Incidence of controlled water restriction on density and chemical profiles in tree rings of Araucaria araucana seedlings  

作　　者：Sofía Papú Daigard Ricardo Ortega‑Rodriguez Fidel Alejandro Roig Florencia Navas 

机构地区：[1]Instituto Argentino de Nivologia Glaciologia y Ciencias Ambientales(IANIGLA,CONICET),Mendoza,Argentina [2]Universidade de Sao Paulo,Escola Superior de Agricultura Luiz de Queiroz,Departamento de Ciências Florestais,Piracicaba,Brazil [3]Facultad de Ciencias Agrarias,Universidad Nacional de Cuyo,Mendoza,Argentina

出　　处：《Ecological Processes》2024年第3期52-66,共15页生态过程(英文)

基　　金：supported by Consejo Nacional de Investigaciones Cientí‑fcas y Técnicas(CONICET,Argentina)through a doctoral fellowship to Sofía Papúand a project funded by the Agencia Nacional de Promoción Científca y Tecnológica(PICT-2679)and the program Bosques Andinos-HELVETAS Swiss Intercooperation;This research is a contribution to the NSF-FAPESP PIRE pro‑ject grants 2009/53951-7,2017/50085-3,2018/22914-8,2020/04608-7.

摘　　要：Background Dehydration of plant tissues caused by water stress affects the dynamics of the lateral cambium, the rate of cell division and differentiation in cell lumen size, wall thickness and wall chemical properties. Based on evidence that ongoing climate change projects longer and more intense water stress conditions, forest dynam-ics and decline are predicted to be affected by increases in drought intensity and frequency. To verify the interaction of these phenomena, we described the modifications in the anatomy and mineral contents of annual growth rings of Araucaria araucana seedlings subjected to water stress treatments, using X-ray densitometry and X-ray fluores-cence techniques.Results Severe water stress conditions during the growing period produced narrower tree rings, with reduced cell lumen size(5–7 μm) and higher tracheid reinforcement factor values, but with lower wood density. Plants subjected to moderate water stress generated intra-annual density fluctuations coinciding with periods of decreased soil moisture. Under the precept that the essential nutrients play a relevant role in the functioning of trees, we found evidence of element allocation and concentration in response to drought. Calcium and phosphorus concentration increased significantly as stress becomes more severe, but with small differences between early- and latewood. On the contrary, potassium and sulfur presented lower values in the most stressed plants, and manganese had the lowest values only for moderate water stress. Finally, S/Ca and K/Ca molar ratios decreased, while Ca/Mn increased as stress becomes more severe.Conclusions Our findings suggested that A. araucana seedlings invested resources aimed at increasing structural components of the cell wall to prevent cavitation. This would maintain metabolism and cell growth even in unfavora-ble environmental conditions. Furthermore, the imbalance of manganese and calcium and their consequent ratio(Ca/Mn) could be linked to early adaptive signals to avoid dieback.

关 键 词：Wood density Wood anatomy Wood chemistry Water stress Intra-annual density fuctuation Climate change 

分 类 号：TG1[金属学及工艺—金属学]