Annuals and Perennials of warm deserts

Ehleringer, James R.

doi:10.1007/978-94-009-4830-3_7

Cited by 76 publications

(51 citation statements)

References 54 publications

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“…High temporal variation of these and productivity. Previous findings do, in fact, factors accompanies this spatial variability, rainfall suggest that genetic differentiation might play an being more unpredictable where amounts are low important role in the capacity of E. farinosa to (Hastings & Turner, 1965;Ehleringer, 1985; occupy contrasting microclimates. Eor example, Comstock & Ehleringer, 1992), while drought length variability of water use has been found in association is most unpredictable along the boundary of summer with isozyme differentiation along microclimatic monsoon advancements (Eig.…”

Section: Introductionmentioning

confidence: 79%

Intraspecific variation of leaf pubescence and drought response in Encelia farinosa associated with contrasting desert environments

1997

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SUMMARYTraits associated with leaf energy balance are especially important for desert plants because decoupling leaf and ambient temperatures can be critical for maximizing productivity and survival in these hot, dry regions. Deserts are also one of the most climatically unpredictable and heterogeneous biomes; thus, variation of energy balance characters due either to plasticity or genetic differentiation might also be crucial to the success of desert plant species. In a common garden environment we examined variation in the traits associated with energy balance and productivity in Encelia farinosa A. Gray (brittlebush) plants. Comparing two populations from contrasting rainfall and drought climates, we found that plants from the wetter site (Superior, Arizona) always maintained higher leaf absorptances than plants from the more xeric region (Oatman, Arizona) when at similar water potentials. Superior plants also increased stomatal conductance and photosynthesis in response to mid-spring rainfall, whereas Oatman plants did not. Oatman plants, however, tended to have greater leaf areas and continuous spring growth, which made them larger than Superior plants, yet both populations produced the same number of flower heads. The differences for these traits, and the associations among them, agree with predictions based on the contrasting drought and rainfall environments of these two populations. Our results suggest that the differences might represent alternative suites of characters of selective importance for maximizing carbon gain over the climatically variable range of this widespread species. Furthermore, these differences, detected in common environment conditions, might have a genetic basis, which might contribute to a greater potential for local adaptation in this species.

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Section: Introductionmentioning

confidence: 79%

Intraspecific variation of leaf pubescence and drought response in Encelia farinosa associated with contrasting desert environments

1997

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“…Three such mechanisms may be particularly important at Buxton. First, the long-lived tissues of long-lived individuals tend to be capable of rapid and reversible cellular adjustments (37)(38)(39) that maintain viability and function despite seasonal and year-to-year shifts of temperature and soil moisture. Second, the rarity of new establishment opportunities, coupled with a low influx of outside propagules, could allow resident populations to locally adapt to a new climate through the expansion and contraction of particular genotypes (19,40).…”

Section: Discussionmentioning

confidence: 99%

Long-term resistance to simulated climate change in an infertile grassland

Grime¹,

Fridley

Askew³

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

276

259

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Climate shifts over this century are widely expected to alter the structure and functioning of temperate plant communities. However, long-term climate experiments in natural vegetation are rare and largely confined to systems with the capacity for rapid compositional change. In unproductive, grazed grassland at Buxton in northern England (U.K.), one of the longest running experimental manipulations of temperature and rainfall reveals vegetation highly resistant to climate shifts maintained over 13 yr. Here we document this resistance in the form of: (i) constancy in the relative abundance of growth forms and maintained dominance by longlived, slow-growing grasses, sedges, and small forbs; (ii) immediate but minor shifts in the abundance of several species that have remained stable over the course of the experiment; (iii) no change in productivity in response to climate treatments with the exception of reduction from chronic summer drought; and (iv) only minor species losses in response to drought and winter heating. Overall, compositional changes induced by 13-yr exposure to climate regime change were less than short-term fluctuations in species abundances driven by interannual climate fluctuations. The lack of progressive compositional change, coupled with the long-term historical persistence of unproductive grasslands in northern England, suggests the community at Buxton possesses a stabilizing capacity that leads to long-term persistence of dominant species. Unproductive ecosystems provide a refuge for many threatened plants and animals and perform a diversity of ecosystem services. Our results support the view that changing land use and overexploitation rather than climate change per se constitute the primary threats to these fragile ecosystems.calcareous grassland ͉ climate manipulation ͉ global change ͉ multivariate analysis ͉ vegetation

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“…In its native xeric environment, Palmer amaranth is opportunistic, rapidly germinating and completing its lifecycle in response to available moisture (Ehleringer 1985). This fast response to favorable germination conditions was characterized in a study in which seeds of nine Amaranthus species were subjected to alternating temperatures with a mean of 30 C; all of the viable Palmer amaranth and smooth pigweed seed germinated on the first day, while seven other Amaranthus species required three to eight days to achieve 50% emergence (Steckel et al 2004).…”

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confidence: 99%

“…In addition to C 4 photosynthesis, Palmer amaranth has the adaptive ability to increase solute concentrations in the leaves in order to maintain positive turgor and keep stomata open under droughty conditions (Ehleringer 1985). Without the change in solute concentrations, Palmer amaranth leaves would wilt and photosynthesis cease at water potentials below À1.55 MPa, while this adjustment enables the stomates to remain open and gas exchange to continue, allowing net positive photosynthesis under low water condition, down to À2.83 6 0.11 MPa (Ehleringer 1985;Forseth et al 1984).…”

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confidence: 99%

Mechanism of extreme genetic recombination in weedy Amaranthus hybrids

Steinau

Skinner²,

Steinau

2003

Weed Science

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Interspecific hybridization of Palmer amaranth and common waterhemp produce hybrids with unique DNA fragments not found in either parent. The objective of this research was to investigate the mechanisms involved in the formation of the polymorphic fragments. Six novel fragments were cloned and sequenced. Five of the six were significantly similar to plant transposons, the sixth was similar to squamosa promoter–binding proteins from other plant species. Southern blot analysis using one of the novel fragments as probe revealed a consistent pattern of repetitive DNA that was species and biotype specific. These results indicate that transposon-like elements may play an important role in the formation of new fragments in Amaranthus hybrids derived from interspecific hybridization, suggesting that considerable instability of the hybrid genome may occur.

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Annuals and Perennials of warm deserts

Cited by 76 publications

References 54 publications

Intraspecific variation of leaf pubescence and drought response in Encelia farinosa associated with contrasting desert environments

Intraspecific variation of leaf pubescence and drought response in Encelia farinosa associated with contrasting desert environments

Long-term resistance to simulated climate change in an infertile grassland

Mechanism of extreme genetic recombination in weedy Amaranthus hybrids

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