牛角瓜离体快繁技术

该文选用牛角瓜茎段为外植体,通过组织培养方法探索牛角瓜组织培养和种苗快繁技术。结果表明:最佳外植体表面消毒方法是以0.1%HgCl_2处理7 min,外植体存活率为32.3%;初代培养基为MS+蔗糖30 g·L~(-1)+琼脂3.5 g·L~(-1),培养20 d后形成3～4 cm高的再生芽。增殖培养前期筛选的较为适宜的增殖培养基为MS+6-BA 1.5 mg·L~(-1)+NAA 0.05 mg·L~(-1)+蔗糖30 g·L~(-1)+琼脂3.5 g·L~(-1),增殖系数4.6。但在后续的培养过程中发现,牛角瓜组培苗易玻璃化,且随着世代更迭,玻璃化程度加重,到了第四代几乎全部玻璃化。因此在上述增殖培养的基础上,以AgNO_3作为玻璃化抑制剂,筛选出最终的增殖培养基为MS+6-BA1.5 mg·L~(-1)+NAA 0.05 mg·L~(-1)+AgNO_31.0 g·L~(-1)+蔗糖30 g·L~(-1)+琼脂3.5 g·L~(-1)。用此增殖培养基,培养25 d,苗高5～8 cm,增殖系数5.8,玻璃化率低于10%,且连续培养多代,玻璃化率维持在10%以下。生根壮苗培养基为1/2MS+NAA 1.0 mg·L~(-1)+蔗糖20 g·L~(-1)+琼脂3.6 g·L~(-1),培养14 d,生根率98%;将生根苗移栽于70%遮阴度的大棚中,30 d后,苗高20 cm左右,成活率85%。利用该方法可对牛角瓜优良种苗进行规模化生产。

Rapid propagation technique of Calotropis gigantea in vitro

Tissue culture and rapid propagation technique of Calotropis gigantea was studied by using stem segments as explants in this paper. The results showed that the optimal sterilization method of explants was to treat 7 min with 0.1% HgCl₂, and the survival rate of explants was 32.3%. The suitable primary induction medium was MS+ sucrose 30 g·L^-1+ ager 3.5 g·L^-1. And after 20 d culture, 3-4 cm high regenerative buds were formed. Pre-multiplication culture test showed that MS+ 6-BA 1.5 mg·L^-1+ NAA 0.05 mg·L^-1+ sucrose 30 g·L^-1+ ager 3.5 g·L^-1 was a suitable multiplication medium, and proliferation coefficient was 4.6. However, during the subsequent culture process, the seedlings were easy to vitrify by using this method. With the change of generation, the vitrification rate increased, and it nearly reached 100% on the fourth generation. Therefore, inhibition of vitrification was the key to succeed. Based on the above multiplication culture treatment, with AgNO₃ as a vitrification inhibitor, the suitable multiplication culture medium of MS+6-BA 1.5 mg·L^-1+ NAA 0.05 mg·L^-1+ AgNO₃ 1.0 g·L^-1+ sucrose 30 g·L^-1+ ager 3.5 g·L^-1 was verified. With this method, 25 d later, seedling height was 5-8 cm, and proliferation coefficient was higher than 5.8 and vitrification rate of multiple shoots was lower than 10%. The optimal medium for rooting was 1/2MS+ NAA 1.0 mg·L^-1+ sucrose 20 g·L^-1 + ager 3.6 g·L^-1, and 14 d later, the rooting rate was 98%. The rooting seedlings were transplanted in the 70% shading greenhouse. And 30 d later, they were about 20 cm high, with 85% survival rate. This method can be used for the large-scale production of excellent clonal seedlings of Calotropis gigantea.