Studies On Technology About Tissue Culture Propagation Of Resistance Families Of Slash Pine (Pinus Elliottii)

Brown spot needle blight has become a serious obstacle in the further expanding of Pinus elliottii. A great deal of studies indicate that breeding for the disease resistance is only efficient way to control the disease at hight disease hazard sites. The seed orchards of resistance to the disease have come into the stage of seeding. Furthermore, it is going that the work of the filial generation's resistance to the disease. Nevertheless, the seed supply of the orchards are far away from the needs of afforestation. Therefore, it is impendent to rapidly proliferate the material of Pinus elliottii which has good wood quality and can strongly resist to the brown spot needle blight. So, this article researched the system of the rapid proliferation in Pinus elliottii by the way of tissue culture. The results are as followed:Embryogenic callus development was initiated in cultured mature embryo explant of Pinus elliottii. There have a few tissue that resemble the embryogenic callus in appearance, cultured in LP medium supplemented with 2,4-D(12mg/L) and 6-BA(4mg/L) or 2,4-D(4.5mg/UK 6-BA(0.1mg/L) and KT(0.1mg/L).Adventitious bud formation was obtained from green cotyledons and mature embros of Pinus elliottii cultured in modified GD with hormones. Adventitious buds were achieved in the modified GD supplemented with 6-BA(5mg/L) and NAA(0.1mg/L), which differentiation frequency was 7.1%. In addition, it was suitable for the direct adventitious buds induction in the modified GD supplemented with 6-BA(5mg/L) and NAA(0.01mg/L). It was 61% for the differentiation frequency of direct adventitious buds in this medium. However, the rate of browning was very high, accounting for 56.5%. These adventitious buds induced by the two ways were very difficult to be cultured. In this study, no medium was found to meet the requirements of the adventitious buds to grow up.It was showed by the whole experiment that selecting the tip sprout c-arrying cotyledons as explants was more easily to build the regeneration system for Pinus elliottii. The modified GD medium was the best elementary medium for axillary buds differentiation of Pinus elliottii. Axillary buds we-re induced from modified GD medium supplemented with different levels of6-BA(0.5~5mg/L) and NAA(0.01~0.1mg/L). The better medium for Pinuselliottii to induce axillary buds was modified GD supplemented with 6-BA(3mg/L) and NAA(0.05mg/L). The differentiation frequency was very high, reaching to 73.3%. At the same time, the buds regeneration coefficient was 4.7.The axillary buds could continue to develop in the modified GD medi-um supplementedwith NAA(0.07mg/L). The elongation of the shoot stem was in the half of modified GD supplemented with AC(0.05%), in which the average length of the stem reached at 0.07cm in a month. The combination of modified GD+NAA0.05mg/L+6-BA1.5mg/L was relatively suitable to the p-roliferation of the axillary buds in Pinus elliottii, in which the differentiation frequency of the second generation buds accounted for 50%. In this study, no medium was found to meet the requirements of the adventitious buds to grow up.The half of MS medium was the better basic medium for the rooting of the regenerated plantlets. It was quite sensitive to NAA for the rooting of the regenerated plantlets. A few of root had come into being when the NAA concentration was 0.01 mg/L. However, it was not so sensitive to IB A. No root formed when the IB A concentration was below 1 mg/L. The half MS medium supplemented with NAA(0.05mg/L) was suitable to the root induction of the regenerated plantlets in Pinus elliottii, in which the rate of induction was 60%. In addition, not only could a few regenerated plantlets direct form root, but the root induced quickly elongated in the half of modified GD.