Studies On Cutting Propagation Techniques And Rooting Mechanism Of Acacia Melanoxylon

The basal material for this research is one-year-old superior cutting clones of Acacia melanoxylon. The study researched on rapid cutting propagation technology (including the cuttings of different part of the same branch and the leaf retention, rooting descriptions, cutting media, water extract of A.melanoxyIon branches and leaves, fungi and slitting styles) and rooting mechanism (including effects of plant growth regulators on endogenesis hormones and soluble sugar and starch) to provide the theoretical basis and necessary technical support for rapid propagation of A. melanoxylon. Main results were as follows:1) It was better to cut the middle branch with two half leaves for rooting, the rooting rate was 47．78% which was 32．22% higher than the rooting rate of shoot.2) The order of the effects of four plant growth regulators on rooting rate of A. melanoxylon was IBA>GA>NAA>B.The effects of IBA was remarkable, and the range was up to 20．12%, the maximum rooting rate was nearly 80%.Furthermore, the better description for rooting wasIBA+NAA+GA+ B·3) The best media for cutting of A. melanoxylon was peat + perlite + vermiculite, with the ratio of 1:1:1, the rooting rate of this media treated by water reached 63．33%.4) The different concentrations of water extracts improved the rooting rate of A. melanoxylon which was 14-16% higher than the controlled treatment. As well as the concentration of water extracts showed less effects.5) Significant differences occurred among all the treatments of different microbial inoculums and slitting styles. The treatment of A. grobacterium rhizogenes 15834 and upright skived was better for rooting, and the rooting rate was up to 56．67%.6) The effects of different plant growth regulators on contents of hormones in the cutting leaves of A.melanoxylon was different during rooting periods. Overall, Extraneous IBA was beneficial to rooting of A.melanoxylon by increasing the contents of IAA,GA and ZR and decreasing the contents of ABA. Effects of extraneous NAA was less than IBA, but it also improved rooting. Extraneous GA increased the contents of IAA,GA and ZR in a certain extent, but in the meantime, it also improved the contents of ABA. The contents of IAA,GA and ZR were improved insignificantly by B, in contrast, the content of ABA was boosted. 7) It was not clear that the effects of different plant growth regulators on contents of soluble sugar and starch in the cutting leaves of A.melanoxylon .But the soluble sugar content was affected most obviously by NAA, while the starch content was affected most obviously by B.