Abstract:

Abstract: In order to tap lacquer scientifically, variation of urushiol content in raw lacquer and the bark structure of Toxicodendron vernicifluum in different seasons were investigated. The bark structure, urushiol content in raw lacquer of untapped and tapped Damu Lacquer Tree and tapped Xiaomu Lacquer Trees in different seasons and urushiol content of tapped Xiaomu Lacquer Trees in tapping seasons in Qinling area were observed and measured with the methods of plant anatomy and spectrophotometry. The results revealed there were differences in the thickness ratio of functional phloem to non-functional phloem, mean values of diameters of laticiferous canals, the number of laticiferous canals per unit area, the number of layers and groups of stone cells and the number of rows of ray cells over the seasons. The thickness ratio of functional phloem to non-functional phloem and the number of layers and groups of stone cells, the number of secretory cells and raw lacquer content in laticiferous canals decreased twice per year. The urushiol content in raw lacquer increased generally with two valleys in different seasons and reached to a peak (67.321 43%) from middle of July to late August which is tapping seasons. Comparison between the change of bark structure and the urushiol content in raw lacquer showed that a close correlation existed.

Key words: Key words: Toxicodendron vernicifluum, microstructure, laticiferous canal, raw lacquer, urushiol