Symbiont nitrogenase, alder growth, and soil nitrate response to phosphorus addition in alder (Alnus incana ssp. rugosa) wetlands of the Adirondack Mountains, New York State, USA

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  • Environmental and Experimental Botany 55 (2006) 97109

    Symbiont nitrogenase, alder growth, and soil nitrate response tophosphorus addition in alder (Alnus incana ssp. rugosa) wetlands


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    0098-8472/doi:10.1016of the Adirondack Mountains, New York State, USAKemal Gokkayaa, Todd M. Hurdb, Dudley J. Raynalc,

    a University of Florida, Institute of Food and Agricultural Sciences, Soil and Water Science Department,106 Newell Hall, PO Box 110510, Gainesville, FL 32611, USA

    b Shippensburg University, Department of Biology, Shippensburg, PA 17257, USAc State University of New York, College of Environmental Science and Forestry, Faculty of Environmental

    and Forest Biology, 350 Illick Hall, 1 Forestry Drive, Syracuse, NY 13210, USA

    Accepted 6 October 2004

    d alder (Alnus incana ssp. rugosa) is a characteristic species of scrub-shrub 1-type wetlands, the second most commonpe in major watersheds of the Adirondack Mountains in New York State. Speckled alder is an actinorhizal nitrogen

    relies heavily on N2 over soil N and fixes substantial amounts of nitrogen in wetlands, resulting in little vegetationof anthropogenic N between alder-shrub wetlands and streams. Phosphorus (P) is an element that limits nitrogen

    d plant growth. However, studies testing this hypothesis in the field, especially for actinorhizal plants, are very few.tives of this study were to evaluate the potential limitation of N fixation and growth in speckled alder by P, and tointeractions between P fertilization and nitrate levels in riparian alder stands in a region that receives elevated N

    heric deposition. P fertilization significantly increased specific nitrogenase activity during the seasonal peak in earlyitrate concentrations were greater in reference plots compared to treatment plots, and phosphate concentrations wereeference plots compared to treatment plots over a period of 6 weeks in the growing season. There was a significantoliar biomass response to P fertilization in the second year after fertilization, but no significant change in individualr relative numbers of different sized nodules. Response of nitrogen fixation to P appears limited to a brief but significant

    specific activity of nitrogenase late in the growing season, but P stimulated growth of above ground tissues 1 yearfertilizer application, and decreased resin-captured nitrate beneath riparian speckled alder. These results suggest thatalder and growth or activity of soil microbes, rather than nitrogen fixation, is P limited in riparian wetlands dominatedd alder, and that P controls nitrate leaching in these near-stream systems.sevier B.V. All rights reserved.

    Alnus; Adirondack Mountains; Actinorhizal; Ion exchange resin; Nitrate; Phosphorus; Nitrogenase activity

    onding author. Present address: University of Florida, Institute of Food and Agricultural Sciences, Soil and Water Science Depart-Newell Hall, PO Box 110510, Gainesville, FL 32611, USA. Tel.: +1 315 470 6782; fax: +1 315 470 6934.dress: (D.J. Raynal)

    $ see front matter 2004 Elsevier B.V. All rights reserved./j.envexpbot.2004.10.004

  • 98 K. Gokkaya et al. / Environmental and Experimental Botany 55 (2006) 97109

    1. Introduction

    Nitrogen (N)-fixing plants are known to have an in-herently hifixers (Ingeimental stunodulationin both leg1974; Israeal., 1989; E2000). The(2002) reveiting nodulin the succplain in intstrated thatlichens (cylitters of theDicranopteditions of PChapin et aof cyanobaditions to y(2000) foulation in Efolium pratconcentratinodulationA. incana sdemonstratnutrition oincana; Naddition whaddition ofalder and Dresulted inacetylene r(Binkley et

    Despiteits N fixatiitation on nactinorhizaUliassi and215 kg P hatenuifoliacreased totcompared tThe treatm

    nase activity per unit nodule dry mass, compared withnodule production response. They concluded that mul-tiple studies in a range of environments are necessary

    neralial terrurd etin a d

    al Adted N). Atmeasterce wa

    ssingn) mayrfacefrom ds in thd nitra; Hurdce offor fuurces

    ). Thetial lilder btilizatirub wezal fix


    e studse of Fa ssp.follow


    e immss we

    phates wass overion inssay


    avail, whergher phosphorus (P) demand than non-Nstad, 1981; Sprent, 1988). Several exper-dies have shown significant responses of

