| Leymus chinensis is an important grass of the Gramineae family. It widely grows in the natural grassland of Northern China. Its value of nutrition is very high and it can grow very well in the saline-alkaline field. There is important economical value. Leymus chinensis whose adaptability is strong can stand coldness, drought, wet, trample, poor soil conditions and some saline-alkaline stress. But the grassland has been excessively exploited, which makes the grassland degradative. In order to protect the resource of Leymus chinensis and improve the productivity of grassland, it is necessary to seek the new technologies and approaches of melioration. It is an urgent problem to solve how to utilize large area of saline-alkaline field.Leymus chinensis is an ideal grass to build meadow and control the saline-alkaline field. Although Leymus chinensis can endure saline-alkaline stress, it can't affect melioration of the saline-alkaline field. According to law of reproductive and characteristic of biology, we can plant and approve Leymus chinensis. We should utilize the capacity of bearing saline-alkaline and breed some new kinds of species enduring saline-alkaline stress, it is basic route to control saline-alkaline.It is extremely slow to select and breed species which bear salt by traditional methods. With the development of molecular biology, we can use technology of gene engineering to improve endurance of saline-alkaline. The most efficient and ultimate method is to utilize saline-alkaline resisted gene in order to breed high-resisted species.This paper studied the law and peculiarity of Leymus chinensis and optimized the tissue culture system. The high efficient regeneration system firstly is founded, which makes it a good foundation to breed the new species which good characteristic and ability to endure saline-alkaline stress. The tissue culture system of mature embryos of Leymus chinensis was optimized. The sensitive characteristic on saline-alkaline of Leymus chinensis calli was studied; first assure Leymus chinensis calli enduring on the saline-alkaline medium. We hope to get saline-endured mutation by selecting with the high-concentration saline-alkaline medium. Studies have been done on genetic transformation and ways of saline-endurance. BADH gene was transferred into the regenerated system of Leymus chinensis by gene-gun and then examined. The results of study were acquired as follows:1. The tissue culture system of mature embryos on Leymus chinensis was optimized.(1) Acquisition of Leymus chinensis calliMature embryo (seed) and root-stock is the ideal part to induce calli. It can be effectively kill germ by using 70% alcohol for 5 minutes and then in 1g/L Hgcl2 for 15 minutes. There is the characteristic of sleeping for Leymus chinensis seed. Low temperature contributed to germination. For some days accumulation germination rate increased. Temperature varieties contributed greatly to germination. 48 hours is the best time for germination by using 100ppm GA3, and germination rate can get to 16%.In order to improve the embryogenic calli induction rate of mature embryos, different media with different hormones were used in the embryogenic calli induction. The experiment results indicated that the selection of suitable medium is the basis to improve the induction rate and the quantity of embryogenic calli inducing from mature embryos. The hormone treatments had certain effects on the calli induction which lead to the significant difference. The mature calli induction of different media is quite different. MB gain very well induction efficiency. Among the difference of hormones, when concentration of 2,4-D was 2.5mg/L it could obviously enhance efficiency of induction and embryos induction.(2) Leymus chinensis calli subcultureIn the experiment, MB and MS media could improve the growth of mature calli and could obtain embryogenesis calli at last. The 2.0mg/L is the best in Leymus chinensis calli subculture when using 2,4-D. Concentration of sugar and proline should be 40g/L and 2500mg/L in su... |
PDF Full Text Request