The Experts below are selected from a list of 3591 Experts worldwide ranked by ideXlab platform

Roger T. Koide - One of the best experts on this subject based on the ideXlab platform.

  • Can ectomycorrhizal colonization of Pinus resinosa roots affect their decomposition
    The New phytologist, 2011
    Co-Authors: Roger T. Koide, Christopher W. Fernandez, Matthew S. Peoples
    Abstract:

    Summary •In many forest ecosystems, fine root litter comprises a large pool of organic carbon and nutrients. In temperate climates ectomycorrhizal fungi colonize the roots of many forest plant species. If ectomycorrhizal colonization influenced root decomposition, it could significantly influence carbon sequestration and nutrient cycling. •Fungal tissues and fine roots may decompose at different rates and, therefore, ectomycorrhizal colonization may either hasten or retard root decomposition. Unfortunately, no comparisons of the decomposition of roots and ectomycorrhizal fungi have yet been made. Therefore, we compared decomposition of Pinus resinosa fine roots and ectomycorrhizal fungi from a Pinus resinosa plantation. We also compared the decomposition rates of nonmycorrhizal Pinus resinosa fine roots with roots colonized by nine species of ectomycorrhizal fungi. •We found that the several tested isolates of ectomycorrhizal fungi decomposed far more rapidly than the fine roots and that ectomycorrhizal colonization either had no significant effect on root decomposition or significantly increased root decomposition depending on the isolate of fungus. •We conclude that the composition of an ectomycorrhizal fungal community may affect carbon and nutrient cycling through its influence on root decomposition.

  • Little evidence for respiratory acclimation by microbial communities to short-term shifts in temperature in red pine (Pinus resinosa) litter
    Global Change Biology, 2009
    Co-Authors: Glenna M. Malcolm, Juan C. López-gutiérrez, Roger T. Koide
    Abstract:

    Forest litter is a large reservoir of organic compounds that adds CO 2 to the atmospheric carbon pool when it decomposes. Predicting CO 2 efflux from litter decomposition is difficult because litter can undergo significant diurnal and day-to-day shifts in temperature. Moreover, the relationship between temperature and respiration may change if the decomposer microorganisms acclimate to short-term temperature changes. Therefore, we studied the relationship between temperature and respiration by litter decomposer microorganisms in a Pinus resinosa (Ait.) system and tested the hypothesis that their respiration acclimates to temperature. We found only limited evidence for acclimation following 6 °C shifts for 7 days. This suggests that increase in respiratory CO 2 loss associated with increased temperature would not be greatly ameliorated by physiological acclimation for periods of up to a week.

  • Interactions between needles of Pinus resinosa and ectomycorrhizal fungi
    New Phytologist, 2008
    Co-Authors: Roger T. Koide, L. Suomi, C. M. Stevens, L. Mccormick
    Abstract:

    Relatively little is known about the factors controlling ectomycorrhizal fungal communities. One possible factor is forest litter chemistry. In a series of experiments we demonstrated that the growth of ectomycorrhizal fungi able to colonize red pine (Pinus resinosa Ait.) are differentially affected by red pine needles and needle chemical components. For example, water extracts of pine needles stimulated the growth of Suillus intermedius (Smith & Thiers) Smith & Thiers and inhibited the growth of Amanita rubescens Pers. Catechin and epicatechin gallate, components of the water extract, acted similarly to the extract. The volatile compounds α- and β-pinene also had differential effects on the growth of the various species of ectomycorrhizal fungi. Our results suggest that forest litter chemistry has the potential differentially to affect the growth of ectomycorrhizal fungal species and so could affect the structure of ectomycorrhizal fungal communities.

  • A possible role for saprotrophic microfungi in the N nutrition of ectomycorrhizal Pinus resinosa
    Soil Biology and Biochemistry, 2005
    Co-Authors: Z. Kabir, Roger T. Koide
    Abstract:

    We determined whether Pinus resinosa, selected ectomycorrhizal and saprotrophic microfungi have access to various organic nitrogen sources commonly found in the forest. Vector analysis demonstrated nitrogen limitation of the P. resinosa in the plantation from which most of the fungi were isolated, establishing this study’s relevance. Nonmycorrhizal P. resinosa seedlings did not absorb significant N from amino acids. The ectomycorrhizal fungi, including Pisolithus tinctorius, Suillus intermedius and Tylopilus felleus, obtained substantial N from amino acids, a limited amount of N from glucosamine, and essentially no N from protein–tannin complex. In contrast, Penicillium and Trichoderma readily acquired N from protein–tannin and glucosamine. Thus, there was an increasing ability to obtain N from complex organic N sources from plant to ectomycorrhizal fungi to saprotrophic fungi. Furthermore, N mineralization from an organic N source by Penicillium depended on the C:N ratio. We conclude that acquisition of relatively simple organic N sources by P. resinosa is likely to be largely indirect via ectomycorrhizal fungi, and that more complex organic N sources may become accessible to ectomycorrhizal fungi (and thus possibly their host plants) following mineralization by saprotrophic fungi such as Penicillium or Trichoderma when C:N ratios are sufficiently low. q 2004 Elsevier Ltd. All rights reserved.

