Lignin Metabolism And Its Regulation In Apple Rootstock M.Hupehensis Rehd.

The experiments were conducted from 2001 to 2003 in the orchard and hormone laboratory, College of Horticulture, Shandong Agricultural University. The 1-3 years old trees of M.hupehensis Rehd were used as materials. The method of the experiment were water culture, soil culture and normal sampling etc. Firstly, the elementary law of lignin synthesis metabolism in different part of the seedlings of M.hupehensis Rehd was studied. On the base of it, then the regulation of weak light on the growth development and lignin synthesis metabolism of leaves of M.hupehensis Rehd seedlings was researched. Finally, using two elicitor, hydroxy radical and chitosan, to regulate the growth development and lignin synthesis metabolism of the seedlings, whose potential apply value was discussed. In addition, the Ultraweak luminescence(UL) assay method of the leaves of M.hupehensis Rehd was studied. The results obtained are summarized as follows. 1. The lignin content and the relative enzymes activity are different among roots, stem and leaves of M.hupehensis Rehd seedlings, the same as among different type of roots and different position leaf of the seedlings. The concrete results is following. The sequence of lignin content is stem>root>leaf and conducting root>transitional root>growing root>absorbing root. The lignin content and POD activity in old roots is obviously higher than those in new roots. The lower the leaf position of the same shoot is, the higher the lignin content and the POD activity are. The lignin content is not according with activity of PAL and 4Cl in leaves of different position. 2. Shade can greatly decrease SLW, lignin content and the relative enzymes activity, such as POD and PAL in leaves of M.hupehensis Rehd seedlings,which indicates that shade has regulation function on the lignin synthesis metabolism. Moreover, shade decrease UL and the activity of CAT of the seedlings leaves, which proved that shade can weaken the resistance of leaves and this is relative to the low level of lignin synthesis metabolism. 3. The treatment of fit concentration of hydroxy radical on M.hupehensis Rehd roots can improve the root development, elicit the seedlings UL and increase the level of lignin synthesis metabolism, which make it possible to apply the agent as elicitor to agricultural production. The treatment of hydroxy radical on roots may increase root weight and decrease cap weight, so the root/cap ratio increase. The treatment of hydroxy radical increase the active absorbing area per., TTC root vigor and CAT activity. The response speed of UL in the seedlings whose roots were dipped in hydroxy radical solution is faster than that in water and the former kept a higher level finally. With the increase of the hydroxy radical concentration, the lignin content and the activity of POD and PAL also increased.4. The treatment of chitosan on M.hupehensis Rehd seedlings not only increase cotyledon weight, promote root development, but also increase the level of lignin synthesis metabolism and chitosan can be applied to agricultural production as an elicitor. With the increase of chitosan concentration ranging from 0.05% to 0.35%, cotyledon weight increases, under the fit concentration (0.2%), the quality of new root and plant growth are improved. To some extent, the treatment of applying chitosan to roots all increase tip number, area, length, average diameter and the vigor of fine roots and improve plant development. Moreover, these treatment increase lignin content and the activity of POD and PAL in roots, promote the lignin synthesis in root.5. The leaf UL intensity of M.hupehensis Rehd seedlings is closely related to putting ways, wafer diameter and wafer number. The UL intensity of tiled leaves is higher than that of piled leaves. The wider the wafer diameter is and the more the number of wafer is, the stronger the UL intensity is.