OF SOMATIC EMBRYOGENESIS AND ORGANOGENESIS IN INDICA RICE

在以幼穗为外植体的诱导培养及其以后的继代培养与悬浮培养中，从以下几个方面对３个籼稻品种的体细胞胚胎发生（Ｅ）与器官发生（Ｏ）的特点作了比较研究．在形态上，（Ｅ）型愈伤由胚状体组成，具有层次分明的结构．胚状体由胚芽、胚根及盾片组成．而（Ｏ）型的愈伤没有上述组织的分化．没有层次结构。植株再生能力方面．与器官发生途径相比较，体细胞胚胎发生途径之分化频率高．保持再生能力持续的时间长．从每个愈伤上发生的再生植株数多．（Ｏ）型愈伤结构较疏松．建立结构良好的、细胞团较小的悬浮细胞系容易．但这种细胞系在液体条件下几乎丧失再生能力．而（Ｅ）型愈伤则相反．建立好的悬浮细胞系．需要时间较长．但在悬浮条件下仍然具有再生植株的能力。在诱导条件方面．２，４－Ｄ及激动素分别作用时可诱导器官发生，共同作用时则诱导体细胞胚胎发生．再生植株途径方面，由于水稻同时具有器官发生及体细胞胚胎发生的特点．无论在诱导条件上还是在（Ｅ）与（Ｏ）本身的特点上均不似萝卜或烟草那样专一．并且有（Ｅ）与（Ｏ）相互转化和混合发生的复杂情况．

Different concentrations (0, 0. 2, 0. 5, 1. 0 and 2. 0 mg/L) of 2, 4-D and kinetin (25combinations of them) in the media were studied for inducing embryoSenesis and orpoogenesisfrom young Panicle of rice. When the medium contained both 2, 4-D and kinetin, the plantletswere regenerated via somatic embryogenesis. When the medium contained 2, 4-D only or kinetinonly, plantlets were regenerated via organogenesis but the former was adventitious bud fromorganogenic callus and the later, from the explant directly. In subCulture condition, the mediumcontaining both 2, 4-band kinetin could maintain the culture keeping a high flequency for embryogenesis and the medium with 2, 4--D only, for organogenesis. Frequency of plant regeneration, duration of keeping the capacity for plant regeneration and number of regenerated plant Percallus in embryogenesis wele hiSher, longer and more than those in organogenesis respectively.Embryogenic callus consisted of embryoids, which was made up coleoptile, coleorhiza and scutellum, POSSessed the structure of distinct and POlylayers. The orgnnogenic callus did not aness thisorganletS and friable in structure.