四种类型栓皮栎栲胶含量

The content of tannin extract in four types of Quercus variabilis

为了阐明不同类型(薄皮深裂、薄皮浅裂、厚皮深裂、厚皮浅裂)栓皮栎各器官栲胶含量,系统采集了秦岭南坡商州区4种类型的栓皮栎不同径级植株根、主干木材、叶片、枝条和树皮样品,用紫外光分光光度法(UV Spectrophotometry)测定了4种类型栓皮栎不同器官栲胶含量,分析了林木生长与栲胶含量的关系。结果表明,(1)4种类型栓皮栎的根、主干木材、叶片、枝条和树皮单宁含量平均值分别为2.64%—3.02%、1.74%—2.02%、6.63%—7.21%、4.69%—5.10%、8.87%—9.46%,叶片、枝条和树皮均可以作为栲胶生产主要原材料。(2)不同类型各器官单宁含量存在极显著差异(P<0.01),4种类型的树皮、叶片、枝条单宁含量均表现为:厚皮深裂型>厚皮浅裂型>薄皮深裂型>薄皮浅裂型;根部和主干木材在4种类型间单宁含量表现为:薄皮深裂型>薄皮浅裂型>厚皮深裂型>厚皮浅裂型;厚皮深裂类型的栓皮栎是提取栲胶的最佳类型。(3)4种类型栓皮栎各器官单宁含量与胸径呈显著正相关,各器官单宁含量随着栓皮栎胸径增大而增多,并最终趋于稳定,在第Ⅳ径级(胸径20.1—25cm)时,栲胶含量均值最大。因此,栲胶生产可以高效利用第Ⅳ径级及其以上径级的栓皮栎,并对第Ⅳ径级以下栓皮栎进行定向培育和重点保护。

Tannin extract is one of the significant forestry chemical products. The main component of tannin extract is tannin. Tannin, which is an important chemical material for forestry, can be extracted from the organs of Quercus variabilis widely in China. To illustrate the variation of tannin content, the barks, shell buckets, fruits, roots, stems and leaves of 72 Q. variabilis trees from the four types were sampled based on different diameters at breast height were on the south slopes of Qinling Mountains in October 2012. The content of tannin in the organs were analyzed by UV spectrophotometry, and the influence of tree growth on the tannin content was detected by Pearson correlation and linear regression. The result indicated that there was a great variation between the individuals of the four types. Our aim is to provide an reference and experiment basis for the directive cultivation and effective utilization of Q. variabilis resources. It was showed concretely as follows. （1） The average tannin content of 2.31%-2.72% was found in the roots of the four typesof Q. variabilis, as well as 1.31%-1.72% in the stems, 6.32%-6.89% in the leasves, 4.49%-4.92% in the branches and 8.17%-8.86% in the barks. The content of tannin in the leaves, branches and barks are much higher than that in the roots and stems obviously. Leaves, branches and barks were suggested as the major raw materials of tannin extract. （2） The significant difference of tannin content was observed among the different organs of the four types of Q. variabilis. In the leaves, branches and barks, the content of tannin ranged from high to low as the thick bark deep crack type, the thick bark shallow crack type, the thin bark deep crack type, the thin bark shallow crack type. The tannin content in the roots and stems of the four types ranged from high to low as the thin bark deep crack type, the thin bark shallow crack type, the thick bark shallow crack type, the thick bark deep crack type. Because of the tannin content in the leaves, branches and barks with a high level, the Q. variabilis with the thick bark deep crack type was the best one in the four types for tannin extract. （3） The tannin content of the different organs in the four types augmented with the increasing DBH of the trees, and the top value was observed in the DBH of 20. 1-25cm. The DBH and the height of trees affected the tannin content positively. The suggestion is that the Q. variabilis with DBH above 25cm should be applied fully and efficiently for tannin extraction, or it should be priority for directive cultivation and special protection.