Preliminary Studies On In-vitro Conversation Of Dimocarpus Longan Lour. Germplasm In Fujian

In this experiment, the embryogenic calli were induced from immature embryos for the conservation materials of longan germplasm including the main and longan local cultivars and special trees or lines in Fujian. Several minimal growth methods were applied to prolonging the subculture cycle of the embryogenic calli(EC) and some physiological changes of longan embryogenic calli were investigated during subculture, and then the changes of the chromosome number and RAPDs were tested for detecting the genetic stability. The main results showed as follows:1. Induction of 51 accessions of longan friable embryogenic calli(FEC) from immature embryos. The obtained results showed that the MS medium containing 2.0 mg·L^-12,4-D was suitable for all kinds of immature embryos from different cultivars, with the average inducing rate of 48.3%. The main reason for the difference of inducing rates was the diameter of immature embryos(the degree of physiological maturation of the embryos). This immature embryos with the diameter of 2-4 mm were the best for inducing EC, from which FEC could be directly obtained on the MS with 2.0 mg·L^-12,4-D; and the other immature embryos were prone to turn browning on the MS medium with 2.0 mg.L"'2,4-D, and the browning could be alleviated via shortly(about 1 week) culturing on the medium supplemented with 0.2% AC.2. The minimal growth conservation of longan EC and the investigation of physiological changes including the activity of TTC and SOD and the content of MDA during subculture. The results showed that there were quite different in senescence among embryogenic calli, and some EC were prone to senescence such as "Youtangben" and "Shieryuelongyan", and some seemed to be resistant to senescence such as "Dongbi" and "Wulongling"; The subculture cycle of longan EC prolonged from 20 d to 40 d on the MS medium with 1.0 mg·L^-12,4-D and 2% mannitol, and further from 40 d to 60 d at 16 ℃. During subculture the investigation of the changes of the activity of TTC and SOD activity and the contents of MDA in longan...