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Massonnet C, Chuste PA, Zeller B, Tillard P, Gerard B, Cheraft L, Breda N, Maillard P. Does long-term drought or repeated defoliation affect seasonal leaf N cycling in young beech trees? TREE PHYSIOLOGY 2024; 44:tpae054. [PMID: 38769932 DOI: 10.1093/treephys/tpae054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 05/14/2024] [Accepted: 05/17/2024] [Indexed: 05/22/2024]
Abstract
Forest trees adopt effective strategies to optimize nitrogen (N) use through internal N recycling. In the context of more recurrent environmental stresses due to climate change, the question remains of whether increased frequency of drought or defoliation threatens this internal N recycling strategy. We submitted 8-year-old beech trees to 2 years of either severe drought (Dro) or manual defoliation (Def) to create a state of N starvation. At the end of the second year before leaf senescence, we labeled the foliage of the Dro and Def trees, as well as that of control (Co) trees, with 15N-urea. Leaf N resorption, winter tree N storage (total N, 15N, amino acids, soluble proteins) and N remobilization in spring were evaluated for the three treatments. Defoliation and drought did not significantly impact foliar N resorption or N concentrations in organs in winter. Total N amounts in Def tree remained close to those in Co tree, but winter N was stored more in the branches than in the trunk and roots. Total N amount in Dro trees was drastically reduced (-55%), especially at the trunk level, but soluble protein concentrations increased in the trunk and fine roots compared with Co trees. During spring, 15N was mobilized from the trunk, branches and twigs of both Co and Def trees to support leaf growth. It was only provided through twig 15N remobilization in the Dro trees, thus resulting in extremely reduced Dro leaf N amounts. Our results suggest that stress-induced changes occur in N metabolism but with varying severity depending on the constraints: within-tree 15N transport and storage strategy changed in response to defoliation, whereas a soil water deficit induced a drastic reduction of the N amounts in all the tree organs. Consequently, N dysfunction could be involved in drought-induced beech tree mortality under the future climate.
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Affiliation(s)
- Catherine Massonnet
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
| | - Pierre-Antoine Chuste
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
| | | | - Pascal Tillard
- UMR 5004, Biochimie et Physiologie Moléculaire des Plantes, INRAE/CNRS/Montpellier SupAgro/Université Montpellier, Place Viala, 34060 Montpellier, Cedex 2, France
| | - Bastien Gerard
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
| | - Loucif Cheraft
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
| | - Nathalie Breda
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
| | - Pascale Maillard
- Université de Lorraine, AgroParisTech, INRAE, Silva, route d'Amance, 54280 Champenoux, France
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He P, Sardans J, Wang X, Ma C, Man L, Peñuelas J, Han X, Jiang Y, Li MH. Nutritional changes in trees during drought-induced mortality: A comprehensive meta-analysis and a field study. GLOBAL CHANGE BIOLOGY 2024; 30:e17133. [PMID: 38273504 DOI: 10.1111/gcb.17133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 12/13/2023] [Accepted: 12/15/2023] [Indexed: 01/27/2024]
Abstract
Both macronutrients and micronutrients are essential for tree growth and development through participating in various ecophysiological processes. However, the impact of the nutritional status of trees on their ability to withstand drought-induced mortality remains inconclusive. We thus conducted a comprehensive meta-analysis, compiling data on 11 essential nutrients from 44 publications (493 independent observations). Additionally, a field study was conducted on Pinus sylvestris L. trees with varying drought-induced vitality loss in the "Visp" forest in southern Switzerland. No consistent decline in tree nutritional status was observed during tree mortality. The meta-analysis revealed significantly lower leaf potassium (K), iron (Fe), and copper (Cu) concentrations with tree mortality. However, the field study showed no causal relationships between nutritional levels and the vitality status of trees. This discrepancy is mainly attributed to the intrinsic differences in the two types of experimental designs and the ontogenetic stages of target trees. Nutrient reductions preceding tree mortality were predominantly observed in non-field conditions, where the study was conducted on seedlings and saplings with underdeveloped root systems. It limits the nutrient uptake capacity of these young trees during drought. Furthermore, tree nutritional responses are also influenced by many variables. Specifically, (a) leaf nutrients are more susceptible to drought stress than other organs; (b) reduced tree nutrient concentrations are more prevalent in evergreen species during drought-induced mortality; (c) of all biomes, Mediterranean forests are most vulnerable to drought-induced nutrient deficiencies; (d) soil types affect the direction and extent of tree nutritional responses. We identified factors that influence the relationship between tree nutritional status and drought survival, and proposed potential early-warning indicators of impending tree mortality, for example, decreased K concentrations with declining vitality. These findings contribute to our understanding of tree responses to drought and provide practical implications for forest management strategies in the context of global change.
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Affiliation(s)
- Peng He
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin, China
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
| | - Jordi Sardans
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, Catalonia, Spain
| | - Xiaoyu Wang
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- Jiyang College, Zhejiang Provincial Key Laboratory of Germplasm Innovation and Utilization for Garden Plants, Zhejiang Agriculture and Forestry University, Hangzhou, China
| | - Chengcang Ma
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin, China
| | - Liang Man
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, Tianjin, China
| | - Josep Peñuelas
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, Catalonia, Spain
| | - Xingguo Han
- College of Life Sciences, Hebei University, Baoding, China
| | - Yong Jiang
- College of Life Sciences, Hebei University, Baoding, China
| | - Mai-He Li
- Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmensdorf, Switzerland
- College of Life Sciences, Hebei University, Baoding, China
- Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains, Ministry of Education, School of Geographical Sciences, Northeast Normal University, Changchun, China
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