A trait-based framework to understand life history of mycorrhizal fungi

Trends in Plant Science, Год журнала: 2013, Номер 18(9), С. 484 - 491

Опубликована: Июнь 5, 2013

Язык: Английский

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Community Assembly Rules, Morphological Dispersion, and the Coexistence of Plant Species

Oikos, Год журнала: 1998, Номер 81(2), С. 309 - 309

Опубликована: Март 1, 1998

In order to find and define any assembly rules for communities, we must first investigate the patterns among species assemblages. We used a series of null models test in wetland plant composition at level species, functional guilds, traits. At level, found significant checkerboard nestedness patterns. Three guilds had some tendency contribute constant percentage richness, but after Bonferroni correction there was no pattern. Coexisting showed consistent overall pattern morphological dispersion. However, when considered each 11 traits turn, that 4 were overdispersed 3 underdispersed. Thus are constrain community composition. These results reconcile contrasting views assembly. Communities can be simultaneously structured by tension between two forces: abiotic external forces certain within limits biotic internal tend keep coexisting from being too similar. Because our sites vary along fertility/disturbance gradient, also investigated how trait dispersion varies space. Trait increases with soil fertility; phosphorus explains about 36% variance mean nearest neighbor distance. Species richness tends decline distance, which contrasts general animal

Язык: Английский

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Responses of wild C4 and C3 grass (Poaceae) species to elevated atmospheric CO₂ concentration: a meta‐analytic test of current theories and perceptions

Global Change Biology, Год журнала: 1999, Номер 5(6), С. 723 - 741

Опубликована: Авг. 1, 1999

Summary C4 plants contribute ≈ 20% of global gross primary productivity, and uncertainties regarding their responses to rising atmospheric CO 2 concentrations may limit predictions future change impacts on C4‐dominated ecosystems. These have not yet been considered rigorously due expectations low responsiveness based photosynthetic theory early experiments. We carried out a literature review (1980–97) meta‐analysis in order identify emerging patterns grass elevated , as compared with those C3 grasses. The focus was nondomesticated Poaceae alone, the exclusion dicotyledonous crop species. This provides clear test, controlled for genotypic variability at family level, differences between ‐responsiveness these functional types. Eleven were considered, ranging from physiological behaviour leaf level carbon allocation whole plant level. Results also assessed context environmental stress conditions (light, temperature, water nutrient stress), experimental growing (pot size, duration fumigation method). Both species increased total biomass significantly by 33% 44%, respectively. Differing tendencies types shoot structural response revealed: showed greater increase tillering, whereas area . At significant stomatal closure use efficiency confirmed both types, higher assimilation rates found (33% 25%, respectively). Environmental did alter ‐response, except loss positive ‐response above‐ground under stress. In species, stimulation rate reduced (overall), tended reduce mean Leaf carbohydrate status nitrogen concentration decreased only conclude that relative concur some extent theory. demand re‐evaluation assumption levels, regard relations. combined will consequential implications balance important catchments range‐lands throughout world, especially semiarid subtropical temperate regions. It be premature predict lose competitive advantage over

Язык: Английский

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The balanced‐growth hypothesis and the allometry of leaf and root biomass allocation

Functional Ecology, Год журнала: 2002, Номер 16(3), С. 326 - 331

Опубликована: Июнь 1, 2002

Summary 1. Many ecological models of plant growth assume balanced growth: that biomass is allocated preferentially to leaves or roots increase capture the limiting external resource. An alternative explanation based on nonlinear (allometric) allocation as a function size. The objective this study was test between these two explanations. 2. A total 1150 plants from 22 different herbaceous species were grown in hydroponic sand culture factorial combinations high (1100 µmol m −2 s −1 ) and low (200 PAR) irradiance crossed with full‐strength 1/6 dilution Hoagland’s solution. Plants harvested at 15, 20, 25, 30 35 days postgermination, dry mass determined for leaf root components. These data used hypotheses allometric allocation. 3. Both nutrient supply affected slope intercept : shoot allometry, contrary hypothesis but agreement growth; decreased increased roots; leaves. 4. relatively more than grew larger. In order balanced‐growth be correct, net rate uptake per unit must have been decreasing relative carbon gain mass. 5. We suggest reasons why might case: (i) older their efficiency uptake; (ii) larger systems rapidly available nutrients flushes 6. results support notion found many growth.

Язык: Английский

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RESPONSES OF N-LIMITED ECOSYSTEMS TO INCREASED CO₂: A BALANCED-NUTRITION, COUPLED-ELEMENT-CYCLES MODEL

Ecological Applications, Год журнала: 1997, Номер 7(2), С. 444 - 460

Опубликована: Май 1, 1997

Ecosystem responses to increased CO2 are often constrained by nutrient limitation. We present a model of multiple-element limitation (MEL) and use it analyze constraints imposed N on the an instantaneous doubling concentration in 350-yr-old eastern deciduous forest. examine effects different exchange rates inorganic with sources sinks external ecosystem (e.g., through deposition leaching) initial ratios net:gross mineralization. Both these factors influence availability vegetation and, therefore, have important CO2. conclude that reliable assessments will require better understanding both factors. The appear at least four characteristic time scales. (1) There is increase net primary production, which results C:N ratio. (2) On scale few years, responds increasing uptake effort for available allocation biomass, energy, enzymes fine roots). (3) decades, there movement from soil organic matter vegetation, enables biomass accumulate. (4) centuries, dominated increases total N, enable accumulate soils. In general, short-term markedly long-term responses.

Язык: Английский

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