  • Ectomycorrhizas and retarded decomposition in a Pinus resinosa plantation
    New Phytologist, 2003
    Co-Authors: Roger T. Koide
    Abstract:

    Summary • Ectomycorrhizas may interact with saprotrophic microorganisms to influence decomposition. These interactions are poorly understood. • We buried mesh envelopes filled with either litter or F-layer material in the forest floor of a Pinus resinosa plantation. After 16 months we characterized decomposition, C : N ratio, water content, and the density of four ectomycorrhiza morphotypes. • For both substrates there were negative correlations between ectomycorrhiza density and decomposition, and between ectomycorrhiza density and water content. The relative proportion of morphotypes was significantly different in litter and F-layer material buried at the same depth in the forest floor. • We conclude that the negative effect of ectomycorrhizas on decomposition could be mediated by extraction of water, particularly in relatively dry years. The ‘Gadgil effect’ may be explained by this phenomenon. In wetter years, water extraction may be less consequential. Also, variation in substrate quality may influence the structure of ectomycorrhizal fungal communities.

R. Kasten Dumroese - One of the best experts on this subject based on the ideXlab platform.

  • Fall fertilization of Pinus resinosa seedlings: nutrient uptake, cold hardiness, and morphological development
    Annals of Forest Science, 2009
    Co-Authors: M. Anisul Islam, Kent G. Apostol, Douglass F. Jacobs, R. Kasten Dumroese
    Abstract:

    Fall fertilization may increase plant nutrient reserves, yet associated impacts on seedling cold hardiness are relatively unexplored. * Bareroot red pine (Pinus resinosa Ait.) seedlings in north-central Minnesota, USA were fall fertilized at the end of the first growing season with ammonium nitrate (NH4 NO3) at 0, 11, 22, 44, or 89 kg N ha−1. Seedling morphology and cold hardiness [assessed by freeze induced electrolyte leakage (FIEL)] were evaluated six weeks after fertilization and following the second growing season. * Seedling height and number of needle primordia increased with fertilizer rate for both sampling years. Seedlings fertilized with 44 and 89 kg N ha−1 attained target height (15 cm) after the second growing season. Shoot and root N concentration increased after the first growing season in fall fertilized seedlings compared to controls. Fall fertilized seedlings had lower FIEL (i.e., increased cold hardiness) compared to controls when tested at -40 °C after the first growing season, but no significant differences in FIEL of control and fertilized seedlings were observed after the second growing season. * Results suggest that fall fertilization of red pine seedlings can help render desired target height in the nursery, while maintaining or increasing cold hardiness levels.

R. Kasten Dumroese - One of the best experts on this subject based on the ideXlab platform.

  • Fall fertilization of Pinus resinosa seedlings: nutrient uptake, cold hardiness, and morphological development
    Annals of Forest Science, 2009
    Co-Authors: M. Anisul Islam, Kent G. Apostol, Douglass F. Jacobs, R. Kasten Dumroese
    Abstract:

    • Fall fertilization may increase plant nutrient reserves, yet associated impacts on seedling cold hardiness are relatively unexplored. • Bareroot red pine (Pinus resinosa Ait.) seedlings in north-central Minnesota, USA were fall fertilized at the end of the first growing season with ammonium nitrate (NH4NO3) at 0, 11, 22, 44, or 89 kg N ha −1 . Seedling morphology and cold hardiness [assessed by freeze induced electrolyte leakage (FIEL)] were evaluated six weeks after fertilization and following the second growing season. • Seedling height and number of needle primordia increased with fertilizer rate for both sampling years. Seedlings fertilized with 44 and 89 kg N ha −1 attained target height (15 cm) after the second

Kent G. Apostol - One of the best experts on this subject based on the ideXlab platform.

