Linkage of root physiology and morphology as an adaptation to soil phosphorus impoverishment in tropical montane forests
Linkage of root physiology and morphology as an adaptation to soil phosphorus impoverishment in tropical montane forests
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DOI：
10.1111/1365-2435.12424
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发表时间：
2015-09-01
影响因子：
5.2
通讯作者：
Kitayama, Kanehiro
中科院分区：
文献类型：
--
作者：
Ushio, Masayuki;Fujiki, Yasuto;Kitayama, Kanehiro
婆罗洲的热带森林即使在磷（P）有限的条件下也保持高水平的生产力/生物量。本文以云南高山热带山地森林3种主要树种为研究对象，分析了其根系酸性磷酸酶活性和根系表面积、直径、组织密度等形态特征，并对根系的磷吸收特性进行了研究。结果表明，在群落水平上，根系磷酸酶活性和比根表面积沿着土壤磷素有效性梯度的变化而变化，在群落水平上，随着土壤磷有效性的降低，根系表面积（每克根系生物量）增加，根系直径减小，即使我们集中在一个单一的树种分布在多个研究地点，不同的土壤磷的有效性的关系并没有改变。根系酸性磷酸酶活性与比根表面积呈显著正相关，与根径呈显著负相关，说明细根具有较高的磷酸酶活性。相关性分析表明，根系磷吸收特性影响叶片磷浓度，反之亦然。树木个体的地下特性（即根系磷获取特性）可能与地上特性（即叶片磷浓度）直接/间接相关。总之，热带山地森林的根系生理和形态特性沿着土壤磷有效性的梯度而变化。此外，根系性状的变化与叶片磷浓度的变化相协调。地上和地下部分性质沿着土壤磷梯度的适应性变化有助于维持婆罗洲热带山地森林的生产力。
Tropical forests in Borneo maintain a high level of productivity/biomass even under phosphorus (P)-limited conditions. The P-acquisition properties of roots may be an important factor that contributes to forest productivity, but they have not been well evaluated compared with above-ground properties of plants.In this study, we analysed root acid phosphatase activity and morphological properties (surface area, diameter and tissue density of roots) of dominant tree species in three tropical montane forests on Mt. Kinabalu, Borneo, to investigate changes in root properties along a soil P availability gradient.We found at the community level that root phosphatase activity and specific root surface area (root surface area per gram root biomass) increased, and root diameter decreased, with decreasing soil P availability at the community level, and the relationship was not changed in general even if we focused on a single-tree species distributed across multiple study sites that differ in soil P availability. Root acid phosphatase was significantly positively correlated with specific root surface area, and negatively correlated with root diameter, suggesting that finer roots have higher phosphatase activities.Furthermore, we compared root acid phosphatase activity with leaf P concentration of a given tree species and found a significant negative correlation between them. The significant correlation suggested that root P-acquisition properties could influence leaf P concentration, and/or viceversa. Below-ground properties (i.e. root P-acquisition properties) might be directly/indirectly linked to above-ground properties (i.e. leaf P concentration) of a tree individual.In conclusion, the root physiological and morphological properties change along a gradient of soil P availability in the tropical montane forests. In addition, the changes in the root properties are coordinated with the changes in leaf P concentrations. The adaptive changes in the above-ground and below-ground properties along the soil P gradient could contribute to the maintenance of forest productivity in the tropical montane forest in Borneo.