Species-specific responses of C and N allocation to N addition: evidence from dual
13C and
15N labeling in three tree species.
THE SCIENCE OF THE TOTAL ENVIRONMENT 2024;
927:172164. [PMID:
38580112 DOI:
10.1016/j.scitotenv.2024.172164]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/29/2024] [Accepted: 03/31/2024] [Indexed: 04/07/2024]
Abstract
Soil nitrogen (N) availability affects plant carbon (C) utilization. However, it is unclear how various tree functional types respond to N addition in terms of C assimilation, allocation, and storage. Here, a microcosm experiment with dual 13C and 15N labeling was conducted to study the effects of N addition (i.e., control, 0 g N kg-1; moderate N addition, 1.68 g N kg-1; and high N addition, 3.36 g N kg-1 soil) on morphological traits, on changes in nonstructural carbohydrates (NSC) in different organs, as well as on C and N uptake and allocation in three European temperate forest tree species (i.e., Acer pseudoplatanus, Picea abies and Abies alba). Our results demonstrated that root N uptake rates of the three tree species increased by N addition. In A. pseudoplatanus, N uptake by roots, N allocation to aboveground organs, and aboveground biomass allocation significantly improved by moderate and high N addition. In A. alba, only the high N addition treatment considerably raised aboveground N and C allocation. In contrast, biomass as well as C and N allocation between above and belowground tissues were not altered by N addition in P. abies. Meanwhile, NSC content as well as C and N coupling (represented by the ratio of relative 13C and 15N allocation rates in organs) were affected by N addition in A. pseudoplantanus and P. abies but not in A. alba. Overall, A. pseudoplatanus displayed the highest sensitivity to N addition and the highest N requirement among the three species, while P. abies had a lower N demand than A. alba. Our findings highlight that the responses of C and N allocation to soil N availability are species-specific and vary with the amount of N addition.
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