Separation, purification, and identification of endogenous inhibitory substances in Pinus massoniana cuttings.

To improve the rooting rate of Pinus massoniana, endogenous inhibitors from cuttings of five P. massoniana lines were purified and separated using extraction and high pressure liquid chromatography (HPLC). Biological assays along with analysis of variance (ANOVA) with 4 treatments of aether extracts and 3 replications with comparisons to Brassica chinensis seeds were employed. Results revealed seven components of endogenous inhibitors in each P. massoniana cutting belonging to flavones, phenols, and abscisic acid(ABA). This indicated that their expression was controlled by genes with significant differences among lines (P = 0.032 9). By comparison, an ANOVA for the influence of endogenous inhibitors on growth of B. chinensis roots was highly significant (P = 0.000 1); whereas compared to the same component of endogenous inhibitors in the root growth of B. chinensis, inhibition with the five P. massoniana lines were not significantly different. Also, except for MI6 (No. 6 of HLPC educts), correlation analyses between the relative content of endogenous inhibitors and the rooting rate of B. chinensis were negative. Biological assays for extractions and their residuals extracted with ether showed two kinds of endogenous inhibitors: one thatdissolved easily in water and the other that was easily soluble in a non-polar solvent.