| Acacia melanoxylon belongs to the genus Acacia in the family Mimosaceae, woody plants,originated in Australia. With so many good characteristics such as adaptability, fast growth, fine material, widely used, etc, A. melanoxylon is one of fast growing timber tree species in the development of the major short-cycle industrial raw material forest of great practical significance. Solving the propagation of the A. melanoxylon seedling should come first for the development of timber Plantation. The propagation of A. melanoxylon depends mainly on seeds and shoot cutting currently. The cutting of A. melanoxylon is difficult to survive when superior trees is tall and difficult to collect explants, or the aged of the tree and the effect of topophysis. And the apical dominance of the plant comes from shoot cutting was weaker than seedlings, thus serious impact the outturn of stand; and the seeds for seedlings cultivated dependent on imports, high cost, instability in offspring traits. In this paper, to solve the problems of A. melanoxylon during propagation, from March to October,2010,the experiment collected the 20 cm-long roots which was 60-80 cm away from the collar from the south area of Fujian tongkou state-own farm area’s 5 years old A. melanoxylon of seven families as material,in a greenhouse with hotline in the sand, no plant growth substances, roots exposing substrate 2 cm and vertical root cuttings as the basic culture conditions, and then root carried out cutting propagation. Through a comparative study to determine the scientific and rational location of the root cutting, the method of root cutting, matrix, family, hurt numbers and hurt ways, buried depth, the diameter at breast height of the stock plants, substrate temperature, determine the impact of effective factors of primary and secondary root cutting and determine the best combination for root cutting of Acacia,afforing the important theoretical basis for A. melanoxylon root cuttingdevelopment. The main conclusions are as follows:1. The experiment of root cutting’s location, length and grow ways carried out with the basic culture conditions except changing the range of distance between the chosen roots and collar, including 0-40 cm, 40-60 cm and 60-80 cm; changing the length of roots, including 5, 10 and 20 cm;changing grow ways, including horizontal, 45°and vertical root cutting. It was found that the root cut about 20 cm in length and then root, a number of seedling quality index were better than the other two treatments (5 cm and 10 cm long root segment), especially in the average buds, its was 6.67 / roots, it was 20 times and 3.3 times of others. A number of seedling indicators of using the vertical cutting root cuttings slight advantage than others, especially in terms of the average diameter was the level of root cuttings, respectively, and 45°angle of root cuttings of 2 times and 1.5 times. Select 60-80 cm from the root to root cuttings, a number of seedlings quality indexes were better than other treatments (40 cm from the root and 40-60 cm of the root segment). In these indicators, the greatest influence was root length, in some significant indicators, such as the average aspects buds. Through analysis, the best combination for root cutting is using 20 cm-long of 60-80 cm away from the root collar, root vertically.2. The experiment of substrates carried out with the basic culture conditions except changing the number of substrates, including sand, the soil, sand: peat soil = 1:1, peat: yellow soil: sand = 1:1:1 (volume ratio), yellow soil.It was found that a number of seedling quality indexes were better when using sand and soil .Indicators of good indicators in higher average seedling significant, and there are 31.33 cm(89.19%) between the highest and lowest value, should choose sand and soil to root cuttings.3. Family chosen has a stong effect on the result of A. melanoxylon root cutting. Chosen family 1 or family 2 to root cuttings,especially in average seedling height, they were 22 cm (84.62%) and 6 cm (27.28%) higher than the other settlement respectiverly. Depth of the buried: Select exposed 2 cm or buried into the substrate 5 cm of cutting methods and the average seedling height were higher 50.34 cm (580.78%)and 30.34 cm (349.94) than buried into10 cm respectiverly. Streak injury: do nothing or several streak injury, scored 7-10 bars.4. This experiment of plant growth substance carried out with the basic culture conditions except adding several plant growth substances. In plant material: According to the height, diameter aspects of data analysis, can not stimulate plant growth substances, the situation in the roots and 50 ppm IBA with 25 ppm 6BA soak for an hour, were making an average diameter greater than 0.1 cm in the number and average length greater than the maximum number of 5 cm; in terms of height to diameter ratio, with 100 ppm PP333, 50 ppm 6BA, 75 ppm Ga3, 50 ppm IBA after soaking for 3 hours cutting, making the best; roots than in stems, the use can be with 100 ppm PP333, 50 ppm 6BA, 100 ppm NAA, 75 ppm Ga3, 50 ppm IBA for 3 hours of soaking cuttings; in terms of emergence can be used with 50 ppm PP333, 25 ppm 6BA, 50 ppm NAA, 150 ppm Ga3 soak for 3 hours after cutting; several areas in the bud with an average of 100 ppm PP333, 50 ppm NAA, 150 ppm Ga3 soak for 1 hour after cutting.5. This experiment carried out with the basic culture conditions except changing heating and shading. Select large diameter trees to root cuttings and average seedling height and average root collar were better than other settlements. Substrate temperature could increase 5 degree. The seeds with heating their seedling height and diameter were 59.39 cm and 0.42 cm respectively which were 2.04 times and 2.6 times higher than without it.6. 5 cm seedling root produced the largest number buds, followed by 20 cm, and finally 10 cm in the amount buds of per unit length. But the height and diameter of 5 cm and 10 cm seedling root buds were small, less than 1/2 of that of 20 cm root. It was recommended that using 20 cm long root, ensure adequate nutrition for the growth of seedlings.7. Chlorophyll fluorescence parameters: the results of each different, but no significant difference.these seedling didn’t affect the inhibition by light and these values did not vary with changes in summer and autumn seasons.8. From April to August was the period of seedling growth, but from June to July more attention should paid to water and nutrition of seedling. The seedling without stock root and with stock root shift plant survival rate were 95% and 83.3% respectiverly. |
PDF Full Text Request