Great Basin Naturalist Volume 54 Number 4 Article 14 10-25-1994 Full Issue, Vol. 54 No. 4 Follow this and additional works at: https://scholarsarchive.byu.edu/gbn Recommended Citation (1994) "Full Issue, Vol. 54 No. 4," Great Basin Naturalist: Vol. 54 : No. 4 , Article 14. Available at: https://scholarsarchive.byu.edu/gbn/vol54/iss4/14 This Full Issue is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. T H E REATGREATG BASIN MTURALISTNA VOLUME 54 NQ 4 OCTOBER 1994 BRIGHAM YOUNG university GREAT basinnaturalistBASIN naturalist editor assistant editor RICHARD W BAUMANN NATHAN M SMITH 290 MLBM 190 MLBM PO box 20200 PO box 26879 brigham young university brigham young university provo UT 84602020084602 0200 provo UT 84602687984602 6879 8013785053801 378 5053 8013786688801 378 6688 FAX 8013783733801 378 3733 emailE mail nmshbll1byuedu associate editors MICHAEL A BOWERS PAUL C MARSH blandy experimental fannfarmearm university of center for environmental studies arizona virginia box 175 boyce VA 22620 state university tempe AZ 85287 J R CALLAHAN STANLEY D SMITH museum of southwestern biology university of department of biology new mexico albuquerque NM university of nevada las vegas mailing address box 3140 hemet CA 92546 las vegas NV 89154400489154 4004 JEFFREY J JOHANSEN PAUL T TUELLER department of biology john carroll university department of environmental resource sciences university heights OH 44118 university of nevada reno 1000 valley road reno NV 89512 BORIS C kondratieff department of entomology colorado state ROBERT C WHITMORE university fort collins CO 80523 division of forestry box 6125 west virginia university Morganmorgantowntown WV 26506612526506 6125 editorial board berranjerran I1 flinders chairmanChainnan botany and range science duke S rogers zoology william hess botany and range science H duane smith zoology all are at brigham young university ex officio editorial board members include steven L taylor college of biology and agriculture stanley L welsh director monte L bean life science museum richard W baumann editor great basin naturalist the great basin naturalist founded in 1939 is published quarterly by brigham young university unpublished manuscripts that further our biological understanding of the great basin and surrounding areas in western north america are accepted for publication subscriptions annual subscriptions to the great basin naturalist for 1994 are 25 for individual sub- scriscribersbers 30 outside the united states and 50 for institutions the price of single issues is 12 all back issues are in print and available for sale all matters pertaining to subscriptions back issues or other busi- ness should be directed to the editor great basin naturalist 290 MLBM PO box 20200 brigham young university provo UT 84602020084602 0200 scholarly exchanges braneslibrariesLi or other organizations interested in obtaining the great basin naturalist through a continuing exchange of scholarly publications should contact the exchange librarian 6385 HBLL PO box 26889 brigham young university provo UT 84602688984602 6889 editorial production staff joanne abel technical editor jan spencer assistant to the editor copyright 0 1994 by brigham young university ISSN 001736140017 3614 official publication date 25 october 1994 109410 94 750 11712 The Great Basin Naturalist PUBLISHED AT PROVO, UTAH, BY BRIGHAM YOUNG UNIVERSITY VOLUME 54 31 OCTOBER 1994 NO.4 Great Basin Naturalist 54(4), © 1994, pp. 291-300 MYCORRHIZAL COLONIZATION, HYPHAL LENGTHS, AND SOIL MOISTURE ASSOCIATED WITH TWO ARTEMISIA TRIDENTATA SUBSPECIES James D. Trentl, Tony J. Svejcar2, and Robert R. Blank! ABsTRACT.-Mycorrhizal fungi are thought to benefit associated plant species via enhanced nutrient uptake and/or improved water relations. However, detailed descriptions of the components of mycorrhizal colonization and mycor­ rhizal hyphal growth are not available for Artemisia tridentata. This species occupies sites characterized by relatively low levels ofboth soil nutrients and moisture. We studied patterns ofvesicular, arbuscular, and hyphal mycorrhizal colo­ nization, mycorrhizal hyphal lengths, and soil moisture associated with two subspecies ofA. tridentata over a 2-year period. A. tridentata ssp. vaseyana (ATV) is generally associated with more mesic and slightly higher elevation sites compared to A. tridentata ssp. tridentata (ATI). Nearly twice as much precipitation was received the first year compared to the second. In general, there were higher levels of colonization and hyphal lengths associated with ATV than with ATT. The ATV site received slightly more precipitation and was lower in available