重庆市渝东地区半野生油桐的桐油品质分析

Analysis of Tung Oil Quality of Semi-wild Tung Trees in the Eastern Part of Chongqing Municipality

渝东地区地处重庆市东部的三峡地域,自然气候、土质条件等非常适宜油桐的生长,为我国油桐生长的最适生区、主产区及老产区.渝东桐油品质优良,各项桐油理化指标优于国家制定的标准,其中云阳桐油曾作为世界桐油检验标准,为出口的免检产品.然而,20世纪80年代末以后,由于桐油替代产品的出现,以及桐油新的利用途径尚未有效开发,渝东油桐生产出现了大滑坡,桐树资源遭到严重破坏,幸存桐林则基本处于荒芜、半野生状态.本研究以渝东典型油桐品种及各品种曾经的优质桐林种植区现存桐林为实验对象,采集全熟桐果用于桐油品质分析,并与我国现行的桐油国家标准比较.结果表明在本实验范围内,渝东现存桐林桐油品质只能达到国家二级或三级标准,各品种品质均有所下降.可见,桐林长年荒芜,无人哺育,品质会逐渐下降,许多过去经过几十年选育的优良种植资源会逐渐消失.

The eastern part of Chongqing（EPC）is located at the upstream of the Three Gorges Reservoir,where natural climate and soil conditions are suitable for the growth of tungoil tree（Vernicia fordii）,and is the main tung oil-producing region of China.Tung oil of EPC is of excellent quality.Its physical and chemical properties are better than what is speculated in the relevant national standard.Tung oil produced in Yunyang,in particular,is an inspection-free product.However,after the end of 1980 s,because of the emergence of tung oil substitute products,and because new applications of tung oil were not well developed,tung oil production sharply decreased.Then tung resources were seriously damaged.The surviving tung trees have been in a semi-wild state since 1990.In an experiment reported in this paper,tung oil of mature tung fruit picked from typical cultivated varieties in formerly growing area of high quality tung trees in EPC were used for quality analysis,and compared to our current tung oil national standards.The result demonstrated that current tung oil quality grade standard of EPC only reached GradeⅡand/orⅢ of Chinese tung oil national standards.This showed that tung oil qualities of cultivated varieties of EPC are decreasing in our experimental range.Therefore,high quality tung trees in EPC have been in wild state for many years,their quality will gradually decline.Moreover,many excellent germplasm resources and good cultivated varieties of tung trees bred for decades will gradually disappear.