Separating water-potential induced swelling and shrinking from measured radial stem variations reveals a cambial growth and osmotic concentration signal
Separating water-potential induced swelling and shrinking from measured radial stem variations reveals a cambial growth and osmotic concentration signal
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DOI：
10.1111/pce.12541
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发表时间：
2016-02-01
影响因子：
7.3
通讯作者：
Nikinmaa, Eero
中科院分区：
文献类型：
--
作者：
Chan, Tommy;Holtta, Teemu;Nikinmaa, Eero
在短时间内形成层生长的量化一直受到阻碍的问题，以区分生长和膨胀和收缩的树干。本文提出了一个模型，分离形成层的生长和可逆的水势引起的日变化，同时测量整个干和木质部的径向变化，从现场测量的苏格兰松树在芬兰。模拟的增长，其中包括渗透浓度的变化，进行了比较（直接）测树仪测量和微芯样品。此外，模型的生长和测树仪测量环境因子的关系进行了分析。结果表明，成功地将水势引起的树径变化与树干生长分离开来。模型预测的日生长量与模型模拟的韧皮部渗透浓度日变化具有高度相关性，并在初夏表现出温度依赖性。夏末的生长更依赖于水的供应和温度。对测树仪测量模型的评价表明，后者掩盖了真正的环境信号，由于水电位引起的变化，在茎生长。该模型提供了更好地了解径向生长生理，并提供了潜在的检查生长动力学和变化，由于渗透浓度，以及环境如何影响生长。
The quantification of cambial growth over short time periods has been hampered by problems to discern between growth and the swelling and shrinking of a tree stem. This paper presents a model, which separates cambial growth and reversible water-potential induced diurnal changes from simultaneously measured whole stem and xylem radial variations, from field-measured Scots pine trees in Finland. The modelled growth, which includes osmotic concentration changes, was compared with (direct) dendrometer measurements and microcore samples. In addition, the relationship of modelled growth and dendrometer measurements to environmental factors was analysed. The results showed that the water-potential induced changes of tree radius were successfully separated from stem growth. Daily growth predicted by the model exhibited a high correlation with the modelled daily changes of osmotic concentration in phloem, and a temperature dependency in early summer. Late-summer growth saw higher dependency on water availability and temperature. Evaluation of the model against dendrometer measurements showed that the latter masked a true environmental signal in stem growth due to water-potential induced changes. The model provides better understanding of radial growth physiology and offers potential to examine growth dynamics and changes due to osmotic concentration, and how the environment affects growth.