黄连体细胞胚的干化处理

DESICCATION OF SOMATIC EMBRYOS OF COPTIS CHINENSIS

黄连(Coptis chinensis F.)体细胞胚经过4℃冰箱低温干化、23±1℃培养箱干化、4—8℃真空干燥快速干化处理后,形态上发生一系列变化:体积缩小、颜色变深、表面粗糙、易碎等。低温慢速干化处理的体细胞胚经42天贮藏后,在1/2MS+0.5mg/L6-BA+0.5mg/LIBA+0.5mg/LGA_3+3％麦芽糖培养基上的萌发率达75％以上;真空低温快速干化处理的体细胞胚萌发率为71％。干化处理后的体细胞胚应保持一定的最低含水限度,实验证明:体细胞胚萌发率为60％时,最低含水量为15％,50％时最低含水量为12％,这是体细胞胚萌发的最低含水限度。相对湿度试验表明:在相对湿度70％和23℃温度条件下,干化处理的体细胞胚保持活力的时间最长,而且萌发率最高。

Somatic embryos of Coptis chinensis F. were dehydrated with 3 different methods; viz. low temperature (4℃)refrigeration; room temperature in either a conventional oven (oven dried 23± 1℃)or a vacuum oven (vaccum dried, 4 to 8℃). During desiccation, somatic embryos decreased in size and became dark yellow and brittle. Embryos were tested for their germination potential by placing them on 1/2 strength MS medium supplemented with 6-BA(0.5mg/L),GA(0.5mg/L), IBA(0.5mg/L)and 3%maltose. No germination of embryo was observed if the water content of the embryo was less than 12.5%. Somatic embryos germinated best (86%) when the relative hu- midity (RH) was 70%to 90% and germination ceased at 30% RH. After 42 days of storage, a germination rate of 75% of the non-encapsulated somatic embryos were obtained by slow desicca- tion at 4℃ a refrigeration, while the germination rate of somatic embryos desiccated at 23±1℃ was zero. On the other hand,germination rates of 82.5% and 30.8% of the encapsulated and non-encapsulated somatic embryos desiccated at 4℃ were gained after 42 days of storage respec- tively. These results indicated that the encapsulated somatic embryos have higher desiccation toler- ance and longer storage time than the non-encapsulated somatic embryos. The relationship be- tween water loss velocity and the vigor of desiccated somatic embryos were also discussed.