西康玉兰(Magnolia wilsonii(Finet et Gagnep.)Rehd.)是木兰科木兰属植物,具有很好的观赏、药用和科研价值。该种繁殖能力弱,对环境要求苛刻,分布区域狭窄、种群较小,被列为国家Ⅱ级珍稀濒危植物。预测气候变化对西康玉兰分布范围的影...西康玉兰(Magnolia wilsonii(Finet et Gagnep.)Rehd.)是木兰科木兰属植物,具有很好的观赏、药用和科研价值。该种繁殖能力弱,对环境要求苛刻,分布区域狭窄、种群较小,被列为国家Ⅱ级珍稀濒危植物。预测气候变化对西康玉兰分布范围的影响,为西康玉兰的野生资源保存与可持续利用提供科学基础和参考依据。利用ArcGIS软件与最大熵模型(MaxEnt)计算西康玉兰主要气候因子的贡献率及对应不同适生等级的阈值范围,分析西康玉兰在全国范围内的潜在地理分布,并统计主要分布区域的不同等级适生区面积和现阶段分布点的比例,在4种气候情景(RCP2.6、RCP4.5、RCP6.0、RCP8.5)下,预测未来西康玉兰适生区分布范围以及其质心转移的变化。结果表明:MaxEnt模型预测西康玉兰潜在生境分布的特征曲线(ROC)训练集的AUC(ROC曲线下的面积)值为0.972;年均降水量、昼夜温差与年温差比值、湿度最小季度平均气温、最冷月份最低温是影响西康玉兰分布的主要气候因子,其贡献率分别为33.8%、26.7%、14.6%、14.3%。现阶段,西康玉兰的高、中、低适生区集中分布于云贵川三省交界地带,适生区总面积104.52×10^(4)km^(2),其中高适生区占总适生面积的16.62%,现有分布点处于高适生区内的比例为65.11%。未来20~50 a,全球气候变暖将有利于西康玉兰在中国的分布,其适生区分布基本格局不变,适生区总面积增加,但高适生区的东侧与南侧有缩减与破碎化的趋势;现阶段西康玉兰的潜在分布中心位于四川省的西昌市德昌县内,西康玉兰潜在分布中心有向西北部迁移的趋势,将迁移至西昌市的盐源县内。因此,对西康玉兰濒危资源的保护应结合地理分布,制定多样性保护策略(野生资源调查、野外回归的迁地保护、建立保护区、开展繁殖与栽培技术等)。展开更多
The contents of flavonoid in the leaf and stem of Sargentodoxa cuneata (Oliv.) Rehd. et Wils. were determined. In a whole growth season, the dynamic chang of flavonoid in the leafblade of S. cuneata showed the two-pea...The contents of flavonoid in the leaf and stem of Sargentodoxa cuneata (Oliv.) Rehd. et Wils. were determined. In a whole growth season, the dynamic chang of flavonoid in the leafblade of S. cuneata showed the two-peak pattern. The first peak appeared at June and the second at September. The seasonal dynamic change of flavonoids in leafstalk, annual twig and perennial stem were different and inconspicuous. The flavonoid cumulated maximally in the leafblade and the followed was seccessively annual twig, leafstalk, and perennial stem. The flavonoid content in leafblade was 31.79 mg/g(DW), while that in annual twig, leafstalk and perennial stem was 5.41 mg/g(DW), 5.30 mg/g(DW) and 3.95 mg/g(DW) respectively. There was markedly higher flavonoid content in leafblade. It is considered that the leaf of Sargentodoxa cuneata is significant in further exploitation.展开更多
文摘西康玉兰(Magnolia wilsonii(Finet et Gagnep.)Rehd.)是木兰科木兰属植物,具有很好的观赏、药用和科研价值。该种繁殖能力弱,对环境要求苛刻,分布区域狭窄、种群较小,被列为国家Ⅱ级珍稀濒危植物。预测气候变化对西康玉兰分布范围的影响,为西康玉兰的野生资源保存与可持续利用提供科学基础和参考依据。利用ArcGIS软件与最大熵模型(MaxEnt)计算西康玉兰主要气候因子的贡献率及对应不同适生等级的阈值范围,分析西康玉兰在全国范围内的潜在地理分布,并统计主要分布区域的不同等级适生区面积和现阶段分布点的比例,在4种气候情景(RCP2.6、RCP4.5、RCP6.0、RCP8.5)下,预测未来西康玉兰适生区分布范围以及其质心转移的变化。结果表明:MaxEnt模型预测西康玉兰潜在生境分布的特征曲线(ROC)训练集的AUC(ROC曲线下的面积)值为0.972;年均降水量、昼夜温差与年温差比值、湿度最小季度平均气温、最冷月份最低温是影响西康玉兰分布的主要气候因子,其贡献率分别为33.8%、26.7%、14.6%、14.3%。现阶段,西康玉兰的高、中、低适生区集中分布于云贵川三省交界地带,适生区总面积104.52×10^(4)km^(2),其中高适生区占总适生面积的16.62%,现有分布点处于高适生区内的比例为65.11%。未来20~50 a,全球气候变暖将有利于西康玉兰在中国的分布,其适生区分布基本格局不变,适生区总面积增加,但高适生区的东侧与南侧有缩减与破碎化的趋势;现阶段西康玉兰的潜在分布中心位于四川省的西昌市德昌县内,西康玉兰潜在分布中心有向西北部迁移的趋势,将迁移至西昌市的盐源县内。因此,对西康玉兰濒危资源的保护应结合地理分布,制定多样性保护策略(野生资源调查、野外回归的迁地保护、建立保护区、开展繁殖与栽培技术等)。
文摘The contents of flavonoid in the leaf and stem of Sargentodoxa cuneata (Oliv.) Rehd. et Wils. were determined. In a whole growth season, the dynamic chang of flavonoid in the leafblade of S. cuneata showed the two-peak pattern. The first peak appeared at June and the second at September. The seasonal dynamic change of flavonoids in leafstalk, annual twig and perennial stem were different and inconspicuous. The flavonoid cumulated maximally in the leafblade and the followed was seccessively annual twig, leafstalk, and perennial stem. The flavonoid content in leafblade was 31.79 mg/g(DW), while that in annual twig, leafstalk and perennial stem was 5.41 mg/g(DW), 5.30 mg/g(DW) and 3.95 mg/g(DW) respectively. There was markedly higher flavonoid content in leafblade. It is considered that the leaf of Sargentodoxa cuneata is significant in further exploitation.
