Water Relations and Leaf Chemistry of Chrysothamnus nauseosus ssp. Consimilis (Asteraceae) and Sarcobatus vermiculatus (Chenopodiaceae)

Donovan, Lisa A.; Richards, James H.; Müller, M.

doi:10.2307/2445840

Cited by 26 publications

(29 citation statements)

References 26 publications

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“…As VPD increased during the day, soil respiration rates dropped. This seasonal change in the pattern of diurnal leaf gas-exchange has been observed before in these shrubs species in the Owens Valley and other Great Basin ecosystems [Donovan et al, 1996;Caldwell et al, 1977]. In the grass ecosystem, leaf gas-exchange would have been likely less affected by water-stress and high temperatures due to the dominance of plants with the C 4 photosynthetic pathway [Schulze and Hall, 1982].…”

Section: The Diel Pattern Of Soil Respirationsupporting

confidence: 59%

Soil respiration in perennial grass and shrub ecosystems: Linking environmental controls with plant and microbial sources on seasonal and diel timescales

2008

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[1] A mechanistic understanding of soil respiration is a major impediment to predicting terrestrial C fluxes spatially and temporally. Automated measurements of soil respiration offer the high-resolution information necessary to observe temporal variation in soil respiration, but spatially these measurements are under-represented in water-limited and non-forested ecosystems. We measured soil respiration with automated chambers over the growing season, at two sites with the same semi-arid climate, but with different dominant vegetation, perennial grasses and shrubs in the Owens Valley, CA, USA. An isotope mass balance technique was used to partition soil respiration into autotrophic and heterotrophic components at two time points, early and late growing season. Results showed large differences in the magnitude of growing season soil respiration between the two sites (910 versus 126 g C m À2 for grasses and shrubs respectively over 5 months). We attribute this to site differences in soil water availability and belowground allocation and productivity. Diel patterns of soil respiration between the two sites were similar. Temperature explained most of the diel variability in the early growing season, when soil moisture was greatest. As soil moisture declined over the growing season, diel patterns became increasingly decoupled temporally from temperature due to increased water-limitation on surface heterotrophic sources and hypothesized strong photosynthetic control over soil respiration rates. Partitioning of soil respiration into autotrophic and heterotrophic sources showed the dominance of autotrophic sources across seasons and ecosystems. However, heterotrophic respiration was more dynamic from early to late growing season, declining in the grass ecosystem; and a surprising increase in the shrub ecosystem, attributed to warming of the soil profile enhancing microbial decomposition at depth.Citation: Carbone, M. S., G. C. Winston, and S. E. Trumbore (2008), Soil respiration in perennial grass and shrub ecosystems: Linking environmental controls with plant and microbial sources on seasonal and diel timescales,

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Section: The Diel Pattern Of Soil Respirationsupporting

confidence: 59%

Soil respiration in perennial grass and shrub ecosystems: Linking environmental controls with plant and microbial sources on seasonal and diel timescales

2008

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“…consimilis (E. Greene) H.M. Hall and Clements (Asteraceae, rabbitbrush) is a co-occurring, deep-rooted, Na-excluding non-halophyte. For these species, PDD was initially suggested by field data (Donovan et al 1996). Glasshouse experiments with smaller plants confirmed large magnitude PDD under well-watered conditions, attributable to nighttime transpiration and putative apoplastic solutes, but not hydraulic conductance limitations (Donovan et al 1999(Donovan et al , 2001.…”

Section: Introductionmentioning

confidence: 85%

“…The research site was located in the cool-desert shrubland north of Mono Lake, California, USA (38Њ5Ј N, 118Њ58Ј W, 1958 m elevation). Healthy reproductive Chrysothamnus and Sarcobatus shrubs (1.30 Ϯ 0.05 and 1.34 Ϯ 0.07 m height [mean Ϯ 1 SE], respectively) were selected in the ''Diverse Dunes'' area, where these species have similar root-depth distribution to groundwater at 3-5 m depth (Donovan et al 1996, Donovan andRichards 2000). Annual precipitation is 163 mm (Toft 1995).…”

Section: Methodsmentioning

confidence: 99%

“…Eight Sarcobatus shrubs (3 NA, 2 SIR, 3 DIR) had a replicate psychrometer at 0.3 m depth to accommodate a concurrent study of hydraulic lift. Psychrometers at 0.3 m depth were expected to measure soil ⌿ w adjacent to shallow roots, based on high root length density at this depth (Donovan et al 1996), the observation of roots excavated during installation, and the insertion of psychrometers into the undisturbed soil in the side of the installation hole. Psychrometers at 2.0 m were expected to measure soil ⌿ w adjacent to deep roots based on the occurrence of roots of both species at this depth and the relatively uniform soil water content.…”

