Research On Rooting Reagents Of Pinus Tabulaeformis

The afforestations on the poor site are the difficult problem and keystone in silvicultural operations at the present stage and silviculture on the arid site is one of main types of those. The low survival rate is a pivotal technical question of which need be urgently solved when we afforest on the arid site. Speed of seedlings'rooting after planting is one critical factor for seedling's survival. Enhancing seedling's vigor and shortening of rooting time are one of the important techniques for enhancing seedling's survival.The research, in which we choose Pinus tabulaeformis among the main conifers that used for plantation in the North China as the experimental species, was engaged in the chemical ways of enhancing seedling's root-system vigor treated by such chemicals as exterior plant hormones and others, therefore it is a preparatory work in order to further develop rapid-rooting reagents by means of single factor block test and orthogonal test. The main conclusions were as follows:1. Results of single chemical regent treatment stage: Treating Pinus tabulaeformis seedling with in concentration of salicylic acid (SA) in 2 to 50 mg / L can improve both the morphological indicators and physiological indicators of Pinus tabulaeformis seedling, including mass growth, net photosynthetic rate, biomass, root mass, dissoluvable sugar content and root-system vigor. The best concentration is 10 mg / L, height growth was improved by 17.2 percent, net photosynthetic rate was increased by 47.85 percent, dissoluvable sugar content was increased by 47.89 percent, root-system vigor was increased by 65 percent, total biomass was increased 32 percent, and root biomass was increased by 16 percent. Methyl jasmonate (JA-Me) treating Pinus tabulaeformais can restrain the height growth and vitality of the root system and the restraint effect strengthens with the increasing of the concentration. While the soluble sugar content of the seedlings was promoted in lower concentration (1 to 20 mg/L) but decreased in higher concentration (beyond 20 mg/L). Compond vitamin B (VB2 + VB6) treating the Pinus tabulaeformis seedling with concentration of VB2 10 to 200 mg / L plus VB6 1 to 20 mg / L on the mass growth of seedlings have a certain role in promoting; the net photosynthetic rate, soluble sugar content and root vigor and other indicators also showed promoting in lower concentrations (10 +1 mg / L ~ 50 +5 mg / L) and in habited in higher concentrations (100 +10 mg / L ~ 200 +50 mg / L). 2. Results of the cross test stage: Filtering out the hormone combinations which have mutual antagonis. The specific combinations are IBA with Eth, VB with IAA, SA with 6-BA, BR with IBA, BR with Fu, BR with Eth, BR with SA, BR with IAA.3. Compond rooting reagents research stage: Orthogonal test results showed that the optimal formula is A2B2C3D2E2F3G3H2. Particularly, the compound rooting promoting reagent combination are: IBA 50 mg / L, Fu 10 mg / L, BR 1 mg / L, 6-BA 0.1 mg / L, Eth 320 mg / L, SA 10 mg / L, IAA 200 mg / L, VB2 and VB6 respectively from 50 mg / L and 5 mg / L. This combination can improve many morphological indicators and physiological indicators of Pinus tabulaeformis seedling.