额济纳绿洲胡杨(Populus euphratica)酚类物质含量和分布及其与土壤水分的关系

Concentration and distribution of phenolic compounds in Populus euphratica in Ejina oasis and their correlation with soil water contents

采用分光光度法测定了额济纳绿洲胡杨（Populus euphratica）的披针形叶、卵圆形叶、嫩枝、枝（D〈5mm）、枝（5～10mm）、主干树皮、根（D〈2mm）、根（2～5mm）和根（5～10mm）9类器官中的总酚、黄酮和缩合单宁含量。结果表明，总酚含量较高的器官为皮（27．93mg／g），叶、根、枝中总酚含量分别为17．64mg／g（两类叶均值）、16．72mg／g（三类根均值）、12．19mg／g（三类枝均值）；黄酮含量较高的器官为皮（51．30mg／g），叶、根、枝中黄酮含量分别为28．45mg／g（两类叶均值）、39．99mg／g（三类根均值）、23．67mg／g（三类枝均值）；根中缩合单宁含量较高，三类根均值为22．10mg／g，皮、叶、枝中缩合单宁含量分别为8．41mg／g、4．03mg／g（两类叶均值）、4．47mg／g（三类枝均值）。披针形叶和卵圆形叶中酚类物质含量没有显著性差异（P〉0．05）；随着枝不断成熟，嫩枝、枝（D〈5mm）、枝（5～10mm）中酚类物质逐渐减少；随着根直径减少，根中缩合单宁逐渐增加，细根（D〈2mm）中的缩合单宁含量最高（25．95mg／g）。分析胡杨各器官中酚类物质含量与土壤水分的关系，结果表明卵圆形叶中酚类物质含量与土壤水分含量成显著负相关关系（P〈0．05，总酚：r=-0．949；黄酮：r=-0．923；缩合单宁：r=-0．944）。研究揭示了极端干旱地区胡杨各器官中酚类物质的变化规律，及其与环境因子的相互作用关系。

With colorimetric methods, the concentrations of total phenolics, flavonoids and condensed tannins were measured in nine categories of organs within Populus euphratica, including lanccolate leaves, ovate leaves, green branches, branches （D 〈5 mm in diameter）, branches （5-10 mm）, barks, roots （D〈2 mm roots （5- 10mm）. The results showed phenolic compounds were present throughout in diameter）, roots （2-5 mm） and the collected organs with the higher total phenolics concentrations in barks （ 27.93 mg/g）, and the mean total phenolics concentrations in two categories of leaves, roots and branches in three classes were 17.64 mg/g, 16.72mg/g, and 12.19 mg/g respectively. The higher flavonoids were present in barks （51.30 mg/g）, and the mean flavonoids contents in two categories of leaves, roots and branches in three classes were 28.45 mg/g, 39.99 mg/g, and 23.67 mg/g respectively. And the higher condense tannins contents were found in roots （ mean = 22.10 mg/g for three categories of roots）, and the average condense tannins contents in barks, leaves in two categories, and branches in three classes were 8.41 mg/g, 4. 03 mg/g, and 4.47 mg/g respectively. There was no significant difference between the phenolic compounds of lanccolate leaves and ovate leaves （ P 〉 0.05 ）. Phenolic compounds in branches decreased with the branches maturation and resulted in the orders as follow： green branches 〉 branches （D 〈5 mm） 〉 branches （5 - 10 mm）. Condensed tannins in roots decreased with the root diameter, and the highest condensed tannins contents were found in small root （D 〈 2mm） （25.95 mg/g）. By analyzing correlation between phenolic compounds in all collected organs and soil water contents, the results indicated that the phenolic compounds in ovate leaves had negative relation with soil water contents （ P 〈 0.05 ）, and the r values for total phenohcs, flavonoids and condensed tannins were - 0. 949, - 0. 923 and - 0. 944 respectively. Data reported here revealed the variation of phenolics compound in different organs of P. euphratica, and their relationships with the environmental factors in extremely arid areas were discussed.