木荷种源鲜叶抑燃和助燃性化学组分的差异

Provenance Differences for Fire-assistant and Fire-resistant Chemical Components in Fresh Leaf of Schima superba

选择木荷15个代表性种源,以研究火险期鲜叶主要抑燃性和助燃性化学组分的种源差异及地理变异模式。结果表明,木荷叶片含水量、灰分、木质素、粗脂肪和苯 乙醇抽出物5个化学组分在种源间存在显著的差异,其最高和最低种源测定值分别相差5%、31%、80%、66%和33%,尤以灰分和粗脂肪两组分的种源差异最大。木荷种源鲜叶的上述5个化学组分都呈现随纬度变化的地理模式,木质素和粗脂肪质量分数还与产地经度有关。较之于分布区北部的种源,木荷南部种源鲜叶的含水量、灰分等抑燃性组分质量分数高,粗脂肪、苯醇抽出物等助燃性组分质量分数低。木质素作为一种不易燃烧但燃烧时能释放大量热量的组分,呈与产地纬度显著正相关的关系,有异于含水量和灰分两个抑燃性组分的地理变异模式。结合苗期种源试验结果,可以初步判定分布区南部的种源生长快,根系发达、叶片数量多,鲜叶抑燃性组分质量分数高,助燃性组分质量分数低,因此防火性能较好。

In fire risk period, l5 provenances of Schima superba was selected to study the geographic differences and its variation patterns for fire-assistant and fire-resistant chemical component in fresh leaves. The results indicated that there were significant differences among provenances for five main chemical components including water content, percentages of lignin,ash,crude fattiness, benzene-ethanol extractive, whose differences between highest and lowest provenances were reached 5%, 31%, 80%, 66% and 33% respectively.A classical latitude clinal variation pattern was found for the 5 main chemical component aboved-mentioned.In addition, lignin and crude fattiness content were related to the longitude of the seed source. Comparing with provenances from the northern, there were more fire-resistant component content (water and ash content) and less fire-assistant component (crude fattiness and benzene-ethanol extractive content) for provenances from the southern. The lignin, as a fire-resistant component with heavy heat value when firing, was found to be related positively to the latitude of the seed source, whose geographic variation pattern was different from water and ash content. Associated with results form the provenance trial at seedling stage, it was primarily concluded that the southern provenances were more resistant to fire with higher growth rate, richer roots and more leaves, more fire-resistant and less fire-assistant chemical components in fresh leaves.