木薯品种新选048体细胞胚发生及植株再生初步研究

Preliminary research on somatic embryogenesis and plantlet regeneration of cassava(cv. Xinxuan 048)

【目的】初步探讨木薯品种新选048体细胞胚发生及植株再生的影响因素，为木薯遗传转化和品种改良奠定基础。【方法】以不同外植体（未完全张开叶、侧芽茎尖、幼嫩叶柄及完全张开叶的顶部、基部、叶缘、中部和全叶）为材料，对木薯体细胞胚发生和愈伤组织生长进行观察，并探讨6．BA（0．01、0．05、0．10、0．50、1．00mg/L）对体细胞胚植株再生的影响。【结果】不同木薯外植体均能诱导愈伤组织，愈伤组织诱导率为48．30％～100．00％，但产生的愈伤组织生长状况表现不同。在MS＋12．0mg／L毒莠定（picloram）＋20．0g／L蔗糖＋6．5g／L琼脂培养基中，侧芽茎尖诱导获得的初生体细胞胚诱导率最高，达22．22％，平均产胚量为5．85个；而叶柄、未完全张开叶片或全张开叶片不同部位均不利于诱导体细胞胚，其诱导率极低，为0～5．00％。随着MS培养基中6．BA用量的增加，体细胞胚的成熟率不断增加（81．3％～100．0％），而在MS＋0．01mg，L6-BA＋0．02mg/L NAA培养基中的植株再生率呈先升高后下降的变化趋势；当6．BA用量为0．10mg/L时，植株再生率最高，为21．8％，且子叶生长正常。在1／3MS＋0．02mg/L NAA生根培养基中，再生植株均能诱导生根；在沙与表土混合基质中生根植株均能正常生长。【结论】新选048可以通过体细胞胚发生途径获得再生植株，但其发生率和再生率较低。

【Objective 】Influence factors of somatic embryogenesis and plantlet regeneration for cassava Xinxuan 048 were investigated preliminarily in order to lay the foundation for genetic transformation and variety improvement of cas-sava. 【 Method 】 Taking different explants viz. fully expanded leaf, axillary buds apex, young petiole, and the top,base, margin, middle and whole of fully expanded leaf as experimental materials, the somatic embryogenesis and callus of cassava were induced, and the effects of 6-BA（0.01, 0.05, 0.10, 0.50 and 1.00 mg/L） on somatic embryo plantlet regeneration were investigated. 【 Result 】 All different explants could induce callus with 48.30 %-100.00 % of induction rate, while the induced callus presented different growing status. In MS medium adding 12 mg/L picloram,20.0 g/L sucrose, and 6.5 g/L agar, the axillary buds could induce primary somatic embryo, its induction rate（22.22%） was the highest, and the average of generating embryo was 5.85. The young petiole, unfully expanded leaf or fully expanded leaf and its different parts were unconducive to the induction of somatic embryo being very low induction rate（0-5.00%）. With the increasing of 6-BA dosage in MS medium, the mature rate of somatic embryo was continuously increasing（81.3%-100.0%）. While in MS medium supplemented with 0.01 mg/L 6-BA and 0.02 mg/L NAA, the plantlet regeneration rate of matured somatic embryo displayed the changing trend of increasing firstly and decreasing later, and its reached the highest（21.8%） as adding 0.10 mg/L 6-BA in MS medium, the cotyledon also grew normally. All induced plantlet regeneration could generate roots in rooting medium of 1/3MS ＋0.02 mg/L NAA,and also grew normally in mixed medium of sand and topsoil. 【Conclusion 】The cassava variety Xinxuan 048 could obtain regenerated plantlet through somatic embryogenesis, however its embryogenesis rate and regeneration rate are lower,and its related influence factors should be made further study.