Section: Methods For Soil ⌿ W Plant ⌿ Pc and ⌿ W And Plant Gas Exmentioning

confidence: 99%

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Magnitude and Mechanisms of Disequilibrium Between Predawn Plant and Soil Water Potentials

Donovan

Richards

Linton

2003

Ecology

Self Cite

146

113

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Predawn plant water potential (Ψw, measured with leaf psychrometers) and surrogate measurements made with the pressure chamber (termed Ψpc here) are used to infer comparative ecological performance, based on the expectation that these plant potentials reflect the wettest soil Ψw accessed by roots. There is growing evidence, however, that some species exhibit substantial predawn disequilibrium (PDD), defined as plant Ψw or Ψpc at predawn substantially more negative than the Ψw of soil accessed by roots. In the western Great Basin desert, the magnitude of PDD calculated as soil Ψw minus predawn leaf Ψw was as large as 1.4 and 2.7 MPa for two codominant shrub species, Chrysothamnus nauseosus and Sarcobatus vermiculatus, respectively. The magnitude of PDD calculated as soil Ψw minus predawn Ψpc was smaller, up to 0.6 and 2.1 MPa for Chrysothamnus and Sarcobatus, respectively. For both species, mechanisms contributing to PDD included nighttime transpiration and putative leaf apoplastic solutes, but not hydraulic conductance limitations. Hydraulic lift also occurred in both species and likely contributed to PDD for Sarcobatus. Finding large magnitude PDD in field populations emphasizes that species differences in predawn plant Ψw or Ψpc do not necessarily reflect differences in accessible soil Ψw and rooting depth, nor does a low predawn plant Ψw or Ψpc value necessarily mean that soil Ψw is also low. Mechanisms contributing to PDD affect relationships between plants and soil resources, as well as the potential for plant–plant interactions. Corresponding Editor: F. C. Meinzer

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“…At Mono Lake, California, declines in the lake level have created a steep abiotic stress gradient by exposing former lakebed substrates. At the Mono Dunes Ecosystem Research Site, the end of the gradient farthest from shoreline consists of marginally saline sand dunes (Toft, 1995;Donovan, Richards, and Muller, 1996). This site supports a diverse plant community dominated by two shrubs: Chrysothamnus nauseosus (Palla.)…”

mentioning

confidence: 97%

Water potential and ionic effects on germination and seedling growth of two cold desert shrubs

Dodd

Donovan

1999

American J of Botany

222

107

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We tested expectations that two desert shrubs would differ in germination and seedling relative growth rate (RGR) responses to Na and Ψ(s) stress. The study species, Chrysothamnus nauseosus ssp. consimilis and Sarcobatus vermiculatus (hereafter referred to by genus), differ in their distribution along salinity gradients, with Chrysothamnus inhabiting only less saline areas. In growth chamber studies, declining Ψ(s) (-0.82 to -2.71 MPa) inhibited germination of both species, and Chrysothamnus was less tolerant of Ψ(s) stress than Sarcobatus. Germination fell below 10% for Chrysothamnus at -1.64 MPa (NaCl and PEG), and for Sarcobatus at -2.4 MPa PEG. Neither species exhibited ion toxicity. There was substantial ion enhancement for Sarcobatus in lower Ψ(s), allowing for 40% germination in -2.71 MPa NaCl. For seedling RGR, species were not different at -0.29 or -0.82 MPa (0 and 100 mmol/L NaCl, respectively), but Chrysothamnus RGR declined substantially at -1.3 MPa (200 mmol/L NaCl). The greater stress tolerance of Sarcobatus was not associated with a lower RGR under nonsaline conditions. Species differences in seed and seedling Ψ(s) stress tolerance probably contribute to the restricted distribution of Chrysothamnus to less saline areas. The Na uptake of Sarcobatus seedlings enhances its ability to deal with declining Ψ(s) and establish in more saline areas.

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Water Relations and Leaf Chemistry of Chrysothamnus nauseosus ssp. Consimilis (Asteraceae) and Sarcobatus vermiculatus (Chenopodiaceae)

Cited by 26 publications

References 26 publications

Soil respiration in perennial grass and shrub ecosystems: Linking environmental controls with plant and microbial sources on seasonal and diel timescales

Soil respiration in perennial grass and shrub ecosystems: Linking environmental controls with plant and microbial sources on seasonal and diel timescales

Magnitude and Mechanisms of Disequilibrium Between Predawn Plant and Soil Water Potentials

Water potential and ionic effects on germination and seedling growth of two cold desert shrubs

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