Fertilization Changes Chemical Defense in Needles of Mature Norway Spruce (Picea abies)
Nitrogen availability limits growth in most boreal forests. However, parts of the boreal zone receive significant levels of nitrogen deposition. At the same time, forests are fertilized to increase volume growth and carbon sequestration. No matter the source, increasing nitrogen in the boreal forest...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2018-06-01
|
| Series: | Frontiers in Plant Science |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/article/10.3389/fpls.2018.00770/full |
| _version_ | 1819020164310499328 |
|---|---|
| author | Line Nybakken Marit H. Lie Riitta Julkunen-Tiitto Johan Asplund Mikael Ohlson |
| author_facet | Line Nybakken Marit H. Lie Riitta Julkunen-Tiitto Johan Asplund Mikael Ohlson |
| author_sort | Line Nybakken |
| collection | DOAJ |
| description | Nitrogen availability limits growth in most boreal forests. However, parts of the boreal zone receive significant levels of nitrogen deposition. At the same time, forests are fertilized to increase volume growth and carbon sequestration. No matter the source, increasing nitrogen in the boreal forest ecosystem will influence the resource situation for its primary producers, the plants, with possible implications for their defensive chemistry. In general, fertilization reduces phenolic compound concentrations in trees, but existing evidence mainly comes from studies on young plants. Given the role of the phenolic compounds in protection against herbivores and other forest pests, it is important to know if phenolics are reduced with fertilization also in mature trees. The evergreen Norway spruce is long-lived, and it is reasonable that defensive strategies could change from the juvenile to the reproductive and mature phases. In addition, as the needles are kept for several years, defense could also change with needle age. We sampled current and previous year needles from an N fertilization experiment in a Norway spruce forest landscape in south-central Norway to which N had been added annually for 13 years. We analyzed total nitrogen (N) and carbon (C), as well as low-molecular phenolics and condensed tannins. Needles from fertilized trees had higher N than those from controls plots, and fertilization decreased concentrations of many flavonoids, as well as condensed tannins in current year needles. In previous year needles, some stilbenes and condensed tannins were higher in fertilized trees. In control trees, the total phenolic concentration was almost five times as high in previous year needles compared with those from the current year, and there were great compositional differences. Previous year needles contained highest concentrations of acetophenone and stilbenes, while in the current year needles the flavonoids, and especially coumaroyl-astragalins dominated. Condensed tannins did not differ between current and previous year needles from control trees. In conclusion, the phenolic defense of current year needles of mature P.abies trees was strongly changed upon fertilization. This may imply that nitrogen deposition and forest fertilization leave forests less robust in a time when pests may take advantages of a changing climate. |
| first_indexed | 2024-12-21T03:46:51Z |
| format | Article |
| id | doaj.art-09455a7a65c841d6b407aff65e6713e1 |
| institution | Directory Open Access Journal |
| issn | 1664-462X |
| language | English |
| last_indexed | 2024-12-21T03:46:51Z |
| publishDate | 2018-06-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Plant Science |
| spelling | doaj.art-09455a7a65c841d6b407aff65e6713e12022-12-21T19:17:03ZengFrontiers Media S.A.Frontiers in Plant Science1664-462X2018-06-01910.3389/fpls.2018.00770382879Fertilization Changes Chemical Defense in Needles of Mature Norway Spruce (Picea abies)Line Nybakken0Marit H. Lie1Riitta Julkunen-Tiitto2Johan Asplund3Mikael Ohlson4Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Akershus, NorwayFaculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Akershus, NorwayDepartment of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, FinlandFaculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Akershus, NorwayFaculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, Ås, Akershus, NorwayNitrogen availability limits growth in most boreal forests. However, parts of the boreal zone receive significant levels of nitrogen deposition. At the same time, forests are fertilized to increase volume growth and carbon sequestration. No matter the source, increasing nitrogen in the boreal forest ecosystem will influence the resource situation for its primary producers, the plants, with possible implications for their defensive chemistry. In general, fertilization reduces phenolic compound concentrations in trees, but existing evidence mainly comes from studies on young plants. Given the role of the phenolic compounds in protection against herbivores and other forest pests, it is important to know if phenolics are reduced with fertilization also in mature trees. The evergreen Norway spruce is long-lived, and it is reasonable that defensive strategies could change from the juvenile to the reproductive and mature phases. In addition, as the needles are kept for several years, defense could also change with needle age. We sampled current and previous year needles from an N fertilization experiment in a Norway spruce forest landscape in south-central Norway to which N had been added annually for 13 years. We analyzed total nitrogen (N) and carbon (C), as well as low-molecular phenolics and condensed tannins. Needles from fertilized trees had higher N than those from controls plots, and fertilization decreased concentrations of many flavonoids, as well as condensed tannins in current year needles. In previous year needles, some stilbenes and condensed tannins were higher in fertilized trees. In control trees, the total phenolic concentration was almost five times as high in previous year needles compared with those from the current year, and there were great compositional differences. Previous year needles contained highest concentrations of acetophenone and stilbenes, while in the current year needles the flavonoids, and especially coumaroyl-astragalins dominated. Condensed tannins did not differ between current and previous year needles from control trees. In conclusion, the phenolic defense of current year needles of mature P.abies trees was strongly changed upon fertilization. This may imply that nitrogen deposition and forest fertilization leave forests less robust in a time when pests may take advantages of a changing climate.https://www.frontiersin.org/article/10.3389/fpls.2018.00770/fullnitrogenfertilizationphenolicschemical defensePicea abiesspruce |
| spellingShingle | Line Nybakken Marit H. Lie Riitta Julkunen-Tiitto Johan Asplund Mikael Ohlson Fertilization Changes Chemical Defense in Needles of Mature Norway Spruce (Picea abies) Frontiers in Plant Science nitrogen fertilization phenolics chemical defense Picea abies spruce |
| title | Fertilization Changes Chemical Defense in Needles of Mature Norway Spruce (Picea abies) |
| title_full | Fertilization Changes Chemical Defense in Needles of Mature Norway Spruce (Picea abies) |
| title_fullStr | Fertilization Changes Chemical Defense in Needles of Mature Norway Spruce (Picea abies) |
| title_full_unstemmed | Fertilization Changes Chemical Defense in Needles of Mature Norway Spruce (Picea abies) |
| title_short | Fertilization Changes Chemical Defense in Needles of Mature Norway Spruce (Picea abies) |
| title_sort | fertilization changes chemical defense in needles of mature norway spruce picea abies |
| topic | nitrogen fertilization phenolics chemical defense Picea abies spruce |
| url | https://www.frontiersin.org/article/10.3389/fpls.2018.00770/full |
| work_keys_str_mv | AT linenybakken fertilizationchangeschemicaldefenseinneedlesofmaturenorwaysprucepiceaabies AT marithlie fertilizationchangeschemicaldefenseinneedlesofmaturenorwaysprucepiceaabies AT riittajulkunentiitto fertilizationchangeschemicaldefenseinneedlesofmaturenorwaysprucepiceaabies AT johanasplund fertilizationchangeschemicaldefenseinneedlesofmaturenorwaysprucepiceaabies AT mikaelohlson fertilizationchangeschemicaldefenseinneedlesofmaturenorwaysprucepiceaabies |