  • Fall fertilization of Pinus resinosa seedlings: nutrient uptake, cold hardiness, and morphological development
    Annals of Forest Science, 2009
    Co-Authors: M. Anisul Islam, Kent G. Apostol, Douglass F. Jacobs, R. Kasten Dumroese
    Abstract:

    • Fall fertilization may increase plant nutrient reserves, yet associated impacts on seedling cold hardiness are relatively unexplored. • Bareroot red pine (Pinus resinosa Ait.) seedlings in north-central Minnesota, USA were fall fertilized at the end of the first growing season with ammonium nitrate (NH4NO3) at 0, 11, 22, 44, or 89 kg N ha −1 . Seedling morphology and cold hardiness [assessed by freeze induced electrolyte leakage (FIEL)] were evaluated six weeks after fertilization and following the second growing season. • Seedling height and number of needle primordia increased with fertilizer rate for both sampling years. Seedlings fertilized with 44 and 89 kg N ha −1 attained target height (15 cm) after the second

  • Fall fertilization of Pinus resinosa seedlings: nutrient uptake, cold hardiness, and morphological development
    Annals of Forest Science, 2009
    Co-Authors: M. Anisul Islam, Kent G. Apostol, Douglass F. Jacobs, R. Kasten Dumroese
    Abstract:

    Fall fertilization may increase plant nutrient reserves, yet associated impacts on seedling cold hardiness are relatively unexplored. * Bareroot red pine (Pinus resinosa Ait.) seedlings in north-central Minnesota, USA were fall fertilized at the end of the first growing season with ammonium nitrate (NH4 NO3) at 0, 11, 22, 44, or 89 kg N ha−1. Seedling morphology and cold hardiness [assessed by freeze induced electrolyte leakage (FIEL)] were evaluated six weeks after fertilization and following the second growing season. * Seedling height and number of needle primordia increased with fertilizer rate for both sampling years. Seedlings fertilized with 44 and 89 kg N ha−1 attained target height (15 cm) after the second growing season. Shoot and root N concentration increased after the first growing season in fall fertilized seedlings compared to controls. Fall fertilized seedlings had lower FIEL (i.e., increased cold hardiness) compared to controls when tested at -40 °C after the first growing season, but no significant differences in FIEL of control and fertilized seedlings were observed after the second growing season. * Results suggest that fall fertilization of red pine seedlings can help render desired target height in the nursery, while maintaining or increasing cold hardiness levels.

Douglass F. Jacobs - One of the best experts on this subject based on the ideXlab platform.

  • Fall fertilization of Pinus resinosa seedlings: nutrient uptake, cold hardiness, and morphological development
    Annals of Forest Science, 2009
    Co-Authors: M. Anisul Islam, Kent G. Apostol, Douglass F. Jacobs, R. Kasten Dumroese
    Abstract:

    • Fall fertilization may increase plant nutrient reserves, yet associated impacts on seedling cold hardiness are relatively unexplored. • Bareroot red pine (Pinus resinosa Ait.) seedlings in north-central Minnesota, USA were fall fertilized at the end of the first growing season with ammonium nitrate (NH4NO3) at 0, 11, 22, 44, or 89 kg N ha −1 . Seedling morphology and cold hardiness [assessed by freeze induced electrolyte leakage (FIEL)] were evaluated six weeks after fertilization and following the second growing season. • Seedling height and number of needle primordia increased with fertilizer rate for both sampling years. Seedlings fertilized with 44 and 89 kg N ha −1 attained target height (15 cm) after the second

  • Fall fertilization of Pinus resinosa seedlings: nutrient uptake, cold hardiness, and morphological development
    Annals of Forest Science, 2009
    Co-Authors: M. Anisul Islam, Kent G. Apostol, Douglass F. Jacobs, R. Kasten Dumroese
    Abstract:

    Fall fertilization may increase plant nutrient reserves, yet associated impacts on seedling cold hardiness are relatively unexplored. * Bareroot red pine (Pinus resinosa Ait.) seedlings in north-central Minnesota, USA were fall fertilized at the end of the first growing season with ammonium nitrate (NH4 NO3) at 0, 11, 22, 44, or 89 kg N ha−1. Seedling morphology and cold hardiness [assessed by freeze induced electrolyte leakage (FIEL)] were evaluated six weeks after fertilization and following the second growing season. * Seedling height and number of needle primordia increased with fertilizer rate for both sampling years. Seedlings fertilized with 44 and 89 kg N ha−1 attained target height (15 cm) after the second growing season. Shoot and root N concentration increased after the first growing season in fall fertilized seedlings compared to controls. Fall fertilized seedlings had lower FIEL (i.e., increased cold hardiness) compared to controls when tested at -40 °C after the first growing season, but no significant differences in FIEL of control and fertilized seedlings were observed after the second growing season. * Results suggest that fall fertilization of red pine seedlings can help render desired target height in the nursery, while maintaining or increasing cold hardiness levels.