Characteristics of chemical components in the trunk xylem sap of pine trees by means of a centrifugation collection method
Characteristics of chemical components in the trunk xylem sap of pine trees by means of a centrifugation collection method
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离心收集法测定松树干木质部汁液化学成分特征
DOI：
10.1016/j.plaphy.2019.08.009
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发表时间：
2019
影响因子：
6.5
通讯作者：
Xinchao Sun
中科院分区：
文献类型：
--
作者：
Lingling Chen;Yanhong Cao;Zhao Zhang;Xueyan Liu;Mengistu T Teramage;Xiaoda Zhang;Xinchao Sun
由于没有合适的方法从树干的这一部分提取木质部汁液，因此对树干木质部汁液中运输的化学成分的特性的了解仍然是缺乏和有限的。因此，我们探讨了木质部汁液成分的差异，通过离心和水置换法提取的树干和不同年龄的松树在中国北方森林的枝条木质部汁液中的化学成分的水平和行为进行了描述。两种方法对木质部汁液中的氮化合物和无机离子的测定结果无显著差异。钾浓度的方法是相似的，并与木本物种从早期出版物获得的值一致。这表明离心法对木质部汁液的污染可以忽略不计，并且该方法将是用于收集树干木质部汁液的可靠且稳健的工具。溶解有机氮是总氮的主要组成部分，其次是硝酸盐（NO3-）和铵（NH 4+）。钾离子和氯离子分别是木质部汁液的主要阳离子和阴离子。NO3-浓度基本上没有变化，而NH 4+浓度更大的运输从树干到树枝的大型乔木类在叶片衰老。幼树中的无机氮组分（主要是NO3-）多于老树。本研究有助于提高对环境变化下成熟林木生理过程和生长的诊断评估。
Knowledge of the characteristics of chemical components transported in the xylem sap of trunks remains deficient and limited because no appropriate method exists to extract the xylem sap from this part of the tree. We thus explored the differences in xylem sap components extracted by means of centrifugation and water displacement methods and depicted the level and behavior of chemical components in the xylem sap of trunks and branches of different aged trees from a pine forest in northern China. There were no significant differences between the two methods with respect to nitrogen (N) compounds and inorganic ions in the xylem sap. Potassium concentrations obtained by the methods were similar and consistent with the values obtained from earlier publications on woody species. This suggests that contamination of the xylem sap by the centrifugation method is negligible, and this method would be a reliable and robust tool for collection of the trunk xylem sap. Dissolved organic N was the dominant component of total N followed by nitrate (NO3−) and ammonium (NH4+). Potassium and chloride were the predominant cation and anion, respectively, of the xylem sap. The NO3−concentration basically did not change, whereas the NH4+concentration was larger transported from the trunk to branches for the large tree class during foliage senescence. More inorganic N components (mainly NO3−) were found in young trees than in old trees. Our study contributes to improve the diagnostic assessments of tree physiological processes and growth in mature forest trees under environmental changes.