    , plant growth and fixation to P fertilizationsuminous and actinorhizal species (Gates,l, 1987; Reddell et al., 1988; Sanginga etkblad and Huss-Danell, 1995; Uliassi et al.,results of a field study by Uliassi and Ruessal that P limits N fixation primarily by lim-e production in thinleaf alder (A. tenuifolia)essional forests of the Tanana River flood-erior Alaska. Vitousek (1999) has demon-N fixation associated with liverworts and

    anolichen, Pseudocyphellaria crocata), thetree Metrosideros polymorpha and the fernris linearis increased significantly with ad-

    on young volcanic substrates in Hawaii.l. (1991) also found significant stimulationcterial acetylene reduction activity by P ad-oung soils in the high Arctic. Wall et al.

    nd that the degree of N inhibition on nodu-uropean Alnus incana ssp. incana and Tri-ense grown in pouches depended on the Pon level, with increased N levels inhibitingat N/P ratios >7, but not at N/P ratios 7, insp. incana. Ekblad and Huss-Danell (1995)ed experimentally an interaction of N and Pn N fixation in seedlings of A. incana ssp.fixation decreased the most under high Nen P was limiting. In a bioassay study, the

    P and sulphur (S) to soils from a stand of redouglas fir on Mt. Benson, British Columbiadoubling of red alder biomass and increasededuction activity per seedling by five-foldal., 1994).

    the general view that low P availability lim-on, research investigating phosphorus lim-itrogen fixation in the field, especially forl plants, is very limited. In a recent study,

    Ruess (2002) applied a 2-year total of1 in several separate applications to Alaska and found that fertilization in-al nitrogen inputs to 140 41 kg ha1 yr1o 59 11 kg ha1 yr1 in unfertilized plots.ent appeared to have little effect on nitroge-

    to genatur

    Hfixedcentreleva2002northsurfaprocecatioto sugas)standevate2003fluenneedbe so2002potenled aP ferin shnorhi

    2. M

    Thsponincanatelying screas

    procephosresinmentadditthis aphosroottrienttemsze about the effects of P on N fixation inestrial (2001) estimated 3743 kg N ha1 yr1ense stand of A. incana ssp. rugosa in the

    irondack Mountains, a region that receivesin atmospheric deposition (NADP/NTN,ospheric N deposition is a concern in the

    n United States, due to nitrate influences onter acidity (Driscoll et al., 2001). Wetlandof excess nitrate (biotic uptake or denitrifi-result in either decreased nitrate or acidity

    waters, and/or increased N2O (greenhouseenitrification. Dense A. incana ssp. rugosae Adirondacks are also associated with el-te in shallow groundwater (Kiernan et al.,and Raynal, 2004), demonstrating the in-

    this species on riparian N cycling and therther studies on what causes wetlands toor sinks for nutrients (Busse and Gunkel,objectives of this study were to evaluate themitation of N fixation and growth in speck-y P, and to determine interactions betweenon and nitrate levels in riparian alder standstlands that receive N inputs from both acti-ation and anthropogenic N deposition.

    ls and methods

    y was designed to measure nitrogenase re-rankia actinomycetes in root nodules of A.rugosa to P addition during weeks immedi-ing treatment at the beginning of the grow-Presumably, nitrogenase activity would in-ediately upon increased P availability, if there P limited. Measurement of nitrate and

    concentration in the soil using ion exchangecoupled to nitrogenase activity measure-the same time period, following fertilizerthe 2001-growing season. The purpose of

    was to examine the changes in nitrate andconcentrations in the substrate, where thes occur to better understand patterns of nu-

    ability and processing in these riparian sys-e especially nitrate leaching is a concern for

  • K. Gokkaya et al. / Environmental and Experimental Botany 55 (2006) 97109 99

    acid-sensitive streams (Driscoll et al., 2001). We mea-sured twig elongation and twig, and foliage mass duringthe growing season of treatment (2001) and the sub-sequent season (2002) to determine response of aldergrowth to P addition. Nodules were harvested at theend of the study in September 2002.

    2.1. Site description

    The study was conducted in two alder-dominatedriparian wetlands (scrub-shrub 1-type; Cowardin etal., 1979) along Fishing Brook and Adjidaumo Flowat the Huntington Wildlife Forest (HWF) located inthe central Adirondack Mountains region within theAdirondack State Park of New York (Fig. 1). Fish-ing brook is large-order inlet to a lake, while Adji-daumo flow is a headwater stream in the same flowsystem. Total annual precipitation averages 101 cm andmean annual temperature is 4.4 C with a dormant sea-son mean of 2.8 C and a growing season mean of14.3 C (Shepard et al., 1989). Surrounding vegeta-tion is composed of mixed northern hardwood forestson the upper slopes. The lower slopes are character-ized by yellow birch (Betula alleghaniensis), balsamfir (Abies bsis), and re

    Common wetland species include A. incana ssp. ru-gosa, Viburnum dentatum, Carex spp., Spiraea alba, S.tomentosa, Chamaedaphne calyculata, Osmunda re-galis, Calamagrostis Canadensis, and Myrica gale.Type SS1 wetlands in the Upper Hudson watershed, inwhich the study wetla