影响籼稻体细胞胚胎发生几个因素的研究

以 IR36、IR50、IR52及 IR54等品种的幼穗及成熟种子为材料,研究了蔗糖浓度、2,4-D、NAA、激动素及脱落酸对体细胞胚胎发生、结构的保持及植株分化的影响。6%蔗糖有利于胚性愈伤组织的诱导;3%的有利于胚性结构的保持及植株分化。当培养基中不含2,4-D,而含激动素与 NAA 时,幼穗直接出芽;当不含激动素而含2,4-D与 NAA 时,外植体产生非胚性愈伤组织;当不含 NAA 而含2,4-D 与激动素时,外植体产生胚性愈伤组织。认为,2,4-D与激动素是籼稻体细胞胚胎发生的基本因素,而 NAA 的作用是不明显的。不同外植体(幼穗与成熟种子)的体细胞胚胎发生,对2,4-D 与激动素的反应略有不同,幼穗更为敏感。在继代培养基中,加入低浓度的脱落酸有利于胚性结构的保持。随着继代世代的延续,分化培养中愈伤组织所表现出的绿色生长点状物不能发育成完整植株。

THE STUDY OF SOME FACTORS AFFECTING SOMATIC EMBRYOGENESIS IN IR LINES OF RICE

Some factors which affect somatic embryogenesis,maintaining embryogenic callus and plant regeneration in Indica rice were investigated.It was found that 6% sucrose was favora- ble for inducing embryogenic callus (E-callus) and 3% sucrose was favorable for maintaining both E-callus and plant regeneration.Rice explant (especially young panicle) was very sen- sirive in this research.The explant (especially young panicle) formed neither E-callus nor non-embryogenic callus (NE-callus) but developed bud directly when the medium was 2,4-D free but with kinetin and NAA added.The explant formed NE-callus with no embryogenesis emerged when only 2,4-D and NAA was added.E-callus emerged from the explants in the me- dium with NAA free and when 2,4-D and kinetin was added.It was concluded that 2,4-D and kinetin were the basic factors for somatic embryogenesis in Indica rice and that the effect of NAA was not obvious.Rice explant (especially young panicle) was very sensitive to 2,4-D and kinetin.Low concentration of these two hormones (0.2 mg/l) was favorable for the develo- pment of the explants.The suitable concentration for 2,4-D and kinetin was 1 mg/1 for somatic embryogenesis in Indica rice.Lower concentration of ABA (0.136 mg/l) in the subculture me- dium was favorable for E-callus maintain in subculture passage.The green meristemoid which could not develop further to plantlet in regeneration culture was found to be a major obstacle in E-callus regeneration of subculture passage.The solution of this problem will increase to a great extent the plant regeneration of E-callus in Indica rice.