The Cryopreservation of Cos Lettuce Callus by Using Liquid Nitrogen

The cryopreservation of cos lettuce (CL) callus by using liquid nitrogen (LN) was further study from the previous research on callus induction and micropropagation of CL. That was studied on seed culture and micropropagation of CL and its embryogenic growth. The result was shown that the most suitable Murashing and Skoog (MS) medium concentration was in 1/2 MS. The medium supplemented with 0.1 mg/l of 6-benzylaminopurine (BAP) and 0.5 mg/l of 2,4-dichlorophenoxyacetic acid (2,4-D) gave the best for leaf inducing callus. Then it was brought to study the effects of cryoprotectants with the different percentages of dimethyl sulfoxide (DMSO). The cryopreserved callus by using LN was brought to subculture for the best inducing shoot in MS medium supplemented with 4.0 mg/l of BAP. The results that the best cryoprotectant at the percentage of DMSO at 7.5 gave the highest average number of shoots at 2.1 shoots/culture and the average shoot length was 1.56 cm. The MS medium supplemented with 0.5 mg/l of 1-Naphthaleneacetic acid was the best inducing root. The results that the best cryoprotectant at the percentage of DMSO at 7.5 gave the highest average number of roots at 9.7 roots/culture and the average root length was 1.59 cm. Plant differentiation from callus of CL leaf was transferred to grow in soil and had the same morphology as normal CL that was grown in soil by seed germination.

CL will be the host of Japanese encephalitis virus expression for the developmental swine vaccine.