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摘要
Few study examined the possible influence of artificially altering soil moisture content on stem respiration (R-s) and stem chemical composition together, we artificially simulated four soil moisture gradients in Dalbergia odorifera (D. odorifera) plantations and investigated R-s, predawn shoot water potential (psi(pd)), nitrogen content, and non-structural carbohydrates (NSCs) over time. Stem temperature (T-s) and R-s declined continuously during the dry period and reached their minimum values in January. Irrigation increased the R-s rate, while drought decreased it. The nitrogen content of the sapwood remained constant until December, after which it decreased when winter began. During the winter, the sapwood nitrogen increased under irrigation but decreased under drought conditions. The soluble sugars tended to increase during the dry period at the cost of starch, which caused a small but non-significant increase in NSCs. The effect of water treatments on total NSCs was limited; however the drought treatments increased the soluble sugars content but decreased the starch content. R-s explained 49, 72 and 40% of the seasonal variation in the stem nitrogen, starch and soluble sugars, respectively. The psi(pd) significantly explained 49, 79 and 85% of the variation in the R-s, stem starch and soluble sugars, respectively. Thus, soil moisture content likely affects R-s by affecting the amount of sapwood nitrogen, starch and soluble sugars. Low soil moisture content induced by drought enhanced the transformation of starch to soluble sugars during the winter, when heartwood formed. These strong relationships may provide interesting implication for future study on heartwood formation.
- 出版日期2017
- 单位华南农业大学; 华南热带农业大学; 中国林业科学研究院热带林业研究所; 中国林业科学研究院
