The Studies On The Promoting Mechanism Of Plant Growth Regulators In The Initialization Of The Cuttings' Adventitious Root Of Pinus Bungeana

Pinus Bungeana is the exclusive species of China. It is creditable in the fields of urban virescence and afforestation at the deserted. But the seedlings of Pinus Bugeana grow slowly, which results in the short supply of seedlings. Cuttings can provide the shortcut to solve the problem of fast propagation. The studies are on the promoting mechanism of plant growth regulators in the initialization of the cuttings of Pinus Bungeana by means of HPLC which are based on the previous experiments. The studies show that:(1) Different sorts of plant growth regulators have different influences on the content of the endogenous hormones, the values of IAA/ABA and IAA/ZT and the activities of the enzyme. The highest content of IAA was measured from the cuttings that treated with IBA+NAA. This content of IAA is 0.2187ng/g. The highest value of IAA/ABA was measured from the cuttings that treated with IBA solution. This value of IAA/ABA is 0.2870.(2) Using methods, Concentration, treating environment, treating time and the age of the mother trees influence the effect of plant growth regulators. The effect of immersion is better that the effect of dipping. The content of IAA, GA₃, ZT and the value of IAA/ABA and the activities of PPO, CAT increase with the increase of the concentration of IBA, NAA or ABT₁ solution. While being treated with IBA, the cuttings' content of IAA and the value of IAA/ABA and the activities of the enzyme are higher with the shutoff of light than that under normal environment. The cuttings' value of IAA/ABA is highest under the treating time of 1h.Considering these studies and the conclusion of the previous studies, the analysis shows that the content of the cuttings' endogenous hormones and the activities of the enzyme are promoted to different degrees, especially the value of IAA/ABA. The higher the value of IAA/ABA, the higher the initial ratio of the cuttings' adventitious root. So the promoting mechanism of the plant growth regulators is that to promote the cuttings' value of IAA/ABA.