Study On Asexual Propagation Technique Of Pinus Tabulaeformis Carr. And Pinus Ponderosa

The pine plays a very important role in the forest resource of our country. It is very necessary to study the asexual propagation technology in order to realize using the high quality varieties of pines to afforest. This experiment uses Pinus tabulaeformis Carr. ,Pinus Ponderosa and Pinus nigra var. austriaca as the materials to study the techniques of the shoot cutting ,the heteroplastic grafting and the solution culture of needle fascicles. The results are the following: (1)Rooting from the callus is the main means of the rooting of the shoot cutting of Pinus tabulaeformis Carr., but it also has the ways of rooting from dermal tissue and from the both. The rooting rate has the strong age effect, that's to say, the rooting rate goes down with the age of the parent trees. The age of the parent tree is from 3 to 5, the rooting rate is from 22.2% to 6.7% accordingly. So it's better to choose the young tree under 5. In addition, the cutting mediums also affect the rooting rate strongly, the coarse sand and the fine sand , which has a suitable retentiveness and venting quality, are both suit for the shoot cutting of Pinus tabulaeformis Carr.. But the soil having a heavy stickiness is not suitable for cuttage. (2) Root-promoting hormone can accelerate the shoot cutting of Pinus tabulaeformis Carr. to root evidently. Different root-promoting hormones have the different effects, even the same root-promoting hormone also has great different effects with the different treatments .For example, the result of using ABT1,NAA and "gentaiyang"to treat the shoot cutting of Pinus tabulaeformis Carr. with low concentration (50mg/L or 2000 multiple ) is better than with high concentration (100mg/L or 1500 multiple). But IBA is reverse. Using the solution of IBA(1000mg/L) to mix with muddy and treat the cutting with it, its effect is better than dipping the cutting with the solution. Using the "gentaiyang"to mix with muddy, the effect of high concentration is better than the low concentration. With IBA (50mg/L) to treat the shoot cutting, the rooting rate is rising at first as the treating time goes on. But it begins to go down about 12hours later. (3) The solution of the sucrose can increase the nourishment of the cutting, but it does harm to the rooting. The rooting rate reduces as the concentration of the sucrose solution increases. The reason why the rooting rate decreases is that the sucrose can cause the base of the cutting to decay. (4) The optimal grafting time of Pinus Ponderosa is in the middle of May. The heteroplastic grafting also has the age effect , so the age of the rootstock should be under 5. The grafting methods and its qualification are the important factors to affect the grafting survive rate. When grafting, you'd better call for the qualified operators to graft with the method of cambium to cambium. Taking the measure of keeping moisture after grafting can height the survive rate badly, the survive rate can reach to 45%, 26.7%higher than the contrast. (5) The factors such as the cold storage time,the picking time,the position of picking,cutting base or not and the condition of temperature all affect the rooting of the needle fascicles. The result indicates that the needle fascicles should be picked in December each year from the lower section of the new shoot ; it is good for rooting to store the needle fascicles under 5~8 ℃for 30 days; it is very important for the rooting to maintain a suitable temperature condition. To Pinus nigra var. austriaca., the length of the needle affects the growth of callus greatly, the callus of the long needle is much and better than the short's. (6) The suitable root-promoting hormone and its processing mode for the needle of Pinus tabulaeformis Carr. to root are the following: Using IBA+IAA(1:1)with 150mg/L or 200mg/L to treat the needle fascicles for 24 hours. The optimum culture solution is B (45~60 mg/L) + VB1 (5~7mg/L) + NH4NO3 (30mg/L) + KH2PO4 (20mg/L). The proper root-promoting hormone and its treating mode for the needle of Pinus nigra var. austriaca to root are to use NAA (150mg/L) to treat the needle fascicles for 24 hours. The optimal culture solution is NH4NO3 (30mg/L or 20mg/L)+ VB1 (20mg/L or 10mg/L).