Chinese Journal of Plant Ecology >
Effects of previous nitrogen addition on aboveground and belowground carbon and nitrogen allocation dynamics in drought-exposed sessile oak seedlings
Received date: 2024-07-04
Accepted date: 2025-01-20
Online published: 2025-01-20
Supported by
National Natural Science Foundation of China(32360259);National Natural Science Foundation of China(32460379);Guizhou Provincial Science and Technology Projects(ZK[2023]YIBAN110);Guizhou Provincial Science and Technology Projects(ZK[2022]YIBAN101)
Aims Drought effects on the carbon (C) balance are considered the major factor of tree mortality and are assumed to be regulated by soil nutrient (e.g., nitrogen (N)) availability. However, the effects of nitrogen addition on trees’ carbon and nitrogen distribution between aboveground and belowground and the coupling between carbon and nitrogen relations in various organs in response to drought are still unclear in trees.
Methods A two-year full factorial microcosm experiment was set up with sessile oak (Quercus petraea). Nitrogen addition was performed in the first year, and a drought treatment was conducted in the second year. Isotope 15N and 13C labelling were carried out before drought and during drought, respectively. Three consecutive samplings were conducted after the dual labelling with 13C and 15N in the second year, and the effects of nitrogen addition on carbon and nitrogen allocation dynamics during progressive drought were tested.
Important findings Our results showed that previous nitrogen addition promoted photosynthetic carbon fixation and nitrogen allocation, increased root nitrogen uptake, reduced the non-structural carbohydrates (NSC) contents in all organs and changed the relationships of carbon and nitrogen in aboveground and belowground organs. In contrast, drought had minor effects on nitrogen and carbon allocation between aboveground and belowground and the relationship of carbon with nitrogen in all organs (represented by the ratio of 13C to 15N in all organs). Drought only significantly reduced the content of NSC. During drought (from day 40 to 73), previous nitrogen addition led sessile oak to prioritise belowground carbon and nitrogen allocation. Our results indicate that sessile oak can change its carbon and nitrogen allocation strategies to adapt to drought, while previous nitrogen addition may increase its drought sensitivity.
FENG Mei , OUYANG Sheng-Nan , Matthias SAURER , LI Mai-He , ZHOU Xiao-Qian , TIE Lie-Hua , SHEN Wei-Jun , DUAN Hong-Lang , Arthur GESSLER . Effects of previous nitrogen addition on aboveground and belowground carbon and nitrogen allocation dynamics in drought-exposed sessile oak seedlings[J]. Chinese Journal of Plant Ecology, 2025 , 49(9) : 1527 -1542 . DOI: 10.17521/cjpe.2024.0218
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