nutrients than the ATI site. Hyphal lengths and arbuscular colonization appeared more responsive to precipitation than were either vesicular or hyphal col­ onization. Hyphal colonization did not necessarily follow the same temporal pattern as hyphal lengths. Thus, mycor­ rhizal activity was greater for the subspecies that received slightly more precipitation and occupied a site lower in avail­ able nutrients. Arbuscular colonization and hyphal lengths appeared to be most closely associated with soil moisture and thus plant activity. Key words: vesicular-arbuscular mycorrhizae, hyphallength, Artemisia tridentata, soil moisture, soil temperature. Understanding ecosystem processes requires 1988). Morphogenesis ofarbuscule and vesicle baseline data that describe spatial and tempo­ formation should be differentiated when ral variations in microbial mediated processes assessing functionality or dependency of the (Burke et al. 1989). Such information is also plant on VAM on a seasonal basis. The pres~ needed to assess the role of mycorrhizae and ence of arbuscules indicates plant"fungal other fungi in native plant communities. In interactions (Hirrel et al. 1978, Allen 1983) native plant communities, vesicular-arbuscu­ since arbuscules are the site for P and C trans­ lar mycorrhizal (VAM) colonization has been fer between syrnbionts (Cox and Tinker 1976, shown to vary both seasonally and among Wilcox 1993). Seasonal changes in extramatri­ .plant species (Read et al. 1976, Rabatin 1979, cal VAM fungal hyphae indicate that plant­ Daft et al. 1980, Gay et al. 1982, Allen 1983, fungal interactions are dynamic (Wilcox 1993). Giovannetti 1985, Brundrett and Kendrick Therefore, itis necessary to measure seasonality 1USDA-ARS, 920 Valley Road, Reno, Nevada 89512. 2USDA-ARS, HC 71, 4.51 Hwy 205, Burns, Oregon 97720. Address reprint requests and correspondence to this author. 291 292 GREAT BASIN NATURALIST [Volume 54 of arbuscular colonization and extramatrical Oryzopsis hymenoides, Elymus hystrix, and hyphae to adequately assess the changing rela­ Bromus tectorum. The soil is classified as a tionship between symbionts in the field. coarse~loamy, mixed, mesic Aridic Argixeroll. The Great Basin environment is character­ This is an alluvial fan soil that was mainly ized by winter precipitation, normally as snow, derived from granitic rocks. The soil consists followed by hot, dry summers (Comstock and of about 40 em of loamy sand to gravelly Ehleringer 1992). Root growth is most abtm­ loamy sand overlying a subsoil ofabout 50 em dant in upper soil horizons in the early spring. of sandy loam. The underlying material to over Rooting activity diminishes in upper soil hori­ 200 em is loamy coarse sand. zons as root growth follows the soil moisture The ATV community is at 1830 m elevation profile into deeper soil layers (Fernandez and and includes the following vegetation: Artemisia Caldwell 1975). In desert soils, N and Pare tridentata ssp. vaseyana, Purshia tridentata, most abundant in upper soil horizons (West Ribes sp., Chrysothamnus viscidijlorus, Stipa 1991), and their availability to plants diminishes columbiana, S. occidentalis, Elymus hystrix, and with decreasing soil moisture. Moisture move~ Bromus tectorum. the soil is classified as a ment from deep roots in moist soils to shallow coarse-loamy, mixed, frigid Ultic Argixeroll. roots in dry soils could make shallow soil nutri~ This type of upland soil formed in a residuum ents available through the process ofhydraulic from granodiorite and consists of about 60 em lift (Passioura 1988, Caldwell and Richards of gravelly coarse sand and loamy coarse sand 1989, Caldwell et al. 1991). Mycorrhizae could overlying a subsoil of about 30 em of loamy playa role in this process (Richards and coarse sand and sandy loam. The underlying Caldwell 1987, Caldwell et al. 1991); however, material consists of about 10 em of weathered little is known about seasonal dynamics of granodiorite. mycorrhizae in arid ecosystems. Fitter (1993) suggests that plant root systems METHODS evolve in a manner that optimizes the use of Sampling was conducted on seven dates in plant carbon. Mycorrhizal colonization and 1989 and five dates in 1990. Four replicate the formation of extramatrical hyphae should macroplots (20 X 20 m) were randomly selected also reflect an optimization of plant carbon at each site. One shrub within a macroplot was usage. But to date there is relatively little selected for sampling each year. We changed information on spatial or temporal variation in shrubs to ensure that the prior year's sampling mycorrhizal activity in the Great Basin. In this did not influence