Studies On The Cutting Propagation Technique And Rooting Mechanism Of Tilia Taishanensis S.B.Liang

Tilia taishanensis S. B. Liang belongs to the Tiliaceae family. Tiliaceae as one of the world's four big trees, is also a good honey plants with high economic value. Tilia taishanensis S. B. Liang flora is narrow, damage is serious, be badly in need of protection.The techniques of cutting propagation of Tilia taishanensis S. B. Liang were studied, which covered with the effect of the different parts(upper, middle and lower), cuttings and the different hormones(IBA, NAA and ABT) and concentrations(500, 1500, 3000, 5000mg/L)on their rooting. Meanwhile the rooting mechanism was revealed by monitoring of the content of endogenous hormones, nutrients and oxidation enzymes activity.(1)The results indicated that rooting cuttings in the middle had the best rotting effect,which had a rooting rate of 45.6%. The upper was 39.7% and 35.2% lower. Different cuttings significantly affected their rooting capacity. The rooting rate of shoot in early August was52.3%, and compared with the hardwood in mid-September, the rooting rate were increased by 1.1 times. The types and concentrations of growth regulators were also important factors that affected cutting rooting. Treated with IBA at a concentration of 3000 mg/L, the cuttings had a rooting rate of 68.5%, root number of 18.6 on an average, root length of 12.35 cm on an average. And compared with the control, they were increased by 2.6 times, 1.4 times and 1.2times respectively. The cutting shoot cuttings and the middle of cuttings shortly dipped with3000 mg/L IBA were appropriate to the cutting rooting of Tilia taishanensis S. B. Liang.(2) By observing the rooting parts of adventitious roots, only a few of them were originated from cortex of the cuttings. The adventitious roots were mostly originated from callus at bottom of cuttings.(3) By measuring the content of endogenous hormones at different positions of the cuttings and rooting of cuttings dynamic changes of endogenous hormone content, contacting the rooting rate of cuttings, it can be seen that the content of endogenous hormones and rooting rate has certain correlation. The content of IAA is positively correlated with rooting rate, GA3 and IAA/ABA is positively correlated with rooting rate and ABA is negativelycorrelation with the rooting rate. High concentration of GA3 and IAA/ABA are beneficial to the growth of root.(4) The correlation of nutrient content and rooting rate is not obvious before cutting, but its good nutritional status is the prerequisite to take root. Treatment of exogenous hormones could accelerate the metabolic processes of nutrients, the content of nutritive substance rised first and then decreased. The rooting of cutting consumes large amounts of nutritive substance during rooting of cuttings. Overall the content of nutrients remain cuttings rooting at a higher level, conversely cuttings rooting rate is low.(5) POD PPO/IAAO activity was increased during rooting of cuttings. POD activity has the two-peak trend, while PPO and IAAO activity have the trend of first increased and then decreased. Compared with the CK cuttings, exogenous hormones increase the activity of the enzyme, promote rooting cuttings.