Dwarf Mistletoe Infection Interacts with Tree Growth Rate to Produce Opposing Direct and Indirect Effects on Resin Duct Defenses in Lodgepole Pine
| Autor: | Scott Ferrenberg |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Pinus contorta Parasitic plant natural enemies 010603 evolutionary biology 01 natural sciences chemistry.chemical_compound pines plant defense Plant defense against herbivory Oleoresin Growth rate Natural enemies Subalpine forest parasitic plant biology fungi oleoresin conifer food and beverages Forestry Arceuthobium americanum lcsh:QK900-989 biology.organism_classification Horticulture chemistry lcsh:Plant ecology tree age 010606 plant biology & botany |
| Zdroj: | Forests, Vol 11, Iss 2, p 222 (2020) Forests Volume 11 Issue 2 |
| ISSN: | 1999-4907 |
| Popis: | Research Highlights: I sought to disentangle the influences of tree age, growth rate, and dwarf mistletoe infection on resin duct defenses in lodgepole pine, Pinus contorta Douglas ex Loudon, revealing the presence of direct positive and indirect negative effects of mistletoe on defenses. Background and Objectives: For protection against natural enemies, pines produce and store oleoresin (resin) in &lsquo resin ducts&rsquo that occur throughout the tree. Dwarf mistletoe, Arceuthobium americanum Nutt. ex Engelm. (hereafter &ldquo mistletoe&rdquo ), is a widespread parasitic plant affecting the pines of western North America. Infection by mistletoe can suppress pine growth and increase the probability of insect attack&mdash possibly due to a reduction in resin duct defenses or in the potency of chemical defenses at higher levels of mistletoe infection, as reported in Pinus banksiana Lamb. However, the influence of mistletoe infection on defenses in other pine species remains unclear. I hypothesized that mistletoe infection would induce greater resin duct defenses in P. contorta while simultaneously suppressing annual growth, which was expected to reduce defenses. Materials and Methods: Using increment cores from P. contorta trees occurring in a subalpine forest of Colorado, USA, I quantified tree age, annual growth, annual resin duct production (#/annual ring), and cross-sectional area (mm2 of resin ducts/annual ring). Results: Mistletoe infection increased with tree age and had a direct positive relationship with resin duct defenses. However, mistletoe infection also had an indirect negative influence on defenses via the suppression of annual growth. Conclusions: Through the combined direct and indirect effects, mistletoe infection had a net positive impact on resin duct production but a net negative impact on the total resin duct area. This finding highlights the complexity of pine defense responses to natural enemies and that future work is needed to understand how these responses influence overall levels of resistance and the risk of mortality. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|