Root responses to nitrogen pulse frequency under different nitrogen amounts |
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| Institution: | 1. School of Nature Conservation, Beijing Forestry University, Beijing 100083, China;2. Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou 318000, China;1. Programa de Pós-Graduação em Biologia de Fungos, Universidade Federal de Pernambuco, Av. da Engenharia, s/n, Cidade Universitária, CEP 50740-600, Recife, PE, Brazil;2. Laboratório de Microbiologia, Universidade Federal do Vale do São Francisco, Campus de Ciências Agrárias, Rodovia BR 407, Km 12, Lote 543, Projeto de Irrigação Nilo Coelho, s/n, ‘‘C1’’, Petrolina, PE CEP 56300-990, Brazil;3. Embrapa Milho e Sorgo, Núcleo de Biologia Aplicada, Rod. MG 424 KM 45 - Bairro Esmeraldas, SN, Caixa Postal 285, CEP 35701-970, Sete Lagoas, MG, Brazil;4. Agroscope, Ecotoxicology, Schloss 1, CH-8820 Wädenswil, Switzerland;1. Division of Conservation Biology, Institute of Ecology and Evolution, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland;2. Swiss Ornithological Institute, Valais Field Station, 1950 Sion, Switzerland;1. Laboratorio de Ecologia, CCBS, Universidade Federal do Mato Grosso do Sul, Campo Grande, MS 79070-900, Brazil;2. Departmento de Ecologia, Universidade Federal do Rio Grande do Norte, Natal, RN, 59078-900, Brazil |
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| Abstract: | Responses of morphology and biomass allocation of roots to frequency of nitrogen (N) pulse potentially influence the fitness of plants, but such responses may be determined by root size. We grew 12 plant species of three functional groups (grasses, forbs, and legumes) under two N pulse frequencies (high vs. low supply frequency) and two N amounts (high vs. low supply amount). Compared to low-amount N supply, high-amount N supply stimulated biomass accumulation and root growth by either increasing the thickness and length of roots or decreasing the root mass fraction. Compared to low-frequency N supply, high-frequency N supply improved biomass accumulation and root growth in forbs or grasses, but not in legumes. Furthermore, the magnitude of the response to N frequency was significantly negatively correlated with root size at the species scale, but this was only true when the N amount was high. We conclude that root responses to N frequency are related to plant functional types, and non-legume species is more sensitive to N frequency than legume species. Our results also suggest that root size is a determinant of root responses to N frequency when N supply amount is high. |
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| Keywords: | Plant functional groups Root growth Root morphology Root size Terrestrial species |
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