Impacts of competition and nitrogen addition on plant stoichiometry and non-structural carbohydrates in two larch species

• Published in: Journal of forestry research Vol. 32; no. 5; pp. 2087 - 2098
• Main Authors: Wu, Xiaoyi, Du, Xuhua, Fang, Shiyan, Kang, Jieyu, Xia, Zhichao, Guo, Qingxue
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01-10-2021; Springer; Springer Nature B.V; College of Life and Environmental Sciences,Hangzhou Normal University,Hangzhou 310036,People's Republic of China%Key Laboratory of State Forestry Administration on Bamboo Resources and Utilization,China National Bamboo Research Center,Hangzhou 310012,People's Republic of China
• Subjects: Biomedical and Life Sciences; Branches; Carbohydrates; Competition; Deciduous trees; Forestry; Life Sciences; Mixed forests; Nitrogen; Nitrogen enrichment; Nutrient concentrations; Organs; Original Paper; Photosynthesis; Plant species; Roots; Species; Starch; Stems; Stoichiometry; Intraspecific and interspecific competition; Resource competition; Non-photosynthetic organs; Remobilization and storage; Mixed forest plantations
• ISSN: 1007-662X; 1993-0607
• DOI: 10.1007/s11676-020-01236-1

Previous research has shown that competition between plants can have differential effects on leaf stoichiometry and non-structural carbohydrate (NSC) in different environments. However, little attention has been given to understanding these effects on non-photosynthetic organs, particularly of deciduous tree species. Here we assess the impact of competition on below and aboveground biomass, stoichiometry, nutrient composition and NSC in pure and mixed forests of two Larch species,
Larix kaempferi
and
L. olgensis
under nitrogen (N) addition. Nitrogen enrichment did not result in stronger intraspecific competition for both species and
L. olgensis
benefited from the presence of
L. kaempferi
under different N levels. Stems kept relatively stable C/N compared to roots and branches in response to competition, while N addition imposed stronger impacts on N/P of different organs rather than competition. In contrast to stable C concentrations, starch and soluble sugar concentrations were more easily impacted by competition and the addition of nitrogen. Competition forced
L. kaempferi
and
L. olgensis
to allocate more carbon into storage by increasing their starch concentration and starch/soluble sugar of stems under competition. However, no significant differences in stoichiometry and NSC concentration between intra- and interspecific competition were found. NSC and nutrient pools of
L. kaempferi
stems, branches and coarse roots consistently declined due to competition regardless of N addition. Coarse and fine roots of
L. kaempferi
accumulated more N when in competition with
L. olgensis
than with a conspecific neighbor under N addition. Our results show that NSC was more sensitive to competition relative to stoichiometric traits (N and P) of non-photosynthetic organs.