Studies On The Softwood Cutting Propagating Technology And Rooting Mechanism Of Ulmus Pumila L.

Elm(Ulmus pumila L.), also known as spring elm, is a deciduous tree of the Ulmaceae, is the main timber tree species with fast growing and long life-span in the north of the China; is an important tree species for soil and water conservation with its strong adaptability of drought-resistant,cold-resistant,barren-resistant,salt-tolerance,wind-resistance,andsoil etention force. Is also a multipurpose tree species because its fruit is edible, bark, leaf and elaeagnus can be medicinal. In recent years,people has cultivated many elm clones. In order to maintain the female parent specific traits, the softwood cutting propagation technique and rooting mechanism were studied to provide guidance for elm clones propagation in this paper. The results are as follows:The results of cutting propagating experiment showed that the rootage percent was the highest when the soft-wood cutting was soaked in ABT500mg·L-1 for 1 hours. Meanwhile rooting percentage is as high as 68%, other rooting morphological indexes was better than different dealing.The results showed that the effects of exogenous hormones on rooting were very different, and the effect of different hormone treatment was different, especially the effect of ABT rooting powder was the best. The cutting matrix and the size of the cuttings are not very significant.The research of Rooting Mechanism showed that the elm belonged to the rooting type of callus. The study indicated that some indexes about the content of nutrient manifested a given rule with the development of rooting, such as soluble sugar, soluble protein, and the rato of C/N etc. The content of soluble sugar and soluble protein had a down-trend at the forming period of callus and all the period of rooting, perhaps they provided energy for callus and rooting process; where after, the content of nutrient had an up-trend, then indicated no fluctuating. It can be explained as the energy requirement is reduction after rooting. The ratio of C/N manifested the rooting ability in some extent. In the study of rooting related enzymes in cuttings, it was found that the rooting of cuttings was closely related to the rooting of cuttings. The rooting related enzymes activity of 500mg·L-1 ABT1 treatment was higher than that of control, and the activity of POD was decreased in the rooting process. The activity of PPO was "low- high- low", and the IAAO activity appeared the change rule of "first- increasing, then decreasing and then decreasing". The synergy of various internal and external factors in the rooting process, the appropriate cutting propagation technology can greatly improve the survival rate of rooting.